The Natural History of the Present, Chapter 1

The Natural History of the Present

Part I: The Problem with Economics

Chapter 1
Some people trace the state of our warming, polluted world to capitalism, with its ability to motivate human effort towards ever more elaborate material lives. Long before capitalism, agriculture greatly increased our effect on the natural world, largely through allowing the human population to increase by many times. The first southerly breath of global warming most likely came from the clearance of forests for agriculture. Fossil evidence suggests human hunters with spears caused a major wave of extinction of large animals 11,500 years ago in the Americas; and that humans using spears, throwing sticks and fire caused one 40,000 years before that in Australia. The fundamental problem with human influence on the natural world is not capitalism (state or corporate) but the human evolutionary imperative to multiply and thus to occupy every possible environment. Like any plant or animal, we remake our environment to make it more suitable for us. Digging sticks, fiber carrying bags, stone blades, fire, crops, the development of machines, the use of fossil fuels, the organizing and motivating abilities of the state, just increased these abilities. How far we can go isn’t clear. There may indeed be limits: we need space to lie down, to move around, and in which to grow food (even if the food is grown in stainless steel fermenters on nutrients derived from sewage). But we could build huge steel and glass above-ground cities (the linear cities of Paolo Soleri), faced with solar cells, their size limited only by the materials, or excavate caverns many hundreds of yards or kilometers underground, like those of ancient Cappadocia or modern Norway (so employing geothermal heat), or build marine cities, powered by wind, or by the difference in temperatures between ocean currents, on floating platforms tethered to the bottom of the sea. None of this interests me here. What interests me here are the possibilities of a modern life in a working natural world, surrounded by and supported by working ecosystems. Ideally, half or less of any landscape would be used by people for the production of commodities of economic value. Some equilibrium would exist between the tribe of humans, the tribe of mice, the tribe of herons, the tribe of salmon. There would be restraints. We would eat salmon but we wouldn’t eat all of them; and we wouldn’t destroy their habitat.

In any case, the practice of pure capitalism is a myth. It exists in no society. Life under it for most of the population would be nasty, brutish and short. The move from an agricultural to an industrial economy, which exacerbated the economic and social failures of capitalism in practice, led to the idea of the social welfare state, with free public education, universal health care, old age and unemployment insurance, some redistribution of wealth from the rich to the poor. Modern western societies vary in how far they go toward establishing such a state. Among those societies that go the farthest—the democracies of northern Europe—are the richest.

Capitalism can also be modified to save the natural environment. A focus on water helps. So do two legal doctrines: the Law of Nuisance, under which an individual may not use his property to cause legally recognized difficulties for his neighbor (consider the rain of metals from the atmosphere, or the warming planet, as well as plumes of industrial discharges in waterways); and the Public Trust Doctrine, which puts the use of certain landscapes, such as riverbanks and shorelines, along with their related benefits (such as swimmable waters and fisheries) under the protection of the state, which must maintain them for the common good. Public Trust landscapes, such as riverbanks, groundwater reserves and shorelines, are only partly controllable by people. In practice, both these doctrines are difficult and expensive for individuals to use, since specific harms must be traced to specific causes. Some writers argue that the notions behind the Public Trust Doctrine form the basis for protecting ecosystem functions in general.

My motives in writing this book are unabashedly sentimental. I am attached to the green world in which, where I live, the ground freezes up in early November (better have your shovel out of the ground), and the wood warblers return in early May. My attachment is something of a misperception on my part, since this green world is recent (at least in its details), certainly no more than 6000 years old. It is also much less abundant than the one I remember from 50 years ago, when as a boy the robin chorus woke me up at dawn. The world for the last 10,000 years has been one of shifting baselines: my world is less abundant than the one my father saw in the 1920s, when he shot ducks from a harbor breakwall on Lake Erie; and his less abundant than my grandfather’s in the 1880s, when deer were extinct in Vermont and Rhode Island, but shorebirds were still shot on the New England beaches for market. (An amateur ornithologist, as a boy my grandfather amassed a collection of bird skins.) Without the heat-trapping gases of modern civilization, my world would probably have been replaced by several hundred feet of ice within another few thousand years. It will now probably be replaced with a warmer and greener world. (‘Probably’ because the results of modifying climate are unpredictable.) This must be fine with me, as long as such changes remain within the limits to which living things can adjust, and as long as the ecosystems that support the green world continue to function.

