THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by James

The impulse to believe the absurd when presented with the unknowable is called religion. Whether this is wise or unwise is the domain of doctrine. Once you understand someone's doctrine, you understand their rationale for believing the absurd. At that point, it may no longer seem absurd. You can get to both sides of this conondrum from here.

Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:31 pm

5: The Middle Ages

Little is known about the important transitional period from about 2.0 billion years ago until about 0.7 billion years ago.

-- Robert Garrels


If you are curious about the Earth and wonder about the history of rocks, there are few better places to be born than England or Wales. My small island, which lies within both of these countries, has as many geological periods as a continent. Along its lengthy shoreline the waves have cut cliffs and these walls of rock display their dissected strata as in a museum diorama. I used to spend childhood holidays at a place called Chapman's Pool on the coast of the county of Dorset; here the somber black cliffs of Kimmeridge shale were speckled with snow-white ammonites and other fossils.

As you move westward across England the rocks go back in history, and by the time you come to Wales their age approaches 570 million years. These old rocks are called Cambrian, after the Roman name for Wales. They are the oldest to bear fossils visible to the unaided eye. There are, of course, older rocks containing microfossils of bacteria, such as those that Barghoorn and Tyler found; but before modern methods of dating there was no sure way of knowing their age. The period with rocks older than those bearing the larger fossils was called Precambrian, because it was further distant in time than the rocks of Cambria. We now know that the Precambrian has parts that are very old indeed. This new knowledge comes from the distribution in these old rocks of the radioactive elements uranium and potassium, and their products, lead and argon. Radioactive decay is an accurate clock; by measuring the proportion of uranium to lead or of potassium to argon in a piece of rock its age can be calculated. Other evidence about ancient rocks comes from the distribution of the isotopes of that stable element, carbon. This, and the discovery of Archean bacterial microfossils, tell us that life was present at least 3.6 eons ago. The Precambrian is now mapped and divided into the Proterozoic period, 0.57 to 2.5 eons before now, and the Archean, 2.5 to about 4.5 eons. Some geologists call the first period, 4.5 to 3.8 eons, the Hadean.

Like the Archean, the Proterozoic was a time when the ecosystems of the Earth were populated by bacteria (the prokaryotes). In the anoxic regions of the sediments the Archean bacteria would have lived on; but in the now mildly oxidizing ocean and surface environments there eventually developed more complicated living cells, the eukaryotes. These are the ancestors of large communities of nucleated cells, like the trees and ourselves.

The Proterozoic is still an enigmatic period of the Earth's history. I feel free, therefore, to use it as a background on which to develop geophysiological models of what it might have been. I shall write this chapter not as history but as an account of the physiology of an unknown animal who lived thousands of years ago, drawn from no more evidence than a few scraps of bone accurately dated from their content of carbon isotopes. My main interest is in the long-term geophysiological processes that kept the Earth constant and fit for life, and in how they worked. With the bones of the Earth in mind, I shall keep returning in thought to that important element, calcium, and its crucial role in all living things from ourselves to Gaia. I shall continue to be concerned with those other important elements, oxygen, carbon, and hydrogen, and with their regulation and with the climate. This chapter will also be about the geophysiology of the oceans; in particular the difficult problem of whether the total salinity is determined by physical and chemical forces alone, or whether there is "machination" on the part of Gaia. Although the setting of the chapter is the Proterozoic, the middle ages of the Earth, most of the topics discussed are not unique to that period; they acted also in the Archean, and continue to act in the present period.

If we aim to start at the boundary between the Archean and the Proterozoic, we shall find that this boundary is still under negotiation. There is no clear-cut frontier, just a no man's land where field geologists set their posts according to their fancy. The Archean geologist Euan Nisbet tells me that there is an informal acceptance of the date 2.5 eons before the present time, although some would prefer to set the fence at the date marked by the appearance of a special suite of rock in Zimbabwe. Just as political frontiers often fail to circumscribe ethnic regions accurately, so boundaries based on geological considerations alone do not always suit the interests of geophysiology. As a geophysiologist, I prefer to set my markers at the time when the environment became predominantly oxidizing -- or to put it more professionally, at the transition from an environment dominated by electron donor molecules, like methane, to one dominated by electron acceptors, like oxygen. As it happens, the uncertainties about the events 2.5 eons ago are large, and for the time being we can take the geological and the geophysical markers to define the same zone of the Earth's history.

For geophysiology, the important thing about the transition from the Archean to the Proterozoic is not the exact date of the event, but that it happened. It is rather like puberty; a profound physiological change but one spread over a finite period of time. In puberty markers of the change -- the appearance of the beard and the deepening of the voice, or the expansion of the breasts -- are secondary to the main event. The switching on of these secondary sex characteristics is the response to an increasing flux of pituitary hormone. This primary event may be sharply defined but the secondary characteristics are somewhat arbitrarily scattered in time. Between the Archean and Proterozoic the appearance of oxygen as a dominant atmospheric gas was the primary event and marked a profound change in the Earth's geophysiological state. The outward and secondary manifestations of this change -- the emergence of a new surface and atmospheric chemistry and of ecosystems as oxygen began to dominate the atmosphere -- is likely to have spanned a significant interval of time, and happened at different times in different places.

From early in the Proterozoic to the present day there has been an excess of free oxygen gas in the air. By an excess, I mean that the atmosphere has carried more oxygen than is needed to oxidize completely the short-lived reducing gases: methane, hydrogen, and ammonia. When the Proterozoic began, geophysiologically speaking, the division of the two great planetary ecosystems, the oxic surface regions and the anoxic sediments, was complete. The Archean, when the environment was full of molecules that donated electrons (that is, reducing agents), did not so much end as become encapsulated as a separate region that exists wherever oxygen is absent. The submission of the anoxic ecosystems to domination by the oxic was somewhat like the Norman conquest with the Archean Saxons driven to a subservient underground position -- the lower classes -- from which, it is often said, they have never escaped.

The change from anoxic to oxic was a crucial step in the Earth's history. In the model of the Archean in the previous chapter (figure 4.2), the end of the period was pictured as very sudden, with oxygen rising from very low to between 0.1 and 1 percent atmospheric abundance in not more than one million years. This is, of course, no more than the prediction of a geophysiological model; one that sees the change from one regime to another as an event driven by powerful positive feedback from the biota and the environment.

The conspicuous difference between the Archean and the Proterozoic is, I think, in the composition of the atmosphere and the oceans; and possibly also in the climate. The simple model in figure 4.2 supposed that the carbon cycle was preserved by the methanogens which returned a massive flux of methane and carbon dioxide to the air from the sediments, and that this state persisted until, quite suddenly, free oxygen appeared. More probably there was some oxygen present even early in the Archean, just as there is methane in our present atmosphere. The difference between the Archean air and the Proterozoic air was not a simple matter of the presence or absence of oxygen, it was in the net tendency. In the Proterozoic, a discarded bicycle left in shallow water would have rusted away to form insoluble ferric oxide which settled on the sea floor; in the Archean, it would have slowly dissolved as water-soluble ferrous iron, and left no trace. During the time that the flux of methane exceeded the flux of oxygen, the lower atmosphere could carry only trace quantities of oxygen. The oceans and surface rocks, rich in the oxygen-scavenging ferrous iron and sulfides, would have absorbed so large a proportion of the oxygen output of the cyanobacteria that the air would have remained in a net anoxic state for most of the Archean period.

We do not know that the oxygen of the air rose suddenly; it may have risen slowly or in a series of steps. It is important also to distinguish between the presence, and the dominance, of oxygen; dominance, in a chemical sense, requires that the ratio of oxygen to methane is greater than two to one. The reason for thinking that the change of regimes, the boundary of the Archean and Proterozoic periods, was abrupt is the evidence of a major glaciation at about 2.3 eons ago. This might have come as a result of a sudden fall in atmospheric methane. Such an event would be accompanied by cooling, since methane and its decomposition products are greenhouse gases. There are also geophysiological arguments that favor a sharply defined transition to an oxidizing state. Once the photosynthetic oxygen became dominant in the atmosphere and oceans, the action of sunlight on oxygen would produce hydroxyl radicals that oxidize the methane in the air. Also, there would be consumers feeding on the organic matter before it could reach the anoxic sediments; this would deny to the methanogens the material for the production of their gaseous excretion. This is the recipe for a powerful positive feedback against methane and in favor of oxygen. These events are likely to have been sudden rather than gradual. Finally, there is the ecology to take into account. There would be ecosystems existing in the Archean that found their world comfortable. As they evolved with their environment, they would resist change, but their resistance would be like that of a locked fault in an earthquake zone. They would tend to resist change, trying to keep the status quo, but when the break came it would be all the more sudden and devastating.

The transition to oxygen dominance may have left its mark in the record of the rocks in the form of the Gowganda glaciation, but the long subsequent period is one of the more obscure periods of the Earth's history. Gaia theory requires that the tightly coupled evolution of living organisms and their material environment will have determined the state of the Earth in this as in the other periods. Can we envisage from this theory a living planet existing in the Proterozoic, and the regulatory systems that may have operated then?

When Earth scientists use the word regulation, they usually have in mind a passive process where the input and output of some component or property are in balance. In geophysiology, by contrast, regulation implies the active process of homeostasis; the preservation of a comfortable Earth by the interaction of life and its environment. The speculations that follow about the regulation of climate, oxygen, salinity and other properties of the environment are in this geophysiological context, in other words, as if they were speculations about the state of a living organism. In no sense is this intended as a teleology, or meant to imply that the biota use foresight or planning in the regulation of the Earth. What we need to think about is how a global regulatory system can develop from the local activity of organisms. It is by no means far-fetched to imagine a single new bacterium evolving with its environment to form a system that can change the Earth. Indeed the first cyanobacterium, progenitor of the ecosystem that used light energy to make organic matter and oxygen, did just this.

If the element oxygen was crucial in the geophysiological evolution of the atmosphere, then calcium must surely be the determining element in the geophysiology of the oceans and the crust. Calcium is one of the alkaline-earth elements occupying the second column of Mendeleev's famous periodic table of the elements. It comes after magnesium and before strontium. It is the third most abundant positive ion of sea water, after sodium and magnesium. We tend to think of calcium as a benign and nutritious element because it is an essential structural component of our bones and teeth. It is also crucial in numerous internal physiological processes from blood clotting to the division of cells. It is essential for life but, paradoxically, it is very toxic in the free ionic state. Within our cells a concentration of calcium ions exceeding a few parts per million is lethal, comparable in toxicity to cyanide, yet calcium ions are free in the oceans at a level ten thousand times greater.

In chapters 2 and 3, I explained the operation of the Daisyworld model in terms of the competitive growth of organisms when one environmental property is sharply circumscribed. Too much and too little are both uncomfortable; there is a preferred state between torrid heat and freezing cold, between excess and starvation. This is particularly true of calcium. Imagine some bacterium in the early oceans able to convert the abundant water-soluble calcium ions of its internal environment into insoluble calcium carbonate. This simple reaction would have effectively reduced the concentration of the potentially toxic calcium ions within the cell, by locking up calcium in a safe insoluble form. Such an action, if calcium were in excess as it usually is in the oceans, would have increased the organism's chances of survival and those of its progeny. These organisms would be at an advantage compared with organisms that merely adapted to the presence of excess calcium. In the sunlit zone of the open ocean, the growth of these organisms would lead to vast masses of calcium carbonate being deposited on the ocean floor. The rain of microscopic "sea shells," called tests by marine biologists, from the sunlit surface to the depths acts like a conveyor belt. Food is brought for consumers lower down, the ocean is swept clear and made transparent, and potentially toxic elements, like cadmium, are taken from the surface regions. Carbon dioxide and calcium are transported, and assembled together by bacterial communities to form the flat or mushroom-shaped rock cities called stromatolites. The concentration of calcium ions in the oceans would have been reduced, and all life would have flourished as a consequence. The ubiquity of limestone deposits of oceanic origin implies the success and continuation of this activity. In contradiction to this view, some geologists believe that early limestone deposition was an inorganic process. I do not see how we can distinguish between the spontaneous crystallization of super-saturated calcium carbonate in the Archean and nucleation induced by organisms. I do think that the nucleation of supersaturated and other metastable states in Nature is a key geophysiological process, and that it originated in the Archean.

I know as an inventor that really good inventions tend to grow and evolve. Only weak inventions take a single step and no more. Consider how the simple semiconducting crystal of those first radio receivers in the 1920s has evolved to become, in a grand eutrophication, the ubiquitous silicon devices of today. The calcium carbonate precipitation step was an even greater invention; it led not merely to the regulation of calcium, carbon dioxide, and climate but also to the vast engineering of the calcium carbonate structures (the stromatolites). Later, these same processes evolved so that our own cells possess intricate mechanisms by which calcium is deposited as bones and teeth.

Most remarkable of all, biological calcium carbonate deposition may have made possible the efficient operation of the endogenic cycle -- the slow movement of the elements from the surface and the ocean to the crustal rocks and back again. The geologist Don Anderson has speculated that the deposition of limestone on the ocean floor is a key factor in the motion of the Earth's crust. He proposed that sometime far back in the Earth's history, sufficient limestone was deposited to alter the chemical composition of the crustal rocks of the ocean floor near the continental margins. As a result an event, called the basalt-eclogite phase transition by geologists, took place. This transition so altered the physical properties of the crustal rocks that it became possible for the great machinery of plate movement to begin turning. Don Anderson commented in an article in Science in 1984:

The Earth is apparently also exceptional in having active plate tectonics. If the carbon dioxide in the atmosphere of Venus could turn into limestone, the surface temperature and those of the upper mantle would drop. The basalt-eclogite phase change would migrate to shallow depths, causing the lower part of the crust to become unstable. Thus there is the interesting possibility that plate tectonics may exist on the Earth because limestone-generating life evolved here.


To me this is an exciting idea, but I admit that most geologists find it extremely improbable. The event may have begun with the activity of a few organisms able to split a dilute solution of calcium bicarbonate into chalk and carbon dioxide, and so avoid calcium poisoning. We do not know when plate tectonics started. If it is connected with life, that connection may not have existed before the development of the intracellular precipitation of calcium carbonate in eukaryotes, late in the Proterozoic.

The study of the intricate biological processes for segregating and concentrating the elements of the crust and ocean in the form of minerals has become a separate topic of the Earth sciences called biomineralization.

Salt regulation is one of the most interesting and tantalizing Gaian systems. There are few organisms able to tolerate salt at concentrations above about 6 percent by weight. Have the oceans always kept below this critical limit of salinity by chance? Or has the tightly coupled evolution of life and the environment led to the automatic regulation of ocean salinity? It is often stated that the preferred internal saline medium of living things, one that is astonishingly similar over a very wide range of organisms, reflects the composition of the oceans when life started. It is true that the salinity of the blood of whales, humans, mice, and of most fish, whether dwelling in the ocean or in fresh water, is the same. Even the circulating fluid of Artemia, the brine shrimp that lives in saturated salt solutions, shares with us the same internal salinity. But to my mind this is no more evidence of the salinity of the Archean ocean than are the oxygen levels now breathed by these organisms evidence of the oxygen abundance at the start of life.

Most cells survive and do best in a medium whose salinity is 0.16 molar (about one percent by weight in water, or normal saline). Many kinds of cells survive the salinity of sea water, 0.6 molar, but above 0.8 molar the membranes that hold the precious interior contents of cells become permeable or disintegrate completely. The reason for the destructive action of salt solutions is simple. Cell membranes are held together by the same kind of forces that hold together a soap bubble. Quite often these forces are very sensitive to the salinity of the medium, usually being weakened when the salinity is high. You can see this for yourself by making bubbles with increasingly strong salt solution as the solvent for the soap. Above about 10 percent salt, bubbles cannot be made. This is because soap molecules are made up of a long chain of carbon atoms tightly linked together and surrounded by hydrogen atoms equally firmly held. These chains are terminated at one end only by a carbon atom with two oxygen atoms attached. When this end of the soap molecule is dissolved in water that is slightly alkaline, as all soap solutions are, it carries a negative charge. The negative electrical charge makes the end group attract water molecules and drags the insoluble oily hydrocarbon chain into solution. Salt is made up from negative chlorine ions and positive sodium ions. When there are many of these in solution they begin to compete with the soap's negative charge for the water molecules. When enough salt is present, the soap separates from the water as curd.

The molecules of a cell membrane are more complex than soap: they include such substances as sterols (for example, cholesterol), hydrocarbons, proteins, and phosphatides. The molecules of phosphatides correspond to those of soap, and are the part of the membrane most affected by an increase in salt concentration. High salt concentrations disrupt cell membranes by disturbing the electrical forces holding the membrane in its correct and complex state. The membrane of the human red blood cell, for example, is made up of more or less equal parts of cholesterol and lecithin (a phosphatide) and a mixture of protein and other fatty substances. The red blood cell will survive exposure to salt solutions up to 0.8 molar (4.7 percent by weight in water). Above this strength the membrane is damaged, and at concentrations above 2.0 molar the cell may be destroyed in seconds. In the mid-1950s I was able to show by direct experiments that the damage to red blood cells commenced when lecithin dissolved away from the membrane into the strong salt solution. This kind of salt damage seems general among living cells and is seen with the cells of all five kingdoms.

The salt concentration of today's sea is always uncomfortably high for living organisms. The larger ones, such as fish, swimming mammals, and some crustacea, have physiological mechanisms to regulate the internal salt at a level close to that of their own bodies (0.16 molar). To prevent the loss of water from their internal medium (osmosis), these animals have to work to stop themselves being squeezed dry by the osmotic pressure. They have to use energy to pump water in against the osmotic pressure difference between their interior and that of the sea. The pressure is close to that needed to pump water 450 feet vertically against gravity, over a thousand times the blood pressure of humans. The advantages of a low-salt interior must be considerable to require such an effort to sustain it. For the small cell of a bacterium, individual regulation is a luxury far beyond its means. This does not just apply to salinity. Take temperature for example: for a microorganism to sustain even a 1°C difference from that of its environment would require the consumption of far more food and oxygen than could cross its surface. Not only this, but a 1° temperature gradient across the cell membrane would generate a thermal osmotic pressure of 56 atmospheres, or 840 pounds per square inch; far beyond the strength of a cell membrane to resist.

The most frequent experience of salt stress is in drying or freezing. When cells freeze, water is removed as pure ice and the salt solution in which they exist becomes concentrated. Freezing and drying must have been common hazards from the beginning of life, and indeed no direct answer to this problem of salt damage to membranes has evolved in all the time since then. There are salt-tolerant bacteria, the halophiles, that live precariously in the saline regions of the Earth. These bacteria have solved the problem directly by evolving a special membrane structure that is not disrupted by salt. It works, but at a price; for these organisms cannot compete with mainstream bacteria when the salinity is normal. They are limited to their remote and rare niche, and depend upon the rest of life to keep the Earth comfortable for them. They are like those eccentrics of our own society whose survival depends upon the sustenance that we can spare but who could barely survive alone.

Mainstream life, therefore, is limited to a maximum salt concentration of about 0.8 molar. This is not much greater than the saltier parts of the ocean, where the salinity reaches 0.68 molar. It is frequently exceeded whenever the tide recedes, leaving organisms soaked in sea water to dry out on the shore. The problem of salinity must have arisen for the Archean bacteria. Their answer to the problem was to synthesize soluble compounds called the sulfur and nitrogen betaines. They make these neutral solutes, which substitute for the salt and are not toxic to the cell. When these are present in the cells and their medium, freezing or drying no longer concentrate the salt to destructive levels. Even so, there is a price to pay for the synthesis of these anti-salt betaines. As much as 15 percent of the dry weight of shoreline algae is betaine; a considerable diversion of the energy that would otherwise be available to the organisms. Clearly, it would be to the advantage of the biota to keep the oceans as dilute as possible -- certainly to keep them from approaching the critical 0.8 molar concentration.

Problems of salt regulation exceed in difficulty anything humankind has so far done in the way of planetary engineering. The Archean bacteria could relatively easily modify that small compartment, the atmosphere, to suit their needs; but the vast mass of the oceans, some ten thousand times larger, was very much more difficult to manipulate. The only way to remove the huge masses of salt in the oceans would be to segregate ocean water in lagoons and allow the sun's heat to evaporate the water away. It would have required the building of vast limestone reefs to trap salt in evaporite lagoons. The sheer magnitude of these reefs would dwarf any conceivable human construction. It may even be possible that the process of lagoon formation was assisted by the folding of rocks at the continental edge as a consequence of the movement of the plates.

Table 5.1 SALTS OF THE OCEANS

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Table 5.1 lists the salts of the oceans. Salt in solution, weathered from the rocks, is entering continuously from the rivers and also from the interior of the Earth at the sea-floor spreading zones that lie at the bottom of all the major oceans. In the ocean, salt is not a single substance, sodium chloride. Rather, it exists as positive sodium and negative chlorine ions, and these behave as two quite independent and separate entities. The sodium ion and the other positive ions of potassium, magnesium, and calcium all have relatively short residence times in the ocean. They are removed by biochemical and chemical processes, and also by hydrothermal chemical reactions within the sea-floor spreading zones, and deposited as sediments, clays, limestones, and dolomite. The salt problem for the biota is actually a problem of getting rid of the negative chloride ions.

Chemically, the chloride ion is rather like an atom of the wholly unreactive gas argon. It is a smooth, slippery, spherical molecule with little or no tendency to attach to anything. There is no significant biochemical trade in chlorine. A few strange systems do make methyl chloride from salt, but the turnover of this compound is too small to affect the salinity of the ocean. Also, the chlorine in methyl chloride soon becomes chloride ions again, and is washed out by the rain and returns to the sea. Chloride ions are removed from the oceans physically by the transfer of sea water to the evaporite lagoons. The water trapped in these lagoons warms in the sun and evaporates; the water vapor moves through the atmosphere and eventually condenses elsewhere as rain -- pure water -- that flows into and dilutes the ocean. The salt, represented by the dominant chloride ion and the positive ions that must go with it to keep the total ionic charge zero, is left behind as crystalline layers. These evaporite lagoons are found in many places on the continental margins. Fossil lagoons exist in many places beneath the Earth's surface, sometimes even beneath the ocean itself.

Before these lagoons can form, barriers are needed at their seaward boundary. Could this activity be part of the tightly coupled evolution of life and the rocks, or is it just the result of chance? The key process in the formation of these barriers is the deposition of calcium carbonate. The carbon dioxide in the air reacts continuously with alkaline rocks on the land surfaces to form bicarbonates. An important reaction of this type is the one between calcium silicate rock and carbon dioxide dissolved in surface water. The product is a solution of silicic acid and calcium bicarbonate, which flows down the rivers to the ocean. In the absence of life, the calcium and bicarbonate ions can coexist in a mildly acid ocean, and the continuous supply of these would eventually lead to the spontaneous crystalization of calcium carbonate. But it would be more or less randomly deposited over the ocean floor. Limestone deposits in the real world are mostly from the action of living organisms. Limestone is not deposited either randomly or according to the expectations of physics and chemistry. The precipitation of calcium carbonate by colonies of microorganisms occurs most extensively in the shallow waters around the continental margins where the abundance of both nutrients and calcium bicarbonate are highest. Without any planning or foresight, the components of those living structures, the limestone stromatolites, would have assembled offshore and eventually sealed off lagoons from which sea water would be progressively evaporated and salt deposited. At first the reef building would have only a local effect, but over time the sheer mass of the limestone would begin to affect the plastic crust of the Earth's surface, depressing it and so extending the size of the lagoon. New rock formers would always be colonizing the surface of a reef as it descended, so tending to keep the lagoon intact. If, as Don Anderson has suggested, the motion of the Earth's crust depends on the continued deposition of calcium carbonate in the sea, the limestone reefs could have led to the complex events of mountain building and the folding of rocks at the continental margins. This, in turn, would extend the range of shorelines where evaporite lagoons could form.

During the course of time salt is being added to the oceans from the lithosphere and removed again. Some of this salt is deposited in evaporite beds and buried beneath sediments. These deposits may be a temporary store which Earth movements and weathering continuously expose and release the contents of back to the sea; but new evaporite lagoons are always forming. The balance of erosion and formation seems always to have kept enough salt sequestered in evaporite beds to keep the oceans fresh and fit for life. The evidence that lagoon formation and maintenance depends on the specific behavior of marine micro' organisms is strong.

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5.1 The evaporite lagoons at Laguna Figueroa, Baja California, Mexico. Sand dunes form a barrier through which sea water percolates. The water then evaporates in the lagoons, and salt crystallizes out to form an evaporite deposit. The surface of the lagoons are often covered by microbial cell communities called mats.

I once had the pleasure of joining an expedition, led by Lynn Margulis, to the microbial mat communities that form in the evaporite lagoons of Baja California in Mexico (as shown in figure 5.1). They are on the western edge of that long, narrow tongue of land that hangs down below San Diego and separates the Gulf of California from the Pacific Ocean. Here I was able to see at first hand the subtle economy of the bacterial mats that covered the lagoon. The red and green communities of microbes at the surface acted as a raincoat, preventing the salt from being dissolved in the rain and washing back into the ocean. Indeed, on one occasion, the whole lagoon was flooded by feet of fresh water. Within two years the flood was evaporated and dispersed without destroying either the microbial communities or the evaporite bed beneath. In normal times, the movement of rain water downward through the mat lowers its salinity and assists the growth of photosynthesizers at the surface, the primary providers of food and energy for the communities beneath. Salt crystals at, or their, the surface are also coated with their own specific varnish and protected against easy solution in rain water.

Is all this a grand, unplanned civil engineering enterprise by Gaia? The steps, from the individual lowering of calcium ions within the cells of a living organism to the movement of the plates, are all those that tend to improve the environment for the organisms responsible. But the links between biomineralization, salt stress, and plate tectonics are so tenuous that most scientists would think them to be connected by chance rather than by geophysiology. I shall continue to wonder about the limits of Gaian manipulation and always seek guidance by asking the simple question: What would the Earth have been like without life? Would limestones have precipitated at the continental margins so as to form evaporite lagoons? Would the salt have deposited in them, or would it have been washed back into the ocean by rain in the absence of a living raincoat of microbial mat? Would limestone have deposited at the sites and densities needed to start the plates moving? Unlikely perhaps, but remember there have been billions of years for geophysiological invention and its trial by natural selection. We should consider the possibility that this long period was sufficient to fine tune the rough geology into a smoothly regulated geophysiology.

So far we have been considering mainly the large-scale engineering works. What about the workers? During the Proterozoic, a new type of cell evolved, those with nuclei, called the eukaryotes. These are cells that contain structures within them, and other organelles (such as chloroplasts, the green-pigmented bodies that do the work of photosynthesis). Lynn Margulis has taught that these more complex cells are really communities of bacteria that once lived free but now are contained within the outer membrane of one of them. In her book Early Life she tells how the presence of oxygen in the Proterozoic set the scene for the appearance of these new and more powerful cells. It was an evolutional step like that which occurred in the Archean, when the ecosystem of photosynthesizers using carbon dioxide came to equilibrium with the methanogens that returned carbon to the atmosphere as methane and carbon dioxide.

Oxygen opened a giant new niche for organisms that could survive in it and use it. At first these new organisms, who gained energy by combining the organic matter with oxygen, may have existed peacefully with the photosynthesizers, merely eating their debris and dead bodies. But before long there would be consumers, organisms that had learnt to eat fresh food and that grazed the photosynthesizers as they grew. Cells do not have mouths, but they can ingest other cells by enclosing them within a pocket in their membrane, a process called phagocytosis. The pocket becomes part of the cell's interior and dissolves away, leaving the captive entrapped within. Digestion would be the normal fate, but sometimes the roles would be reversed and the ingested organism could be the aggressor. Tubercle and leprosy bacteria do this trick even today, attacking the phagocytes that ingest them instead of succumbing as victims to the phagocytes' powerful digestive system. The results of warfare, however, are rarely genocide; instead war can lead to a peaceful coexistence mutually beneficial to the victim and the aggressor. In this way, the chloroplasts have as ancestors the cyanobacteria of the Archean, and today they power the cell communities of cabbages and redwood trees. Although briefly discussed by nineteenth-century biologists, this powerful association of organelles working within cells in a process of symbiosis, called endosymbiosis, is recognized due to Lynn Margulis more than to anyone else. Endosymbionts enlarged and expanded the possibilities of planetary manipulation by the biota and were a main feature of the history of the Earth during the Proterozoic.

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Eukaryote. Prokaryote.
5.2 Eukaryotic and prokaryotic cell structures compared. The eukaryotes differ in having membrane-bound organelles which include the nucleus, mitochondria, and chloroplasts. (Drawing by Christie Lyon.)


The formation of collectives gives power to the assembly greater than that possessed by its individual components; but this is never without a price. For the early bacteria (the prokaryotes), aging was not a problem. They had neither nucleus nor organelles, and they carried their genetic information on a few strands of DNA within the cell membrane (see figure 5.2). Genetic information lost by an individual bacterium during its brief life span was recovered by the exchange of plasmids and other pieces of polymeric software with other organisms. But for the eukaryotic cell with its complex internal organization and organelles (figure 5.2), each carrying a different set of genetic instructions, the loss of some vital item of information by one organelle could mean the death of the cell. The invention of a method and mechanism for the deliberate transfer of information between cells before division greatly reduced the chances of a lethal decision. It was this need that led to the invention of sex. It is much too interesting a story to try to abstract here, and is given in full detail in Lynn Margulis and Dorion Sagan's book The Origins of Sex.

An unanswered question about the Proterozoic is, What was the concentration of oxygen? Did it just stay at around 0.1 to 1 percent, or did it rise in concentration to present levels or higher?

Free oxygen comes from two sources: the escape of hydrogen to space and the burial of carbon or sulfur. The sequestering of elemental hydrogen, carbon, or sulfur always leaves free oxygen behind. As we saw in the previous chapter, once oxygen appears in the free state in the air, the escape of hydrogen becomes vanishingly small. This is because only traces of hydrogen or hydrogen-bearing gases like methane can exist in the free state in an oxygen atmosphere. The one exception is water, which cannot be further oxidized, and is confined to the lower atmosphere by the low temperatures at the base of the stratosphere. Quite literally, it is frozen out; and the upper atmosphere contains only a few parts per million of water vapor. The present rate of escape of hydrogen to space is limited by the dryness of the upper air and is only 300,000 tons a year. This is equivalent to just under 3 million tons of water, and would leave behind an excess of 2.5 million tons of oxygen. It sounds a lot, but a loss of water of that rate would have removed less than one percent of the oceans in the age of the Earth.

Once hydrogen loss was reduced to trivial significance, the only way to add more oxygen was to separate carbon and sulfur from combination with oxygen in carbon dioxide and sulfates. If the separated carbon and sulfur could be buried in the sediments before they had an opportunity to react again with oxygen, a net increment of this gas would be added to the air. This process of separation starts with photosynthesis, which splits carbon dioxide into oxygen, which then enters the air, and into the living and dead parts of the plants and bacteria. Most of this carbonaceous material is recombined with oxygen by consumers, but a little, about 0.1 percent, is buried more or less permanently. Some of the carbon in the sediments is used to reduce sulfate to sulfides. The burial of sulfides also leaves a net increment of oxygen in the air. The carbon and sulfides are buried in the sediments mixed with shales and limestones. The burial can take place in such a way as to form fossil fuels, coal and oil; but these represent only a small proportion of the total carbon and sulfur in the sediments. The burial of all the oxidizable material is like a loan drawn against the oxygen account. So long as it is buried or lost in the Earth's interior, the debt is not presented and free oxygen can remain in circulation in the air.

At present about 100 million tons of carbon are buried each year -- equivalent to the release of 266 million tons of free oxygen gas to the air. (This does not mean that oxygen of the atmosphere is increasing, for the increment is all used up by the oxidizable materials released by volcanoes, by weathering, and by processes at the sea floor.) The rate of carbon burial has been constant throughout the history of life on Earth; there is very little difference between the Archean and now. This is curious when you consider that the mass and the activity of the biota may have been less in the Archean. The puzzle can be solved if we remember that because there was only a trace of oxygen present, the proportion of oxic consumers to anaerobes would have been less than now. This means that the methanogens and other organisms of the anoxic sector were digesting nearly all the products of photosynthesis, but buried the same amount of carbon as now. The high rate of photosynthesis today must, in part, be due to the rapid recycling of carbon by the oxygen-breathing consumers. They metabolize 97.5 percent of the products from photosynthesis, leaving only 2.5 percent for the anaerobes. In the Proterozoic, there were consumers present feeding on organic matter and using oxygen to metabolize it. Their activity is likely to have been less than now but greater than in the Archean.

The key point is that oxygen production is determined by the amount of carbon buried, and this in turn depends upon the proportion of the products from photosynthesizers that reach the anoxic sector. Obviously, if the consumers eat all the organic matter there would be none left to be buried and, therefore, no source of oxygen. If we recall that the rate of carbon burial has been more or less constant, then it follows that the input of oxygen from this source has also been constant. In the Archean all this oxygen went to oxidize the reducing substances in, and being added to, the environment, but when free oxygen appeared an increasing proportion of it was used by consumers. The continued existence of the Archean anoxic ecosystems ensured the continuous burial of carbon and a continued input of oxygen to the air. These possibilities are summarized in table 6.1. What, then, determined the oxygen level of the air? Arguing from geophysiology, we can suppose that the inherent toxicity of oxygen is not entirely overcome by the antioxidant systems and by the enzymes of the organisms of the oxic sector; in these circumstances oxygen may set its own limit. Like temperature, it would be an environmental property with a lower and an upper limit for mainstream life. Such properties can be geophysiologically regulated.

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Oxygen (%)
5.3 The effect of oxygen on the growth of organisms (solid line) and the effect of the presence of organisms on the abundance of oxygen (dashed line). Where the two curves intersect is the level of oxygen at which the system regulates.

Figures 5.3 and 5.4 illustrate how it might have been done in the Proterozoic. Figure 5.3 depicts the effects of oxygen on the growth of the oxic ecosystem and the effect of the size of the oxic ecosystem on oxygen. The solid line is the relationship between a steady level of oxygen and the population of oxygen-using consumers; at low oxygen levels they could not metabolize and at high levels they would be poisoned by oxygen. The dashed line indicates the relationship between the population of the oxic ecosystem and the steady-state level of oxygen; the more photosynthesizers, the more oxygen. The two curves intersect at an oxygen level that would be kept in homeostasis by the system.

Figure 5.4 illustrates the calculations of a computer model where photosynthesizers, consumers, and anaerobes coexist on a planet before, during, and after the appearance of oxygen. It is assumed that, as on the Earth, the constant burial of carbon and a declining turnover of reducing rocks and gases oxidizes the planet until free oxygen becomes a dominant gas. Thereafter oxygen rises until the geophysiological properties of the system establish a new steady level where the abundance of oxygen is kept constant by a balance between the quantity of carbon buried and the quantity of reducing material exposed. The lower panel illustrates the planetary temperature variations, in comparison with those of a lifeless planet of the same composition. The middle panel shows the variation of the oxygen, carbon dioxide, and methane gases. The upper panel shows the population levels of the different life forms. This model is a linear descendant of the climate models in chapters 2 and 3, where the competitive growth of differently colored daisies is shown to be capable of regulating the temperature of a model planet. It accepts that, in the long term, a constant amount of the carbon produced by photosynthesis is buried and that this source of oxygen is constant. The sink for oxygen would be declining. At the end of the Archean, oxygen rose in abundance. The presence of excess oxygen would have increased the rate of weathering and so increased the supply of nutrients, which in turn would have favored a larger ecosystem. More carbon would have been buried, and the rise in oxygen would have accelerated until toxicity began to set a limit. By this time, the anaerobic sector from which carbon burial takes place would have shrunk to the same size as in the Archean, and oxygen production would again equal oxygen loss by the exposure of oxidizable substances during weathering.

Image
Time (eons before present)
5.4 Model of the transition from the Archean to the Proterozoic. The lower panel shows climate with a lifeless world (dashed line) compared with a live world (solid line). Note the sudden fall of temperature when oxygen appears. The middle panel shows the abundance of atmospheric gases (carbon dioxide, dashed line; oxygen and methane, solid lines). The upper panel illustrates the changes in population of the ecosystems as the transition is entered and passed. Note how both photosynthesizers and methanogens increase when oxygen first appears and how methanogens fall back to a steady level when the oxygen-breathing consumers (dashed line) become established.


In one sense the oxic ecosystems existed right from the beginning of Gaia; from the moment when the first cyanobacteria converted sunlight into high potential chemical energy and were able to make organic compounds and oxygen from water and carbon dioxide. As the cyanobacteria spread, they would always have occupied a surface position to enjoy and feed on the sunlight. The anoxic systems, whose food was the dead bodies and products of the cyanobacteria, would naturally have existed below the photosynthesizers to take advantage of the conveyance by fallout of the food from above. From the start, there would have been a segregation of these two ecosystems, and a gradient of oxygen concentration declining away from the region of its production.

In the real world, the oxygen cycle cannot be disconnected from the carbon dioxide cycle; as oxygen rises it would be anticipated that carbon dioxide would fall. The carbon dioxide cycle is coupled with the climate, and this in turn affects the growth of both consumers and producers. The environmental feedback from carbon dioxide and climate would further stabilize the system. Once the initial oxygen crisis was over the Proterozoic could have been a comfortable time for Gaia, apart from the persistent annoyance of planetesimals. The natural level of carbon dioxide would have provided a pleasant climate, and no great effort would be needed to regulate it.

A bizarre consequence of the appearance of oxygen was the advent of the world's first nuclear reactors. Nuclear power from its inception has rarely been described publicly except in hyperbole. The impression has been given that to design and construct a nuclear reactor is a feat unique to physical science and engineering creativity. It is chastening to find that, in the Proterozoic, an unassertive community of modest bacteria built a set of nuclear reactors that ran for millions of years.

This extraordinary event occurred 1.8 eons ago at a place now called Oklo in Gabon, Africa, and was discovered quite by accident. At Oklo, there is a mine that supplies uranium mainly for the French nuclear industry. During the 1970s, a shipment of uranium from Oklo was found to be depleted in the fissionable isotope 235U. Natural uranium is always of the same isotopic composition -- 99.27 percent 238U, 0.72 percent of 235U, and traces of 234U. Only the 235U isotope can take part in the chain reactions necessary for power production or for explosions. Naturally, the fissionable isotope is guarded carefully and its proportion in uranium subjected to thorough and repeated scrutiny. Imagine the shock that must have passed through the French atomic energy agency when it was discovered that the shipment of uranium had a much smaller proportion of 235U than normal. Had some clandestine group in Africa or France found a way to extract the potent fissionable isotope, and were they now storing this for use in terrorist nuclear weapons? Had someone stolen the uranium ore from the mine and substituted spent uranium from a nuclear industry elsewhere? Whatever had happened, a sinister explanation seemed likely. The truth, when it came, was not only a fascinating piece of science but must also have been an immense relief to minds troubled with images of tons of undiluted 235U in the hands of fanatics.

The chemistry of the element uranium is such that it is insoluble in water under oxygen-free conditions, but readily soluble in water in the presence of oxygen. When enough oxygen appeared in the Proterozoic to render the ground water oxidizing, uranium in the rocks began to dissolve and, as the uranyl ion, became one of the many elements present in trace quantities in flowing streams. The strength of the uranium solution would have been at most no more than a few parts per million, and uranium would have been but one of many ions in solution. In the place that is now Oklo such a stream flowed into an algal mat that included microorganisms with a strange capacity to collect and concentrate uranium specifically. They performed their unconscious task so well that eventually enough uranium oxide was deposited in the pure state for a nuclear reaction to start.

When more than a "critical mass" of uranium containing the fissionable isotope is gathered together in one place there is a self-sustaining chain reaction. The fission of uranium atoms sets free neutrons that cause the fission of more uranium atoms and more neutrons and so on. Provided that the number of neutrons produced balances those that escape, or are absorbed by other atoms, the reactor continues. This kind of reactor is not explosive; indeed it is self-regulating. The presence of water, through its ability to slow and reflect neutrons, is an essential feature of the reactor. When the power output increases, water boils away and the nuclear reaction slows down. A nuclear fission reaction is a perverse kind of fire; it burns better when well watered. The Oklo reactors ran gently at the kilowatt-power level for millions of years and used up a fair amount of the natural 235U in doing so.

The presence of the Oklo reactors confirms an oxidizing environment. In the absence of oxygen, uranium is not water soluble. It is just as well that it is not; when life started 3.6 eons back, uranium was much more enriched in the fissile isotope 235U. This isotope decays more rapidly than the common isotope 238U, and at life's beginning the proportion of fissile uranium was not 0.7 percent as now but 33 percent. Uranium so enriched could have been the source of spectacular nuclear fireworks had any bacteria then been unwise enough to concentrate it. This also suggests that the atmosphere was not oxidizing in the early Archean.

Bacteria could not have debated the costs and benefits of nuclear power. The fact that the reactors ran so long and that there was more than one of them suggests that replenishment must have occurred and that the radiation and nuclear waste from the reactor was not a deterrent to that ancient bacterial ecosystem. (The distribution of stable fission products around the reactor site is also valuable evidence to suggest that the problems of nuclear waste disposal now are nowhere near so difficult or dangerous as the feverish pronouncements of the antinuclear movement would suggest.) The Oklo reactors are a splendid example of geophysiological homeostasis. They illustrate how specific minerals can be segregated and concentrated in the pure state -- an act of profound negentropy in itself, but also an invaluable subsystem of numerous geophysiological processes. The separation of silica by the diatoms and of calcium carbonate by coccolithophoridons and other living organisms, both in nearly pure form, are such processes and have had a profound effect on the evolution of the Earth.

If some descendant of the alien chemist who visited in the Archean returned in the Proterozoic, it would find an Earth not so different from now. The sky would have been a paler shade of blue with perhaps less cloud cover. On the beach, the sea would be blue-gray, rather than the brown of the Archean. Inland, behind the sand dunes and pebbles, the bacterial mats would lie, enlivened by the origin of certain green and golden yellow algae, protecting the anoxic sector that overlay and kept intact the evaporite beds beneath with their deep layers of lifeless salt, the accumulation of thousands or even millions of years. Out to sea there would again be the rock structures of stromatolite colonies. I wonder if our alien would have observed a remarkable geophysiological property of reefs that has recently been revealed in coral reefs. Satellite photographs showed that the wavelength of ocean waves in the vicinity of the reefs was unusual and unexpected for the surface wind and sea conditions. Subsequent investigation uncovered the remarkable fact that the coral microorganisms secreted a lipid substance that formed a monomolecular layer on the ocean surface and so altered its surface tension as to modify the waves. It is engaging to speculate about the geophysiological development of this remarkable action in microorganisms, and to wonder when it developed and whether it is a mechanism for protecting the reefs from wave damage.

During the Proterozoic, the constant rain of planetesimals continued. As well as numerous smaller ones, there were at least ten that did damage to Gaia comparable in severity to that of a burn affecting 60 percent of the skin area of a human. These events are not in themselves the main interest; we have no detailed information of the dates and consequences of their occurrence. What is interesting is the recovery of the system from these insults. We are tolerably certain that none of them killed Gaia, so that a new Gaia had to be born from the debris. The ability to recover from major perturbations is a test of the health of a geophysiological system; the fact that life persisted and recovered from so many of these catastrophes is more evidence in favor of the existence of a powerful homeostatic system on Earth.

At the beginning of the Proterozoic, the Sun was cooler. The problem facing Gaia was to keep the carbon dioxide greenhouse from collapsing and so causing the Earth to freeze. Without the cooling tendency of life today, the Earth would be uncomfortably hot. It could be said that life is at present keeping the Earth cool by pumping down carbon dioxide. In the middle ages of the Proterozoic, some 1.5 eons ago, the Sun's output was about just right for life and no great effort was needed for thermostasis. The atmospheric carbon dioxide was probably around one percent by volume. It was at a level where physicists and geophysiologists would have no cause for disagreement.
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:33 pm

6: Modern Times

I never knew how soothing trees are -- many trees and patches of open sunlight, and tree presences -- it is almost like having another being.

-- D.H. Lawrence, Selected Letters


This chapter is about the period of the Earth's history when living organisms large enough to be seen with unassisted eyes were growing or moving on the land and in the sea. The microorganisms were still there flourishing and still responsible for much of the regulation of the Earth. But the arrival of large, soft, bodied cell communities changed the surface of the Earth and the tempo of life upon it: Plants that could stand erect supported by structures of deep underground roots. Consumers that could travel on the ground and in the air or sea. All these things left fossil remains. Their presence delineates this period called the Phanerozoic, going from the Cambrian some 600 million years ago until the present day. Because we live in it, and because recent historical records are so much more detailed than those of the ancient past, it seems a period well known and familiar. This is an illusion. We know little about the Earth even in our own time. For the Cambrian there are just catalogs of species and rocks. They give some insight into the life of the Earth, but only in the abbreviated way that a telephone book does about the private lives and the economy of a town.

If we take Gaia to be a living organism, the Phanerozoic can be viewed as the most recent stage in her life, and the one she is still in. This may be easier than considering independently the lives of the billions of organisms from which she is made. Getting to know a friend does not usually require a detailed knowledge of her cellular structure. Similarly, geophysiology, concerned with the whole Earth, need not be too confused by the mass of undecomposed detail that lies, like thick layers of fallen leaves, beneath the branches of the tree of science. So let us look at the physiology of Gaia during this period. In an ideal history the description would be of the whole system, but the habit of reduction dies hard. At the present stage of ignorance it is much easier to divide the chapter into parts, each concerned mainly with the regulation of one important chemical element and of the climate.

Geologists see the transition from the Proterozoic to the Phanerozoic as occurring about 570 million years ago. The first organisms that we would recognize as animals with skeletons appeared on Earth somewhat earlier than this. As a geophysiologist I prefer to see this transition as also marked by a change in oxygen abundance, an event not unlike the one that occurred between the Archean and the Proterozoic.

My colleagues have made it very clear to me that what follows about oxygen is speculative and often contrary to conventional wisdom. I have included it in spite of their protest because it illustrates a view of the evolution of free oxygen in the light of Gaia theory. Whether it is right or wrong seems to me less important than its value in stimulating new experiments and measurement.

So let us consider oxygen. This gas comes from the use of sunlight by the green chloroplasts within cells to convert carbon dioxide and water into free oxygen and the biochemicals from which they are made. Most of the oxygen is used up again by the consumers who eat the plants and algae, oxidize the food, and return carbon dioxide to the air and the sea. From the beginning the producers, the photosynthesizers, have had a love-hate relationship with the consumers. Producers do not care to be eaten, but the presence of the consumers is essential for their health and that of the larger organism they constitute. When plants and animals appeared, the fine details of this constructive aggression became visible. The plants were seen to possess poisons, spines, and stings; and the animals and microorganisms were obliged to develop new techniques for grazing. A balance is always struck because, without the consumers, the survival of the plants and algae would be threatened. There is only a few years' supply of carbon dioxide in the air. The removal of consumers from the scene would be disastrous for plants, and within a short time span. Not only would there be too little carbon dioxide for photosynthesis, but there would be major climate changes as the gases of the atmosphere and the albedo of the Earth responded to the demise of the plants. Not least, the intricate recycling of nutrients and gardening of the soil would cease. On a human time scale the coexistence of consumers and producers could be compared with the long peace that has reigned between the hostile yet mutually dependent superpowers.

Oxygen is also used up in its reaction with, for example, the sulfur gases emitted by volcanoes, or the reducing chemicals in the igneous rocks that solidify from the magma emerging from below the sea floor. Oxygen is kept at a constant level by the burial of a small proportion of the photosynthetic carbon, about 0.1 percent, just enough to equal the losses. We know that the level of oxygen must have changed at the end of the Proterozoic, because of the new forms of life that appeared.

When the organisms were mostly living in water, or as colonies of algal mats on the surface of the land, the upper limit of oxygen would have been set by its toxicity. For such ecosystems, fires are less a problem than they are to standing vegetation. They could have tolerated an atmosphere containing as much as 40 percent oxygen, provided that the extra atmospheric pressure did not so exacerbate the gaseous greenhouse as to lead to an intolerably hot climate.

However, the free-swimming eukaryotes that appeared in the early Proterozoic would not have required much oxygen since the gas could diffuse easily across the small distance between the walls of their microscopic cells; as little as 0.1 percent in the atmosphere may have been sufficient. The larger organisms that appeared in the Phanerozoic, such as the dinosaurs, which were composed of massive volumes of cells in juxtaposition, could have existed only in a richer oxygen environment. This is especially true where there was a need for a greater power output during swimming. Even today, with oxygen at 21 percent, our muscles cannot be supplied with sufficient oxygen at maximum power output; a backup temporary power supply, called glycolysis, operates when we run as fast as we can. Peter Hochachka, in an unusual book called Living Without Oxygen, describes the intricate mechanisms by which large animals cope with the problem of power production in a world which, for them, can be limited in its oxygen supply. An example of this size effect is illustrated by the poison carbon monoxide. For animals as large as ourselves, carbon monoxide is inescapably deadly. It kills by preventing the red blood cells from conveying oxygen to our tissues. A smaller animal, the mouse, can survive the complete saturation of its blood with carbon monoxide. It survives the poison because enough oxygen can diffuse to its tissues from the skin and from the surface of the lungs.

There has to be an upper limit of oxygen concentration at which these large animals can live because of the toxic effects of this gas. We are so accustomed to think of oxygen as lifesaving and essential that we ignore its potent toxicity. Oxidative metabolism, the extraction of energy from food through its reaction with oxygen, is inevitably accompanied by the escape of highly poisonous intermediates within the cell. A substance like the hydroxyl radical is such a powerful oxidant that were it present as a gas at the same concentration as oxygen, almost anything flammable would instantly burst into flame. It reacts with methane at room temperature, whereas free oxygen does not until nearly 600°C. Other undesirable products from oxygen are hydrogen peroxide, the superoxide ion, and oxygen atoms. Living cells have developed mechanisms to detoxify all those products: Enzymes, such as catalase, that decompose hydrogen peroxide to oxygen and water, and the superoxide dismutase, which converts the malign superoxide ion to harmless products. Antioxidants, such as tocopherol, that mop up hydroxyl radicals. We and other animals alive today, from the largest to the smallest, owe our life spans to this system of chemical protection developed by our distant bacterial ancestors. If there is no great excess of oxygen, its toxicity can be contained.

Why did the level of oxygen rise? At the end of the Archean, the supply of reductants -- sulfides and ferrous iron -- of the early Earth became insufficient to match the flux of oxygen coming from the burial of carbon, and the oxygen increased. It reached a low steady state in the early Proterozoic, much less than in the present atmosphere, representing a balance between the needs of early consumers and the toxicity of oxygen to the early photosynthesizers. There is no similar clear-cut event in the Proterozoic corresponding to the appearance of oxygen at the end of the Archean (see table 6.1). We do not know why the level of oxygen began to rise again, although Robert Garrels proposes that it was associated with the development of bacteria that reduce sulfates. This would have led to the burial of more of the products from the photosynthesizers, as sulfur or sulfides, so leaving behind an excess of oxygen in the air. However it happened, the reactions of this free oxygen with other elements such as carbon and sulfur would release acids into the air, and these would increase the weathering of crustal rocks so that more nutrients were released, leading to a greater abundance of living organisms. The positive feedback on the growth of oxygen would continue until the disadvantages of its presence overcame the benefits. Rather like the growth of car population in some cities, it continues until movement is choked by its presence.

Table 6.1 OXYGEN SOURCES AND SINKS

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At some time in this period organisms began synthesizing, on a large scale, the precursors of those enigmatic substances, lignins and humic acids. It may have been the result of the invention of some new antioxidants. The precursors of lignins are phenols, well known to react vigorously with hydroxyl radicals. A typical member of this class of acid substances is coniferyl alcohol: when it reacts with hydroxyl it produces lignin, a carbon-containing polymer that has great chemical stability and a resistance to biodegradation. Because of these properties lignin would, if made in quantity, increase the rate of carbon burial, and thus the rate of oxygen production. In a geophysiological fashion, lignin has turned out to be a structural material as important for land plants as the bioceramics of bone and shells are for animals. Just as calcite deposition in cells may have originally been part of a device to lower the concentration of the toxic calcium in the cell fluids, so lignin production may have initially come from a method of detoxifying oxygen. Both of these materials enabled the construction of vast cell communities of a new kind. At first in the oceans, but now in the living organisms we recognize as plants and animals.

The model of the evolution of oxygen and carbon dioxide regulation, illustrated in figure 5.4, can be extended to the present day. But it is unable, as it stands, to account for the precise regulation of oxygen observed for the past several hundred million years. Oxygen has been constant at 21 percent by volume in the Phanerozoic. The evidence of this constant high concentration is the presence in the sediments of layers containing charcoal. These can be found as far back as 200 million years. The presence of charcoal implies fires, probably forest fires. This sets sharp limits on the atmospheric oxygen abundance. My colleague, Andrew Watson, showed that fires cannot be started, even in dry twigs, when oxygen is below 15 percent; above 25 percent oxygen, fires are so fierce that even the damp wood of a tropical rain forest would burn in an awesome conflagration. Below 15 percent there could be no charcoal; above 25 percent no forests. Oxygen is 21 percent, close to the mean between these limits.

It might be that fires themselves are the regulator of oxygen. There is no shortage of lightning strikes for their ignition. If fires are the regulator it cannot be a simple relationship. Oxygen in the air comes from the burial of carbon. Consumers are efficient, and only about 2 percent of carbon photosynthesized reaches the sediments, where a further 95 percent is returned to the oxidized environment as methane. So only one part in a thousand of the carbon fixed by the plants is buried deep. Combustion, on the other hand, is inefficient. As any charcoal maker will tell you, up to 70 percent of the carbon of wood can remain from a controlled combustion. Fires, therefore, would lead to the burial of much more carbon, because charcoal is entirely resistant to biological degradation. Paradoxically, then, fires lead to more oxygen in the long run. If this grim scenario is followed to a conclusion there would at first be a positive feedback on oxygen, but soon the forests would be so devastated that carbon production would fall to the point where oxygen was near or below its present level. The cycle would then repeat. It is true that the layers of charcoal present in the sediments suggest recurrent fires, but the proportion of buried carbon existing as charcoal is much too small to account for such a cycle.

A more subtle regulation involving fire would come from the use of fires by certain species of tree as a weapon to sustain its possession of territory. The conifers and eucalyptus trees have both independently evolved to produce on the forest floor a highly flammable detritus: piles of kindling rich with resin and terpenes that ignite and burn fiercely at a lightning stroke. This contrived form of fire does not damage the tall trees themselves, but is death to competing species such as oaks. Furthermore, these fires leave little charcoal; combustion is nearly complete. So developed is the fire ecology of forests that some conifer species require the heat of fire to release their seeds from the seed capsules. The regulation of oxygen so precisely at the convenient level of 21 percent does suggest that the large plants, flammable and nonflammable, who are the victims and beneficiaries both, play a key part. I can't help wondering if those flammable trees that use fire ecology also carry less lignin than other vegetation. If so, they would be a lesser source of buried carbon and so serve to regulate oxygen at a level where fires did take place but not so fiercely as to do more harm than good.

The separate discussion of oxygen is justified by its historical significance; it is almost as if oxygen were the conductor who led the players in their evolutionary orchestra. But we need remember that in Gaia the evolution of the organisms and their environment constitute a single and inseparable process. In addition the cycles of all the elements that make up Gaia are closely coupled among themselves, as well as with the species of the organisms. Attempts to describe the role of each of these parts of the system separately are crippling to insight but made necessary by the unavoidable use of the linear form of written expression. With this thought in mind, and remembering that the geophysiology of oxygen and carbon cannot be separated, let us now look at carbon dioxide.

In modern times, carbon dioxide is a mere trace gas in the atmosphere compared with its dominance on the other terrestrial planets or with the abundant gases of Earth, oxygen and nitrogen. Carbon dioxide is at a bare 340 parts per million by volume now. The early Earth when life began is likely to have had 1,000 times as much carbon dioxide. Venus now has 300,000 times as much; and even Mars, with much of its carbon dioxide frozen in the surface, has 20 times as much. James Walker and his colleagues tried to explain the low carbon dioxide of the Earth by a simple geochemical argument. Their model was based on the facts that the only source of the gas is volcanic emission and the only sink its reaction with calcium silicate rock. In their world, life played no part in the regulation of carbon dioxide. As the Sun warmed, two processes took place. The first was an increase in the rate of evaporation of water from the sea and, hence, rainfall; the second, an increase in the rate of the reaction of carbon dioxide with the rocks. Together, these processes would increase the rate of weathering of the rocks and so decrease the carbon dioxide. The net effect would be a negative feedback on the temperature rise as the solar output increased. Unfortunately, this imaginative and plausible model could not explain the facts. The carbon dioxide it predicted for the present was about 100 times more than it is observed to be.

James Walker's model can be brought to life by including within it living organisms. If the soil of a well-vegetated region almost anywhere on Earth is examined, the carbon dioxide content is between 10 and 40 times higher than the atmosphere. What is happening is that living organisms act like a giant pump. They continuously remove carbon dioxide from the air and conduct it deep into the soil where it can react with the rock particles and be removed. Consider a tree. In its lifetime it deposits tons of carbon gathered from the air into its roots, some carbon dioxide escapes by root respiration during its lifetime, and when the tree dies the carbon of the roots is oxidized by consumers, releasing carbon dioxide deep in the soil. In one way or another living organisms on the land are engaged in the business of pumping carbon dioxide from the air into the ground. There it comes into contact with, and reacts with, the calcium silicate of the rocks to form calcium carbonate and silicic acid. These move with the ground water until it enters the streams and rivers, on their way to the sea. In the sea, the marine organisms continue the burial process by sequestering silicic acid and calcium bicarbonate to form their shells. In the continuous rain of microscopic sea shells, the products of rock weathering -- sedimented limestone and silica -- are buried on the sea floor and eventually subducted by the movements of plate tectonics. Were life not present, the carbon dioxide from the atmosphere would have to reach the calcium silicate of the rocks by slow inorganic processes like diffusion. To sustain the same soil carbon dioxide as now the atmospheric concentration would have to be even higher, perhaps as much as 3 percent. This is why the Walker model will not work.

Considered in this way, we have an explanation for the low carbon dioxide of today's Earth. This great geophysiological mechanism has served since life began as one part of climate regulation. But as the Sun grows hotter, it can have little chance of continuing to keep our planet cool. There is an inverse relationship between the abundance of carbon dioxide and the abundance of vegetation. Assuming that the health of Gaia is measured by the abundance of life, then periods of health will be at times of low carbon dioxide. During the normal healthy state of Gaia, with the comfortable coolness of a glaciation, carbon dioxide is a bare 180 parts per million by volume -- uncomfortably close to the lower limit for the growth of plants. Not surprising is the emergence in the Miocene, some 10 million years ago, of a new type of green plant able to grow at lower carbon dioxide concentrations. These plants have a different biochemistry and are called C4 plants to distinguish them from the mainstream C3 plants. The names C3 and C4 come from a difference in the metabolism of carbon compounds in these two types of plant: the C4 plants are able to photosynthesize at much lower carbon dioxide levels than the older C3 plants. The new C4 plants include some, but not all grasses, whereas trees and broad, leaved plants generally use the C3 cycle. Eventually, and probably suddenly, these new plants will take over and run an even lower carbon dioxide atmosphere to compensate for the increasing solar heat. But it will serve only temporarily, because in as short a time as 100 million years, assuming nothing else had changed, the Sun will have warmed up enough to require a zero carbon dioxide atmosphere to keep the present temperature. As we shall shortly see, there are other cooling mechanisms that could come into play. Also a different ecosystem could evolve that was comfortable with a global mean temperature even as high as 40°C. The carbon dioxide crisis is serious but not necessarily life-threatening to Gaia.

If I am right that the glacial cool is the preferred state of Gaia, then the interglacials like the present one represent some temporary failure of regulation, a fevered state of the planet for the present ecosystem. How do they come about?

Active systems of regulation or control are well known to exhibit instability when close to the limit of their operating range. This can be clearly seen in the Daisyworld model in figure 3.6 where, as the star warming the imaginary planet grows hotter, the effects of a cyclical plague affecting the plants appear in an amplified form as cyclical fluctuations of temperature until the system fails from overheating. We do not yet know the cause of the glaciations, but we do know that they are a periodic phenomenon, synchronized with small variations in the amount of solar radiation reaching the Earth and with long-term variations in the Earth's inclination and orbit. This astrophysical link between glaciation and the Earth's orbit and inclination was proposed by a Yugoslavian, Milutin Milankovich. The magnitude of the change in warmth received from the Sun is not in itself enough to account for the range of temperature between the glacials and interglacials, but it could be the trigger synchronizing the change from one state to another. According to a Japanese physicist, Shigeru Moriyama, the mathematical analysis of the periodicity of the Earth's mean temperature during the past million years is more consistent with an internal oscillation, triggered externally, than with an oscillation that was free running, or simply a response to the changes in radiant energy received from the Sun.

Geophysiology suggests that, to regulate the climate in face of increasing heat from the Sun, glacials are the normal state and the interglacials, like now, are the pathological one. Thinking this way, the low carbon dioxide during the glacials can be explained by the presence of a larger or more efficient biota. There must have been more living organisms on Earth; how else could the carbon dioxide have been so low? If more organisms were doing the pumping, where were they? At first thought it might seem that the ice sheets would leave less room for life as it covered much of what is now, or was before humans, forested land. However, as water was used to form the land-based glaciers, the level of the sea could have fallen by some 100 meters, exposing vast areas of rich and fertile soil on the continental shelves. A glance at a map of the continental shelves reveals that much of the new land would have been in the humid tropics, such as in present-day Southeast Asia. It could have covered an area comparable with that of Africa now, and could have supported tropical forests.

Such a world is inherently unstable. If a warming trend, as by the Milankovich effect, led to a decrease of land area, then increased carbon dioxide together with the geophysical feedback of a diminution in the area of reflective ice and snow cover would lead to a runaway rise of both temperature and carbon dioxide. The system would also be unstable in a biological sense. Close to the lower limit of carbon dioxide for photosynthesis there would have been intense selection pressure for plants to emerge that could live at even lower carbon dioxide. There are other critical events that could precipitate a rise of carbon dioxide and temperature. One that comes to mind is some effect connected with the increase of salt in the oceans as water froze to form ice. Acid rain from the sulfur emitted by the marine algae as a result of excess salinity (or a failure of the supply of sulfur volatiles from marine biota, which could lead to a decline of land plants by depriving them of an essential element) could be another. A decrease of cloud cover and planetary albedo is yet another. The cycles of the ice ages are known. Figure 6.1 illustrates the time history of temperature during the past million years.

Image
Time (105 years before present)
6.1 Temperature history of the recent series of glaciations. (After S. W. Matthews.)


We also need to take into account regional processes that may oppose the general tendency for cooling. In the northern temperate regions the great conifer forests are dark in color and easily shake off or shed the white snow that falls on them in winter. The length of the winter season must be considerably reduced by their presence. The late winter sunshine at continental latitudes greater than 50° is not powerful enough to melt fresh snow; the whiteness of it reflects the radiant energy skywards. Dark pine trees, though, absorb the sunlight and warm not just the trees themselves but the region. Once the snow has melted then even the bare ground can absorb sunlight, making it warm enough for seeds to germinate and letting the spring commence.

The circularity of explanations of physiological control systems makes it difficult to choose a point of entry. Which came first, the low carbon dioxide and dense cloud cover, or the low temperature? This question, like that about the priority of chickens and eggs, could be pointless. Let us look instead at a recent evolutionary development, the emergence of the C4 plants that are able to grow at lower concentrations of carbon dioxide than the older C3 plants. These C4 plants could be both the result of the glaciations and an encouragement for further glacial periods. Now there is ample carbon dioxide for all plants, so there is not much competition between C3 and C4 plants for habitats, except through the agency of humans who, in agriculture, remove the older C3 plants and replace them by wheat, rice, bamboo, sugar cane, and so on, many of which are C4 plants. During a glaciation, when the carbon dioxide is near the lower limit tolerable for C3 plants, the advantages of the C4 metabolism begins to tip the balance in their favor.

The human propensity to interfere was the plot of a doom scenario in my first Gaia book. The central character was an earnest, well-meaning agricultural biologist, Dr. Intensli Eeger. He succeeded, where all other hazards had failed, in eliminating all life by his meddling. He developed, using genetic engineering, a combined nitrogen-phosphorus fixing microorganism. It was intended to improve the yield of rice grown in the humid tropics so that the hunger of the Third World would at last be overcome. Unfortunately, his organism found a free-living unicellular alga much more to its liking than rice plants. So successful was this combination that it conquered the world. It was a Pyrrhic victory, because the bicultural world of the algal-bacterial combination could not, on its own, maintain planetary homeostasis.

I have had a certain guilt about ascribing, even to a fictional character, so awful a punishment for meddling, and it seems only fair to give him a second chance. This time he uses his impressive skill to develop a new form of tree starting with wild oats, one that would operate on the C4 cycle and grow vigorously in the humid tropics. It would have a rich sap, a delicious fruit full of vitamins and nutrients, and an ability to grow well in arid areas. Its plantations could reverse the spread of desert.

The replacement of much of the humid tropical forests with Avena eegeriansis at first gave the impression that the bad days of environmental degradation were over. Lush plantations were sprouting everywhere, greening the Sahel and bringing back rain to regions that had been desert for thousands of years. Under the shade of the new trees, the complex tropical ecosystems began to return. Soon it was noticed that the carbon dioxide greenhouse problem was abating; the lush growth of the trees had so increased the rate of carbon dioxide uptake by the soil that the sink was now larger than the source. Some scientists, though, were commenting that cloud cover, and, hence, albedo had increased. There was a fierce scientific debate. In line with current thinking, and encouraged by the generous supply of research funds, theorists blamed the increased cloudiness on the activities of the chemical and nuclear industries.