* * *

The usefulness of market economics comes from its reduction of human activity to matters of efficiency and profit. Reductionism has a long history in modern life: children are educated in school, not the home (reducing the influence of parents); work and life are separate activities; one does not grow one’s food or sew one’s clothes (farmers grow food and garment workers sew clothes); and entertainers provide entertainment. Specialization of economic and social roles goes along with economic development. Social roles, such as schooling and child care, become economic professions, performed by teachers and nannies. Thus new jobs are created and parents work outside the home. One could argue that economic specialization makes economic development possible. Distinctions among work, entertainment, and schooling are obscure in peasant, or gathering and hunting cultures, where all or none of one’s activities might be considered work, and few, if any, yielded a profit; but together they constituted a life: that whole life was what children learned. While economic development has made possible the continuing elaboration of modern life, economic development also requires that elaboration. Without increasing consumption, how can capital grow?

In early modern times in Europe, walking was replaced by riding in carriages, then carriages were replaced by trains, which were replaced by automobiles and airplanes. A long time ago people drank from streams, then from hand-dug wells or public fountains, then had piped household water, then drinkable piped water; now people choose from a thousand kinds of carbonated drinks and bottled waters. All this costs the individual more: soda or apple juice costs more than tap water, or a sip from the local brook, which is anyway no longer drinkable because of the side effects of economic development. In New York City, maintaining a car costs 8 to 10 times more than taking public transportation, and despite the state of traffic in the city, where in 1960 cars moved at half the speed of horse-cars in 1907, about half the households have one. (The number is close to 100% in the suburbs.) The additional costs per person mean that each person supports a higher level of economic activity, and that the cost of necessities has fallen relative to total income. Late twentieth-century Americans spend 8% of their income on food, while the figure for eighteenth-century France was 90%. Much improvement has been recent: in turn-of-the-century America food, clothing and shelter accounted for 80% of a family’s budget; in 2000 one-third. So more income is available for other things. Spending income on other things employs the people who provide them; as their incomes rise, they also spend more, and the general level of economic activity rises further—the capitalist gift of growth.

Economic growth has some counter-intuitive consequences. If you earn more than, say $6 an hour, it is probably not worth your while to grow your own food: carrots and cabbage are too cheap. Walking across the United States, a journey of 200 to 300 days, is much more expensive than flying. A one-way ticket from New York to San Francisco costs $150. Food and drink for 200 days costs several times that. (Even biking, which takes 30 days, costs considerably more.) Partly, the direct costs of walking are so high because one can no longer drink the water one comes across, hunt or gather one’s food, camp out beside the road, or sew new shoes from animal skins. Capitalist development has made flying cheap and walking expensive, and travel more polluting; walking generates no extra carbon dioxide, and flying somewhat more than driving (6 times more than taking the train). A Sioux or a Tewa would have set out on foot on a trading journey of some hundreds of miles to realize what he or she considered a profit (perhaps a change of scene was also a benefit); or a medieval Frenchman walk from Arras in northern France to Saint James of Campostella in Spain for the good of his soul. Along the road the pilgrim would have been given food and lodging by others for the good of their souls. To walk the length of France at that time took 40 days. It was somewhat faster by horse: 20 to 22 days from Flanders to Navarre in the fourteenth century. For capitalist traders the time such journeys took represented a cost. Some profited by it; the distances allowed bankers in Florence and Sienna (such as the Medicis) to use the different rates of exchange in local currencies as a substitute for charging interest. Charging interest constituted usury, a sin. Periodic improvements in transport would give a tremendous boost to trade.

While capitalist development divides up the social and material world to create more scope for profit, scientific investigation divides up the natural world in order to understand it. Science cannot yet deal with whole views of the world, though some scientists are trying. So our world is made up of many pieces that don’t fit together. We have many worlds, not one whole. Such disconnectedness is a rather recent development. Most pre-industrial conceptions of the world were wholes. The Sumerians, one of the earliest irrigation societies, lived in the valley of the Tigris and Euphrates rivers, in the flat, hot countryside of what is now Iraq. All agriculturists, but especially irrigators, have to be able to predict the seasons, and the Sumerians, like all irrigators, were astronomers. They mathematically interpreted (explained, in modern terms) the cyclical movements of the planets and stars. These predictable heavenly cycles were used to predict the cycles of earthly life—the time of the river floods, the time to plant, the time to clean the canals; the time to build new ones. The cycles of the heavens determined the cycles of human society, and the cyclic life of the society that of the man or woman in it, one life within another, microcosm within macrocosm. Like the stars, the people were fixed in their professions and social classes, the son of a farmer became a farmer, the son of a potter a potter; the society was one whole in its place under the night sky. While such ancient worlds are wholes, they have their limitations. Doubters are banished to other worlds. The Catholic Church came close to banishing Galileo to the world of the dead for teaching that the earth circled the sun. (It didn’t help that he had a bad attitude toward the Church.) Tribal groups banish those whose behavior isn’t socially acceptable. Banishment in this case usually means death from starvation or loneliness. Many have pointed out that the word for non-Greeks in Greek is barbarian. This is true in many languages, where the word for man is often the same as that for a member of the tribal or linguistic group. Fundamentalist Christians and Muslims banish non-believers to hell. So wholeness has its price.