Soon the winter snow was lingering in Moscow, Boston, Chicago, Bonn, and Beijing until May; further north it was snowbound year round. Nuclear power stations and the chloro-fluorocarbon industry were closed down. But, faster than the great urban populations of the Northern Hemisphere could grasp, the world would be deep into the next and greatest glaciation. Gaia would breathe free again, cool and comfortable at a total atmospheric carbon dioxide of 100 parts per million. It would not be long, in Gaia's terms, before the oceans receded from the vast areas of continental shelf. Australia and Papua New Guinea would once again be joined by land covered with an ever-extending forest. The lands and cities of the superpowers of yesterday would nearly all be buried under the glaciers. C4 plants would have taken over, with the help of humankind, and liberated Gaia for the start of another long period of homeostasis -- an ice age to last for millions of years, not just hundreds of thousands.

This is an unlikely story, but it does serve to illustrate the way that a punctuation can happen as a result of a change in dominant species. We might be the highest form of animal life, but without doubt trees are the highest form of plant life. A fully developed C4 tree might be formidable competition for the forest trees we now know. Dr. Eeger would have redeemed himself and led humans back into a seemly existence within Gaia.

In living organisms, the element sulfur is widely used in structures and functions. So next I would like to explain how information gathered in the past decade has enlarged our understanding of the physiological role of sulfur in Gaia.

In the summer of 1971 I attended a Gordon Conference held in New Hampton School in the town of the same name in New Hampshire. The title of the conference was "Environmental Science: Air," and the chairman James Lodge, an atmospheric chemist and a friend. It is no small tribute to his powers of organization that this conference could be said to have marked the start of a deep new interest in the atmosphere that has continued to this day.

It was there that I first presented experimental measurements of the halocarbons and sulfur gases in the air. I also learnt that the conventional wisdom about the natural cycle of sulfur was that it required large quantities of hydrogen sulfide to be emitted from the oceans to make up for the losses of sulfur, as the sulfate ion, in the run-off of rivers. Without some return of sulfur, the land organisms would soon have been starved of this essential element. I knew from Professor Frederick Challenger's work at the University of Leeds in the 1950s that many marine organisms emitted sulfur as the gaseous compound, dimethyl sulfide. I also knew, as a one-time chemist, that hydrogen sulfide was rapidly oxidized in water containing dissolved oxygen, and that it stunk. It seemed to me that, on both these grounds, it could not be the major carrier of sulfur from the ocean to the land. On the other hand, that elusive smell of the sea is much like that of dilute dimethyl sulfide. Indeed, once you have smelt this gas, pleasant when diluted, it is recognizable ever after as a significant component of the aroma of fresh fish straight from the sea. It is not part of the smell of fresh fresh-water fish.

When I returned home to England I thought that it might be a good idea to go by ship from the Northern Hemisphere to the Southern Hemisphere, measuring the sulfur-carrying gases in the air and the sea to try to find out if dimethyl sulfide were indeed the carrier of sulfur in the natural world. I also wanted to take the opportunity to measure the halocarbon gases, such as are used in aerosol sprays, in the hope that these effectively "labeled" the air and would allow us to observe its movement over the oceans. This was to be the last occasion that I applied for research funds through the regular system of writing a proposal and submitting it to a funding agency. What I sought was a small grant, no more than a few hundred pounds, to make some apparatus and take it by ship from the Northern Hemisphere to the Southern, measuring the gases each day the ship sailed. I should have known better. Both proposals were rejected. To the peer reviewers it was pointless to look for dimethyl sulfide, since it was known that the missing sulfur flux was conveyed by hydrogen sulfide. The second proposal, to look for halocarbons, was rejected as frivolous because it was "obvious" that no apparatus existed sensitive enough to measure the few parts per trillion of chlorofluorocarbons I was proposing to seek.

I was lucky in being independent. All that I needed for approval to make the voyage was the agreement of my wife Helen, whose housekeeping funds would be somewhat diminished by the cost of the research. She did not share the opinions of my "peers." I made a simple gas chromatograph (shown in figure 6.2) whose total cost could not have been more than a few tens of pounds. Some kindly civil servants of the Natural Environment Research Council, who also disagreed with their panel of academic advisers, provided my travel and subsistence expenses from a discretionary fund. I traveled on a research ship, the RV Shackleton, on its journey from Wales to Antarctica and back. I returned from Montevideo after three weeks on the ship, sadly all the time I could afford; but a fellow voyaging scientist, Roger Wade, kindly continued the measurements when the ship was in Antarctica. My colleague, Robert Maggs, flew out to Montevideo in the spring of 1972 to complete the run home across the equator to Britain. The measurements made on this voyage were reported in three small papers in Nature. The first reported the halocarbon measurements, which showed that the chlorofluorocarbons were persistent and long-lived in the Earth's atmosphere, and that two other halocarbon gases, carbon tetrachloride and methyl iodide, were to be found wherever the ship sailed. These findings led to among other things, the "ozone war" and to the disbursement of an ocean of research funds, recommended by the same committees that had rejected the first applications. Speculations about the threat to "the Earth's fragile shield," the ozone layer, were more plausible than the idea of a voyage of discovery stimulated by no more than the curiosity of an individual scientist.

Image
6.2 Homemade apparatus used to measure gases, in the sea and air, aboard the RV Shackleton on its voyage from Britain to Antarctica and back in 1971 to 1972.

The second and third papers on the sulfur gases reported the ubiquitous presence of dimethyl sulfide and carbon disulfide in the oceans. These findings were, apart from the pioneering calculations of the fluxes by Peter Liss of the University of East Anglia, largely ignored -- until M. O. Andreae showed by his careful and extensive measurements of the oceanic sulfur gases, in the early 1980s, that the output of dimethyl sulfide from the oceans was indeed sufficient to justify its role as the major carrier of the element sulfur from the sea to the land.

Dimethyl sulfide would not have been sought as a candidate chemical transporter had it not been for the stimulus of Gaia theory that required the presence of geophysiological mechanisms for such transfers. But what on earth, you may ask, could be the mechanism? Why should marine algae out in the open oceans care a fig for the health and well-being of trees, giraffes, and humans on the land surfaces? How could such an amazing altruism evolve through natural selection?

The answer is not yet known in detail, but we have a glimpse of how it might have evolved from the properties of a strange compound called dimethylsulfonio propionate. This substance is what organic chemists call a betaine, after the discovery long ago of a similar compound, trimethylammonio acetate or betaine, first isolated from beets. The importance of betaines for the health of marine organisms living in a salty environment was discovered by A. Vairavamurthy and his colleagues. Betaines are electrically neutral salts. They carry a positive charge, associated with the sulfur or nitrogen, and a negative charge, associated with the propionic acid ion, on the same molecule. In an ordinary salt, such as sodium chloride, solution in water separates the charges, which become independent free-floating ions. As we saw in the preceding chapter, marine life lives near the limit of tolerable salt concentration. Salt concentrations above 0.8 molar for sodium chloride are toxic, but this does not apply to betaines. The internal neutralization of their ionic charges renders them nontoxic as salts, and they act in a cell like sugars, glycerol, and the other neutral solutes. Cells that are able to substitute a large proportion of betaine for salt are at an advantage.

I wonder if some time, long ago, marine algae were left by the ebbing tide on some ancient beach. The sunlight would soon dry them. As water evaporated from their cells, the internal salt concentration would rise above the lethal limit, and they would die. In the way of evolution, those algae that had present in their cells neutral solutes like the betaines would be less damaged by desiccation and would tend to leave more progeny. In time, the synthesis of betaines would be common among marine algae. Sulfur is plentiful in the sea, whereas nitrogen is often scarce. On the land the reverse is true. This may be why dimethylsulfonio propionate was the chosen betaine rather than the nitrogen betaine of beets and other land plants. (Incidentally beets, also, are able to deal with high concentrations of salt.) This may not be the whole explanation of the presence of dimethylsulfonio propionate as a prominent algal betaine, but there is no doubt that algae that contain it are the source of dimethyl sulfide. When the algae die or are eaten, the sulfur betaine decomposes easily to yield the acrylic acid ion and dimethyl sulfide. Algae that were prone to being left high and dry on the beach would, therefore, have evolved this sulfur gas, and onshore breezes would have carried it inland where atmospheric reactions would slowly decompose it and deposit sulfur as sulfate and methanesulfonate on the ground. Sulfur is scarce on the land and this new source could have enhanced the growth of land plants. The increased growth would increase rock weathering and so increase the flow of nutrients to the ocean. It is not difficult to explain the mutual extension of the land-based ecosystems from the supply of sulfur and of the sea-based ecosystems from the increased flux of nutrients. By this, or some similar series of small steps, the intricate geophysiological regulation systems evolve. They do so without foresight or planning, and without breaking the rules of Darwinian natural selection.

Before leaving the beach, so to speak, I have wondered also about the widespread production of methyl iodide by marine plants. Unlike the innocuous dimethyl sulfide, this compound is toxic. It is a mutagen and a carcinogen. The first stimulus for its production may have been as an antibiotic to help the algae to compete, or to discourage predators. The release of methyl iodide to the air from the sea is an essential mechanism for the maintenance of a continuous supply of iodine, an element that is vital for land organisms. It might be worth investigating the possibility that a specific betaine, methyliodonio propionate, exists in large algae such as the brown seaweed, Laminaria, which are a strong source of methyl iodide. If it does, then it suggests a common link with the sulfur betaine story.

But there is more to the sulfur and iodine cycles than just the recycling of nutritious elements. The Alaskan geophysicist, Glen Shaw, had a stimulating idea for an efficient geophysiological climate control system. Knowing that a small (in Earthly terms) quantity of sulfur in the stratosphere could profoundly affect the climate, he proposed that the emission of sulfur gases by marine organisms was the most efficient method of climate control. There is a fair body of evidence to suggest that major volcanic eruptions are followed by a global fall in mean surface temperatures. The volcanic gases injected into the stratosphere by the eruption include sulfur dioxide and hydrogen sulfide. (The volcanic cloud also contains an aerosol of solid material, but this soon settles downward.) The sulfur gases remaining in the stratosphere oxidize and, with the water vapors present there, form submicroscopic droplets of sulfuric acid. Because they are so small, they settle only slowly and may persist for several years. These droplets form a white haze in the stratosphere that returns to space the sunlight that might otherwise warm the Earth. Between eruptions, there remains a background of sulfuric acid droplets that are continuously formed from the oxidation of sulfur gases from living organisms. The most important of these are carbonyl sulfide and carbon disulfide. They are minor emissions compared with that of dimethyl sulfide, but in the lower atmosphere they are only slowly oxidized (carbonyl sulfide is especially slow), and persist long enough to enter the stratosphere and be oxidized there. Glen Shaw's proposal was that global overheating could be offset by marine life increasing its output of carbonyl sulfide and carbon disulfide, leading to a thickening of the haze of sulfuric acid droplets in the stratosphere and so to a cooling of the Earth. This may indeed be one of several available geophysiological mechanisms for climate regulation. But it set my colleagues thinking of what might be a much more potent use of sulfur gases for the same end.

During extensive investigations of the world oceans, M. O. Andreae has shown that marine organisms emit vast quantities of dimethyl sulfide. These emissions are particularly marked over the "desert" areas of the open oceans far away from the continental shelves. This finding led the meteorologists Robert Charlson and Stephen Warren to propose that the rapid oxidation of dimethyl sulfide in the air over the ocean could be the source of the nuclei needed for the condensation of water vapors to form clouds. Small droplets of sulfuric acid are ideal for this purpose, and over the open oceans there is no other significant source of condensation nuclei from which to form clouds. The aerosol of sea salt which might be thought to nucleate cloud droplets is much less efficient than are the microdroplets of the sulfur acids. The oceans cover about two-thirds of the Earth's surface and their color is a dark blue. Anything that affected the cloud cover over the oceans could powerfully affect the climate of the Earth. In a joint paper, the four of us have reported calculations to estimate the effect that the present natural emissions of dimethyl sulfide could have; these suggest that it is comparable in magnitude with that of the carbon dioxide green-house, but in opposition to it.

We have shown the possibility of a powerful link between the growth of algae on the ocean surface and the climate. As a geophysiologist I would further ask: Could these processes serve as a significant part of a responsive climate regulation system? And if so, how did this system evolve? We may also need to take into account the iodine cycle, because the oxidation of dimethyl sulfide in the marine atmosphere is catalyzed by iodine compounds. The production of methyl iodide by the algae may also be a part of this system of climate control.

The sites we are proposing for cloud regulation by sulfur emission are the open desert areas of the tropical oceans, about 40 percent of the surface area of the Earth. These regions are low in productivity compared with the continental shelves and inshore waters. They are bare of life, like the great land deserts that span the 30° latitudes north and south of the equator. On land, it is a lack of water that makes the desert; on the oceans it is a lack of nutrients, particularly nitrogen. What are these ocean deserts like? Their waters are clear and blue and, like land deserts, they are by no means devoid of life. One of these deserts is the Sargasso Sea. I recall reading when I was a boy an adventure story about the perils faced on a sailing ship trapped in the dense entangling weed of the Sargasso Sea. When I passed right through that region in 1973 aboard the German research ship Meteor, I was amazed at the difference between the reality and my recollections of the story. There was floating weed, but no more than well-dispersed thin strands of bladder wrack -- the ocean equivalent of sagebrush in an arid desert, and no more impediment to the motion of the ship than would be the sagebrush to walking across the desert floor.

The algae at the surface of these ocean deserts do not produce the precursors of cloud condensation nuclei for our benefit nor as a part of some grand design to keep the planet cool. The process must have its origins in the local environmental effects of algal biochemistry. I have discussed the possibility that the production of the sulfur betaine, dimethylsulfonio propionate, may have been a cellular response to salt stress. Although it may have been discovered by marine algae drying out on the shore, successful inventions tend to spread. The concentration of salt in the sea is always uncomfortably high for living organisms. For the unicellular or small-floating organisms, unable to regulate their internal salt by osmotic pressure, synthesizing betaines may have been the cheapest way, in terms of energy, of achieving a low-salt interior. Again dimethylsulfonio propionate would have been the natural choice, because sulfur (in the convenient form of the sulfate ion) is abundant, whereas nitrogen is not. The dimethylsulfonio propionate persists in the cells of the algae during their lifetime, but when they die or are eaten it disperses in the ocean, where it slowly decomposes to yield dimethyl sulfide. Both of these compounds are consumed by other organisms, but there is a steady flux of dimethyl sulfide to the air. In the air, the gas is rapidly oxidi4ed by the ubiquitous hydroxyl radicals until nearly all is converted to sulfuric and methanesulfonic acids. The vapors of these acids are carried aloft by the motions of the air until they reach the heights supersaturated with water vapor, where they act as cloud droplet nuclei.

The escape of dimethyl sulfide to the air can bring to the algae inadvertent benefits. The extra cloud cover from the presence of sulfuric acid nuclei changes the local weather. Timothy Jickells of the University of East Anglia has drawn my attention to the fact that clouds over the ocean increase wind velocity, and stir the surface waters, mixing in the nutrient-rich layers beneath the depleted photosynthesizing zone. This is an effective reward for the production of cloud condensation nuclei, and has just been confirmed by the work of the meterologist, John Woods. I doubt if the fresh water of the rain assists much with the salt-stress problem of the algae, but it is no disadvantage. In some regions of the sea, the air carries an aerosol of dust particles blown from the continents; such dust is well known to travel thousands of miles across the oceans. Professor J. M. Prospero, a geophysicist, has regularly found Saharan dust in the air over the West Indies. The Hawaiian islands similarly receive dust from the Asian continent some 4,000 miles distant. The mineral content of this dust when rained out onto the sea may also help the nutrition of the algae there. The surface of the dust particles is not such as to make them suitable as cloud condensation nuclei, but they are washed out of the air by rain induced by the dimethyl sulfide. Lastly, the clouds formed above the ocean filter the radiation reaching the water surface and reduce the proportion of potentially harmful short, wavelength ultraviolet. Visible light needed for photosynthesis is not a limiting factor in the nutrient-poor ecosystems of the oceans, so the shading effect of the clouds is not an adverse one.

None of these effects is large, but taken together they may be enough to improve the meadows of the sea and enable the algal species there to leave more progeny. The geophysiological system requires the continuing production of dimethylsulfonio propionate and of the algae that make it. The difficult question is, How does this system become a part of global climate regulation? The oceans become saltier when water freezes out as ice on the polar surfaces; this might lead to increased emission of dimethyl sulfide, increased cloudiness, and so a positive feedback on further cooling. It might be that the greater biomass associated with the glaciations provides more nutrient for ocean life and so sustains the algae.

As I write, our first scientific paper on this affair has been published in Nature. These are the early days of this research, and already it looks like becoming an exciting scientific area for research. Two groups of French glaciologists -- Robert Delmas and his colleagues, and C. Saigne and M. Legrand -- have recently reported their discovery of sulfuric and methane sulfonic acids in antarctic ice cores, going from the present to 30,000 years ago. Their data shows a strong inverse correlation between global temperature and the deposition in the ice of these acids. Sulfuric acid has several natural sources, but methane sulfonic acid is unequivocally the atmospheric oxidation product of dimethyl sulfide. There was 2 to 5 times larger a deposition of this sub, stance during the ice age and it seems probable that this was due to a greater output from the ocean ecosystems. If confirmed, it suggests that cloud cover and low carbon dioxide operated in synchrony as part of a geophysiological process to keep the Earth cool. More conservative scientists favor a geophysical explanation arising from the theory of the ocean scientist W. S. Broecker, who has proposed that the glaciations are associated with large-scale changes in the circulation of water in the oceans. Certainly the increase in supply of nutrients that would accompany such an event would alter biological productivity and hence the rate of removal of carbon dioxide and the production of dimethyl sulfide. It looks like becoming an interesting debate.

I thought that it might be useful to end this section with a geophysiologist's view of the evolution of the climate and the chemical composition of the atmosphere (see figure 6.3). It is a view of long periods of homeostasis punctuated by large changes.

Image
Time (eons before present)
6.3 A geophysiologist's view of the evolution of the climate and atmospheric composition during the life span of Gaia. The upper panel compares the probable temperatures in the absence of life with the stepped but long-term constancy of the actual climate. The lower panel illustrates the stepped fall of carbon dioxide steadily from 10 to 30 percent to its present low level of about 300 parts per million. The early dominance of methane and later of oxygen is also shown. The scale of gaseous abundance is in parts per million by volume and in logarithmic units so that 1 equals 10 parts per million and 5 equals 100,000 parts per million.

We seem to be approaching the end of one of these long stable periods. When life began, the Sun was less luminous and the threat was overcooling. In the middle ages of the Proterozoic, the Sun shone just right for life and little regulation was needed, but now it grows hot and overheating becomes an ever-increasing threat to the biosphere of which we are a part.
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:39 pm

Part 1 of 2

7: Gaia and the Contemporary Environment

A day like today I realize what I've told you a hundred different times -- that there is nothing wrong with the world. What's wrong is our way of looking at it.

-- Henry Miller, A Devil in Paradise


A rough, stony track led forward across the thin moorland grass and then dropped into the bare, rock-strewn bed of the River Lydd; straight ahead rose the small mountain of Widgery Tor, a sort of turret on the walls of that castle-like massif that was Dartmoor. On a clear, sunny day it was a grand and romantic prospect to reward the small effort of a country walk.

The second day of August 1982 was just such a sunny day, but the moorland vision was all but lost in a dense and dirty brown haze. The air was corrupted by the fumes of Europe's teeming millions of cars and trucks. Their flatus oozed in a gentle easterly drift of wind from the continent; ineluctable chemistry driven by sunlight stewed the fumes into a witches' brew that seared the green leaves. Even my eyes, though washed by the flow of tears, began to smart; soon personal discomfort drew my attention from the contemplation of the mask of photo-chemical smog that obscured the jeweled brightness of the West Country scene. A visitor from Los Angeles would instantly have recognized it for what it was, but Europeans, still in the late stages of their honeymoon with personal transport, cannot admit to themselves that their beloved cars fart anything so foul as smog.

This vision of a blighted summer's day somehow encapsulates the conflict between the flabby good intentions of the humanist dream and the awful consequences of its near realization. Let every family be free to drive into the countryside so that they can enjoy its fresh air and scenic beauty; but when they do, it all fades away in the foul haze that their collective motorized presence engenders. As I climbed the Tor and thought these thoughts I knew also that, in driving myself to the foothills at the start of the walk, I had added a small but culpable increment of hydrocarbons and of sulfur and nitrogen oxides to the over-laden air. I also knew that my dislike of this kind of air pollution was a value judgment, and a minority one at that.

There can be very few who do not in some way add to the never-ceasing demolition of the natural environment. Characteristically, arrogantly, we blame technology rather than ourselves. We are guilty, but what is the offence? Many times in the Earth's history new species with some powerful capacity to change the environment have done as much, and more. Those simple bacteria that first used sunlight to make themselves and oxygen were the ancestors of the trees today but eventually, simply by living and by doing their photochemical trick, they so profoundly altered the environment that vast ranges of their fellow species were destroyed by the poisonous oxygen that accumulated in the air. Other simple microorganisms have in their communities acted so that mountain ranges formed and continents were set in motion over the surface of the Earth.

Looked at from the time scale of our own brief lives, environmental change must seem haphazard, even malign. From the long Gaian view, the evolution of the environment is characterized by periods of stasis punctuated by abrupt and sudden change. The environment has never been so uncomfortable as to threaten the extinction of life on Earth, but during those abrupt changes the resident species suffered catastrophe whose scale was such as to make a total nuclear war seem, by comparison, as trivial as a summer breeze is to a hurricane. We are ourselves a product of one such catastrophe. Could it be that we are unwittingly precipitating another punctuation that will alter the environment to suit our successors?

A group of scientists from all parts of the world met in 1984 at Sao Jose dos Campos in Brazil. The meeting, held at the request of the United Nations University, posed the question, "How does human intervention in the natural ecosystems of the human tropics affect the forest, the regions around it, and the whole world?" It soon became clear that, whatever their disciplines, the specialists had little to offer other than a frank and honest admission of ignorance. Asked, "When shall we know the consequences of removing the forest from Amazonia?" they could only answer, "Not before the forests have gone." It seemed as if we were at a stage in understanding the health of Gaia rather like that of a physician before scientific medicine existed.

In The Youngest Science, Lewis Thomas lets us identify with a young medical practitioner whose first experiences were in the 1930s. Even for those who knew medicine then, it is astonishing to be reminded how little there was that a physician could do to cure a patient. The practice of medicine was largely a matter of administering symptomatic relief and trying to insure that the environment of the patient was that most favorable for the powerful natural processes of healing that we all possess.

Early in its history, medical wisdom accumulated by shrewd observation and by trial and error. The discovery of the curative value of drugs like quinine, or of that wonderful panacea for pain and discomfort, opium, was not in some brightly lit laboratory. Rather, it was in the early experiments or observations of a village genius who realized that there were real benefits to be had from chewing that bitter bark of the cinchona tree or real comfort implicit in the dried latex of the poppy head. Physiology, the systems science of people and animals, was at first an unrecognized background, but later came to influence further progress. The recognition by Paracelsus that the poison is the dose is a physiological enlightenment still to be discovered by those who seek the unattainable and pointless goal of zero for pollutants.

Innovative technology using poisonous gases to help heal wounds is one step closer thanks to an award made to researchers at the University of St Andrews.

Professor Russell Morris, of the University’s School of Chemistry, has been awarded almost £200,000 by the Royal Society to help further develop technology that could also significantly cut NHS treatment costs.

The funding was part of the Royal Society Brian Mercer Award for Innovation 2012 presented to Professor Morris by The Duke of York in a ceremony in London last night (Wednesday 5 December).

The research involves an exciting development in chemical technology that can be used to apply small, beneficial amounts of the gas, nitric oxide, to wounds safely, in order speed up healing. Nitric oxide is a simple gas molecule which in large amounts is significantly toxic; however in small amounts it has essential roles in the body, such as controlling blood pressure in the cardiovascular system and also in wound healing.

The funding will allow Professor Morris and his team to develop the concept – which could speed up wound healing significantly in diabetes sufferers, the elderly and the obese - for commercial exploitation and clinical trials.

Professor Morris explained, “When a wound occurs in normal skin the body produces nitric oxide to fight infection through its antibacterial properties and then to signal the production of new blood vessels to increase blood flow to the damaged area. Unfortunately people who suffer from diabetes, or those who are elderly or obese often don’t produce enough nitric oxide naturally which can lead to poor wound healing. In bad cases such as chronic wounds which do not heal, the affected limbs may need to be amputated.”

Among chronic wounds the highest prevalence lays in the venous leg ulcer, diabetic foot/leg wound and pressure ulcer categories. Estimates of annual VLU incidence around the world are around 2 million (1 million alone in the US). Patients with type I or II diabetes have a 1-4% annual chance of foot ulceration and a lifetime risk as high as 25%.

The NHS currently spends £8.8 billion per annum on care for patients with type II diabetes alone. Estimates for the UK indicate that 15% of all diabetes patients develop DFUs and that they lead to 84% of lower leg amputations.

There is strong evidence that the addition of nitric oxide to wounds can be extremely beneficial in these situations. However, because it is a toxic gas, there needs to be a method of applying small, beneficial amounts of gas to wounds safely.

The technology - metal-organic frameworks (MOFs) - being developed by Professor Morris offers a safe new way of treating such wounds with gases. By incorporating MOFs into wound dressings, nitric oxide can be delivered slowly and at levels which do not cause any toxic or inflammatory effects, aiding wound recovery safely.

Professor Morris commented, “The highly porous metal-organic frameworks act as miniature gas tanks, allowing us to deliver only safe and beneficial amounts of nitric oxide from something as easy to use as a wound dressing. This will transform how we can use this gas to help people with debilitating chronic wounds.”

-- The benefits of poison, by www.st-andrews.ac.uk


Everything in this Universe of differentiated matter has its two aspects, the light and the dark side, and these two attributes applied practically, lead, the one to use, the other to abuse. Every man may become a botanist without apparent danger to his fellow-creatures; and many a chemist who has mastered the science of essences knows that every one of them can both heal and kill. Not an ingredient, not a poison, but can be used for both purposes -- aye, from harmless wax to deadly prussic acid, from the saliva of an infant to that of the cobra di capella. This every tyro in medicine knows -- theoretically, at any rate. But where is the learned chemist in our day who has been permitted to discover the "night side" of an attribute of any substance in the three kingdoms of Science, let alone the seven of the Occultists? Who of them has penetrated into its Arcana, into the innermost Essence of things and its primary correlations? Yet it is this knowledge alone which makes of an Occultist a genuine practical Initiate, whether he turns out a Brother of Light or a Brother of Darkness. The essence of that subtle, traceless poison, the most potent in nature, which entered into the composition of the so-called Medici and Borgia poisons, if used with discrimination by one well versed in the septenary degrees of its potentiality on each of the planes accessible to man on earth. -- could heal or kill every man in the world; the result depending, of course, on whether the operator was a Brother of the Light or a Brother of the Shadow. The former is prevented from doing the good he might, by racial, national, and individual Karma; the second is impeded in his fiendish work by the joint efforts of the human "Stones" of the "Guardian Wall."

It is incorrect to think that there exists any special "powder of projection" or "philosopher's stone," or "elixir of life." The latter lurks in every flower, in every stone and mineral throughout the globe. It is the ultimate essence of everything on its way to higher and higher evolution. As there is no good or evil per se, so there is neither "elixir of life" nor" elixir of death," nor poison, per se, but all this is contained in one and the same universal essence, this or the other effect, or result, depending on the degree of its differentiation and its various correlations. The dark side of it produces life, health, bliss, divine peace, etc.; the dark side brings death, disease, sorrow, and strife. This is proven by the knowledge of the nature of the most violent poisons; of some of them even a large quantity will produce no evil effect on the organism, whereas a gram of the same poison kills with the rapidity of lightning; while the same grain, again, altered by a certain combination, though its quantity remains almost identical -- will heal. The number of the degrees of its differentiation is septenary, as are the planes of its action, each degree being either beneficent or maleficent in its effects, according to the system into which it is introduced. He who is skilled in these degrees is on the highroad to practical Adeptship; he who acts at haphazard -- as the enormous majority of the "Mind Curers," whether "Mental" or "Christian Scientists," -- is likely to rue the effects on himself as well as on others. Put on the track by the example of the Indian Yogis, and of their broadly but incorrectly outlined practices, which they have only read about, but have had no opportunity to study -- these new sects have rushed headlong and guideless into the practice of denying and affirming. Thus they have done more harm than good. Those who are successful owe it to their innate magnetic and healing powers, which very often counteract that which would otherwise be conducive to much evil. Beware, I say; Satan and the Archangel are more than twins; they are one body and one mind -- Deus est Demon inversus.

-- The Esoteric Papers of Madame Blavatsky


The discovery by William Harvey of the circulation of the blood added to the wisdom of medicine, just as the discovery of meteorology added to our understanding of the Earth. The expert sciences of biochemistry and microbiology came much later, and it was a long time before their new knowledge could enhance the practice of medicine. Even as I write, a paper has appeared in Nature describing the molecular structure of the virus responsible for the acquired immune deficiency syndrome; but it will be a long time before this astonishing feat of biochemistry rescues those now dying of AIDS and comforts those who fear that strange and deadly malady.

It seemed oddly appropriate to gather in Brazil; as if we were old-style clinicians conferring at the bedside of a patient with an untreatable disease. We recognized the inadequacy of our expertise and the need for a new profession: planetary medicine, a general practice for the diagnosis and treatment of planetary ailments. We thought that it would grow from experience and empiricism just as medicine had done. It also seemed to some of us that geophysiology, the systems science of the Earth, might serve as did physiology in the evolution of medicine, as a scientific guide for the development of this putative profession.

This chapter, therefore, will be a look at the real and imaginary problems of Gaia through the eyes of a contemporary practitioner of planetary medicine. The scientific background, geophysiology, has already been touched on in the preceding chapters. So let us look at the physical signs, the clinical features, to see if anything can be diagnosed. It is true that, in the case of Gaia, the complaint comes not from the patient but rather from the intelligent fleas that infest her. There is nothing to stop us, however, from going through a routine examination of the temperature charts and the biochemical analyses of the body fluids.

The Carbon Dioxide Fever

Carbon dioxide is a colorless gas with a faintly pungent odor and acid taste. It occurs naturally in the Earth's atmosphere where it serves as an essential plant nutrient and an important determinant of the Earth's thermal balance. Human activities release carbon dioxide to the atmosphere through the burning of wood, coal, oil, natural gas, and other organic materials. Due at least in part to these activities, the concentration of carbon dioxide has increased some 7 percent over the last two decades. There has been much debate over how and when the Earth will respond and what impact this will have on mankind.


So begins the first chapter of that splendid book, Carbon Dioxide Review 1982, edited by William Clark. Unless some significant new discoveries have been made between the time of its publication and your reading of this, I suspect that it will still be among the best sources of information on this complex subject.

From the very beginning of life on Earth, carbon dioxide has had a contradictory role. It is the food of photosynthesizers and therefore of all life; the medium through which the energy of sunlight is transformed into living matter. At the same time it has served as the blanket that kept the Earth warm when the Sun was cool, a blanket that, now the Sun is hot, is becoming thin; yet one that must be worn, for it is also our sustenance as food. We have seen earlier how the biota everywhere on the land and sea are acting to pump carbon dioxide from the air so that the carbon dioxide which leaks into the atmosphere from volcanoes does not smother us. Without this never-ceasing pumping, the gas would rise in concentration within a hundred thousand years to levels that would make the Earth a torrid place, and unfit for almost all life here now. Carbon dioxide for Gaia is like salt for us. We cannot live without it, but too much is a poison.

Is the sun heating up?

Best Answer: No, in fact it is cooling down. As it burns the hydrogen into helium, energy is released (the radiation we get from the Sun) and expands in all directions. Since heat is the measurement of energy in a system and the energy of the Sun is being bled off, the heat is reducing. The Helium that is left after the process has a lower internal energy than the separate Hydrogen before fusion: the sun is radiating it's heat. It's a very slow process (it should take between 1 and 3 billion years) for the conversion of Hydrogen to Helium to show remarkable change in energy levels. That is, till the energy we receive on Earth begins to reduce by any substantial amount. Until the Sun dies (most likely as a Red Giant), it will slowing become cooler and cooler.

-- Is the Sun Heating Up, by http://www.wiki.answers.com


Earth is heating up lately, but so are Mars, Pluto and other worlds in our solar system, leading some scientists to speculate that a change in the sun’s activity is the common thread linking all these baking events. Others argue that such claims are misleading and create the false impression that rapid global warming, as Earth is experiencing, is a natural phenomenon. While evidence suggests fluctuations in solar activity can affect climate on Earth, and that it has done so in the past, the majority of climate scientists and astrophysicists agree that the sun is not to blame for the current and historically sudden uptick in global temperatures on Earth, which seems to be mostly a mess created by our own species.

-- Sun Blamed for Warming of Earth and Other Worlds, by Ker Than, March 12, 2007, http://www.livescience.com


For humans, a hundred thousand years is almost indistinguishable from infinity; to Gaia, who is about 3.6 eons old, it is equivalent to no more than three of our months. Gaia has cause for concern about the long-term decline of carbon dioxide, but the rise of carbon dioxide from burning fossil fuels is, for her, just a minor perturbation that lasts but an instant of time. She is, in any case, tending to offset the decline.

Before we dismiss Gaia from our worries about carbon dioxide, we should bear in mind that among the things that can happen in an instant is the impact of a bullet in full flight. Small it may be, and short the time of contact, but disastrous are its consequences. So it could be with Gaia and carbon dioxide. Humans may have chosen a very inconvenient moment to add carbon dioxide to the air. I believe that the carbon dioxide regulation system is nearing the end of its capacity. The air in recent times has been uncomfortably thin in carbon dioxide for mainstream vegetation and, as was mentioned in the last chapter, new species with a different biochemistry are evolving. These new species, the C4 plants, can live at very low carbon dioxide levels and might at some future time replace the older obsolete C3 models, as the gas continues its progressive down-ward course. The progression is not a smooth one, but more like the trembling and jerky gait of the elderly. We know that carbon dioxide has fallen in abundance during the Earth's history, but it jumped from 180 to near 300 parts per million within a hundred years as the last glaciation ended. A rapid rise like this can have come only from the sudden failure of the pumps. It cannot be explained by the slow processes of geochemistry.

The rate and the extent of the rise of carbon dioxide now under way as a result of our actions is comparable with that of the natural rise that terminated the last ice age. Some time in the next century it seems likely that the increment we add will be equal to that caused by the failure of the pumps some 12,000 years ago. The change of climate we need to think about, therefore, is possibly one as large as that from the last ice age until now; one that would make winter spring, spring summer, and summer always as hot as the hottest summer you can recall. To comprehend such a change at the personal level, imagine you are a citizen of a mid-continental town such as Chicago or Kiev. The change is as great as from the bitter cold of winter that has passed to the fierce heat of summer soon to come.

In his book, William Clark compares the predictions that economists have made of growth from now until the middle of the next century. Among them is listed the prediction by Amory and Hunter Lovins, who argue plausibly that growth may be close to zero into the foreseeable future. This is a very different prediction from that of the late, great Herman Kahn, who saw the whole world in the next century as a vast and wealthy suburban development. Scarsdale writ large. There is strong objective evidence from the record of industrial production that the Lovins' prediction is nearer the truth. Since 1974 the turnover of energy and materials by the human world has been in steady state. Even so, unless we greatly decrease the rate of burning fossil fuel, the atmospheric carbon dioxide will continue to rise to its own steady state and will have doubled in concentration by between 2050 and 2100.

I can only guess the details of the warm spell due. Will Boston, London, Venice, and the Netherlands vanish beneath the sea? Will the Sahara extend to cross the equator? The answers to these questions are likely to come from direct experience. There are no experts able to forecast the future global climate.

Some wisdom comes from geophysiology, which reminds us that the Earth is an active and responsive system and not just a damp and misty sphere of rock. Systems in homeostasis are forgiving about perturbations, and work to keep the comfortable state. Maybe, if left to herself, Gaia could absorb the excess carbon dioxide and the heat that it brings. But Gaia is not left to herself; in addition to carbon dioxide increments, we are also busy removing that part of the plant life, the forests, that by responsive extra growth might serve to counteract the change.

Much more serious than the direct and predictable effects of adding carbon dioxide to a stable system are the consequence of disturbing a system that is precariously balanced at the limits of stability. From control theory, and from physiology, we know that the perturbation of a system that is close to instability can lead to oscillations, chaotic change, or failure. Paradoxically, an animal close to death from exposure to cold, whose core temperature is below 25°C, will die if put into a warm bath. The well-intentioned attempt to restore heat succeeds only in warming the skin to the point where its oxygen consumption is greater than the slowly beating, still-cold heart and lungs can supply. In a vicious circle of positive feedback the blood vessels of the skin dilate; this so reduces blood pressure that death comes rapidly from the failure of the heart as a pump to circulate blood that is too depleted in oxygen for the system's needs. A hypothermic animal will recover if left to warm slowly, or if heat is supplied internally as by diathermy.

We know too little about the carbon dioxide climate system to be able to provide a detailed forecast of the consequences of the current increase, but there are some solid facts of observation from which some general conclusions can be drawn. The Earth's mean temperature is well below the optimum temperature for plant life. There are periodic climatic oscillations as we cycle between the glaciations and their intermissions, and carbon dioxide is attenuated close to its lower possible limit. All these are physical signs of a system on the verge of failure.

Like our latter-day physician, we find that diagnosis is easier than a cure. We are left with the uneasy feeling that to add carbon dioxide to the Earth now could be as unwise as warming the surface of our hypothetical hypothermic patient. It is not much comfort to know that, if we inadvertently precipitate a punctuation, life will go on in a new stable state. It is a near certainty that the new state will be less favorable for humans than the one we enjoy now.

A Case of Acid Indigestion

The greenhouse effect of carbon dioxide is not the only problem to arise from the burning of fossil fuels. In the northern temperate regions of the Earth there is an increased morbidity and mortality of the ecosystems. Trees, and the life in lakes and rivers, are particularly affected. The symptoms seem to be connected with an observed increase in the rate of deposition of acidic substances. Combustion is said to be the cause of acid deposition and of all the harm it does to forest ecosystems. Does geophysiology have any different view on this?

It could be said that it is all the fault of oxygen. If those ancient godfathers, the cyanobacteria, had not polluted the Earth with this noxious gas there would be no oxides of nitrogen and of sulfur to trouble the air, and therefore no acid rain. Oxygen, the acid maker, the gaseous drug that both gives us life and kills us in the end, not for nothing did those French chemists of the eighteenth century call it the acidifying principle. In their time there were not many chemicals for them to experiment with; those they did have, such as sulfur, carbon, and phosphorus, all gave acids when combined with oxygen. It was only later, when the discovery of electricity allowed chemists to isolate elements like sodium and calcium, that combustion was found to produce alkalis as well. Later still, they realized that an acid was a substance that freely donated positively charged hydrogen atoms, and it was these protons that were the true principle of acidity. In addition that great chemist, G. N. Lewis, observed that it was the electric charge that mattered, not the atom that carried it. He showed that acids can be substances that attract electrons, the fundamental carriers of the negative charge. In some ways oxygen itself is one of these "Lewis" acids.

It is not so surprising that there is free oxygen in the air from life's chemical transactions. The bundle of elements that form the chemicals that go to make up the Earth's crust have more oxygen than anything else; 49 percent of the elemental composition is oxygen. As Lavoisier observed, of all the principal light elements that go to make up living matter -- carbon, nitrogen, hydrogen, sulfur, and phosphorus -- only hydrogen does not give acids when combined with oxygen. Long before humans trod the planet, the rain that fell was acid. The natural acid in the rain were carbonic acid, the gentle acid of fizzy carbonated water; formic acid, one of the end products of methane oxidation; and nitric, sulfuric, methanesulfonic, and hydrochloric acids. Although the last four of these are strong and corrosive, the rain that fell did no harm, for the acids were present at great dilution. They came mostly from the oxidation of gases emitted by living things; some came also from the gases vented by volcanoes, or from high-energy processes, such as lightning and cosmic rays, that cause nitrogen and oxygen to react. The biological precursors of the acids -- for example methane, nitrous oxide, dimethyl sulfide, and methyl chloride -- are not acids, but they oxidize in the air to produce the catalog of acids listed above.

Pollution by acid rain deposition is again a matter of dosage: pollution is due to an increase to intolerable levels of acids that previously were benign in their abundance. Quite separate from the demolition of ecosystems by acids and oxidants is the reduction of the quality of life by this kind of pollutant. The smog and haze that I complained of in the opening paragraphs of this chapter, and that masks so much of the Northern Hemisphere in summer, is for the most part a fog of sulfuric acid droplets.

Any detached observer of the heated European or North American debate over acid rain might gather the impression that all acid rain was due to the burning of sulfur-rich fossil fuel in power stations, industrial furnaces, and domestic heating systems. Coal and oil both contain about one percent of sulfur. This element leaves the chimney stacks as sulfur dioxide gas, and soon this gas is oxidized to sulfuric acid which condenses as droplets that attract water vapor from the air to form an acid fog or haze. Eventually, this either settles out or is rained out. Where it falls on land that is rich in alkaline rocks like limestone, and particularly if there is a shortage of sulfur there, its fallout is welcome. But when it falls on land that is already acid, its addition is unwelcome and potentially destructive. Canada, Scandinavia, Scotland, and many other northern regions are on ancient rocks, the hard, soluble residue of eons of weathering. The ecosystems that survive on this unpromising, and often normally acidic, terrain have less capacity to resist the stress of acidification. It is from the countries of these regions that comes a justifiable complaint that their industrial neighbors are destroying them. To the Canadians and the Scandinavians it seems unarguable that the emission of sulfur dioxide by countries downwind should cease. Few can doubt the natural justice of their case, but naturally the offenders are reluctant to spend the very large sums needed to stop the escape of sulfur dioxide from their power stations and industries.

The geophysiological contribution to this debate is to observe that this acid indigestion may have another source in addition to the sulfuric vinegar of neighbors. The fitting of sulfur dioxide removers to the chimneys might only alleviate, not cure, the problem. The neglected source of acid is the natural sulfur carrier, dimethyl sulfide. In the past two years, Meinrat Andreae and Peter Liss (ocean chemists based, respectively, in Florida and the United Kingdom) have shown that the emission of this gas from phytoplankton blooms at the surface of the oceans around western Europe is so large as to be comparable with the total emissions of sulfur from industry in this region. Moreover, the phytoplankton emissions are seasonal and seem to coincide with the maximum of acid deposition.

It might be asked, with reason, that if this is the case, why was the pollution not observed until recently? If dimethyl sulfide from the sea is the source of sulfuric acid, then surely wouldn't Scandinavia always have suffered the ill effects of acid deposition? In fact, two changes in recent years may have made the natural transfer of sulfur from the sea to the land a curse instead of a benefit. Before Europe became intensively industrialized, dimethyl sulfide from the sea was probably carried far inland by the westerly wind drift, and slowly dropped its sulfur in dilute form over a vast area. Industrialization has not only increased the total burden of acid but also has greatly increased the abundance of oxides of nitrogen and other chemicals from combustion. In sunlight, these can react to make the powerful oxidant hydroxyl. Most important as a source of these agents is the internal combustion engine that powers personal and public transport. Hydroxyl radicals are now locally at least ten times more abundant than they used to be before private transport became ubiquitous. Because of this, dimethyl sulfide that used to oxidize slowly over all of Europe may now dump its burden of acid rapidly over the regions near the coast where the sea air encounters the polluted air.

In addition to this increase in the rate of oxidation, and hence acid production, the output of dimethyl sulfide has itself probably increased in recent years. Patrick Holligan, of the Marine Biological Laboratory in Plymouth, tells me that satellite photographs have revealed dense algal blooms clustered around the outlets of the continental rivers of Europe. Peter Liss and his colleagues have found that these algal blooms emit dimethyl sulfide, apparently stimulated by the rich flow of nutrients down the rivers of Europe. The excessive use of nitrate fertilizer, and the increased output of sewage effluent into the rivers feeding the North Sea and the English Channel, have gone to overnourish the sea above the European continental shelf and to make it like a duck pond. The relative amount of acid from this source is not yet known. It might turn out to be insignificant. However, prudent legislators concerned over acid rain should urge their scientific advisers to investigate the relative importance of the various sources of acid. My personal sympathy is with those who ask for action on the basis that sulfur dioxide emissions are the prime culprit. I do wonder, though, what would happen if reducing these did not work. Would governments then have the will to tackle the very much more expensive acts, if these were the best way to prevent acid rain deposition, of sewage reform, or the control of nitrogen oxide emissions?

The affair of acid rain is as much an issue of politics and economics as of environmental science. Before accepting as inevitable a long and costly battle involving national and commercial interests, it is useful to go back and re-examine the conduct of the ozone war. There are some interesting parallels and possibly some lessons to be learnt.
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:39 pm

Part 2 of 2

The Dermatologists' Dilemma: Ozonemia

In the late 1960s I developed a simple apparatus able to detect chlorofluorocarbons (CFCs) in the atmosphere down to parts per trillion by volume. This is an exquisite sensitivity; at such levels even the most toxic of chemicals could be breathed in or swallowed without harm, indefinitely. In 1972, I took this apparatus on the voyage to Antarctica and back of the RV Shackleton (see chapter 6). The measurements I made on that ship showed that the CFCs were distributed throughout the global environment. There was about 40 parts per trillion in the Southern Hemisphere and 50 to 70 in the Northern. When I reported these findings in a Nature paper in 1973, I was concerned that some enthusiast would use them as the basis of a doom story. As soon as numbers are attached to the presence of a substance, these numbers seem to confer a spurious significance. What previously was a mere trace becomes a potential hazard. The hypochondriac, on hearing that his blood pressure is 110/60, becomes worried: "Surely, doctor, isn't that too low?" As a putative planetary physician I felt the need to add at the beginning of my paper the sentence, "The presence of these compounds constitutes no conceivable hazard." This sentence has turned out to be one of my greatest blunders. Of course I should have said, "At their present level, these compounds constitute no conceivable hazard." Even then I knew that, if their emissions continued unchecked, they would accumulate until sometime near the end of the century they could be a hazard. I knew nothing of their threat to the ozone layer, but I did know that they were among the most potent of greenhouse gases and that by the time they reached the parts per billion level the climatic consequences of their presence could be serious. This opinion is recorded in the proceedings of a conference on fluorocarbons held at Andover, Massachusetts, in October 1972.

At this time in the 1970s there was a fear of impending catastrophe. "Earth's fragile shield," the ozone layer, was said to be in imminent danger of demolition as a consequence of the release into the stratosphere of nitric oxide in the exhaust gases of supersonic aircraft. The atmospheric chemist Harold Johnson first alerted us to this particular threat. Then, tentatively at first, Ralph Cicerone and his colleague Richard Stolarski drew our attention to chlorine as an another danger to ozone. Then in 1974 there appeared in Nature a paper by Sherry Rowland and Mario Molina which argued with great clarity and force that the CFCs, as a result of stratospheric photochemistry, were a potent source of chlorine and hence a threat to ozone. This paper stands like a beacon, a natural successor to Rachel Carson's book Silent Spring. It heralded the start of the ozone war. In their enthusiasm with the science and the battle, scientists, somewhat uncharacteristically, convinced themselves and the public of the need for immediate action to ban the emission of CFCs. To me, wrong-footed by my earlier assertion that CFCs were harmless, it seemed to be a remote and hypothetical threat. But I was among a minority, and legislators in many parts of the world were persuaded to act precipitately and to enact legislation banning CFC gases as aerosol propellants. It is interesting to ask what is special about ozone that made legislators act this way. No one was dying of the effects of CFC emissions; crops and livestock were unharmed by their presence; the substances themselves were among the most benign of chemicals that enter our homes, neither toxic, corrosive, nor flammable. Indeed, they would have been imperceptible but for the sensitivity of the instrument that I used for their detection. Their presence at between 40 and 80 parts per trillion, even to the most committed environmentalist, was no threat to ozone. The concern came from the fact that the emissions were growing exponentially, and if the growth rate of the sixties continued until the end of the century, there would be an ozone depletion of between 20 and 30 percent. This would be disastrous.

Ozone is a deep blue, explosive, and very poisonous gas. It is strange that so many have regarded it as if it were some beautiful endangered species. But it was the mood of the 1970s to respond to environmental hazards much as previous generations had responded to witchcraft. It was not easy to oppose the widely held belief that only immediate action by scientists and politicians could save us and our children from an otherwise ineluctable depletion of the ozone layer and the dire consequences of an ever-increasing flux of carcinogenic ultraviolet radiation. This was also the time when the word "chemical" became pejorative, and all products of the chemical industry were assumed to be bad unless proved harmless. In a more sensible environment, we might have regarded the predictions of doom in the next century due to a single industrial chemical as far fetched -- something to watch closely, but not something requiring immediate legislation. But the 1970s was not the time for a long, cool look at things.

At a university in the small Rocky Mountain town of Logan, Utah, the principal scientists and lawyers concerned with the fluorocarbon affair met in 1976. Among those present were Ralph Cicerone, who had first hypothesized that chlorine in the stratosphere might catalyze the destruction of ozone, and Mario Molina and Sherry Rowland, who had developed the complex reaction sequence that explained how the CFCs could be the source of the chlorine and delineated the intricate details of the destruction mechanism. There were also scientists from industry and from the regulatory agencies, and there were, of course, lawyers and legislators. It could have been a reasoned debate leading to agreement about a safe upper limit for the CFCs in the light of current knowledge. It was instead a kind of tribal war council where the decision to fight was taken. Anyone who was not for the immediate banning of the CFCs was clearly a traitor to the cause. I shall never forget the adversarial encounter between Commissioner R. D. Pittle and Dr. Fred Kaufman, who was representing the National Academy of Sciences. The commissioner forgot he was not in a courtroom and demanded a yes or no answer to the question of whether CFCs should be banned. In certain ways it reminded me of another encounter, long ago: the one between Galileo and the authorities of his time.

The processes of science are very different from those of the courtroom. Both have evolved to satisfy the needs of their practitioners. Scientific hypotheses are best tested by the accuracy of their predictions; the establishment of a fact of science does not greatly affect the Universe, only the wisdom of scientists. By contrast, facts in law are tested in an adversarial debate and established by judgment. The establishment of a legal fact alters society from then on. At the best of times, and even with near certainties, science and the law do not mix well. At Logan they tried to form legal judgments on plausible but untested scientific hypotheses. It is not so surprising that the result was of little credit to any of the participants.

Once again the wisdom of Paracelsus that the poison is the dose was ignored, and in its place the "zero" shibboleth took charge. "There is no safe level of ultraviolet radiation," was the cry. "Ultraviolet, like other carcinogens, should be reduced to zero." In fact, ultraviolet radiation is part of our natural environment, and has been there as long as life itself. It is the nature of living things to be opportunistic. Ultraviolet, although potentially harmful, can also be used by living organisms for the photosynthesis of vitamin D. When it is a threat, it can be avoided by synthesizing such pigments as melanin to absorb it.

There is still a lack of knowledge about the relationships between natural ecosystems and the ultraviolet to which they are exposed. But we do know that ultraviolet radiation varies sevenfold (700 percent) in intensity between the Arctic and the tropics, whereas visible light varies only 1.6 times (160 percent) over the same range of latitude. In spite of this large range of intensity, there is nowhere a region where the growth of vegetation is limited by ultraviolet. In contrast, a sevenfold change of rainfall makes the difference between forests and deserts. There are no ultraviolet deserts on Earth, and life seems well adapted to the radiation over this wide range of intensity. Damage does occur but seems to be limited to recent migrants from high to low latitudes. There is also evidence that a lack of ultraviolet can be harmful to migrants from the tropics to the temperate regions.

Exposure to any radiation with a high quantum energy that penetrates the skin can damage the genetic material of our cells and corrupt their program of instructions. Among the adverse effects is the conversion from normal to malignant growth. This is frightening stuff, but we can keep our cool by remembering that these carcinogenic consequences are no different from those of breathing oxygen, which is also a carcinogen. Breathing oxygen may be what sets a limit to the life span of most animals, but not breathing it is even more rapidly lethal. There is a right level of oxygen, namely 21 percent; more or less than this can be harmful. To set a level of zero for oxygen in the interests of preventing cancer would be most unwise.

Wars do not usually start from a single isolated incident, and so it was with the ozone war. The historical basis was, as mentioned in chapter 4, the proposal by Berkner and Marshall that the colonization of the land surfaces of the Earth did not take place until oxygen and its allotrope, ozone, first entered the atmosphere. Ozone, they said, prevents the penetration of hard ultraviolet radiation that otherwise would keep the land sterilized and uninhabitable by life. This was a decent scientific hypothesis and a very testable one at that. Indeed it was tested by my colleague Lynn Margulis, who challenged it by showing that photosynthetic algae could survive exposure to ultraviolet radiation equivalent in intensity to that of sunlight unfiltered by the atmosphere. But this did not stop the hypothesis from becoming one of the truly great scientific myths of the century; it is almost certainly untrue, and it survives only because of the apartheid that separates the sciences. Physical scientists regard biology as extraterritorial and biologists reciprocate. The members of each discipline tend to accept uncritically the conclusions of the other. This apartheid is a triumph of expertise over science, and it is expressed with great innocence when scientists try to explain the separation of their findings into physical and biological parts as a necessary consequence of expertise. Biologists concerned with the effects of ultraviolet know it to be beneficial as well as harmful. But until recently they had no reason to doubt the expertise of their physical science colleagues, and therefore thought only of the consequences of ozone depletion. As a counterpoint, most physical scientists are unaware that ultraviolet might in any way have benefits. Consequently, they tend to think of ozone accretion as a benefice. However, the diseases of vitamin D deficiency -- rickets and osteomalacia -- are associated with a reduced exposure to solar ultraviolet. Also it seems that the incidence of multiple sclerosis varies with latitude reciprocally to that of skin cancer. The variation of skin color with latitude suggests that we have, in the absence of migration, adapted to the ultraviolet levels of our habitats.

Once more ozone is news. J. C. Farman and B. G. Gardiner, of the British Antarctic Survey, have discovered a thinning of the ozone layer over the south polar regions, moreover a thinning that has grown rapidly each year until now it is almost a hole. This event is entirely unexpected and in great contrast to the fact that over most of the world the level of ozone is either unchanged or even slightly increased. But this is exciting and fearful stuff. What if the hole should spread and threaten populated regions? Before we become too deeply involved, it seems worth asking what were the benefits of the first ozone conflict? Who won and who lost? The only clear losers were those small industries, and their employees, dependent upon the use of CFCs in the products that were banned. For various and complex reasons, the manufacturers of CFCs were not much affected. The loss of the doubtfully profitable CFC-propellant section of their market, together with the rationalization of their industry, did little to change their economy. Politicians and the environmental movement lost some of their credibility, but public memory tends to be short. The clear winners were science and the scientists. Vast sums have been disbursed for atmospheric research, which would never have been available but for the ozone war. We now know much more about our atmosphere, and this knowledge will be essential in the understanding of other atmospheric problems. Among them is the greenhouse warming effect of minor atmospheric gases. Three key properties of the CFCs make them dangerous. First is their long atmospheric life times, which allow them to accumulate unchecked, second their ability to carry their burden of chlorine directly and without loss to the stratosphere, and third the intensity with which they absorb long-wavelength infrared radiation. Their presence in the atmosphere adds to the carbon dioxide greenhouse effect. This is a danger that is potentially more serious than that of ozone depletion. We have reason to be glad that one of the pioneers of the original concern about CFCs, Ralph Cicerone, has turned his attention to the graver and more certain dangers of their greenhouse effect.

It may turn out that I was very wrong to have opposed those who sought instant legislation to stop the emission of CFCs. I regard the strange phenomenon over the south polar regions as a warning of other more serious surprises yet to come. It seems possible that other changes, including the concomitant increase of CO2 and methane from human industry and agriculture, are responsible for the extra effect of chlorine compounds in polar regions, but there is little doubt in my mind that without the chlorine from industrial gases there would be no thinning of the ozone layer at the South Pole. The CFCs and other industrial halocarbons have increased by 500 percent since I first measured them in 1971. They were harmless then, but now there is too much halocarbon gas in the air. The first symptoms of poisoning are now felt. I now join with those who would regulate the emissions of the CFCs and other carriers of chlorine to the stratosphere.

To return to our clinical analogy, we could say that the fear of skin cancer as a consequence of ozone depletion led at first to a global hypochondria -- something all too easily acquired by identifying our fears with the plausible account of symptoms described in a textbook. Good physicians know that hypochondria can be a cry for help and mask the existence of a real malady; perhaps the same is true of the global state of health. Could fears about the CFCs and the ozone layer have presaged discovery of the ozone hole and the climate-threatening greenhouse effect of CFCs?

A Dose of Nuclear Radiation

Carl Sagan once observed that if an alien astronomer were to look at the Solar System in the radio-frequency part of the spectrum, it would see a truly remarkable object. Two stars eclipsing one another: one of them a normal, small, main-sequence star and the other a very small, but intensely luminous body with an apparent surface temperature of millions of degrees, our Earth. Were that distant observer a scientist, it might speculate on the nature of the energy source that powered, what seemed to be, one of the hottest objects in the Galaxy. I wonder how high on the list of probable sources it would place chemical energy. Would it include energy coming from the reaction between fossil fuels and oxygen from plants?

It is easy to ignore the fact that we are the anomalous ones. The natural energy of the Universe, the power that lights the stars in the sky, is nuclear. Chemical energy, wind, and water wheels: such sources of energy are, from the viewpoint of a manager of the Universe, almost as rare as a coal-burning star. If this is so, and if God's Universe is nuclear-powered, why then are so many of us prepared to march in protest against its use to provide us with electricity?

Fear feeds on ignorance, and a great niche was opened for fear when science became incomprehensible to those who were not its practitioners. When X rays and nuclear phenomena were discovered at the end of the last century, they were seen as great benefits to medicine -- the near-magic sight of the living skeleton and the first means to palliate, even sometimes cure, cancer. Roentgen, Becquerel, and the Curies are remembered with affection for the good their discoveries did. Sure enough, there was a dark side also, and too much radiation is a slow and nasty poison. But even water can kill if too much is taken.

It is usually assumed that the change in attitude towards radiation came from our revulsion at that first misuse of nuclear energy at Hiroshima and Nagasaki. But it is not that simple. I well remember how the first nuclear power stations were a source of national pride as they quietly delivered their benefice of energy without the vast pollution of the coal burners they replaced. There was a long spell of innocence between the end of the Second World War and the start of the protest movements of the 1960s. So what went wrong?

Nothing really went wrong, it just happens that nuclear radiation, pesticides, and ozone depleters share in common the property that they are easily measured and monitored. The attachment of a number to anything or anyone bestows a significance that previously was missing. Sometimes, as with a telephone number, it is real and valuable. But some observations -- for example, that the atmospheric abundance of perfluoromethyl cyclohexane is 5.6 x 10-15, or that as you read this line of text at least one hundred thousand of the atoms within you will have disintegrated -- while scientifically interesting, neither confer benefit nor have significance for your health. They are of no concern to the public.

But once numbers are attached to an environmental property the means will soon be found to justify their recording, and before long a data bank of information about the distribution of substance X or radiation Y will exist. It is a small step to compare the contents of different data banks and, in the nature of statistical distributions, there will be a correlation between the distribution of substance X and the incidence of the disease Z. It is no exaggeration to observe that once some curious investigator pries open such a niche, it will be filled by the opportunistic growth of hungry professionals and their predators. A new subset of society will be occupied in the business of monitoring substance X and disease Z, to say nothing of those who make the instruments to do it. Then there will be the lawyers who make the legislation for the bureaucrats to administer, and so on. Consider the size and intricacy of the radiation-monitoring agencies, of the industry that builds monitoring and protective devices, and of the academic community that has radiation biology as its subject. If the strong public fear of radiation were dispelled, it would not be helpful to their continued employment. We see that there is a very biological, Gaian, feedback in our community relationship with the environment. It is not a conspiracy or a selfishly motivated activity. Nothing like that is needed to maintain the ceaseless curiosity of explorers and investigators, and there are always opportunists waiting to feed on their discoveries.

If this alone were not enough, there are the media, ready to entertain us. They have in the nuclear industry a permanent soap opera that costs them nothing. Why, we can even experience the excitement of a real disaster, like Chernobyl, but in which, as in fiction, only a few heroes died. It is true that calculations have been made of the cancer deaths across Europe that might come from Chernobyl, but if we were consistent, we might wonder also about the cancer deaths from breathing the coal smoke smogs of London and look on a piece of coal with the same fear now reserved for uranium. How different is the fear of death from nuclear accidents from the commonplace and boring death toll of the roads, of cigarette smoking, or of mining -- which when taken together are equivalent to thousands of Chernobyls a day.

It was Rachel Carson, with her timely and seminal book, Silent Spring, who started the Green Movement and made us aware of the damage we can so easily do to the world around us. But I do not think that she could have made her case against pesticide poisoning without the prior discovery that agricultural pesticides were distributed ubiquitously throughout the whole biosphere. Numbers could even be attached to the wholly insignificant quantities of pesticide in the milk of nursing mothers or in the fat of penguins in the Antarctic. In Rachel Carson's time, pesticides were a real threat, and the blind exponential increase of their use put all our futures in hazard. But we have responded in a fashion, and that one experience ought not be extrapolated to all environment hazards real or imagined.

The foregoing paragraphs are not intended as support for the nuclear industry, nor to imply that I am enamoured of nuclear power. My concern is that the hype about it, both for and against, diverts us from the real and serious problem of living in harmony with ourselves and the rest of the biota. I am far from being an uncritical supporter of nuclear power. I often have a nightmare vision of the invention of a simple, lightweight nuclear fusion power source. It would be a small box, about the size of a telephone directory, with four ordinary electricity outlets embedded in its surface. The box would breathe in air and extract, from its content of moisture, hydrogen that would fuel a miniature nuclear fusion power source rated to supply a maximum of 100 kilowatts. It would be cheap, reliable, manufactured in Japan, and available everywhere. It would be the perfect, clean, safe power source; no nuclear waste nor radiation would escape from it, and it could never fail dangerously.

Life could be transformed. Free power for domestic use; no one need ever again be cold in winter or overheated in the summer. Simple, elegant pollution-free private transport would be available to everyone. We could colonize the planets and maybe even move on to explore the star systems of our Galaxy. That is how it might be sold, but the reality almost certainly is ominously expressed by Lord Acton's famous dictum, "Power tends to corrupt and absolute power corrupts absolutely." He was thinking of political power, but it could be just as true of electricity. Already we are displacing the habitats of our partners in Gaia with agricultural monocultures powered by cheap fossil fuel. We do it faster than we can think about the consequences. Just imagine what could happen with unlimited free power.

If we cannot disinvent nuclear power, I hope that it stays as it is. The power sources are vast and slow to be built, and the low cost of the power itself is offset by the size of the capital investment required. Public fears, unreasoning though they sometimes are, act as an effective negative feedback on unbridled growth. No one, thank God, can invent a chain saw driven by a nuclear fission power source that could cut a forest as fast and heedlessly as now we cut down a tree.

To my ecologist friends, many of whom have been at the sharp end of protest against nuclear power, these views must seem like a betrayal. In fact, I have never regarded nuclear radiation or nuclear power as anything other than a normal and inevitable part of the environment. Our prokaryotic forebears evolved on a planet-sized lump of fallout from a star-sized nuclear explosion, a supernova that synthesized the elements that go to make our planet and ourselves. That we are not the first species to experiment with nuclear reactors has been touched on earlier in this book.

I am indebted to Dr. Thomas of Oak Ridge Associated Universities, who gave me a new insight on the nature of the biological consequences of nuclear radiation. As I listened to his words, spoken in the quiet privacy of his room, I felt an emotion like that described by Keats in his verses about first reading Chapman's Homer. What Dr. Thomas said may have been no more than hypothetical, but to me it was exciting stuff. Let's look at his proposition: "Suppose that the biological effects of exposure to nuclear radiation are no different from those of breathing oxygen."

We have long known that the agents within the living cell that do damage after the passage of an X-ray photon, or a fast-moving atomic fragment, are an assortment of broken chemicals; things called free radicals that are reactive and destructive chemicals. As an X-ray photon passes through the cell, the radiation severs chemical bonds just as a bullet might sever blood vessels and nerves. By far the greater part of this destruction is of molecules of water, for they are the most abundant in living matter. The broken pieces of a water molecule form, in the presence of oxygen, a suite of destructive products including the hydrogen and hydroxyl radicals, the superoxide ion, and hydrogen peroxide. These are all capable of damaging, irreversibly, the genetic polymers that are the instructions of the cell. This is now conventional scientific wisdom; the novel insight from Dr. Thomas was to remind us that these same destructive chemicals are being made all the time, in the absence of radiation, by small inefficiencies in the normal process of oxidative metabolism. In other words, so far as our cells are concerned, damage by nuclear radiation and damage by breathing oxygen are almost indistinguishable.

The special value of this hypothesis is that it suggests a rule of thumb for comparing these two damaging properties of the environment. If Dr. Thomas were right, then the damage done by breathing is equivalent to a whole body radiation dose of approximately 100 roentgens per year. I used to wonder about the risk-benefit ratio of a medical X-ray examination. A typical hospital X ray of the chest or abdomen could deliver 0.1 roentgen of radiation, enough to blacken the film of a personal radiation monitor and to have caused terror to the inhabitants of Three Mile Island. Now, thanks to Dr. Thomas, I look upon it as no more than one-thousandth of the effect of breathing for a year. Or to put it another way, breathing is fifty times more dangerous than the sum total of radiation we normally receive from all sources.