While the idea of an unfettered market economy is a modern sort of whole outlook, examples of the destructiveness of market economics are many. (To paraphrase another writer, markets are a great way to organize economic activity but need adult supervision.) One is the abundance of abandoned downtowns throughout the United States. City downtowns, built for streetcars and foot traffic, were unadaptable to automobile transportation. Automobiles require parking space, which didn’t exist downtown. Land was cheaper outside the city, so shops and investment moved to the suburbs. Another is the abundance of leaking mines: 40% of rivers in the western United States are polluted by mines. Reclamation of surface coal mines comes to 4% of production costs in a free market, and is therefore affordable, while reclamation of hard rock mines (most of those in the West) is not economically possible at current prices for metals. From a market point of view, reclamation costs are costs without returns. Then there is the continuing failure of the Atlantic right whale population to recover, despite the end of hunting. The cause is probably high levels of anthropogenic nitrogen in coastal waters; these, together with overfishing, have shifted the plankton soup the whales feed on to mostly plants, rather than a mix of plants and animals, and put the whales on a vegetarian diet—which doesn’t allow them to put on sufficient weight to breed. (They are also killed in collisions with ships and get entangled in fishing gear.) There are the silty rivers of the American Middle West, once full of game fish, waterfowl, and turtles, now used for barge transport, hydroelectric power, sewage disposal, disposal of industrial effluent, and water supply. Under the same agricultural region lie pools of ground water contaminated with fertiliser and pesticide, some with pools of perchloroethylene collecting below, and pools of motor oil and gasoline sitting on top. Such hydrocarbons don’t mix well with water (though fats and oils take them up). The chloroethylenes are solvents, degreasers, dry cleaning fluids. Much ground and surface water and most processed foods are contaminated with them. Perchloroethylene interferes with the action of hormones, attaches to chromosomes, cripples immune systems, and over-stimulates the activity of some enzymes. About half the population of the United States gets its drinking water from ground water. Ground water eventually becomes river water, and thus everybody else’s drinking water, and the water in which fish and amphibians live and waterbirds swim. Bacteria will eventually break down most of these chemicals but not before they have accumulated in our bodies (the process takes too long in nature).

There is acid precipitation, a side effect of the combustion of fossil fuels, which has resulted in the dying trees, declining birds, acidified lakes and calcium-leached soils of the higher elevations of the eastern United States, Central Europe, and Scandinavia. About 70% of soils in the eastern United States are calcium poor. As the rain leaches more calcium out and the soils further acidify, aluminum ions are released from their oxydized (and harmless) state. Aluminum is the most abundant positive ion in the soil and once it is available, trees take it up instead of calcium, and transfer it to their crowns in an attempt to neutralize the acidic water condensing on their needles, which degrades chlorophyll (and if it forms trichloroacetic acid, acts as a defoliant). But aluminum is toxic to plants and animals and interferes with the trees’ metabolism. Leaves lower in calcium are less nutritious for grazing insects and the insects make less nutritious meals for birds, who must accumulate calcium for their eggshells. Nesting songbirds lay fewer eggs in acidified northern European woodlands. With less calcium available, soil animals such as earthworms, millipedes, pillbugs and snails, food for thrushes and other birds of the forest floor, decline. Such effects may explain the strong declines of nesting songbirds on the high plateaus of the eastern United States. The first snowmelt in the spring carries much of the winter’s acid precipitation (the accumulated snow and rain) into streams, and mobilizes the bio-accumulated acids from the soil, killing young trout and essentially sterilizing the water.
Research increasingly implicates the human environment in the growing epidemics of asthma, autism, adult onset diabetes and attention deficit disorder. The increase in diabetes is probably caused by changes in diet, specifically by the rise in the use of corn syrup, cheaper than cane or beet sugar, to sweeten ever-larger bottles of soft drinks, while the incidence of the other three disorders is likely influenced by the chemical soup in which we live. There are also inexplicable clusters of childhood leukemia and breast cancer. Virtually all the atrazine (an herbicide) used on cornfields in the Great Lakes Basin is still in the Great Lakes, as is most of the DDT that periodically wells up from their depths; in very small doses (one thirtieth of the Environmental Protection Agency’s standard for drinking water) atrazine makes male northern leopard frogs hermaphroditic. Atrazine is also an immune suppressant. Its use is probably the main reason for the collapse of amphibian populations in the Middle West in the 1970s. The capacity to act as a hormone in very small doses is characteristic of many chlorinated hydrocarbons. Very low levels of 2,4-D (one seventh of the Environmental Protection Agency’s recommendation for drinking water) has the greatest effect in reducing fertility in mice. Larger doses of the same chemical are ignored by the endocrine system, which normally responds to very low levels of blood-borne hormones.