The early battles at the end of the Archean against the planet-wide pollution by oxygen are still apparently with us. Living systems have invented ingenious countermeasures: antioxidants such as vitamin E to remove the hydroxyl radicals, superoxide dismutase to destroy the superoxide ion, catalase to inactivate hydrogen peroxide, and numerous other means to lessen the destructive effects of breathing. Nevertheless, it seems likely that the life span of most animals is set by a fixed upper limit of the quantity of oxygen that their cells can use before suffering irreversible damage. Small animals such as mice have a specific rate of metabolism much greater than we do; that is why they live only a year or so even if protected from predation and disease. Oxygen kills just as nuclear radiation does, by destroying the instructions within our cells about reproduction and repair. Oxygen is thus a mutagen and a carcinogen, and breathing it sets the limit of our life span. But oxygen also opened to life a vast range of opportunities that were denied to the lowly anoxic world. To mention just one of these: free molecular oxygen is needed for the biosynthesis of those special structure-building amino acids, hydroxylysine and hydroxyproline. From these are made the structural components that made possible the trees and animals.

Paul Crutzen, an atmospheric chemist, was the first to draw our attention to the far-reaching geophysiological consequences of a major nuclear war, the "nuclear winter." We need to be reminded, often, just how bad that ultimate sanction can be so that it remains a deterrent. But, like oxygen, nuclear energy provides opportunities and challenges us to learn to live with it.

The Real Malady

When things are bad, or if we witness some particularly depressing piece of environmental demolition, we often say that people are like a cancer on the planet; they grow in numbers unchecked and they destroy all that comes in contact with them. Was it fear of cancer, that great standby of all environmentalist demagogues, that stirred our worries about the Earth? If it was, we can cease worrying on that account. Life exists in many forms, and of these, neither organisms living as single cells nor Gaia suffer the unique rebellion of cancer. That is limited to the metaphyta and metazoa -- those life forms, such as trees and horses, that consist of vast but intensely organized cell communities. People are not in any way like a tumor. Malignant growth in an animal requires the transformation of instructions encoded in the genes of a cell. The descendants of the transformed cell then grow independently of the animal system. The independence is never complete; the cancerous cells still, to some extent, respond and contribute to the system. To be like a cancer we should need first to become a different species and then to be a part of something far more intensively organized than Gaia.

The longevity and strength of Gaia comes from the informality of the association of her constituent ecosystems and species. She operated for nearly a third of her life populated with no more than prokaryotic bacteria. She still is largely run by these, the most primitive part of life on Earth. The consequences for Gaia of the environmental changes that we have made are as nothing compared with those that you or I would experience from unfettered growth of a community of malignant cells. Although Gaia may be immune to the eccentricities of some wayward species like us or the oxygen bearers, this does not mean that we as a species are also protected from the consequences of our collective folly.

When I wrote the first Gaia book, nearly ten years ago, it seemed that there might be critical ecosystems whose damage or removal might have serious consequences for the present collection of organisms which inhabit the Earth and find it comfortable. The forests of the humid tropics and the ecosystems of the waters of the continental shelves seemed at that time to be those most likely to be crucial for keeping the environmental status quo. Already we see the beginnings of malfunction, in the form of rain that is too acid as a consequence of the proliferation of algae in the overnourished waters off the European coast. Also, the general decline of the ecosystems in several parts of Africa may be a consequence of removing the trees that once grew there.

The maladies of Gaia do not last long in terms of her life span. Anything that makes the world uncomfortable to live in tends to induce the evolution of those species that can achieve a new and more comfortable environment. It follows that, if the world is made unfit by what we do, there is the probability of a change in regime to one that will be better for life but not necessarily better for us. In the past, changes of this kind, like the jump from a glaciation to an interglacial, have tended to be revolutionary punctuations rather than gradual evolutions.

The things we do to the planet are not offensive nor do they pose a geophysiological threat, unless we do them on a large enough scale. If there were only 500 million people on Earth, almost nothing that we are now doing to the environment would perturb Gaia. Unfortunately for our freedom of action, we are moving towards eight billion people with more than ten billion sheep and cattle, and six billion poultry. We use much of the productive soil to grow a very limited range of crop plants, and process far too much of this food inefficiently through cattle. Moreover, our capacity to modify the environment is greatly increased by the use of fertilizers, ecocidal chemicals, and earth-moving and tree-cutting machinery. When all this is taken into account we are indeed in danger of changing the Earth away from the comfortable state it was once in. It is not just a matter of population; dense population in the northern temperate regions may be less a perturbation than in the humid tropics.

There is no way for us to survive without agriculture, but there seems to be a vast difference between good and bad farming. Bad farming is probably the greatest threat to Gaia's health. We use close to 75 percent of the fertile land of the temperate and tropical regions for agriculture. To my mind this is the largest and most irreversible geophysiological change that we have made. Could we use this land to feed us and yet sustain its climatic and chemical geophysiological roles? Could trees provide us with our needs and still serve to keep the tropics wet with rain? Could our crops serve to pump carbon dioxide as well as the natural ecosystems they replace? It should be possible, but not without a drastic change of heart and habits. I wonder if our great-grandchildren will be vegetarian and if cattle will live only in zoos and in tame life parks.

As understanding about the dangers inherent in farming grows, it reinforces the insight from conventional modeling. Thus large-scale changes of land use, even in one region alone, will not be limited in their effects to that region only. Geophysiology also reminds us that the climatic effects of forest clearance are likely to be additive to those of carbon dioxide and other greenhouse gases. Even the most intricate climate models of the present type cannot predict the consequences of these changes. A complete model requires the biota to be included in a way that recognizes its very active presence and its preference for a narrow range of environmental variables. Putting the biota in a box with inputs and outputs, as in a biogeochemical model, does not do this. By analogy, we need physiology to understand how we sustain a constant personal temperature when exposed to heat or cold, biochemistry can only tell us what reactions produce heat in our bodies, not how we regulate our temperature.

There is as yet no answer as to what proportion of the land of a region can be developed as open farmland or forest without significantly perturbing either the local or the global environment. It is like asking what proportion of the skin can be burnt without causing death. This physiological question has been answered by the direct observations of the consequences of accidental burns. It has not been modeled, so far as I am aware. It may be that detailed geophysiological modeling can answer the parallel environmental question, but, if human physiology is a guide, empirical conclusions drawn from a close study of the local climatic consequences of regional changes of land use are more likely to yield the information we seek.

In some ways the ecosystem of, for example, a forest in the humid tropics is like a human colony in Antarctica or on the Moon. It is only self-supporting to a limited extent, and its continued existence depends upon the transport of nutrients and other essential ingredients from other parts of the world. At the same time, ecosystems and colonies try to minimize their losses by conserving water, heat, or essential nutrients; to this extent they are self-regulating. The tropical rain forest is well known to keep wet by modifying its environment so as to favor rainfall. Traditional ecology has tended to consider ecosystems in isolation. Geophysiology reminds us that all ecosystems are interconnected. As an analogy, an animal's liver has some capacity to regulate its internal environment, and the cells of the liver can be grown in isolation. But neither the animal without a liver, nor the liver itself, can live independently alone; each depends upon the interconnection between the two. We do not know if there are vital ecosystems on the Earth, although it would be difficult to imagine life continuing without the ubiquitous presence of those ancient bacteria who live in the dark and smelly places of mud and feces. Those bacteria found, 3.5 eons ago, that the perfect way of life for them was turning used carbon into methane gas, and they have done it ever since. The ecosystems of the waters of the continental shelves transfer essential elements like sulfur and iodine from the sea to the air and hence to the land. The forests of the humid tropics act on a global scale by pumping vast volumes of water back into the air (evapotranspiration); this has the potential to affect climate locally by causing the condensation of clouds. The white tops of the clouds reflect away the sunlight that otherwise would heat and dry the region. The evaporation of water from the liquid state absorbs a great deal of heat, and the climate of distant regions outside the tropics is considerably warmed when damp tropical air masses release their latent heat in the condensation of rain. The transfer of nutrients and the products of weathering by the tropical rivers are obviously part of their interconnection and must also have a global significance.

If evapotranspiration, or the additions of the tropical rivers to the oceans, is vital to the maintenance of the present planetary homeostasis, then this suggests that its replacement with an agricultural surrogate or a desert not only would deny those regions to their surviving inhabitants but would threaten the rest of the system as well. We do not yet know; we can only guess that tropical forest systems are vital for the world ecology. It may be that they are like the temperate forests that seem to be expendable without serious harm to the system as a whole; temperate forests have suffered extensive destruction during glaciations as well as during the recent expansion of agriculture. It would seem, therefore, that the traditional ecological approach of examining the forest ecosystem in isolation is as important to our understanding as is the consideration of its interdependence with the whole system. Geophysiology is at the information-gathering stage, rather as was biology when Victorian scientists went forth to distant jungles to collect specimens.

We do recognize the needs of the Earth, even if our response time is slow. We can be altruistic and selfish simultaneously in a kind of unconscious enlightened self-interest. We most certainly are not a cancer of the Earth, nor is the Earth some mechanical contraption needing the services of a mechanic.

If it turns out that Gaia theory provides a fair description of the Earth's operating system, then most assuredly we have been visiting the wrong specialists for the diagnosis and cure of our global ills. These are the questions that must be answered: How stable is the present system? What will perturb it? Can the effects of perturbation be reversed? Without the natural ecosystems in their present form, can the world maintain its present climate and composition? These are all within the province of geophysiology. We need a general practitioner of planetary medicine. Is there a doctor out there?
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:39 pm

8: The Second Home

Better to be kind at home than to burn incense in a far place.

-- Chinese Proverb


In the summer of 1969 I was in our second home on the shores of Bantry Bay, that part of Ireland where long thin rocky peninsulas point southwest, like fingers on a hand stretched out towards America. It was Monday, July 21, the day after the astronauts Neil Armstrong and Edwin Aldrin had walked on the Moon. The news of their historic journey came to us by radio. So remote and mountainous was this part of Ireland in those days that we were denied the pleasure of seeing the landing on a television screen. To our family, raised in the contemporary scientific culture, the ascent to the Moon was a consummation. For our Irish neighbors on the Beara Peninsula, it was a mind-quake that shook the foundations of their belief. Throughout the week that followed they often asked us, "Is it really true that men have landed on the Moon?" We were puzzled by the question, and replied, "Of course it is true. Did you not hear it on the radio?" Yes, they had heard it, but they wanted to hear from ourselves that there were men up there on the Moon.

It took a long time and some prompting from my friends and neighbors, Michael and Theresa O'Sullivan, before I realized that what was an undoubted fact for me was, for the different culture that surrounded me, news of a much more profound and deep significance. To many of those living on the remote Beara Peninsula, Heaven was still simply up there in the sky and Hell beneath their feet. Their faith was not perturbed by the news of the men walking on the Moon, but their religious belief seemed to be undergoing an internal reorganization. I can only compare the intensity of their experience with that of the change of mind that came to many in the last century from the news that Darwin brought back after the voyage of the Beagle.

In this century it is the tales of astronauts and the harvest of space exploration that has moved the locked plates of our minds. It should not therefore be necessary to explain why there is a chapter about Mars in a book on Gaia, but I will remind you that the Gaia hypothesis was a serendipitous discovery, arising directly from the invention of a method of planetary-life detection intended for use on Mars. Nearly twenty years later I found myself speculating on the possibility of changing the physical environment of Mars so that it becomes a self-sustaining living system and a brother to Gaia. Like the Gaia hypothesis, this notion also had an indirect and unexpected origin, and I shall digress in the next few paragraphs to explain it.

It came about because of a book called The Greening of Mars, written with my friend Michael Allaby, a fluent writer on environmental topics. He wanted a world on which to act out a new colonial expansion; a place with new environmental challenges and free of the tribal problems of the Earth. I just wanted a model planet on which to play new games with Gaia, or rather Ares, the proper name for Gaia's sibling.

The idea of developing Mars as a colony has received surprisingly little attention except from science fiction writers. Our book was written as fiction although, as wisely observed by Brian Aldiss in his review, it was more a pamphlet, a serious idea in a fictional setting. We chose this format because of a chastening experience following the publication of a previous book, one about the great extinction of 65 million years ago when the great lizards and much of the rest of the biota perished. It was written as a popular science book, stimulated by the imaginative science of the Alvarez family and their collaborators, who attributed the extinction event to the impact of a large planetesimal. They supplied what seemed to us to be convincing evidence of such a collision, the discovery that iridium and other rare extraterrestrial elements were significantly more abundant at the boundary of the Cretaceous and Tertiary rocks. This is the place in the geological record that marks a large change in the populations and species of the living things that made the rocks. Shortly after its publication, the book was savagely criticized by paleontologists who wrote in those journals that set the scientific trend. Maybe their criticisms were necessary and the punishment was just. We should have, as travelers to an unfamiliar scientific territory, taken steps to learn its language and history and to have had the right visas and letters of introduction to the princes there -- above all, to have been prepared for trouble in a land that was the home of greatest macho, Tyrannosaurus.

But we learnt our lesson, and wrote The Greening of Mars as fiction in the expectation that it would not be adversely criticized on points of intricate factual detail. Our book was intended as the scene for a series of imaginary, gedanklich, experiments on another planet. What if Mars, now a hopelessly barren desert, could be made fit for life? How could we then seed it and how would it develop? Neither of us expected it to be taken as more than entertainment. We should have known that everyone, or almost everyone, takes fiction much more seriously than fact. Just think for a moment: if you want to know the sociology of Victorian England, you could read Marx, who was the first social scientist, but more likely, even if you are a Marxist, you will read Dickens. Within months of publication in 1984, our second book stirred far more serious attention than its light-hearted writing seemed to merit. Three scientific meetings on the topic of making a second home on Mars were held, and at one of them, Robert Haynes, a distinguished geneticist from Toronto, coined the word ecopoiesis -- literally, "the making of a home" -- for the practice of transforming an otherwise uninhabitable environment into a place fit for life to evolve naturally. I prefer it to the word terraforming, often used when considering this act for planets. Ecopoiesis is more general. Terraforming has the homocentric flavor of a planetary-scale technological fix.

A key step in the development of a new geophysiological system is the acquisition of some novel and inheritable activity by a single organism. It follows that the first act in the ecopoiesis of Mars would have to be made by an entrepreneur. It would be an opportunistic act for private selfish gain; the larger communal act of colonization would come later. Columbus, I think, was not the chairman of a committee, but I suspect that those who traveled later aboard the Mayflower were the members of one.

To make Mars a fit home for life we shall first have to make the planet comfortable for bacterial life. In the book, we proposed that this impossible and outrageous act, the changing of the environment of a whole planet, could only be done by a slightly disreputable entrepreneur; the type of man about whom it is said, "He never breaks the law but whenever he does something, legislation is needed to stop him from doing it again." People like this are needed to probe the boundaries and to do those things that are forbidden, things that are apparently too costly or are beyond the possibility of achievement by the well-meant but sometimes undesirable caution of the planned enterprise of governmental agencies.

The scenario of The Greening of Mars included therefore a buccaneering character called Argo Brassbottom; later in life, success induced a snobbish gentility that caused him to change his surname to Foxe. He was a dealer in surplus weapons, and had the notion that there must be money to be made from the disposal of the vast accumulation of large, out-of-date ICBMs and other military rocket vehicles. The nuclear warheads could be, and would be, reprocessed as plutonium plowshares or future swords under strict governmental control. But what of the rocket carcasses full of solid propellant? These could not safely be disassembled and reused but they could, without modification, be the key components of a private space program. Brassbottom, through his many contacts in the civil and military services of the West and East, soon found that there would indeed be a reward for disposing of these unwanted rockets. Then he had another bright idea. His main line of business was as an industrial scavenger, a human dung beetle who profited from the disposal of toxic wastes and other noxious products that we prefer not to notice. Why not, he thought, use the rockets to propel the toxic wastes right outside the Earth? Deep space could be a safe dumping place.

Moving as he did among the black markets of the world, he was well acquainted with those unscrupulous scientists who will supply their skills, for a fee, to political fanatics or criminals. One of these commented that the recent anxiety over the state of the ozone layer had led to legislation banning chlorofluorocarbon aerosol propellants. Maybe there was a surplus of these products that required their expensive enclosure in vast pressurized tanks. These gases are among the most harmless and benign of chemicals that enter the home. They are not flammable, nor are they toxic or noxious. They were banned because their presence in the atmosphere could deplete stratospheric ozone. Why not, thought Brassbottom, propel them out into deep space and be paid for so doing? It was not long before another scientist suggested sending them to Mars. The chlorofluorocarbons are 10,000 times more potent than carbon dioxide as greenhouse gases to absorb the infrared radiation that escapes from the Earth. On Mars this property might lift off the frozen atmosphere. Brassbottom was enough of a businessman to get title to develop Mars, realizing that the stocks of his Mars development company would boom should the planet get a temperate climate and so become potentially habitable. As a final step, with the help of friends in the United Nations agencies he convinced the new government of the small archipelago of New Ulster in the Indian Ocean to participate in building a launch site for his rockets on the temporarily quiescent volcanic island of Crossmaglen. It was heralded as the space program of the underdeveloped world. Earnest scientists who persisted in taking our fictional scenario as if it were up for peer review have pointed out to me that this would not have worked because the CFCs are rapidly destroyed by solar ultraviolet, and that carbon tetrafluoride, which is not destroyed, should have been proposed instead. Maybe they are right.

When you are building imaginary worlds in the spaces of the mind, tiresome details such as the solidity of the planetary foundations and the presence or absence of rising damp or dry rot tend to be ignored. What counts is the position of the property and the grand view across the untouched landscape. Neither Mike Allaby nor I realized the extent to which our dream worlds would be seen as real estates. It is essential therefore, before any of us are carried away, to go back and re-examine our book as if it were a prospectus and not a work of fiction. If we are to avoid, even in the imagination, accusations of fraudulent deception, we need to include also a report on the state of Mars from an independent surveyor. By rights this should have been the task of the two Vikings, but sadly their directors were obsessed by another fictional dream, that of finding life on Mars. They should have made the necessary, albeit dull, measurements of the abundance of light elements in the surface rocks, the ratio of hydrogen and deuterium in the atmosphere, and the structure of the Martian crust; instead these were given less attention than the feverish but pointless search for life.

So what do we know of Mars? The best and most readable summary of the information gathered by the spacecraft that orbited or landed on the Martian surface is Michael Carr's splendid and beautifully illustrated book, The Surface of Mars. It includes many photographs taken from orbiting spacecraft. Mars is seen to resemble the Moon much more than the Earth. Impact craters pockmark the surface and reveal a preserved chronicle of events going back to the planet's beginnings. This is in stark contrast to the Earth, where the ceaseless motions of the crust and the weathering by wind and water forever keep her face fresh and clean. Mars differs from the Moon in having an atmosphere, thin though it may be. It also has volcanoes, similar in form to those of the Hawaiian Islands but much larger. There are canyons and channels and dried-out river systems, suggesting that once long ago Mars had flowing water (see figure 8.1); there are polar caps that change their extent with the seasons; and there are clouds and dust storms in the thin remnants of its atmosphere.

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8.1 Water channels on Martian surface. The photographs from space show evidence of channels along which water may once have flowed early in the history of Mars.

Mars may seem to be dry, but much water has outgassed from the interior during the planet's history. The total quantity is thought to be somewhere between 12 and 25 million cubic kilometers (2.6 to 5.2 million cubic miles), enough to provide an ocean between 80 and 160 meters deep over the whole planet were it a smooth round sphere, or about 200 meters deep for a distribution of land and sea as on the Earth.

Michael McElroy of Harvard University has drawn on data for the isotopic composition of the element oxygen in the Martian atmosphere to argue that there has been little loss of water to space despite the lesser gravitational pull of Mars. Surprisingly the same arguments, when applied to the element nitrogen, lead to the conclusion that Mars has lost a large proportion of its nitrogen to space. There is strong evidence of massive floods and enough water to have produced river valleys nearly 1,000 kilometers long, but this was in the remote past. Where has all this water gone? According to Michael Carr's summary of the available evidence, most of the water now present is likely to be permafrost extending as deep as 1 or 2 kilometers below the surface. Layers of brine, with a freezing point as low as -20°C, may underlay the ice. In addition, the polar regions may overlay domes of ice.

That, then, is the present consensus among scientists about Mars. There may seem to be plenty of water, but for various reasons it would be as inaccessible to a colonizing biota as the water below the desert of Australia. In addition, to melt and vaporize the water deep below the surface, heat must be transferred from above. Heat transfer through a surface layer of dust can be astonishingly slow; if limited to the process of simple diffusion it could take millions of years to melt the subsurface ice. This may be a pessimistic conclusion. Frazer Fanale and his colleagues at the Jet Propulsion Laboratory have proposed that the movement of carbon dioxide gas through the rock dust will exert a flushing action and so transfer water to the surface. Changes of atmospheric pressure due to the condensation and evaporation of carbon dioxide are the driving force for this motion. But, on a human time scale, the act of ecopoiesis to bring Mars to the point of seeding could still be unbearably slow.

Before we take the drastic step of selling up our home on Earth, we need a great deal more information about our future home than was given by the Viking survey report. We need to know what could be the worst in store for us, and indeed for Mars itself, as a place for ecopoiesis.

If you look again at the lunar-like surface of Mars you will see that the channels and flow systems, which so strongly suggest the presence of water, are ancient indeed; almost all date to the period before 3.5 eons ago when planetesimal impacts were more frequent. Mars may have had a thicker atmospheric greenhouse and a warmer climate; also, there may have been heating from the impacts. Four eons ago, the Sun was at least 25 percent less luminous than now. If Mars is frozen now, a thick blanket would have been needed then to sustain an atmosphere and flowing water. Since those distant times, the Sun has warmed and there have been more large planetesimal impacts, although less frequent than in the early days. In spite of this no signs of further water flows are seen. The present conventional wisdom that envisages an ocean of frozen water 100 meters thick may be wrong. Not enough account has been taken of the probability that Mars, like the Earth, was originally rich in chemical substances that react with water to form hydrogen that escapes to space. The water may once have been there, but the escape of hydrogen left oxygen behind, not as free oxygen, but chemically bound in nitrates, sulfates, and iron oxides.

Consider the state of Mars 3.5 eons ago. This would be just after the planetesimals had rained down so immoderately and turned to rock and dust the entire planetary surface to a depth of at least 2 kilometers, a process that the planetologists coyly call "gardening." At that time the Earth was reducing; the environment was rich in those chemical compounds of iron and sulfur that have a considerable capacity to react with oxygen. There is no reason to believe that Mars was different. In addition, those early rocks had a considerable capacity to react with carbon dioxide. A 2-kilometer layer of powdered rock derived from basic basalt has the capacity to react with about 600 meters of water and carbon dioxide (3 bars), enough to make the surface atmospheric pressure of Mars three times greater than that on Earth now. Could this account for the thin atmosphere and aridity of Mars now? The abundant water that flowed 3.5 eons ago could have reacted with the ferrous iron of the rock dust, releasing the hydrogen it carried so that it escaped to space. It might be thought that the gas-solid reactions of weathering would be too slow to have removed much oxygen and carbon dioxide. This would be true of the present conditions on Mars; but if free water were present, much of the ferrous iron and sulfides could have been dissolved by the water, or dispersed as a fine slurry, hastening both the reactions themselves and the process of rock digestion. The oxidized state of Mars now, which gives the planet its deep red color, may be only skin deep. But until another surveyor, like Viking, goes there and tests the rocks at depth we cannot be sure that there is an atmosphere and water waiting for us.

It is worth reminding ourselves how the Earth avoided the same fate and why we also are not now desiccated. The carbon dioxide originally in the atmosphere has nearly all gone to form limestones and carbonaceous sedimentary rocks. Vast quantities of sulfides and ferrous iron have been oxidized, and the oxygen retained by this process may well have originally been associated with hydrogen in water. The Earth was saved from drying out by the abundance of its water, and by the presence of Gaia, who acts to conserve water. Mars could soon have lost its meager first water, and that may be why those channels are so ancient and why there is so little evidence of bulk water of recent origin. Mars may be irredeemably arid, and what little water is left may be deep below the surface in aquifers as salt and bitter as the Dead Sea. For most living organisms, saturated brine is hardly better than no water.

I must confess a personal intuition that Mars is nearer to a state of aridity. I cannot so easily envisage Mars as some potentially lush but deep-frozen sleeping beauty of a planet that waits to have the breath of life blown in from Earth. But fairy stories are much more entertaining than a dry-as-dust view of Mars; so let us accept the current scientific consensus that predicts abundant water and carbon dioxide waiting to be thawed, and let us use this pleasing model as the inspiration for our ecopoietic colonists. There remains only the questions of how we move in and what we should do to prepare the garden for planting. If you were to visit Mars on a sunny summer afternoon in latitudes corresponding to those of Buenos Aires or Melbourne you might be surprised by the warmth of the climate. Daytime temperatures could be as high as 70°F. If only the air were breathable, it would be a shirt-sleeve environment. But on other days it might be below freezing. And always when the Sun went down the temperature would fall, with frightening rapidity, to reach -120°F by midnight; cold enough for solid carbon dioxide to form a frost of dry ice at the bottom of the valleys or depressions.

The ground beneath your feet would seem like desert on the Earth. But this would be an illusion, for few deserts anywhere on Earth are devoid of life. There is almost everywhere on Earthly deserts a thin cover of bacterial growth called the desert pavement. There is no soil on Mars, only a lifeless mix of rocks of all sizes from dust to boulders that has been given, almost onomatopoeically, that dry, harsh name, regolith (shown in figure 8.2). Mars is not yet ready for life; it is not only inhospitable to any form of life, it is also poisonous and destructive to organic matter. The air at the surface of Mars is in a chemical state like that of the stratosphere above the Earth. If the stratospheric air 10 miles above our heads could be compressed without changing its composition, we could not breathe it. Ozone is present there at 5 parts per million. Ozone may shield us from solar ultraviolet radiation, but at this abundance it is painful and soon lethal to breathe. The surface of Mars after a planetary lifetime exposed to such an atmosphere is rich in exotic chemicals, such as pernitric acid, that can rapidly destroy seeds, bacteria, or indeed almost all organic matter. Mars is no place for gardening.

The highly oxidized surface on Mars today means that life cannot spontaneously develop there. Unlike the Archean Earth, the organic precursors of living matter would not have the chance to accumulate and assemble. The only route for ecopoiesis is, first, for us to change the environment until it is suitable for life and, then, either to allow it to evolve spontaneously or to seed the planet. If we achieve the environmental maturation, I cannot believe that we would have the patience to leave Mars to develop life alone. Someone would seed it, if only by accident.

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8.2 Regolith seen from Viking Lander. Mars has no soil -- soil is the structured active surface of a living planet, regolith is rubble spread on the surface of a dead planet.

Planetary life needs an operating system like Gaia, otherwise it is vulnerable to any change in its environment that could happen as a result either of its own evolution or of an external disaster such as the all-too-frequent impact of planetesimals. I do not believe that sparse life, existing only in a few oases on a planet, is viable. Such a system is incomplete; unable to control its environment and powerless to resist adverse change. It follows that, even if we sprayed every bit of the planet's surface with every species of microorganism, we could not bring Ares to life. Some organisms might survive and even grow for a brief spell, but there would be no invasion, no infection with the rapid spread of life to take over and control the planet. I find it unusual that otherwise capable organizations like NASA should strive so hard to sterilize their spacecraft when they well know that Mars itself is a great sterilizer. They also know that were the same craft to land unsterilized on the much more hospitable terrain of the antarctic ice cap or the Australian desert, their small complement of microbial passengers would have no chance of establishing a permanent home there.

Parts of Mars may now have equable temperature on sunny afternoons, but this does not mean that little needs be done to bring it alive. When life began on Earth, the heat received from the Sun was 60 percent greater than that now warming Mars. There was abundant water on Earth and a dense enough atmosphere to provide a comfortable climate. The only thing in Mars' favor is that it is darker than the Earth and absorbs more of the sunlight falling on it. But this advantage is only for its present state; once water is set free it will evaporate to form clouds and snow cover. This will increase the albedo of Mars so that it reflects to space the heat that it might otherwise have gained. Mars by itself may never be able to provide the conditions needed to start and sustain life, not even in a billion years' time when the Sun is hotter and what is left of the Martian air and water has been set free.

What can we then do to start Mars on the evolutionary course that would eventually bring it to a condition like that on Earth now and so become our second home? First, the Martian environment must be changed sufficiently to allow spontaneous growth and spread of microorganisms over a large proportion of the planetary surface. At first glance the notion of planetary engineering, the ecopoiesis of a planet, seems a grandiose impertinence. But it is not so impertinent if Mars is a deep-frozen planet needing only to be thawed; moreover this is the consensus view among planetary scientists, who report that as much as 2 atmospheres pressure of carbon dioxide and enough water to cover the planet to a depth of 100 meters or so have outgassed from its interior over the past 4 eons. If we accept this conclusion, then we could think of Mars as poised on the edge of a cliff of environmental stability; a small push may be enough to change it to a state much more suited to life.

In his book on Mars, Michael Carr discusses the possibility that liquid water exists in aquifers beneath the surface of the planet, also the likelihood that such water might be salt. It is often forgotten that the stable state of the element nitrogen is as the nitrate ion, dissolved in water. On Earth, nitrate is formed continuously by high-energy processes (fires, lightning, and nuclear radiation) in the atmosphere. It quickly reaches the ground in rain, and the biota equally promptly return it to the atmosphere as nitrogen gas. There is no life on Mars, and I have often wondered if most of the nitrogen is there as nitrate dissolved in the brines. Or maybe there are vast salt deposits, evaporite beds, left after the ancient water flows dried out. Nitrate and nitrite locked up in these deposits could also account for the relative lack of nitrogen in the present Martian atmosphere.

It will take another Viking to find the answers to these questions, and for now we can only speculate about what changes would have to occur to convert the present infertile Mars into a seedbed for planetary life. That is why Mike Allaby and I chose to write our tale of Martian ecopoiesis as fiction, and to warm Mars by projecting surplus CFCs from Earth. I have my doubts about whether enough of these powerful greenhouse gases could be sent, but this idea was intended to titillate the imagination of those who might want to convert Mars by some other means, rather than as a serious engineering proposal. I have often found in my practice as an inventor that a slightly wrong or incomplete invention is more attractive to engineers than one that is a fait accompli. In any event it seems greedy to attempt more than one's proper part of a project, to take from others the chance to exercise their special skills and artistry.

Instead of sending CFCs to Mars expensively by spacefreight delivery as proposed in our book, someone may design an automatic plant to manufacture them on Mars from indigenous materials. If the Martian brines exist, and can be tapped, it should be no great task to synthesize fluorocarbons and other potential greenhouse gases, such as carbon tetrafluoride, using the salts of the brines and atmospheric carbon dioxide as the raw materials. It would require a moderate-sized nuclear power plant. Maybe environmentalists would be glad to see one shipped to Mars instead of sited here on Earth. If nitrate and nitrite are present in the brines, then these will provide a convenient local source of both oxygen and nitrogen. Not enough to change the atmosphere, but plenty for early explorers and technicians to breathe in their enclosed habitats.

We have proposed the warming of Mars by sending greenhouse gases there; would it work? The basic mechanism of the greenhouse effect looks simple enough, but to calculate the temperature rise corresponding to a stated increase in carbon dioxide is far from simple. On a planetary scale many other things must be taken into account, including the reflection of sunlight by clouds and ice cover; the transport of heat by air movement and by the evaporation and condensation of water; and atmospheric and ocean structure. Not surprisingly, these calculations require the help of the largest computers that are available, and even they are inadequate. So far as I am aware, no models have included the dynamic responsive feedback from the biota. The Martian greenhouse effect is likely to be a great deal easier to calculate -- or at least it will be in the first stages before enough water has evaporated to introduce cloudiness, snow cover, and water vapor. Cloud and ice both are white and sunlight-reflecting. Broadly speaking, ice has the opposite effect of carbon dioxide and causes cooling; clouds can either heat or cool according to their form and altitude. To complicate the problem further, water vapor absorbs infrared, and its presence amplifies the heating effect of carbon dioxide.

The idea of warming Mars by introducing CFCs into the atmosphere depends upon a set of favorable coincidences. First, there is a broken pane in the greenhouse. Neither carbon dioxide nor water vapor are effective absorbers of infrared at wavelengths between 8 and 14 micrometers, and a fair amount of heat radiates away to space from the planetary surface and atmosphere at these wavelengths. The CFCs absorb intensely in this region and serve as a new pane of glass, still transparent to sunlight but opaque in what previously was a gap in the infrared. Second, greenhouse gases have a way of amplifying one another's effects. It is not commonly known outside meteorology that the carbon dioxide greenhouse depends mainly on the infrared absorption by water vapor. Carbon dioxide does absorb infrared radiation, but not at the same wavelengths or as strongly as does water vapor. An increase of carbon dioxide will cause some warming and this in turn will increase the water vapor content of the air. The increased water vapor increases the warming and so amplifies the smaller effect of carbon dioxide. On Mars there will be a double amplification. The CFCs will warm the surface a little, this will lift off carbon dioxide and so increase the warming, which will in turn evaporate water and still further warm the planet. This is why it may be possible, using a practical quantity of these strange chemicals, to change the climate of a whole planet. We cannot say, until the modeling is done, how much CFCs would be needed. It might be as little as 10,000 tons or more than one million tons. If it as large as the latter, Brassbottom's enterprise would not succeed; it would, however, still be within the capacity of an automated chemical plant shipped to Mars with the purpose of synthesizing these or other greenhouse gases from indigenous materials.

The success or failure of ecopoiesis for Mars is likely to depend on how much carbon dioxide and how much water is there in an available form. With a dense carbon dioxide atmosphere, 2 bars or more, a tolerable climate is likely. With less carbon dioxide, a great deal will depend on the distribution of water and on the effect of snow and clouds on the planetary albedo. In other science fiction scenarios water has been transported to Mars as asteroids of ice, taken from their frigid orbits far from the Sun. Simple calculations show the impracticality of this notion without some incredible new motive power. An asteroid of pure ice, 200 miles in diameter, is needed to equal the quantity of water now thought to be on Mars. Few would be prepared to take on the contract for moving it there.

When the CFCs have done their job of lifting an atmosphere from the previously frozen surface, what world do we have? Let us assume, for a start, that we have a planet with an atmosphere of between 0.5 and 2 bars pressure and composed almost wholly of carbon dioxide. The climate is still cold by Earthly standards but the diurnal fluctuations are less extreme; at low altitudes in the tropical regions the night frosts are no longer as frequent or severe. Most important, enough water has evaporated for precipitation to occur in some regions. The surface is still regolith but no longer highly oxidizing; the lethal pernitric acid and other stratospheric oxidants have moved up in the atmosphere to those high-altitude regions where they exist on Earth.

I can only guess at the ecosystem that could survive in such an environment. It would be unlikely to include the land plants and animals, at least not initially. The first life on Earth was the prokaryotic microorganisms, and their descendants still flourish in the soil. Our first objective would be to introduce a microbial ecosystem that could convert the regolith into topsoil, and at the same time to introduce surface-dwelling photosynthetic bacteria. These could provide the food, energy, and raw materials for the bulk of the ecosystem dwelling below the surface. If we could arrange that the photosynthesizers be colored dark, they would absorb the Sun's warmth and so be warmer than their surroundings. On a local scale this is like the advantage possessed by dark daisies on Daisyworld; it could encourage the ecosystem that they were a part of to spread across the Martian surface. If this happened the climate might tend towards homeostasis, at first by regions and finally globally.

There are other ways available to the biota for regulating climate in addition to the control of albedo. Probably most important is the regulation of the composition of the atmospheric gases. The first act of ecopoiesis was to build an artificial greenhouse made of CFC gases at a few parts per billion in the air. In the early life of Ares, the control of the CFC emissions would still be available from the human colonists. This may be especially important if the atmospheric carbon dioxide is significantly reduced or if snow and cloud cover increase the planetary albedo. There are two ways that carbon dioxide might be removed in significant amounts. The first is if the life is so successful in its spread that it splits large quantities of the gas into carbonaceous organic matter and free oxygen. The second is by the reaction of carbon dioxide with calcium silicate rocks to form carbonates and silicic acid. The first reactions would release free oxygen, which might accumulate in the air; it might be that the rocks of the regolith and the water of the Martian brines contain a fair quantity of materials that scavenge oxygen, such as the element iron in its ferrous form. In any case, the first oxygen to appear in the atmosphere will be too dilute to permit the easy reoxidation of the surplus organic matter produced by photosynthesis. The surplus carbon of the dead photosynthesizers would be reoxidized by other organisms of the bacterial ecosystem using as oxidants the sulfate and nitrate of the regolith. This would return carbon dioxide, nitrogen, and nitrous oxide to the air. Before long, however, the soil of Mars would be tending towards a state where there would be insufficient oxidants as nonrenewable resources to sustain the reoxidation of carbonaceous matter and the return of carbon dioxide to the air. When this point was reached on the early Earth in the Archean, it opened for exploitation a giant niche of surplus organic matter. It was then, I think, that the methanogens evolved to take an opportunistic advantage of this gift from the photosynthesizers. In doing so they converted the organic matter to a mixture of methane and carbon dioxide. Methane is also a greenhouse gas, so the potentially disastrous cooling that might otherwise have occurred was avoided.

Already in this brief discussion we have postulated the need for photosynthesizers, nitrate and sulfate reducers, and methanogens. All are normal inhabitants in a sample of soil from almost anywhere on Earth. Aerobic and anaerobic ecosystems peacefully coexist with their respective territories segregated on a vertical basis so that the oxygen-tolerant are at the surface and the anaerobes at the lowest point of the soil. The soil is a complex and intricate assembly, and diverse in its population of species. Successfully establishing the bacterial ecosystem of soil in the Martian regolith is not a matter of finding, or making by genetic engineering, species that will grow there; it is a matter of changing Mars to a state where the microbial ecosystems of the Earth can flourish and convert the regolith to soil. But that is still only the start, for if Mars is to become a self-sustaining system it is necessary for the organisms and their environment to become as tightly a coupled system as they are on Earth. The acquisition of planetary control can come only from the growing together of life and its environment until they are a single and indivisible system.

One family in a dwelling does not make a village, still less does it constitute a city with a self-sustaining infrastructure. In the same way there is a critical mass of biota needed for planetary homeostasis, the size of which depends mainly upon how much effort is needed to sustain homeostasis and how large are the perturbations likely to take place. Simple models, derived from Daisyworld, suggest that a stable system requires at least 20 percent cover of the planetary surface if the commoner perturbations are to be withstood. These would be changes in the intensity of sunlight, planetesimal impacts, internal disturbances from the evolution of species that adversely affected the environment, or the exhaustion of some essential resource. If Ares is to grow strong he will need to cover more than just a few oases of the Martian desert.

In romantic novels, the excitement is placed before the wedding. That is great for entertainment, but it is no guide for successful married life. So it is with ecopoiesis; the physical and chemical conversion of Mars would be an incredible feat of engineering, a great and enduring saga. In contrast, the nursing of the infant planetary life, though fulfilling, would seem an anticlimax. Great patience and love would need be given to the unremitting task of nurture and the daily guidance of the newborn planetary life until it could, by itself, sustain homeostasis.

Thoughts of Gaia will always be linked with space exploration and Mars, for in a sense Mars was her birthplace. Rusty Schweickart and his fellow astronauts have shared with us their revelation on looking back at the Earth from the distance of the Moon; their realization that it was their home. In a lesser, but still significant way, our vicarious view of the planets of the Solar System seen through the splendid eyes of the Voyager and other spacecraft has touched our minds and set in motion the locked plates of the Earth sciences.

Lord Young, prominent for his work towards the founding of the open university in the United Kingdom, has been so moved by the idea of bringing life to Mars that he has formed the Argo Venturers to think and act towards this end. He believes that the prospect of colonizing Mars, even before or without its final achievement, is a powerful source of inspiration. I share his view, and think that the contemplation of the daunting difficulties of bringing Ares to life may help us better to understand the awful consequences of so damaging Gaia that we have to take on the never-ceasing responsibility of keeping the Earth a fit place for life, a service now provided for free.
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:40 pm

9: God and Gaia

Gaia, mother of all, I sing, oldest of gods,
Firm of foundation, who feeds all creatures living on Earth,
As many as move on the radiant land and swim in the sea
And fly through the air -- all these does she feed with her bounty.
Mistress, from you come our fine children and bountiful harvests,
Yours is the power to give mortals life and to take it away.

-- J. Donald Hughes, Gaia: An Ancient View of Our Planet


Photographs, like biographies, often reveal more of the artist than of the subject. Maybe this is why passport photographs, taken in mechanically operated booths, look so lifeless. How could a mere machine capture the soul of its subject, stiffly sitting and gazing into the blind eye of the camera? Trying to write about God and Gaia, I share some of the limitations of a mechanical camera, and I know that this chapter will show more about myself than about my subjects. So why try?

When I wrote the first book on Gaia I had no inkling that it would be taken as a religious book. Although I thought the subject was mainly science, there was no doubt that many of its readers found otherwise. Two-thirds of the letters received, and still coming in, are about the meaning of Gaia in the context of religious faith. This interest has not been limited to the laity; a most interesting letter came from Hugh Montefiore, then Bishop of Birmingham. He asked which I thought came first, life or Gaia. My attempts to answer this question led to a correspondence, reported in a chapter of his book The Probability of God. I suspect that some cosmologists are similarly visited by enquiries from those who imagine them to be at least on nodding terms with God. I was naive to think that a book about Gaia would be taken as science only.

So where do I stand about religion? While still a student I was asked seriously, by a member of the Society of Friends, if I had ever had a religious experience. Not understanding what he meant, imagining that he referred to a manifestation or a miracle, I answered no. Looking back from 45 years on, I now tend to think that I should have said yes. Living itself is a religious experience. At the time, however, the question was almost meaningless because it implied a separation of life into sacred and secular parts. I now think that there can be no such division. In any relationship there are high points of delight, as well as pitfalls in the great plain of contentment. For me one high point came when I was asked by Jim Morton, the Dean of the Cathedral Church of St. John the Divine in New York, to serve as a participant in a religious celebration. I still recall with wonder being part of that colorful procession, with him and other clerics, dressed in medieval costume. The music of the choir singing "Morning Is Broken" seemed to take on a new significance in the ambience of that sacred place. It was a sensual experience, but to me that does not make it less religious.

THE WICCA CULT: The WICCA cult came to the surface early during the post-war period, as a legalized association for the promotion of witchcraft. It is the leading publicly known international association of witches in the world today. In the United States, WICCA's outstanding sponsor is the New York Anglican (Episcopal) diocese, under Bishop Paul Moore. Officially, New York's Anglican Cathedral of St. John the Divine has promoted the spread of WICCA witchery through its Lindisfarne center. The late Gregory Bateson conducted such an operation out of the Lindisfarne center during the 1970s. No later than the 1970s, and perhaps still today, the crypt of the Cathedral of St. John the Divine, is the headquarters for solemn ceremonies of the British (Venerable) Order of Malta. Key figures, such as Gregory Bateson's former spouse, Dame Margaret Mead, associated with that British order, have been associated with projects in support of the Satanist "Age of Aquarius" cause.

-- Real History of Satanism, by Lyndon LaRouche


My thoughts about religion when a child grew from those of my father and the country folk I knew. It was an odd mixture, composed of witches, May trees, and the views expressed by Quakers, in and outside the Sunday school at a Friends' meeting house. Christmas was more of a solstice feast than a Christian one. We were, as a family, well into the present century, yet still amazingly superstitious. So ingrained was my childhood conditioning about the power of the occult that in later life it took a positive act of will to stop touching wood or crossing fingers whenever some hazard was to be faced. Christianity was there not so much as a faith, rather as a set of sensible directions on how to be good.

When I first saw Gaia in my mind I felt as an astronaut must have done as he stood on the Moon, gazing back at our home, the Earth. The feeling strengthens as theory and evidence come in to confirm the thought that the Earth may be a living organism. Thinking of the Earth as alive makes it seem, on happy days, in the right places, as if the whole planet were celebrating a sacred ceremony. Being on the Earth brings that same special feeling of comfort that attaches to the celebration of any religion when it is seemly and when one is fit to receive. It need not suspend the critical faculty, nor can it prevent one from singing the wrong hymn or the right one out of tune.

That is only what I feel about Gaia. What about God? I am too committed to the scientific way of thinking to feel comfortable when enunciating the Creed or the Lord's Prayer in a Christian Church. The insistence of the definition "I believe in God the Father Almighty, Maker of Heaven and Earth" seems to anesthetize the sense of wonder, as if one were committed to a single line of thought by a cosmic legal contract. It seems wrong also to take it merely as a metaphor. But I respect the intuition of those who do believe, and I am moved by the ceremony, the music, and most of all by the glory of the words of the prayer book that to me are the nearest to perfect expression of our language.

I have kept my doubts in a separate place for too long. Now that I write this chapter, I have to try somehow to explain, to myself as well as to you, what is my religious belief. I am happy with the thought that the Universe has properties that make the emergence of life and Gaia inevitable. But I react to the assertion that it was created with this purpose. It might have been; but how the Universe and life began are ineffable questions. When a scientist colleague uses evidence about the Earth eons ago to explain his theory of the origins of life it stirs a similar sense of doubt. How can the events so long ago that led to the emergence of anything so intricate as life be treated as a fact of science? It is human to be curious about antecedents, but expeditions into the remote past in search of origins is as supremely unimportant as was the hunting of the snark. The greater part of the information about our origins is with us here and now; so let us rejoice in it and be glad to be alive.

At a meeting in London recently, a wise man, Dr. Donald Braben, asked me: "Why do you stop with the Earth? Why not consider if the Solar System, the Galaxy, or even the Universe is alive?" My instant answer was that the concept of a living Earth, Gaia, is manageable. We know that there is no other life in this Solar System, and the nearest star is utterly remote. There must be other Gaias circling other docile long-lived stars but, curious though I may be about them and about the Universe, these are intangible-concepts for the intellect, not the senses. Until, if ever, we are visited from other parts of the Universe we are obliged to remain detached.

Many, I suspect, have trodden this same path through the mind. Those millions of Christians who make a special place in their hearts for the Virgin Mary possibly respond as I do. The concept of Jahweh as remote, all-powerful, all-seeing is either frightening or unapproachable. Even the sense of presence of a more contemporary God, a still, small voice within, may not be enough for those who need to communicate with someone outside. Mary is close and can be talked to. She is believable and manageable. It could be that the importance of the Virgin Mary in faith is something of this kind, but there may be more to it. What if Mary is another name for Gaia? Then her capacity for virgin birth is no miracle or parthenogenetic aberration, it is a role of Gaia since life began. Immortals do not need to reproduce an image of themselves; it is enough to renew continuously the life that constitutes them. Any living organism a quarter as old as the Universe itself and still full of vigor is as near immortal as we ever need to know. She is of this Universe and, conceivably, a part of God. On Earth she is the source of life everlasting and is alive now; she gave birth to humankind and we are a part of her.

"If you put God outside," Gregory Bateson warns, "and set him vis-a-vis his creation and if you have the idea that you are created in his image, you will logically and naturally see yourself as outside and against the things around you. And as you arrogate all mind to yourself, you will see the world around you as mindless and therefore not entitled to moral or ethical consideration. The environment will seem to be yours to exploit. Your survival unit will be you and your folks or conspecifics against the environment of other social units, other races, and the brutes and vegetables."

-- Green Paradise Lost, by Elizabeth Dodson Gray


Nature is the evolved being of the all, and Nature depends upon the properties and limitations of Matter and Motion, and therefore, when we read the phenomena of Matter and Force we are learning from the highest of possible sources of truth — there can be no higher and better source....

How much more is it evident that we must acquire an accurate knowledge of Nature, when we realize that All that Is constitutes one Infinite Conscious Organism, of which we and the other portions of existence, are but parts!

-- A Call to the "Awakened" From "The Unseen and Unknown," for an Esoteric College, and For G.....R Dept. No. 1, by Vidya-Nyaika.


This is why, for me, Gaia is a religious as well as a scientific concept, and in both spheres it is manageable. Theology is also a science, but if it is to operate by the same rules as the rest of science, there is no place for creeds or dogma. By this I mean theology should not state that God exists and then proceed to investigate his nature and his interactions with the Universe and living organisms. Such an approach is prescriptive, presupposes his existence, and closes the mind to such questions as: What would the Universe be like without God? How can we use the concept of God as a way to look at the Universe and ourselves? How can we use the concept of Gaia as a way to understanding God? Belief in God is an act of faith and will remain so. In the same way, it is otiose to try to prove that Gaia is alive. Instead, Gaia should be a way to view the Earth, ourselves, and our relationships with living things.

The life of a scientist who is a natural philosopher can be deeply religious. Curiosity is an intimate part of the process of loving. Being curious and getting to know the natural world leads to a loving relationship with it. It can be so deep that it cannot be articulated, but it is nonetheless good science. Creative scientists, when asked how they came upon some great discovery, frequently state, "I knew it intuitively, but it took several years work to prove it to my colleagues." Compare that statement with this one by William James, the nineteenth-century philosopher and psychologist, in The Varieties of Religious Experience:

The truth is that in the metaphysical and religious sphere, articulate reasons are cogent for us only when our inarticulate feelings of reality have already been impressed in favor of the same conclusion. Then, indeed, our intuitions and our reason work together, and great world ruling systems, like that of the Buddhist or of the Catholic philosophy, may grow up. Our impulsive belief is here always what sets up the original body of truth, and our articulately verbalised philosophy is but a showy translation into formulas. The unreasoned and immediate assurance is the deep thing in us, the reasoned argument is but a surface exhibition. Instinct leads, intelligence does but follow.


This was the way of the natural philosophers in James Hutton's time in the eighteenth century and is still the way of many scientists today. Science can embrace the notion of the Earth as a superorganism and can still wonder about the meaning of the Universe.

How did we reach our present secular humanist world? In times that are ancient by human measure, as far back as the earliest artifacts can be found, it seems that the Earth was worshipped as a goddess and believed to be alive. The myth of the great Mother is part of most early religions. The Mother is a compassionate, feminine figure; spring of all life, of fecundity, of gentleness. She is also the stern and unforgiving bringer of death. As Aldous Huxley reminds in The Human Experience:

In Hinduism, Kali is at once the infinitely kind and loving mother and the terrifying Goddess of destruction, who has a necklace of skulls and drinks the blood of human beings from a skull. This picture is profoundly realistic; if you give life, you must necessarily give death, because life always ends in death and must be renewed through death.


At some time not more than a few thousand years ago the concept of a remote master God, an overseer of Gaia, took root. At first it may have been the Sun, but later it took on the form we have with us now of an utterly remote yet personally immanent ruler of the Universe. Charlene Spretnak, in her moving and readable book, The Spiritual Dimensions of Green Politics, attributes the first denial of Gaia, the Earth goddess, to the conquest of an earlier Earth-centered civilization by the Sun-worshipping warriors of the invading Indo-European tribes.

Picture yourself as a witness of that decisive moment in history, that is, as a resident of the peaceful, artful, Goddess-oriented culture in Old Europe. (Don't think "matriarchy"! It may have been, but no one knows, and that is not the point.) It is 4,500 B.C. You are walking along a high ridge, looking out across the plains to the east. In the distance you see a massive wave of horsemen galloping towards your world on strange, powerful animals. (The European ancestor of the horse had become extinct.) They brought few women, a chieftain system, and only a primitive stamping technique to impress their two symbols, the sun and a pine tree. They moved in waves first into southeastern Europe, later down into Greece, across all of Europe, also into the Middle and Near East, North Africa and India. They brought a sky god, a warrior cult, and patriarchal social order. And that is where we live today -- in an Indo-European culture, albeit one that is very technologically advanced.


The evolution of these horsemen to the modern men who ride their infinitely more powerful machines of destruction over the habitats of our partners in Gaia seems only a small step. The rest of us, in the cozy, comfortable hell of urban life, care little what they do so long as they continue to supply us with food, energy, and raw materials and we can continue to play the game of human interaction.

In ancient times, belief in a living Earth and in a living cosmos was the same thing. Heaven and Earth were close and part of the same body. As time passed and awareness grew of the vast distances of space and time through such inventions as the telescope, the Universe was comprehended and the place of God receded until now it hides behind the Big Bang, claimed to have started it all. At the same time, as population increased so did the proportion forced to lead urban lives out of touch with Nature. In the past two centuries we have nearly all become city dwellers, and seem to have lost interest in the meaning of both God and Gaia. As the theologian Keith Ward wrote in the Times in December 1984:

It is not that people know what God is, and have decided to reject him. It seems that very few people even know what the orthodox traditional idea of God, shared by Judaism, Islam and Christianity, is. They have not the slightest idea what is meant by the word God.

It just has no sense or possible place in their lives. Instead they either invent some vague idea of a cosmic force with no practical implications at all; or they appeal to some half-forgotten picture of a bearded super-person constantly interfering with the mechanistic laws of Nature.


I wonder if this is the result of sensory deprivation. How can we revere the living world if we can no longer hear the bird song through the noise of traffic, or smell the sweetness of fresh air? How can we wonder about God and the Universe if we never see the stars because of the city lights? If you think this to be exaggeration, think back to when you last lay in a meadow in the sunshine and smelt the fragrant thyme and heard and saw the larks soaring and singing. Think back to the last night you looked up into the deep blue black of a sky clear enough to see the Milky Way, the congregation of stars, our Galaxy.

The attraction of the city is seductive. Socrates said that nothing of interest happened outside its walls and, much later, Dr. Johnson expressed his view of country living as "One green field is like another." Most of us are trapped in this world of the city, an everlasting soap opera, and all too often as spectators, not players. It is something to have sensitive commentators like Sir David Attenborough bring the natural world with its visions of forests and wilderness to the television screens of our suburban rooms. But the television screen is only a window and only rarely clear enough to see the world outside; it can never bring us back into the real world of Gaia. City life reinforces and strengthens the heresy of humanism, that narcissistic devotion to human interests alone. The Irish missionary Sean McDonagh wrote in his book, To Care for the Earth: "The 20 billion years of God's creative love is either seen simply as the stage on which the drama of human salvation is worked out, or as something radically sinful in itself and needing transformation."

The heartlands of the great religions are now in the last bastions of rural existence, in the Third World of the tropics. Elsewhere God and Gaia that once were joined and respected are now divorced and of no account. We have, as a species, almost resigned from membership in Gaia and given to our cities and our nations the rights and responsibilities of environmental regulation. We struggle to enjoy the human interactions of city life yet still yearn to possess the natural world as well. We want to be free to drive into the country or the wilderness without polluting it in so doing; to have our cake and eat it. Human and understandable such striving may be, but it is illogical. Our humanist concerns about the poor of the inner cities or the Third World, and our near-obscene obsession with death, suffering, and pain as if these were evil in themselves -- these thoughts divert the mind from our gross and excessive domination of the natural world. Poverty and suffering are not sent; they are the consequences of what we do. Pain and death are normal and natural; we could not long survive without them. Science, it is true, assisted at the birth of technology. But when we drive our cars and listen to the radio bringing news of acid rain, we need to remind ourselves that we, personally, are the polluters. We, not some white-coated devil figure, buy the cars, drive them, and foul the air. We are therefore accountable, personally, for the destruction of the trees by photochemical smog and acid rain. We are responsible for the silent spring that Rachel Carson predicted.

There are many ways to keep in touch with Gaia. Individual humans are densely populated cellular and endosymbiont collectives, but clearly also identities. Individuals interact with Gaia in the cycling of the elements and in the control of the climate, just like a cell does in the body. You also interact individually in a spiritual manner through a sense of wonder about the natural world and from feeling a part of it. In some ways this interaction is not unlike the tight coupling between the state of the mind and the body. Another connection is through the powerful infrastructures of human communication and mass transfer. We as a species now move a greater mass of some materials around the Earth than did all the biota of Gaia before we appeared. Our chattering is so loud that it can be heard to the depths of the Universe. Always, as with other and earlier species within Gaia, the entire development arises from the activity of a few individuals. The urban nests, the agricultural ecosystems, good and bad, are all the consequences of rapid positive feedback starting from the action of an inspired individual.

A frequent misunderstanding of my vision of Gaia is that I champion complacence, that I claim feedback will always protect the environment from any serious harm that humans might do. It is sometimes more crudely put as "Lovelock's Gaia gives industry the green light to pollute at will." The truth is almost diametrically opposite. Gaia, as I see her, is no doting mother tolerant of misdemeanors, nor is she some fragile and delicate damsel in danger from brutal mankind. She is stern and tough, always keeping the world warm and comfortable for those who obey the rules, but ruthless in her destruction of those who transgress. Her unconscious goal is a planet fit for life. If humans stand in the way of this, we shall be eliminated with as little pity as would be shown by the micro-brain of an intercontinental ballistic nuclear missile in full flight to its target.

What I have written so far has been a testament built around the idea of Gaia. I have tried to show that God and Gaia, theology and science, even physics and biology are not separate but a single way of thought. Although a scientist, I write as an individual, and my views are likely to be less common than I like to think. So now let me tell you something of what the scientific community has to say on this subject.

In science, the more discovered, the more new paths open for exploration. It is usual in science, when things are vague and unclear, for the path to be like that of a drunkard wandering in a zigzag. As we stagger back from what lastly dawns upon our befuddled wits is the wrong way, we cross over the true path and move nearly as far to the equally wrong, opposite side. If all goes well, our deviations lessen and the path converges towards, but never completely follows, the true one. It gives a new insight to the old tag in vino veritas. So natural is this way to find the truth that we usually program our computers to solve problems too tedious to do ourselves by setting them to follow the same trial-and-error, staggering, stumbling walk. The process is dignified and mystified by calling it "iteration," but the method is the same. The only difference is that, so quickly is it done, the eye never sees the fumbling.

We have lost the instinctive understanding of what life is and of our place within Gaia. Our attempts to define life are much in the stage of the drunkard's walk. The two opposing verges representing the extremes of iteration are illustrated by a splendid philosophical debate that has gone on for the past twenty years between the molecular biologists on the one side and the new school of thermodynamics on the other. Jacques Monod's Chance and Necessity, although first published in 1970, most clearly and beautifully conveys the clear, strong, and rigorous approach of solid science based firmly in a belief in a materialistic and deterministic Universe. The other verge is represented by those, like Erich Jantsch, who believe in a self-organizing Universe. It is concerned with the thermodynamics of the unsteady state of which dissipative structures such as flames, whirlpools, and life itself are examples. Although the participants are all well known and respected in the English-speaking world, most of this entertaining debate has gone on in French, so many of us have missed the fun.

The essence of this contest is a rerun of the ancient battle between the holists and the reductionists. As Monod reminds us:

Certain schools of thought (all more or less consciously or confusedly influenced by Hegel) challenge the value of the analytical approach to systems as complex as living beings. According to these holist schools which, phoenix like, are reborn in every generation, the analytic attitude (reductionist) is doomed to fail in its attempts to reduce the properties of a very complex organization to the "sum" of the properties of its parts. It is a very stupid and misguided quarrel which merely testifies to the holists' total lack of understanding of scientific method and the crucial role analysis plays in it. How far could a Martian engineer get if trying to understand an earthly computer, he refused on principle to dissect the machine's basic electronic components which execute the operation of propositional algebra.


These strong words were in the 1970 edition of Chance and Necessity. Maybe they are by now less extremely held, but they serve well to express what was and still is an important scientific constituency.

No one now doubts that it was plain, honest reductionist science that allowed us to unlock so many of the secrets of the Universe, not least those of the living macromolecules that carry the genetic information of our cells. But clear, strong, and powerful though it may be, it is not enough by itself to explain the facts of life. Consider Jacques Monod's Martian engineer. Would it have been sensible to have dashed in with a kit of tools and disassembled analytically the computer he found? Or would it have been better, as a first step, to have switched it on and questioned it as a whole system? If you have any doubts about the answer to this question then consider the thought that the hypothetical Martian engineer was an intelligent computer and the object he examined, you.

By contrast, in 1972 Ilya Prigogine wrote:

It is not instability but a succession of instabilities which allow the crossing of the no man's land between life and no-life. We start to disentangle only certain stages. This concept of biological order leads automatically to a more blurred appreciation of the role of chance and necessity to recall the title of the well-known work by Jacques Monod. Fluctuation which allows the system to depart from states near thermodynamic equilibrium represents the stochastic aspect, the part played by chance. Contrariwise, the environmental instability, the fact that the fluctuations will increase, represents necessity. Chance and necessity cooperate instead of opposing one another.


I wholly agree with Monod that the cornerstone of the scientific method is the postulate that Nature is objective. True knowledge can never be gained by attributing "purpose" to phenomena. But, equally strongly, I deny the notion that systems are never more than the sum of their parts. The value of Gaia in this debate is that it is the largest of living systems. It can be analyzed both as a whole system and, in the reductionist manner, as a collection of parts. This analysis need disturb neither the privacy nor the function of Gaia any more than would the movement of a single commensal bacterium on the surface of your nose.

Prigogine was not the first to recognize the inadequacies of equilibrium thermodynamics. He had many illustrious predecessors, among them the physical chemists J. W. Gibbs, L. Onsager, and K. G. Denbigh, who explored the thermodynamics of the steady state. But it was that truly great physicist, Ludwig Boltzmann, who pointed the way towards the understanding of life in thermodynamic terms. And it was by reading Schrodinger's book What Is Life? in the early 1960s that I first realized that planetary life was revealed by the contrast between the near-equilibrium state of the atmosphere of a dead planet and the exuberant disequilibrium of the Earth.

When we cross from the sharp clarity of the real world into that nightmare land of dissipating structures, what do we learn that makes the next staggering lurch less erroneous than the last? I have gained from Prigogine's world view a confirmation of a suspicion that time is a variable much too often ignored. In particular, many of the apparent contradictions between these two schools of thought seem to resolve if viewed along the time dimension instead of in space. We have evolved from the world of simple molecules through dissipative structures to the more permanent entities that are living organisms. The further we go from the present, either into the past or the future, the greater the uncertainty. Darwin was right to dismiss thoughts about the origins of life; as Jerome Rothstein has said, the restrictions of the second law of thermodynamics prevent us from ever knowing about the beginning or the end of the Universe.

In our guts and in those of other animals, the ancient world of the Archean lives on. In Gaia, also, the ancient chaotic world of dissipating structures that preceded life still lives on. A recent and relatively unknown discovery of science is that the fluctuations at every scale from viscosity to weather can be chaotic. There is no complete determinism in the Universe; many things are as unpredictable as a perfect roulette wheel. An ecologist colleague of mine, C. S. Holling, has observed that the stability of large-scale ecosystems depends upon the existence of internal chaotic instabilities. These pockets of chaos in the larger, stable Gaian system serve to probe the boundaries set by the physical constraints to life. By this means the opportunism of life is insured, and no new niche remains undiscovered. For example, I live in a rural region surrounded by farmers who keep sheep. It is impressive how adventurous young lambs, through their continuous probing of my boundary hedges, can find their way through onto the richer, ungrazed land on my side. The behavior of young men is not so different.

My reason for wandering onto the battlefield of the war between holists and reductionists was to illustrate how polarized is science itself. Let me conclude this digressionary visit and return to the theme of this chapter, God and Gaia. And let me start by reminding you of Daisyworld -- a model which is reductionist and holistic at the same time. It was made to answer a criticism of Gaia, that it was teleology. The need for reduction arose because the relationships between all the living things on Earth in their countless trillions and the rocks, the air, and the oceans could never be described in full detail by a set of mathematical equations. A drastic simplification was needed. But the model with its closed loop cybernetic structure was also holistic. This also applies to ourselves. It would be pointless to attempt to disentangle all the relationships between the atoms within the cells that go to make up our bodies. But this does not prevent us from being real and identifiable, and having a life span of at least 70 years.

We are also in an adversary contest between our allegiance to Gaia and to humanism. In this battle, politically minded humanists have made the word "reductionist" pejorative, to discredit science and to bring contumely to the scientific method. But all scientists are reductionists to some extent; there is no way to do science without reduction at some stage. Even the analyzers of holistic systems, confronted with an unknown system, do tests, such as perturbing the system and observing the response, or making a model of it and then reducing that model. In biology it is impossible to avoid reduction, even if we wished. The material and relationships of living things are so phenomenally complex that a holistic view is seen only when it suits the biota to exist as an identifiable entity such as a cell, a plant, a nest, or Gaia. Certainly, the entities themselves can be observed and classified with a minimum of invasion, but sooner or later curiosity will drive an urge to discover what the entities are made of and how they work. In any case, the idea that mere observation is neutral is itself an illusion. Someone once said that the reason the Universe is running down is that God is always observing it and hence reducing it. Be this as it may, there is little doubt that a nature reserve, a wildlife park, or an ecosystem is reduced in proportion to the amount of time that we and our children perturb the wildlife by watching them.

In The Self Organizing Universe, Erich Jantsch made a strong argument for the omnipresence of a self-organizing tendency; so that life, instead of being a chance event, was an inevitable consequence. Jantsch based his thoughts on the theories of those pioneers of what might be called the "thermodynamics of the unsteady state" -- Max Eigen, Ilya Prigogine, Humberto Maturana, Francisco Varela, and their successors. As scientific evidence accumulates and theories are developed in this recondite topic, it may become possible to encompass the metaphor of a living Universe. The intuition of God could be rationalized; something of God could become as familiar as Gaia.

For the present, my belief in God rests at the stage of a positive agnosticism. I am too deeply committed to science for undiluted faith; equally unacceptable to me spiritually is the materialist world of undiluted fact. Art and science seem interconnected with each other and with religion, and to be mutually enlarging. That Gaia can be both spiritual and scientific is, for me, deeply satisfying. From letters and conversations I have learnt that a feeling for the organism, the Earth, has survived and that many feel a need to include those old faiths in their system of belief, both for themselves and because they feel that Earth of which they are a part is under threat. In no way do I see Gaia as a sentient being, a surrogate God. To me Gaia is alive and part of the ineffable Universe and I am a part of her.

The philosopher Gregory Bateson expressed this agnosticism in his own special way:

The individual mind is immanent but not only in the body. It is immanent also in pathways and messages outside the body; and there is a larger mind of which the individual mind is only a sub-system. This larger mind is comparable to God and is perhaps what some people mean by God, but it is still immanent in the total interconnected social systems and planetary ecology.