Some cancer clusters may really be inexplicable (so-called statistical artifacts common to small sample populations), and some increases in disease a matter of better diagnosis. Some may be the result of atmospheric circulation having concentrated radioactive fallout in certain places during the testing of nuclear weapons 40 years ago. (One argument for this is an apparent rise in the incidence of breast cancer in American women who were adolescents living in downwind locations from 1957 to 1963). Two rather interesting explanations have been put forward to explain clusters of childhood leukemia. One suggests such clusters may be related to the ease of movement of modern people. Genetic studies indicate that many people in rural areas of Europe are descendants of people who have lived there for hundreds or thousands of years. If a nuclear powerplant or nuclear fuel reprocessing facility is built in such a place (remote places are favored and nuclear facilities are always suspect in terms of cancer-related diseases), people move into the area for the jobs, from hundreds or thousands of miles away. Their newly born children are exposed to leukemia-causing viruses endemic to the area, for which their mothers—not from the area—have transmitted to them no immunuty. In this case connections with radioactive hazards are incidental.

So the hazards of development are not obvious. A second explanation concerns clusters of leukemia in children who live near industrialized river estuaries in Britain. Such children have unusual levels of alpha radiation in their tissues and two to three times the normal rate of childhood leukemia. Large river estuaries like the Severn which are surrounded by fossil fuel burning industry, by a large car and truck traffic, and much space and water heating, end up with a considerable load of hydrocarbons in the water. They fall into the water from the air, or wash in off the land. Hydrophobic, the hydrocarbons tend to float on the surface and are concentrated by tidal action at the interface of fresh and salt water. The chemicals are mobilized in spray, which is carried inland by the wind and inhaled by people, settles out on their clothes and migrates into their houses. The hydrocarbons contain uranium and radon as contaminants. (Radioactive materials are natural contaminants of oil and coal.) These materials or their radioactive daughters (radioactively unstable lead) are concentrated in bone and fat. The release of alpha particles during further radioactive breakdown irradiates developing blood cells in bone marrow, and is thought to cause the leukemias. Children, whose cells divide more rapidly, are more sensitive to ionizing radiation.

Economics is concerned with prices, not with intrinsic values, so things of little intrinsic use—diamonds, gold, Cabbage Patch dolls—may be priced highly by the market. Production of such goods, like that of necessities, generates toxic materials and carbon dioxide. In general, scarcity sets prices. Social goods become valuable only when they threaten market stability, and ecological ones (like clean water) only when they become scarce. Abundant resources (including labor in some markets, and timber, land and water in many developed societies until recently) are cheap. Disposal of the waste products of production into air or water is free. The social problems of capitalist societies are more likely to be ameliorated than the biological ones. Social problems of capitalist, or market, societies include (in addition to those described above) the working homeless, who don’t earn enough for shelter; the non-working homeless, often mentally ill, who live on the street; the great spread of incomes in many capitalist or capitalist-socialist countries, which reduces growth; the unaffordability of medical care. Biological problems include the upward curve of man-made carbon dioxide in the atmosphere and the rising level of nitrogen in coastal ecosystems, which degrades them back to more primitive ecological structures: more algae and jellyfish, fewer oysters and salmon. Capitalist systems are open but not inherently democratic: without state direction, capitalism inevitably produces inequality in incomes that is likely to undermine democractic systems of government.