Dr. Gregory Bateson, anthropologist with the OSS, and the former husband of anthropologist Margaret Mead, became the director of a hallucinogenic drug experimental clinic at the Palo Alto Veterans Administration Hospital. Through drug experimentation on patients, already hospitalized for psychological problems, Bateson established a core of “initiates” into the nest of Isis Cults, which Huxley had founded in southern California and in San Francisco. Foremost among his Palo Alto recruits was Ken Kesey. By 1967, through Kesey’s efforts in disseminating the drug, they created the “Summer of Love”, in the Haight-Ashbury district of San Francisco.

-- Terrorism and the Illuminati -- A Three Thousand Year History, by David Livingston


For the unprepared mind, however, LSD can be a nightmare. When the drug is administered in a sterile laboratory under fluorescent lights by white-coated physicians who attach electrodes and nonchalantly warn the subject that he will go crazy for a while, the odds favor a psychotomimetic reaction, or "bummer." This became apparent to poet Allen Ginsberg when he took LSD for the first time at the Mental Research Institute in Palo Alto, California, in 1959. Ginsberg was already familiar with psychedelic substances, having experimented with peyote on a number of occasions. As yet, however, there was no underground supply of LSD, and it was virtually impossible for layfolk to procure samples of the drug. Thus he was pleased when Gregory Bateson, [Formerly a member of the Research and Analysis Branch of the OSS, Bateson was the husband and co-worker of anthropologist Margaret Mead. An exceptional intellect, he was turned on to acid by Dr. Harold Abramson, one of the CIA's chief LSD specialists] the anthropologist, put him in touch with a team of doctors in Palo Alto. Ginsberg had no way of knowing that one of the researchers associated with the institute, Dr. Charles Savage, had conducted hallucinogenic drug experiments for the US Navy in the early 1950s.

-- Acid Dreams, The Complete Social History of LSD: The CIA, The Sixties, And Beyond, by Martin A. Lee & Bruce Shlain


After Oklahoma City, the potential of the right-wing anti-government evangelical fanatics for terrorism and violence was re-affirmed by an armed standoff between police and "Republic of Texas" activists demanding the secession of Texas in April 1997. This insurrection was led by Richard Otto, alias "White Eagle," who put out a call inviting members of militias around the country to come to the site, armed for a shootout. The agent provocateur Otto turned out to have been "trained and set into motion by an Air Force officer who toured the world practicing New Age pagan rituals, in consultation with senior British intelligence drug-rock-sex gurus such as Gregory Bateson." Otto finally surrendered on May 3, 1997. (Tony Chaitkin, "The Militias and Pentecostalism")

-- 9/11 Synthetic Terrorism Made in USA, by Webster Griffin Tarpley


Harold Abramson apparently got a great kick out of getting his learned friends high on LSD. He first turned on Frank Fremont- Smith, head of the Macy Foundation which passed CIA money to Abramson. In this cozy little world where everyone knew everybody, Fremont-Smith organized the conferences that spread the word about LSD to the academic hinterlands. Abramson also gave Gregory Bateson, Margaret Mead's former husband, his first LSD. In 1959 Bateson, in turn, helped arrange for a beat poet friend of his named Allen Ginsberg to take the drug at a research program located off the Stanford campus. No stranger to the hallucinogenic effects of peyote, Ginsberg reacted badly to what he describes as "the closed little doctor's room full of instruments," where he took the drug. Although he was allowed to listen to records of his choice (he chose a Gertrude Stein reading, a Tibetan mandala, and Wagner), Ginsberg felt he "was being connected to Big Brother's brain." He says that the experience resulted in "a slight paranoia that hung on all my acid experiences through the mid-1960s until I learned from meditation how to disperse that."

Anthropologist and philosopher Gregory Bateson then worked at the Veterans Administration Hospital in Palo Alto. From 1959 on, Dr. Leo Hollister was testing LSD at that same hospital. Hollister says he entered the hallucinogenic field reluctantly because of the "unscientific" work of the early LSD researchers. He refers specifically to most of the people who attended Macy conferences. Thus, hoping to improve on CIA- and military-funded work, Hollister tried drugs out on student volunteers, including a certain Ken Kesey, in 1960. Kesey said he was a jock who had only been drunk once before, but on three successive Tuesdays, he tried different psychedelics. "Six weeks later I'd bought my first ounce of grass," Kesey later wrote, adding, "Six months later I had a job at that hospital as a psychiatric aide." Out of that experience, using drugs while he wrote, Kesey turned out One Flew Over the Cuckoo's Nest. He went on to become the counterculture's second most famous LSD visionary, spreading the creed throughout the land, as Tom Wolfe would chronicle in The Electric Kool-Aid Acid Test.

-- The Search for the "Manchurian Candidate": The CIA and Mind Control, by John Marks


It was at UCSC that Bandler met John Grinder, a radical young professor of linguistics. In the laid-back university community, Grinder cultivated an iconoclastic mystique, boasting that he had been a Green Beret. He collected a small, devoted group of followers, the most prominent of whom was Richard Bandler. Together they began using linguistics to study psychology. Even before it had a name, their work was controversial: some students referred to Grinder's class, in which Bandler taught, as Mindfucking 101. In March 1973, Bandler earned his bachelor's degree, and two years later a master's in theoretical psychology from Lone Mountain College in San Francisco.

First Bandler, then Grinder, had moved to a commune in the Santa Cruz Mountains owned by Robert Spitzer, who envisioned it as a self-sustained artistic and intellectual community. Among those who lived at the former nudist colony were Raven Lang, whose Birth Book had helped spawn a home birth movement; and Gregory Bateson, the British anthropologist who conceived the double-bind theory of schizophrenia.

A lean, wiry man with a goatee and piercing brown eyes, Bandler did not get along with many residents of the Alba Road community. He was intense and temperamental, one remembers, and did not participate in communal life. Within a few weeks of his arrival, members of the commune asked Spitzer to evict him. Spitzer refused.

While living on Alba Road, Bandler bragged about using large amounts of cocaine.

For Grinder and Bandler it was a fertile time. They sat for hours in the sun room of Bateson's house, listening to Bateson discuss his innovative ideas, which became the intellectual foundation of NLP. (As described by one student, Bateson taught that "[Human beings] create the world that we perceive ... because we select and edit the reality we see to conform to our beliefs about what sort of world we live in.") Working with films and tape recordings, Bandler and Grinder dissected the work of Satir and Perls, hoping to understand the techniques -- linguistic and nonverbal -- that caused seemingly magical changes in their clients. Through Bateson, they met and studied with Milton Erickson, the famed psychiatrist-hypnotist, and began using hypnosis to treat clients.

Bandler was only 25 when his first book, The Structure of Magic, was published in 1975. Written with Grinder, it attempted to codify and describe their analysis of Satir's and Perls's therapies. In separate introductions, Satir and Bateson expressed excitement about this research, for it seemed to hold potential for developing better therapists: if effective therapy, like all "magic," had discernible structure, then anyone could learn to perform it.

-- The Bandler Method, by Frank Clancy and Heidi Yorkshire


As a scientist I believe that Nature is objective but also recognize that Nature is not predetermined. The famous uncertainty principle that the physicist Werner Heisenberg discovered was the first crack in the crystalline structure of determinism. Now chaos is revealed to have an orderly mathematical prescription. This new theoretical understanding enlightens the practice of weather forecasting. Previously it was believed, as the French physicist Laplace had stated, that given enough knowledge (and, in this age, computer power) anything could be predicted. It was a thrill to discover that there was real, honest chaos decently spread around the Universe and to begin to understand why it is impossible in this world ever to predict if it will be raining at some specific place or time. True chaos is there as the counterpart of order. Determinism is reduced to a collection of fragments, like jewels that have fallen on the surface of a bowl of pitch.

Science has its fashions, and one thing guaranteed to stir interest and start a new fashion is the exploration of a pathology. Health is far less interesting than disease. I well recall as a schoolboy visiting the Museum of the London School of Hygiene and Tropical Medicine where there were on display life-sized models of subjects stricken by tropical illnesses. Although less well crafted, they were so strange and horrible as to make tame the professional horrors of Madame Tussaud's waxworks. The sight of full-sized models of the victims of elephantiasis or leprosy and the imagination of their suffering made bearable the adolescent agonies of a schoolboy. Contemporary science is similarly fascinated by pathologies of a mathematical kind. Theoretical ecology, as we have already discussed, is more concerned with sick than with healthy ecosystems. The vagaries of weather are more interesting than the long-term stability of climate. Continuous creation never had a chance in face of the ultimate pathology of the Big Bang.

Interest in the pathologies of science has a curious link with religion. Mathematicians and physicists are, without seeming aware of it, into demonology. They are found investigating "catastrophe theory" or "strange attractors." They then seek from their colleagues in other sciences examples of pathologies that match their curious models. Perhaps I should explain that in mathematics, an attractor is a stable equilibrium state, such as a point at the bottom of a smooth bowl where a ball will always come to rest. Attractors can be lines, planes, or solids as well as points, and are the places where systems tend to settle down to rest. Strange attractors are chaotic regions of fractional dimensions that act like black holes, drawing the solutions of equations to their unknown and singular domains. Phenomena of the natural world -- such as weather, disease, and ecosystem failures -- are characterized by the presence of these strange attractors in the clockwork of their mathematics, lurking like time bombs as harbingers of instability, cyclical fluctuations, and just plain chaos.

The remarkable thing about real and healthy living organisms is their apparent ability to control or limit these destabilizing influences. It seems that the world of dissipating structures, threatened by catastrophe and parasitized by strange attractors, is the foreworld of life and of Gaia and the underworld that still exists. The tightly coupled evolution of the physical environment and the autopoietic entities of pre-life led to a new order of stability; the state associated with Gaia and with all forms of healthy life. Life and Gaia are to all intents immortal, even though composed of entities that at least include dissipative structures. I find a curious resemblance between the strange attractors and other denizens of the imaginary world of mathematical constructs and the demons of older religious belief. A parallel that goes deep and includes an association with sickness not health, famine not plenty, storm not calm. A saint of this fascinating branch of mathematics is the Frenchman, Benoit Mandelbrot. From his expressions in fractional dimensions it is possible to produce graphic illustrations of all manner of natural scenes: coastlines, mountain ranges, trees, and clouds, all startlingly realistic. But when Mandelbrot's scientific art is applied to strange attractors we see, in graphic form, the vividly colored image of a demon or a dragon.

Gaia theory may seem to be dull in comparison with these exotica. A thing, like health, to be taken for granted except when it fails. This may be why so few scientists and theologians are interested in it; they prefer the exploration of the Universe, or of the origins of life, to the exploration of the natural world that surrounds them. I find it difficult to explain to my colleagues why I prefer to live and work alone in the depths of the country. They think that I must be missing all the excitement of exploration. I prefer a life with Gaia here and now, and to look back only to that part of her history which is knowable, not to what might have been before she came into being. A friend has asked why, if this is so, I chose to spend so much of this book on the history of the Earth. I find it easiest to explain my reasons for this apparent inconsistency in a fable.

Imagine an island set in a warm blue sea with sandy beaches. The lush forest in the foreground gives way to small rocky mountain peaks as sharp and clear as a line drawing on the distant horizon. There is no sign of habitation, human or other. What at first sight looks like a village of white stone houses turns out, on closer inspection, to be a chalk outcrop, laser bright in the sunlight. Something looks odd, though; you blink, for the light is very bright, and look again. It is not an illusion, the trees are not green, they are a dark shade of blue.

The island in view is somewhere on Earth 500 million years from now. The exact details are unpredictable and unimportant to this travel tale, but we can say it is hotter than any seaside place on Earth today, with a sea temperature near 30°C; it often reaches 60°C in the desert inland. There is little or no carbon dioxide in the air, but otherwise it is much the same as now, with just the right amount of oxygen for breathing but not so much as to make fires uncontrollable. There has been a major punctuation, and the dominant life forms on the land surface are of a structure no botanist or zoologist of our time would recognize.

In a small meadow near the shore, a group of philosophers is gathered for one of those civilized meetings hosted by a scientific society. A symposium that leaves ample time for swimming and walking and just talking idly. A participant has a theory that their form of life, so unlike that of many of the organisms in the sea and of the microorganisms, did not just evolve but was made artificially by a sentient life form living in the remote geological past. She bases her argument on the nature of the nervous system of the philosophers and of land animals generally. It operates by direct electrical conduction along organic polymer strands, whereas that of the ocean life operates by ionic conduction within elongated cells (which we, of course, would recognize as nerves). The brains of the philosophers operate by semi-conduction, in contrast to the chemically polarized systems of the sea organisms. In this new form of life, males do not exist as mobile sentient organisms, merely as a vegetative form that supplies the necessary separate pathway for genetic information so that recombination can reduce the expression of error. Marriage is still a lifelong relationship, but with males rooted in the soil like plants, it is more one of that between a loving gardener and the flowers. Our philosopher argues that such a system could never have originated by chance but must have been manufactured at some time in the past. Not surprisingly, her theory is not well received. Not only is it outside the paradigm of the science of those times, but the theologians and mythopoets find the notion repugnant to their view of a single, spontaneous origin of a living planet. To bring back the Creationist heresy is unacceptable.

These occupants of a future Atlantis have no need for speech or writing. The possession of an electronic nervous system makes speech redundant; they are able to use radio frequencies to communicate directly a wide range of images and ideas. In spite of these advantages and their superior wisdom, they are, like the whales of today, neither mechanically adept nor interested in mechanisms. This being so, the very idea of making anything as intricate as a brain or nervous system as an artifact is beyond their understanding, and therefore, in their minds, beyond the capabilities of a past life form.

The point of the fable is to argue that it is not necessary to know the intricate details of the origin of life itself to understand the evolution of Gaia and of ourselves. In a similar way, the contemplation of those other remote places before and after life, Heaven and Hell, may be irrelevant to the discovery of a seemly way of life. We may well have been assisted by the nature of the Universe to cheat chaos and evolve spontaneously, on some Hadean shore, into our ancestral form of life. It seems unlikely that we come from a life form planted here by visitors from elsewhere; or even arrived clinging to some piece of cometary debris from outer space. I like to think that Darwin dismissed enquiries about the origins of life not merely because the information available in his time was so sparse that the search for life's origin would have had to remain speculative, but, more cogently, because he recognized that it was not necessary to know the details of the origin of life to formulate the evolution of the species by natural selection. This is what I mean by the concept of Gaia being manageable.

The belief that the Earth is alive and to be revered is still held in such remote places as the west of Ireland and the rural parts of some Latin countries. In these places, the shrines to the Virgin Mary seem to mean more, and to attract more loving care and attention, than does the church itself. The shrines are almost always in the open, exposed to the rain and to the sun, and surrounded by carefully tended flowers and shrubs. I cannot help but think that these country folk are worshipping something more than the Christian maiden. There is little time left to prevent the destruction of the forests of the humid tropics with consequences far-reaching both for Gaia and for humans. The country folk, who are destroying their own forests, are often Christians and venerate the Holy Virgin Mary. If their hearts and minds could be moved to see in her the embodiment of Gaia, then they might become aware that the victim of their destruction was indeed the Mother of humankind and the source of everlasting life.

When that great and good man Pope John Paul travels around the world, he, in an act of great humility and respect for the Mother or Father Land, bends down and kisses the airport tarmac. I sometimes imagine him walking those few steps beyond the dead concrete to kiss the living grass; part of our true Mother and of ourselves.
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:48 pm

Epilog

I will not cease from Mental Fight,
Nor shall my sword sleep in my hand
Till we have built Jerusalem
In England's green and pleasant Land.

-- William Blake, Milton


In letters and conversation, people often ask, "How should we live in harmony with Gaia?" I am tempted to reply, "Why ask me? All that I have done is to see the Earth differently; that does not qualify me to prescribe a way of life for you." Indeed, after nearly twenty years of writing and thinking about Gaia, it still seems that there is no prescription for living with Gaia, only consequences. Knowing that the question about how to live with Gaia is serious and that such a reply would be discourteous, as well as unhelpful, I will try to show what living with Gaia means to me. Then, perhaps, the questioner will discover something that we share in common.

My life, as a scientist-hermit, would suit very few. Most people are gregarious and enjoy the lively chattering of human company in pubs, churches, and parties. Living alone with Nature, even as a family unit, is not for them. So let me take you on a tour around the place where we live in north Devon, and as you walk with me I will try to explain why we prefer to live as we do. Then maybe you will see your own way to live with Gaia.

Soon after Helen and I came to live at Coombe Mill we adopted a peacock and a peahen. It was a delusion of grandeur coming from recollections of stately homes where peafowl strutted sedately and displayed their amazing colored tails. Coombe Mill is, in fact, a small cottage with thick mud-and-straw walls and a slate roof, an English adobe. But we did have 14 acres of land to start with, now grown to 30 acres. With the nearest neighbor about a mile away, it is room enough to keep the noisiest birds there are. Noisy they may be, but to us their triumphant trumpet sound at mating time is fitting and seems to usher in the spring. For the rest of the year, their extensive vocabulary ranges from a gentle clucking or purring sound to cries like a donkey braying. Then there is the sharp bark of their alarm call when, all too often, wild dogs stray onto our land. Helen, the dedicated gardener and keeper of our environment, calls them mobile shrubs, and we both have enjoyed their colorful company over the years. There is only one disadvantage -- their habit, either through friendliness or the expectation of snacks, of gathering on the pavement outside the door. There they leave their smelly dung. I used to curse them when I trod in it unawares or had to clean it up. But then it came to me that I was wrong and they were right. Those ecologically minded birds were doing their best to turn the dead concrete of the path back to living soil again. What better way to digest away the concrete than by the daily application of nutrients and bacteria in the shedding of their shit?

Why should we need 30 acres to live on? We are not farmers. I think the purchase of a house with so large a garden was a reaction to the changes that took place in our last village, Bowerchalke, some 130 miles to the east. In the twenty years that we lived there, we saw a living village dispossessed of its country people, and its hinterland of seemly countryside destroyed. It was a quiet rape and pillage, no savage hordes swept upon us from the downs. The destruction was by a thousand small changes over the years, until the match between our model of what the countryside should be and the reality no longer coincided. To a casual visitor the village would have looked as beautiful as ever, but with each year that passed the farms underwent metamorphosis into agribusiness factories. Fields that in the summer were Wiltshire's glory, scarlet with poppies among the grain, became a uniform green sea of weed-free barley. Meadows that once had been gardens of wildflowers were plowed and sown with a single highly productive strain of grass. When we moved, we were determined to find a place where the environment was not likely to change so drastically again. The best way to achieve this seemed to be to find a house with enough land around it to allow us to control what happened to it.

I first saw Bowerchalke in 1936 on a journey by bicycle across southern England during a summer holiday from school. Of all the places between Kent and Cornwall that I traveled, none left so lasting a memory of perfection, and I resolved there and then that one day it would be my home. I had planned my journey with the single-mindedness of a general going to war. Like him, I scrutinized ordnance maps, one inch to the mile. So detailed were these maps that they marked almost every house and tree, and finely drawn contour lines conveyed the lay of the land. I spent most winter evenings imagining the places I would visit. In those days there were few cars, and fewer still traveled on the minor roads I intended to use. With the aid of the ordnance maps, I traced a path through the network of winding lanes that joined in vertices at the villages and hamlets. Each county had its own style of architecture and its own accent. My journey was about 500 miles long and lasted for two weeks. The scale of life in England then made such a journey seem as much an expedition as does a trip to Australia now. It was not that we were diminished; it was the slower and more human pace of travel which enlarged the world.

As a novice scientist I was interested in things like wild plants, especially the poisonous ones like henbane, aconite, and deadly nightshade. I experimented once by chewing a fraction of a leaf of one of them and learnt the hard way the discomfort of atropine poisoning. Fossils too had a fascination, and the coastline of Dorset and Devon, where they lie as pebbles on the beaches, was part of my itinerary. I was led to Bowerchalke by the strange names of the Wiltshire and Dorset villages. I had to see what Plush, Folly, and Piddletrenthide looked like. I had to discover what Sydling St. Nicholas was, and hear the sonorous sounding Whitchurch Canonicorum. To reach these villages, my map showed that I had to follow the Ebble Valley that led through Bowerchalke in a gentle rising slope to the high downs of Dorset. The only tight-packed contour lines, marking a steep hill, were at the head of the valley just beyond Bowerchalke, an ideal road for a traveling by bicycle.

I can still remember passing up the road from Broadchalke, with the watercress beds on my left, and rounding a corner to see before me the small thatched village of Bowerchalke, the stage of an amphitheatre of green and shrubby down land hills. I arrived there at about four on a sunny Sunday afternoon in July. I was thirsty but, unusually, there were no signs outside the cottages offering teas. In those days walkers and cyclists were common enough to make it worth the while of villagers to sell refreshments. So remote was this region, and so few the travelers, that such efforts would have brought a poor return. I asked a man walking if there was anyone who would supply my needs, and he said, "Why, yes, Mrs. Gulliver in the white cottage over there sometimes will make you a tea"; and she did. It was the memory of the quiet tranquility of Bowerchalke then, when the countryside and the people merged in a natural seemliness, free from any taint of the city, that lingered in my mind and brought me back some twenty years later to make it our family home.

The recent act of destruction of the English countryside is a vandalism almost without parallel in modern history. Blake saw the threat of those dark satanic mills a century ago, but he never knew that one day they would spread until the whole of England was a factory floor. Humans and Nature had evolved together to form a system that sustained a rich diversity of species; something that stirred poets and even Darwin, who wrote about the mystery of the "tangled bank." It was so familiar, so taken for granted, that we never noticed its going until it was gone. Had anyone proposed building a new road through the close of Salisbury Cathedral the reaction would have been immediate. But farmers were paid by the Ministry of Agriculture to emulate the prairies, those man-made deserts in which nothing grows but grain, and nothing lives but farmers and their livestock. The yearly tromp of vast and heavy machines and the generous spraying of herbicides and pesticides ensured that all but a few resistant plant and insect species were eliminated. The older-style farmers could not stomach it, and left the land to young agricultural college graduates working as managers for city institutions. One old farmer said to me, "I didn't do farming to be a mechanic in a factory." But it was wonderfully efficient, and soon England was producing far more food than could be eaten.

The destruction still goes on. Even here in Devon, the hedgerows and small copses still fall to the chain saws and diggers. Rachel Carson was right in her gloomy prediction of a silent spring, but it has come about not simply by pesticide poisoning, as she imagined, but by the attack on all fronts of the farmers enemies, "weeds, pests, and vermin." Birds need a place to nest, and where better than the hedges, those marvelous linear forests that once divided our fields. Government, on the advice of negligent civil servants, paid handsome subsidies to farmers to root out the hedgerows, until the wildlife was destroyed, just as effectively as if the land had been sprayed with pesticide. The environmentalists, who should have seen what was happening and protested before it was too late, were much too busy fighting urban battles, or demonstrating outside the nuclear power stations. Their battle, whatever was claimed otherwise, was more against authority, represented by the monolithic electricity supply board, than for saving the countryside. They sometimes noticed poisonous sprays, for they were the products of the hated multinational chemical industries. But few were the friends of the soil who protested the agribusiness farms, or noticed the mechanized army of diggers and cutters working to make the landscape sterile for next year's planting of grain. There is no excuse for their neglect. Marion Shoard, in her moving and well-publicized book, The Theft of the Countryside, said all that I have said and much more.

To those who see the world in terms of a conflict between human societies and groupings for power, my personal view of the changing landscape must seem obsessional and irrelevant. They also are the vast majority everywhere, whether in the cozy comfort of air-conditioned suburban homes of the First World, or in the squalor of a Bidonville.

Who was most to blame for the destruction? Without doubt it was the scientists and agronomists who worked to make farming efficient. The experience of near starvation in the Second World War was a powerful stimulant to make Britain self-sustaining in food. Their intentions were good, it was just that they could not foresee the consequences. I know, because I was a small part of it. In my role of inventor, I helped friends and colleagues at the Grassland Research Institute near Stratford-upon-Avon in the 1940s. They were intent on improving the output of food from the small-scale English farms. I recall their sermons to young farmers on the inefficiency of hedgerows that hindered the free movement of machinery around a field; on the waste of meadows left as permanent pasture compared with a good crop of Italian rye grass grown as a monoculture. We never dreamt that the message would be so well heard that the government would be persuaded to pass the legislation that led to the removal of hedges and to the nurturing of agribusiness. Nor did we have the imagination to see that most young farmers share, with young males everywhere, a delight in mechanical toys. We, and through us the government, were giving them the money to buy, and the license to use, some of the most dangerously destructive weapons ever used. Weapons to fight the farmer's enemies, which were all life other than crops, livestock, hired help, and the farmer's family.

Should anyone think that I have got it wrong, that this was another example of heartless exploitation done by a government of capitalist nominees for the profit of a few multinationals, I would remind them that it started in the late 1940s during the period of the post-war Labor government, an administration secure in power, confident, and committed to its socialism. The destruction of the countryside was independent of politics; it was carried through by good intentions aided by the tendency of civil servants to apply positive feedback by subsidies, or a negative one through taxes. Farmers work on very small margins. They may own land worth up to a million pounds, but their returns may be very small compared with the returns from simple investment. A minuscule subsidy can turn a slight loss into a comfortable profit. The countryside has vanished from most of England, and what little remains here in the West Country is passing away because the government continues to pay farmers a subsidy which is just enough to make it worth their while to act as destroyers rather than as gardeners. The small subsidy to remove hedgerows has led to the loss of over 100,000 miles of them in the past few decades. An equally small subsidy would put them back again, although it would be generations before they served once more as the linear ecosystems and artistic landscape features of the countryside.

So what should we do instead? My vision of a future England would be like Blake's: to build Jerusalem on this green and pleasant land. It would involve the return to small, densely populated cities, never so big that the countryside was further than a walk or a bus ride away. At least one-third of the land should revert to natural woodland and heath, what farmers now call derelict land. Some land would be open to people for recreation; but one-sixth, at least, should be "derelict," private to wildlife only. Farming would be a mixture of intensive production where it was fit so to be, and small unsubsidized farms for those with the vocation of living in harmony with the land. In recent years, the overproduction of food by immoderate farming in the European Economic Community, including England, has been so vast that events have made my vision the basis of a practical plan for countryside management.

In their humorless despair, I have sometimes heard Greens parody Sir John Betjeman's verse, written near the beginning of the Second World War:

Come, friendly bombs, and fall on Slough,
To get it ready for the plough.
The cabbages are coming now;
The Earth exhales.


with

Come friendly nukes and strike them down
And blast their ever spreading town ...


Even for the desperate, such an evil catharsis is not needed. Left to herself, Gaia will relax again into another long ice age. We forget that the temperate Northern Hemisphere, the home of the rich First World, now enjoys a brief summer between long, long periods of winter that last for a hundred thousand years. Even the nukes would not so devastate the land; nor would a "nuclear winter," if it could happen at all, last long enough to return the land to its normal frozen state. The natural state here in Devon has been, for most of the past million years, a permanent arctic winter. Even though close to the ocean, it was still as bitterly cold and barren as is Bear Island in the Arctic Ocean now. A mere 50 miles to the north or east of Coombe Mill were the great permanent glaciers of the "ice ages." These bulldozer blades of ice scraped off every vestige of surface life that had flowered in the brief interglacials like now.

So why should I fret over the destruction of a countryside that is, at most, only a few thousand years old and soon to vanish again? I do so because the English countryside was a great work of art; as much a sacrament as the cathedrals, music, and poetry. It has not all gone yet, and I ask, is there no one prepared to let it survive long enough to illustrate a gentle relationship between humans and the land, a living example of how one small group of humans, for a brief spell, did it right?

The little that is left of old England is still under threat. The donnish guardians of the landscape seem unaware of its existence. They see the countryside through romantic notions of scenic beauty. In my part of Devon they look only at the tundra of Dartmoor, and see it as something of inestimable value to be preserved at all costs. Tundra -- the waterlogged bog, too wet and too cold for trees to grow -- is a common place where the polar and temperate zones merge, a memory of what this region was in the last glaciation. In great contrast, the same guardians regard the land to the north of Dartmoor, with its small low-efficiency farms, rich wildlife, and village communities that have changed little since the Domesday Book, as of no account and expendable, a fit place for new schemes, such as a reservoir, a new road, or an industrial site.

I often think that those city planners who act so destructively have been misled by that great novelist Thomas Hardy. His writing deeply influenced my city-born and city-bred mother, a woman who easily saw the countryside through Hardy's distorting spectacles. My father, though, was born in Hardy's Wessex, and he showed me how very different was the reality. Hardy, for all the brilliance of his characterization, did not understand the countryside and used it merely as a background to act out his own tragic view of the human condition.

The England I knew as a child and a young man was breathtakingly beautiful, hedgerows and small copses were abundant, and small streams and rivers teemed with fish and fed the otters. It inspired generations of poets to make coherent the feelings we could not ourselves express. Yet that landscape of England was no natural ecosystem; it was a nation-sized garden, wonderfully and carefully tended. The degraded agricultural monocultures of today -- with their filthy batteries for cattle and poultry, their ugly sheet-metal buildings, and roaring, stinking machinery -- have made the countryside seem to be a part of Blake's dark satanic mills. I know it seems that way because I knew it as it was. Visitors come to Coombe Mill from the cities and abroad, and eulogize over the few glories that remain. They, and the planners of the countryside, do not understand that, unless we stop the ecocide soon, Rachel Carson's gloomy prediction of a silent spring will come true, not because we have poisoned the birds with pesticides, but because we have destroyed their habitats, and they no longer have anywhere to live.

Being a typical Englishman, I did not expect "them," the establishment, to change their ways. There was nothing for it but for my family to try to do our best with the land we owned at Coombe Mill; make it a habitat and a refuge for some of the plants and animals that agribusiness is destroying. This is how we, personally, choose to live with Gaia.

There are only three of us here, but 30 acres is not much more difficult to manage than a suburban garden. A garden lawn forever needs mowing, feeding, watering, and weeding; a ceaseless labor or a cost if someone else is to do it. Ten acres of our land is grass. It is no nightmare lawn requiring the ceaseless attention of an army of gardeners; it grows as meadows rich with wildflowers and small animals. The meadows divide and form a setting for the 20 acres of planted trees. It needs only to be enjoyed and cut once a year when the grass has grown long. Local farmers are glad to come and cut it; they use the grass for fodder and pay for it. The cost of keeping 10 acres of meadow is comparable with that of a well-kept suburban garden. The trees need more attention, but not so much as to be in any way a burden for the three of us.

The River Carey divides our land into two equal parts, which posed a problem. The river runs by the house, which was once a water mill, and is about 60 feet wide. It cannot easily be crossed by wading, and we soon discovered that to reach our new land involved a five-mile walk. Bridges across the Carey are widely spaced apart. Two years ago, we decided to build a bridge so that we could more easily tend the 10,000 trees that were newly planted on the west bank of the Carey. As metaphors go, building a bridge has almost become a cliche. But just try building a bridge in real life; it is amazing to experience, personally, the power of reducing a metaphor to practice.

As you will have gathered, we are solitary people and don't much mix with our neighbors. Yet in this part of west Devon we were welcomed as soon as we came and have experienced more spontaneous kindness than in any other place that we have lived. Helen and I and our son John are in various ways physically handicapped so that we add up to make one able-bodied person, not enough to run a place as large as this. It would not have flourished had it not been for the unstinting care and generous help of our friends from the village, Keith and Margaret Sargent. Our home and the buildings that go to make up the rest of this place are of mud and straw, with slate roofs. They would never have survived the winter storms but for the skillful repairs of our other village friends, and former occupants of Coombe Mill, Ernie and Bill Orchard. But it was not until we started to plan our bridge that we experienced the full vigor of the community in which we are immersed.

When these friends knew what was in our minds, the bridge began to form -- first in the imagination as an exciting project, and then more solidly as the plans were drawn and the materials gathered. They had the skills needed to do with elan and enjoyment a challenging task, one that arose from no more than a passing personal thought. The project showed, in a Gaian way, how a thought became an act that brought personal and then local benefit.

Our bridge is made of steel; it was built by a blacksmith, Gilbert Rendall, and is in every way a mechanical construction. I am never quite comfortable with things mechanical. I well recall a conversation with my friends Stewart Brand, editor of CoEvolution Quarterly, and Gary Snyder, the poet. They were shocked and indignant when I said, "Chain saws are an invention more evil than the hydrogen bomb." To me a chain saw was something that cut down in minutes a tree that had taken a hundred years to grow. It was the means of destroying the tropical forests. To Gary Snyder it was a benign gardening tool with which he could carefully, like a surgeon, remove the scars of years of bad husbandry in his forests. It is not what you do but the way it is done; the more powerful the tool, the harder it is to use it right.

How, you may ask, do these rambling thoughts tell us about how to live with Gaia? I would reply that as a metaphor, Gaia emphasizes most the significance of the individual organism. It is always from the action of individuals that powerful local, regional, and global systems evolve. When the activity of an organism favors the environment as well as the organism itself, then its spread will be assisted; eventually the organism and the environmental change associated with it will become global in extent. The reverse is also true, and any species that adversely affects the environment is doomed; but life goes on. Does this apply to humans now? Are we doomed by our destruction of the natural world? Gaia is not purposefully antihuman, but so long as we continue to change the global environment against her preferences, we encourage our replacement with a more environmentally seemly species.

It all depends on you and me. If we see the world as a living organism of which we are a part -- not the owner, nor the tenant; not even a passenger -- we could have a long time ahead of us and our species might survive for its "allotted span." It is up to us to act personally in a way that is constructive. The present frenzy of agriculture and forestry is a global ecocide as foolish as it would be to act on the notion that our brains are supreme and the cells of other organs expendable. Would we drill wells through our skins to take the blood for its nutrients? If living with Gaia is a personal responsibility, how should we do it? Each of us will have a personal solution to the problem. There must be many simpler ways of living with Gaia than the one we have chosen at Coombe Mill. I find it useful to think of things that are harmless in moderation but malign in excess. For me these are the three deadly Cs: cars, cattle, and chain saws. For example, you could eat less beef. If you do this, and if the clinicians are right, your health might improve and at the same time you would ease the pressures to turn the forests of the humid tropics into absurdly wasteful beef farms.

Gaia theory arose from a detached, extraterrestrial view of the Earth, too distant to be much concerned with humans. Strangely, the view is not inconsistent with the human values of kindness and compassion; indeed it helps us to reject sentimentality about pain and death, and accept mortality, for us as well as for our species. With such a view in mind, Helen and I wish our eight grandchildren to inherit a healthy planet. In some ways, the worst fate that we can imagine for them is to become immortal through medical science -- to be condemned to live on a geriatric planet, with the unending and overwhelming task of forever keeping it and themselves alive for our kind of life. Death and decay are certain, but they seem a small price to pay for the possession, even briefly, of life as an individual. The second law of thermodynamics points the only way the Universe can run-down, to a heat death. The pessimists are those who would use a flashlight to see their way in the dark and expect the battery to last forever. Better to live as Edna St. Vincent Millay advised:

My candle burns at both ends;
It will not last the night;
But, ah, my foes, and, oh, my friends --
It gives a lovely light.
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:48 pm

References

Hutton, James. 1788. "Theory of the Earth; or an investigation of the laws observable in the composition, dissolution, and restoration of land upon the globe." Roy. Soc. Edinburgh, Tr., 1, 209-304.

Doolittle, W. F. 1981. "Is Nature Really Motherly?" CoEvolution Quarterly 29, 58-63.

Holland, H. D. 1984. The Chemical Evolution of the Atmosphere and the Oceans. Princeton, N.J.: Princeton University Press, 539.

Lovelock, J. E. 1972. "Gaia as Seen through the Atmosphere." Atmospheric Environment 6, 579-80.

Lovelock, J. E.; Maggs, R. J.; and Rasmussen, R. A. 1972. "Atmospheric Dimethyl Sulphide and the Natural Sulphur Cycle." Nature 237, 452-53.

Margulis, L., and Lovelock,]. E. 1974. "Biological Modulation of the Earth's Atmosphere." Icarus 21, 471-89.

Charlson, R.J.; Lovelock,]. E.; Andreae, M.O.; and Warren, S.J. 1987. "Ocean Phytoplankton, Atmospheric Sulfur, Cloud Albedo and Climate." Nature 326, 655- 61.

Whitfield, M., and Turner, David R. 1987. "The Role of Particles in Regulating the Composition of Seawater." In Aquatic Surface Chemistry, ed. Werner Stumm. Chichester, Eng.: Wiley.
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:49 pm

Further Reading

CHAPTER 1


For an alternative view of the work at JPL, what would be better to read than The Search for Life on Mars, by Henry Cooper (New York: Holt, Rinehart and Winston, 1976)?

CHAPTER 2

A beautiful and entirely comprehensible book about entropy is P. W. Atkins's The Second Law (New York and London: Freeman, 1986).

The classic account of the problem of defining life is What Is Life?, by Erwin Schrodinger, written in Dublin during the Second World War (Cambridge: Cambridge University Press, 1944).

The lightest of Ilya Prigogine's books on the difficult subject of the thermodynamics of the unsteady state is From Being to Becoming (San Francisco: Freeman, 1980).

For a straightforward account of the evolution of the Earth from a geologist's viewpoint, there is no better book than The Chemical Evolution of the Atmosphere and Oceans, by H. D. Holland (Princeton, N.J.: Princeton University Press, 1984).

A similar book on climatology is The Coevolution of Climate and Life, by Stephen Schneider and Randi Londer (San Francisco: Sierra Club Books, 1984).

CHAPTER 3

Those interested in geophysiological theory should read Alfred Lotka's classic book, Elements of Physical Biology (Baltimore: Williams and Wilkins, 1925).

Autopoiesis, the organization of living things, and many other concepts helpful for understanding life as a process, are described in The Tree of Knowledge, by Humberto R. Maturana and Francisco J. Varela (Boston: New Science Library, 1987).

CHAPTER 4

For those interested in the synthesis of elements within stars and about the life of stars in general, there is a splendid account of these awesome events in Sir Fred Hoyle's Astronomy and Cosmology (San Francisco: Freeman, 1975).

In Early Life, Lynn Margulis provides a beautiful and clearly written account of the known and the conjectured of the obscure period before and after life began, including a picture of the evolution of nascent life (Boston: Science Books International, 1982).

If you are interested in the beginnings, then read Origins of Life, by Freeman Dyson (Cambridge: Cambridge University Press, 1986) and Origins: A Skeptic's Guide to the Creation of Life on Earth, by Robert Shapiro (New York: Summit, 1986).

A rare geological text that restores soul to the misty Archean world is E. G. Nisbet's book, The Young Earth (London: Allen and Unwin, 1986).

The work of some of the pioneers of the new field of biomineralization is recorded in Biomineralization and Biological Medical Accumulation. by P. Westbroek and E. W. de Jong (Dordrecht: Reidel, 1982).

For those interested in the evolution of eukaryotic cells, there is a detailed account in Lynn Margulis's book Symbiosis in Cell Evolution (San Francisco: Freeman, 1981).

A splendid account of the four eons of evolution from our microbial ancestors is in Lynn Margulis and Dorion Sagan's book Microcosmos (New York: Simon and Schuster, 1986).

CHAPTER 6

A fair amount of Gaia theory has come from evidence about the atmosphere and atmospheric chemistry. A book that summarizes the evidence of this subject in a readable way is Chemistry of Atmospheres, by Richard P. Wayne (Oxford: Oxford University Press, 1985).

For a professional account drawn from conventional wisdom, The Planets and 'Their Atmospheres by John S. Lewis and Ronald G. Prinn is to be recommended as an antidote to Gaia (Orlando, Fla.: Academic Press, 1984).

CHAPTER 7

The proceedings of the meeting in Brazil mentioned in the chapter are now published as a book, The Geophysiology of Amazonia, edited by Robert E. Dickinson (New York: Wiley, 1987).

An account of the battlefield scenes of the chlorofluorocarbon conflict is to be found in The Ozone War, by Lydia Dotto and Harold Schiff (New York: Doubleday, 1978).

Rachel Carson stands, like Marx, as the major influence behind a revolution, this time in environmental thought and action. Her seminal book, Silent Spring (Boston: Houghton Mifflin, 1962), must be included in any further reading of the topics related to this chapter.

Environmental affairs are in the realm of politics, and for a wise and understanding view from that perspective you should read Climatic Change and World Affairs, by Sir Crispin Tickell (Lanham, Md.: University Press of America, 1986).

An outstanding figure among environmental scientists is Paul R. Erlich, his book with Anne H. Erlich, Population Resources Environment, is essential reading to capture the heart and mind of the ecology movement (New York: Freeman, 1972).

A contemporary view of environmental problems is provided in Sustainable Development of the Biosphere, edited by William C. Clark and R. E. Munn (Cambridge: Cambridge University Press, 1986).

CHAPTER 8

If you really want to know what the surface of Mars looks like, then there is no better source than the descriptive writing and photographs in Michael Carr's beautiful book, The Surface of Mars (New Haven and London: Yale University Press, 1981).

CHAPTER 9

A theologian's view of Gaia is expressed in Hugh Montefiore's The Probability of God (London: SCM Press, 1985).

An unusual and very readable book is God and Human Suffering, by Douglas John Hall. Although it is not directly concerned with Gaia, I found it to be helpful and moving while revising this chapter (Minneapolis: Augsburg, 1986).

For me the most important book to connect with this chapter is Angels Fear: Towards an Epistemology of the Sacred, by Gregory Bateson and Mary Catherine Bateson (New York: Macmillan, 1987).

For an understanding of scientists' views of the Universe, perhaps the best summary is in The Self-Organizing Universe, by Erich Jantsch (Oxford: Pergammon, 1980).

A subject often linked with Gaia, but which is in fact very different, is The Anthropic Cosmological Principle, by John D. Barrow and Frank J. Tipler (Oxford: Oxford University Press, 1986).

GENERAL

For those who find the topic of Gaia entertaining, probably no one has written with more feeling than Lewis Thomas in his many books, in particular The Lives of a Cell (New York: Viking Press, 1975), and 'The Youngest Science (New York: Viking Press, 1983).

No guide to the world would be complete without an atlas, and the most appropriate would be Gaia: An Atlas of Planet Management, edited by Norman Myers (New York: Doubleday, 1984).

The evolution of the Earth from a geologist's viewpoint is clearly expressed and beautifully illustrated by Frank Press and Raymond Siever in Earth (San Francisco: Freeman, 1982).

For a physicist's view of the evolution of the cosmos and life, see Eric Chaisson's book, The Life Era (New York: Atlantic Monthly Press, 1987).

And for a mainstream ecologist's view of the Earth written at the same time but in great contrast to the views expressed in the first Gaia book, I strongly recommend Paul Colinvaux's book, Why Big Fierce Animals Are Rare (Princeton, N.J.: Princeton University Press, 1978).

The world of the scientists who have participated in the discoveries recorded in this book is captured in Planet Earth, by Jonathan Weiner (New York: Bantam Books, 1986).
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Re: THE AGES OF GAIA: A BIOGRAPHY OF OUR LIVING EARTH by Ja

Postby admin » Fri Oct 09, 2015 8:49 pm

Index

Abercrombie, M., 16
acid rain, 137, 159-63
agriculture, 179-81, 228-31
AIDS, 155
"albedo, " definition of, 36
Aldiss, Brian, 185
algae, 144-45, 146, 148, 149-50, 163,
168
Allaby, Michael, 184, 196
Alvarez family, 185
Anderson, Don, 104, 105, 111
Andreae, Meinrat, 144, 147, 162
animal and plant coexistence, 127-
28
anoxic ecosystems, 96, 100, 118
of the Archean, 76, 78-84
antioxidents, 130, 176
aperiodic crystals, 23, 75
the Archean, 13, 66-67, 98
atmosphere, 82, 83-84
carbon cycle, 79, 83, 101
climate regulation, 81-82
conventional model of, 84
Earth's appearance during, 85-86
end of, 82-83, 95-96, 99-102,
120
Gaian model of, 81-83
genetic information on, 67-68
geological information on, 68-70
impacts of planetesimals, 86
life, 65-66, 70, 75-76, 87
lifeless Earth, 66, 70-75, 81, 82
nutritious elements, 93-95
oceans preserved by life, 86-87
oxygen in the air, 80, 82, 95-96
photosynthesizers and decomposers,
ecosystem of, 76, 78-84, 120
rainfall, 90-93
salinity problem of bacteria, 108
tropopause, 79-80, 90
ultraviolet radiation, 88-90
Arrhenius, Svante, 73
atmosphere, 150-51
life's impact on, 8, 9, 28-29, 71-72,
82, 83-84
of lifeless Earth, 71-72, 73-74
see also carbon dioxide in the air; oxygen
in the air
Atmospheric Environment. xviii, 8
Attenborough, David, 210
attractors, 219

bacteria, 87, 89-92, 96, 108, 122-24
see also cyanobacteria
Balandin, R. K., 9-10, 11
Barghoorn, Elso, 87
basalt-eclogite phase transition, 105
Bateson, Gregory, 218
Berkner, L. v., 87-88, 168
Bernal, J. D., 25
Bernard, Claude, 18
betaines, 108, 144-45, 146, 148
Betjeman, John, 231-32
Big Bang theory, 66, 67, 219
biogeochemistry, 30, 34, 62
biogeophysics, 34
biological science, xviii, 12-13, 20, 30-
31
life, perspective on, 16-17
see also molecular biology
biomineralization, 105, 113
biosphere, 10, 19, 30
"biota, " definition of, 19
Blake, William, 228
Boltzmann, Ludwig, 24, 215
Bourdillon, Robert, 89
Braben, Donald, 206
Brand, Stuart, 235
Broecker, W. S., 150

Cairns-Smith, A. G., 75
calcium, 69, 99, 103
calcium carbonate precipitation, 103-5,
110-11
Calder, Nigel, 65
Cambrian period, 97-98, 126-27
cancer, 168, 177
Cannon, Walter, 18
carbon as evidence of life, 70
carbon burial, 116-18, 121, 132
carbon dioxide cycle, 121-22
carbon dioxide in the air, 63, 78
in the Archean, 73, 74, 78, 81, 82-
83, 84, 86-87
geochemical model of, 133-34, 135
increase in the 1980s, 156-59
regulation of, 134-40
Carbon Dioxide Review 1982. 156, 158
carbon monoxide, 129
Carr, Michael, 188, 190, 195-96
Carson, Rachel, 173, 211, 229, 233
catastrophic events (perturbations):
in Daisyworld, 52, 53, 54-57
evolution and, 55-56
Gaia theory and, 43--45, 54, 86
internal sources of, 44
theoretical ecology and, 53-54
see also impacts of planetesimals
cell communities, origin of, 113-16
cell membranes, 106-7
Cess, R. D., 72
CFCs, see chlorofluorocarbons
C4 plants, 135, 139--40, 157
Challenger, Frederick, 141
Chance and Necessity (Monod), 213-14
chaos, 215-16, 218, 219
Charlson, Robert, 92, 147
The Chemical Evolution of the Atmosphere and the Oceans (Holland), 32,
73-74
Chernobyl accident, xx-xxi, 173
chloride ion, 110
chlorofluorocarbons (CFCs), 142--43
greenhouse effect of, 170
Martian atmosphere, used to warm,
187-88, 196-98
ozone layer threatened by, 164-70
Cicerone, Ralph, 165, 166, 170
Clark, William, 156, 158
climate, evolution of, 150-51
climate regulation, 13, 39, 57, 63, 81-
82, 90-93, 134-40, 146-50
cloud formation, 92-93, 147-50
The Coevolution of Climate and Life
(Schneider and Londer), 32
CoEvolution Quarterly, 31
continuous creation theory, 42, 219
countryside, destruction of, 228-34
Coyne, Leila, 75
Crutzen, Paul, 176-77
C3 plants, 135, 139
cyanobacteria, 76, 77, 78, 102-3, 114,
121
cybernetics, 60-61

Daisyworld (Gaian model), 34-35, 45
catastrophic event (perturbation) experiment,
52, 53, 54-57
criticism of, 46
as cybernetic model, 60--61
daisy-environment relationship, 52,
59-60
mathematical expression of, 57-{j()
numerical model of, 38-39
one-species model, 57-59
rabbits and foxes model, 52, 53
reductionist-holist nature of, 216
stability of, 45-46, 52, 57
steady state of the system, 58-59
technical paper on, 35, 46
temperature regulation, 39
theoretical ecology and, 48, 63
three-species model, 46-47
twenty-species model, 48, 49
two-species model, 35-38
Darwin, Charles, 184, 215, 222, 228-
29
dating of rocks, 98
Dawkins, Richard, 32
Delmas, Robert, 150
Denbigh, K. G., 25, 215
Dickinson, R.]., 73
dimethyl sulfide, 141-42, 143, 144, 145,
147, 148-49, 150, 162...(;3
dimethylsulfonio propionate, 144-45
dinosaurs, 128
dissipative structures, 26-27, 75
Doolittle, W. Ford, 31-32

Early Life (Margulis), 114
Earth:
in the Archean, 85-86
origin in supernova, 68-70
in Protero~oic period, 124
Earth as living organism, see Gaia
Earth Mother myths, 208
Earth's Earliest Biosphere, 10-11
"Earth's fragile shield" myth, 87-90, 168
"ecopoiesis, " definition of, 186
ecopoiesis of Mars, see under Mars
Eigen, Max, 75, 217
Eldredge, Niles, 13, 55-56
The Elements of Physical Biology (Lotka),
61-62
Emiliana huxley ii, iv
endogenic cycle, 104-5
endosymbiosis, 114
entropy, 21-26, 67, 237
environmental evolution, 153-54
life and, 11-12, 19, 30-31, 33-34
environmentalists, xix, 173, 229-30
eukaryotes, 98, 105, 113-16, 128
evolution, xviii, 55-56, 153-54
environmental and species, relationship
between, 11-12, 19, 30-31,
33-34
evolutionary biology, 12-13, 30-31
Evolution Now (essays), 30
The Extended Phenotype (Dawkins), 32

Fanale, Frazer, 190
Farman, J. C., 169
field ecology, 50
fire as oxygen regulator, 132-33
forests, 132-33, 178, 180-81
fractional dimensions, 220
free radicals, 175

Gaia:
atmosphere's composition and, 8, 9,
28-29, 34, 71-72
calcium carbonate precipitation, 103-
5, 110-11
carbon dioxide problem, 156-59
carbon dioxide regulation, 134-40
cell communities, 113-16
chaos as element of, 215-16
components of, 39-40
critical ecosystems, 178, 180-81
glaciations, use of 136-37, 138, 139,
140
homeostasis of Earth maintained by,
13, 19, 31, 45, 124
iodine's role in, 145-46, 147
life as central to, 15-19, 41
living in harmony with, 225-26, 231-
32, 234-37
Lovelock's vision of, 212
as manageable concept, 206, 222
mankind as threat to, 177-81
origin of, 41, 66, 76, 78-84
oxygen regulation, 118-19, 120, 121-
22, 131-33
as planetary being, 19, 39-40
redwood analogy, 27-28
salt regulation, 105-13
strength of, 86, 125, 177
sulfur's role in, 141-45, 146--50
water preserved by, 86-87, 192
see also climate regulation; religious
aspects of Gaia
Gaia (Lovelock), 8
"Gaia, " meaning of, 3
Gaian model, see Daisyworld
Gaian Universe, 206
Gaia science, see geophysiology
Gaia theory, xix, 14, 25, 63-64
atmospheric evidence, 8, 9
catastrophic events as evidence for,
43-45, 54, 86
criticisms of, 31-33, 34, 45
evolution, perspective on, 11-12, 19,
30-31, 33-34
experimental investigation of, 43-45;
see also Daisyworld
historical antecedents, 9-11
origin of, xviii, 4-8
sciences, appeal for, 12-13
teleological concept, 33, 34, 39
top-down view of life, 29-30
Gardiner, B. G., 169
Garrels, Robert, 78, 84, 86, 130
gas chromatograph, 142, 143
genetic material as information about the
past, 67-68
geophysiology (Gaia science), 11, 14
acid rain, perspective on, 162-63
planetary medicine, xix-xxi, 155
"regulation" as defined in, 102
Gibbs, J. W., 215
glaciations, 57, 101, 136--37, 138, 139,
140, 150, 232
glycolysis, 129
God, 205, 208-10, 217
Golding, William, 3
Gould, Stephen Jay, 13, 30-31, 55
greenhouse effect, 73, 156--59
The Greening of Mars (Lovelock and
Allaby), 184-88
Green Movement, 173, 231-32

the Hadean, see lifeless Earth
halocarbon gases, 141, 142-43
halophiles, 108
Hardy, Thomas, 233
Harvey, William, 155
Haynes, Robert, 186
Heisenberg, Werner, 218
Henderson-Sellers, Ann, 73
Hickman, C. J., 16
Hitchcock, Dian, 5, 6, 71
Hochachka, Peter, 129
holist science, 213-17
Holland, H. D., 32, 73-74, 81
Holligan, Patrick, 163
Holling, C. S., 216
"homeostasis, " definition of, 18
homeostasis of Earth maintained by
Gaia, 13, 19, 31, 45, 124
Horowitz, Norman, xviii, 7
'The Human Experience (Huxley), 208
Hutchinson, G. Evelyn, 10, 30
Hutton, James, xix, 10, 11, 30
Huxley, Aldous, 208
hydrogen production by lifeless Earth,
74-75
hydroxyl radicals, 80, 101-2, 129-30,
131, 149, 163

Icarus. xviii, 8
impacts of planetesimals, 43-44, 70-71,
86, 125
information theory, 24-25, 67
An Introduction to Physical Geography
(Yermolaev), 30
An Introduction to the Study of Man
(Young), 31
iodine cycle, 145-46, 147

James, William, 207
Jantsch, Erich, 213, 217
Jet Propulsion Laboratory, xviii, 4, 5,
7, 190
Jickells, Timothy, 149
John Paul II, Pope, 223
Johnson, Harold, 165
Johnson, M. L., 16
Johnson, Samuel, 210

Kahn, Herman, 158
Kaufman, Fred, 166
Korolenko, Yevgraf Maksimovich, 9-10
Krumbein, Wolfgang, 93

lagoons, evaporite, 109, 110-13
Laplace, Pierre-Simon, 218
Lavoisier, Antoine-Laurent, 160
Legrand, M., 150
Lewis, G. N., 160
Lidwell, Owen, 89
life, 15-19, 41
atmosphere, impact on, 28-29, 34, 71-
72, 82, 83-84
beginnings of, 65-66, 70, 75-76, 205-
6, 222
boundaries of living systems, 27, 40,
52
cell communities, 113-16
colligative nature of, 18
definitions of, 17-18
entropy and, 23-24, 25-26
environmental evolution, role in, 11-
12, 19, 3(}-31, 33-34
genetic information about, 67-68
nutritious elements, transfer from
ocean to land, 93-95
oceans preserved by, 86-87, 192
oxygen toxicity and, 129-30
photosynthesizers and decomposers,
ecosystem of, 76, 78-84, 120
rainfall problem, 90-93
salt regulation mechanism, 105-13
scientific understanding of, 16-17,
20-24, 25-28
sparse life, 6, 76
top-down view of, 29-30
ultraviolet radiation and, 88-90
unconscious understanding of, 16
lifeless Earth, 66, 70-75, 81, 82
life on planets:
NASA project regarding, 4-7
signs of, 5-6, 8
lignin, 131, 133
limestone, 104-5, 11(}-11
Liss, Peter, 143, 162, 163
Living Without Oxygen (Hochachka),
129
Lodge, James, 141
Londer, Randi, 32
Lotka, Alfred, 10, 12, 30, 48, 61-62
Lovins, Amory and Hunter, 158
Lowenstam, Heinz A., 30

McDonagh, Sean, 210
McElroy, Michael, 190
Mclntyre, Donald, xix
McLuhan, Marshall, 96
Maggs, Robert, 142
Mandelbrot, Benoit, 220
Margulis, Lynn, xviii, 8, 18, 31, 111,
113-14, 116, 168
Mariner spacecraft, 6
Mars:
atmosphere, 8, 9, 28, 29, 133, 193
ecopoieses of (making the planet suitable
for life), xxi, 184, 193-96,
201-2
bacterial ecosystem, 199-201
fictional account of, 184-88
Gaian system, 200-201
warming the atmosphere, 187-88,
196-98
life-detection experiments by NASA,
4-7, 63
physical conditions, 188-93
water present within, possible, 189-
90, 191, 192, 195-96
Marshall, L. C., 87-88, 168
Mary, Virgin, 206, 222-23
Maturana, Humberto, 217
May, Robert, 51
medical profession, xix-xx, 154-55
meteorites, 70
methane, 76, 79-80, 81, 82, 83-84, 87
methyl iodide, 145-46
microbial mat communities, 111-13
Milankovich, Milutin, 136
Milankovich effect, 136, 137
Millay, Edna St. Vincent, 237
molecular biology, 20, 29, 213-17
Molina, Mario, 165, 166
Monod, Jacques, 213-14
Montefiore, Hugh, 203-4
Moon, 70, 183-84
Moriyama, Shigeru, 136
Morton, Jim, 204

NASA, 4-7, 28, 63, 188
natural phenomena, math of, 61-62
Nature, 12, 142, 150, 155, 164, 165
negentropy, 24, 25, 29, 124
Nisbet, Euan, 94, 99
nitrogen, 83-84
nitrous oxide, 95-96
nuclear energy controversy, xx-xxi,
171-77
nuclear reactors, natural, 122-24
nuclear winter, 177, 232

oceans, 74, 86-87, 93-95, 192
cloud formation over, 147-50
salt regulation, 105, 107-13
Odum, Eugene, xxi, 30
Onsager, Lars, 26, 215
Orchard, Ernie and Bill, 235
The Origin of Sex (Margulis and Sagan),
116
O'Sullivan, Michael and Theresa, 184
Owen, T., 72
oxic ecosystem, origin of, 95
oxygen, 129
toxic properties, 129-30, 175-76
oxygen cycle, 121, 127-28
oxygen in the air, 60, 85
acid rain and, 160-61
Berkner-Marshall theory on, 87-88
carbon burial and, 116-18, 121
dominant atmospheric gas, 99-102
Gaian regulation of, 11&--19, 120,
121-22, 131-33
initial appearance, 80, 82, 95-96
lifeless Earth, absent from, 74
in Phanerozoic period, 127-32
in Proterozoic period, 99-102, 116-
19, 121-22, 130
ozone layer, 8&--90, 143
depletion due to CFCs, 164-70
ozone on Mars, 193

"The Parable of Daisyworld" (Lovelock
and Watson), 35, 46
pathologies of science, 21&--20
peer review system, xvi
periodic crystals, 23
perturbations, see catastrophic events
Perutz, Max, 23-24
pesticides, 173
phagocytosis, 114
Phanerozoic period, 13, 126-32
phenols, 131
photosynthesizers and decomposers, ecosystem
of, 76, 7&--84, 120
phytoplankton, iv, 162
Pirie, N. W., 16-17
Pittle, R. D., 166
plant and animal coexistence, 128
plate tectonics, 104-5, Ill, 113
potassium, 69
Precambrian period, 98
Prigogine, Ilya, 26, 75, 213, 214, 217
The Probability of God (Montefiore), 204
prokaryotes, 115-16
Prospero, J. M., 149
Proterozoic period, 13, 9&--99, 127
beginning of, 99-102, 120
calcium carbonate precipitation, 103-
5, 110-11
Earth's appearance during, 124
eukaryotes, 98, 105, 113-16
impacts of planetesimals, 125
oxygen concentration in the air, 99-
102, 116-19, 121-22, 130
protolife, 75
Proxmire, William, 6
pseudomonads, 91

radioactivity of Earth, 68, 69-70
rainfall, 9D-93
see also acid rain
Ramanathan, v., 72
Redfield, Arthur, 10, 30
reductionist science, 213-17
reefs, 111, 12+-25
religion, 20+-8, 217
see also God
religious aspects of Gaia, xxi, 203-4,
205, 207
agnostic perspective, 217-18
Earth Mother myths and, 208
God concept and, 208-9
secular humanism and, 208-11
Virgin Mary analogy, 206, 222-23
Randall, Gilbert, 235
Reynolds, Osborne, 26
Rothstein, Jerome, 27, 215
Rowland, F. S., 94, 165, 166

Sagan, Carl, 6, 171
Sagan, Dorion, 116
Saigne, C., 150
salt regulation, 105-13
Sargasso Sea, 148
Sargent, Keith and Margaret, 235
Schidlowski, Manfred, 70
Schneider, Stephen, 32-33, 34
Schopf, J. W., 10
Schrooinger, Erwin, 22-24, 27, 215
Schweickart, Rusty, 201
Science, 12, 105
science, apartheid of, 11, 61, 168
scientists, independent, xvi-xvii
secular humanism, 208-11
'The Self-Organizing Universe Gantsch),
217
sex, invention of, 116
Shannon, Claude, 2+-25
Shaw, Glen, 146
Shoard, Marion, 230
Silent Spring (Carson), 173
Sillen, Lars, 10, 30
Silverstein, Abe, 4
Smith, John Maynard, 30
smog, 152-53, 161
Snyder, Gary, 235
The Spiritual Dimensions of Green Politics
(Spretnak), 208-9
Spretnak, Charlene, 208-9
Sputnik satellite, 4
Stolarski, Richard, 165
strange attractors, 219
structured hierarchy of species, 50
Suess, Eduard, 10, 11, 30
sulfur in acid rain, 161-63
sulfur's role in Gaia, 141-45, 14~
50
supernova, Earth's origin in, 68-70
The Surface of Mars (Carr), 188, 190,
195-96

Tellus, xviii, 8, 35, 46
terraforming, 186
The Theft of the Countryside (Shoard),
230
theoretical ecology, 12, 48, 50-54, 61-
62, 63
Theoretical Ecology (May), 51
theories in science, 42-43
thermodynamics, 20-24, 25-27, 67,
213-17, 237
The Thermodynamics of the Steady State
(Denbigh), 25
Thomas, Dr., 175, 176
Thomas, Lewis, 154
thorium, 6~70
Timescale (Calder), 65
To Care for the Earth (McDonagh),
210
tropopause, 79-80, 90
Tyler, Stanley, 87

ultraviolet radiation, 88-90, 167-69
uncertainty principle, 218
Universe as Gaian body, 206
unsteady state, 2~27
uranium, 6~70, 122-24

Vairavamurthy, A., 144
Varela, Francisco, 217
The Varieties of Religious Experience
(James), 207
Venus, 7, 8, 9, 28, 29, 86, 133
Vernadsky, Vladimir, 9-10, 11, 30
Viking spacecraft, 5-6, 7, 63, 188
volcanic eruptions, 74, 146


Redfield, Arthur, 10, 30
reductionist science, 213-17
reefs, 111, 124-25
religion, 204-8, 217
see also God
religious aspects of Gaia, xxi, 203-4,
205, 207
agnostic perspective, 217-18
Earth Mother myths and, 208
God concept and, 208-9
secular humanism and, 208-11
Virgin Mary analogy, 206, 222-23
Randall, Gilbert, 235
Reynolds, Osborne, 26
Rothstein, Jerome, 27, 215
Rowland, F. S., 94, 165, 166
Sagan, Carl, 6, 171
Sagan, Dorion, 116
Saigne, C., 150
salt regulation, 105-13
Sargasso Sea, 148
Sargent, Keith and Margaret, 235
Schidlowski, Manfred, 70
Schneider, Stephen, 32-33, 34
Schopf, J. W., 10
SchrOdinger, Erwin, 22-24, 27, 215
Schweickart, Rusty, 201
Science, 12, 105
science, apartheid of, 11, 61, 168
scientists, independent, xvi-xvii
secular humanism, 208-11
'The Self-Organizing Universe Gantsch),
217
sex, invention of, 116
Shannon, Claude, 24-25
Shaw, Glen, 146
Shoard, Marion, 230
Silent Spring (Carson), 173
Sillen, Lars, 10, 30
Silverstein, Abe, 4
Smith, John Maynard, 30
smog, 152-53, 161
Snyder, Gary, 235
The Spiritual Dimensions of Green Politics
(Spretnak), 208-9
Spretnak, Charlene, 208-9
251
Sputni~ satellite, 4
Stolarski, Richard, 165
strange attractors, 219
structured hierarchy of species, 50
Suess, Eduard, 10, 11, 30
sulfur in acid rain, 161-63
sulfur's role in Gaia, 141-45, 146-
50
supernova, Earth's origin in, 68-70
'The Surface of Mars (Carr), 188, 190,
195-96
'Tellus, xviii, 8, 35, 46
terraforming, 186
'The 'Theft of the Countryside (Shoard),
230
theoretical ecology, 12, 48, 50-54, 61-
62, 63
Theoretical Ecology (May), 51
theories in science, 42-43
thermodynamics, 20-24, 25-27, 67,
213-17, 237
The Thermodynamics of the Steady State
(Denbigh), 25
Thomas, Dr., 175, 176
Thomas, Lewis, 154
thorium, 69-70
Timescale (Calder), 65
To Care for the Earth (McDonagh),
210
tropopause, 79-80, 90
Tyler, Stanley, 87
ultraviolet radiation, 88-90, 167-69
uncertainty principle, 218
Universe as Gaian body, 206
unsteady state, 26-27
uranium, 69-70, 122-24

Vairavamurthy, A., 144
Varela, Francisco, 217
'The Varieties of Religious Experience
Games), 207
Venus, 7, 8, 9, 28, 29, 86, 133
Vernadsky, Vladimir, 9-10, 11, 30
Viking spacecraft, 5-6, 7, 63, 188
volcanic eruptions, 74, 146
Volterra, Vito, 12, 48
Von Neumann, John, 25

Wade, Roger, 142
Walker, James, 133, 134
Ward, Keith, 209-10
Warren, Stephen, 147
water's presence on Earth, reasons for,
74-75, 86-87, 192
Watson, Andrew, 35, 46, 57, 63, 132
What Is Life? (Schrodinger), 22, 215
Whitfield, Michael, 63
Woods, John, 149

X-ray photons, 175, 176

Yermolaev, M. M., 30
Young, J. Z., 10, 31
Young, Lord, 202
The Youngest Science (Thomas), 154

Zivadin, Stephen, xxi
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