To keep up with the present rate of global warming, plants and animals would have to move poleward at 30 feet a day. But as far as global warming goes, the colder, less populated regions have experienced it most. High latitudes respond more quickly to temperature changes because of the feedback effects of snow cover. New snow reflects 80% of incoming sunlight, while water absorbs 90%, bare earth somewhat less, and thus leads to more snow and cooler temperatures. Less snow leads to bare ground, more absorption of heat, and warmer ones. In the modern Arctic, spring comes 10 days earlier, summers are warmer, sea ice is less abundant and thinner, permafrost is thawing, and the pulse of summer productivity on land is greater, than 20 years ago. Red squirrels in the Yukon give birth 18 days earlier than 10 years ago. (Some of this change may be genetic, that is, evolved change favoring earlier breeders, and not behavioral.) In 1998 Arctic terns were laying eggs 18 days earlier than in 1929. Robins and barn swallows visit Banks Island in the Canadian Arctic, and the Island has thunderstorms: birds and weather for which the Inuit have no words. Sea ice is melting. Annual fluctuations in the extent of Arctic sea ice corresponds almost exactly with the length of the melting season, which has been increasing by 5 days per decade. The Arctic without sea ice will be warmer and wetter. Since the 1970s Alaskan mean temperatures have risen 5° Fahrenheit (F.) in summer, 10° F. in winter. Legal travel days for heavy equipment on the tundra of the Arctic Slope (requiring six inches of snow and ground frozen to a foot) have fallen from 200 days a year to 100. Bark beetles, now able to produce two generations a summer rather than one, and whose females lay many more eggs in warmer temperatures, have killed 95% of the spruce trees on Alaska’s Kenai Peninsula. For a time, this was the largest insect infestation in North America. Now pine and spruce trees are dying throughout the forests of the west. Forests covering 150 million acres of the western United States and Canada have died from warming-related beetle infestations over the last ten years. As they burn or decay, the trees release more carbon dioxide to the atmosphere, creating a positive feedback. The situation is not only hard on seals and polar bears, which live on sea ice. Gray jays at the southern edge of their range in the Canadian province of Ontario are declining. Fall temperatures in this region have risen 5° F. in the last 30 years. The jays breed at the end of winter and in the autumn lay up a supply of perishable food (up to 50 pounds a bird: berries, mushrooms, insects, small mammals) for the winter and for the breeding season. In the warmer temperatures the stored foods rot, leaving the jays starving and in poor condition for breeding.

Being animals of the subtropics who carry our climate with us in clothes or buildings, we find the perennial polar ice with its noise and movement threatening. But for many animals the pack ice provides a basis for life. It lets mammals like seals and polar bears inhabit an open ocean, parts of which are rich in fish and squid. Algae live throughout the ice but are concentrated in the bottom half inch or so, which, saturated with seawater, is soft. The algae remain dormant during the lightless winters but begin to grow with the return of sunlight, eventually exceeding the number of algae in the water, and providing a concentrated and accessible food resource for krill, the basis of many food webs in both Arctic and Antarctic oceans, and also for nematodes (non-swimmers, but very abundant in some locations), ciliates, bacteria, rotifers, copepods. So the ice helps support the abundant avian and mammalian life (whales, penguins, bears, seals arctic foxes, ravens, scavenging gulls) of Arctic and Antarctic waters. The colored algae, by absorbing the sun’s heat, may speed the melting of pack ice in the spring. Melting ice seeds the water with algae, which reproduce in a bloom (marking the recent ice); crustaceans and zooplankton feed on the algae, and fish on all three. So loss of the ice is likely to reduce the biotic abundance of the polar regions, as well as—by changing currents and the transport of cold water out of the polar oceans—influence weather patterns thousands of miles away. (The spring thawing of sea ice in the Antarctic influences rainfall on the soybean fields in southern Brazil, the anchovy harvest off Peru, Sahel winds.) The disappearance of 20% of the pack ice about Antarctica since 1950 corresponds with a reduction of krill of 40% per decade since 1976 (when the disappearing ice was noticed) and a decline of emperor penguins of 50%, of adelie penguins 70% in the last 30 years. Ways of coping with ice vary: spectacled eiders winter in small openings in the Bering Sea, kept open by the warmth of their bodies (aggregations can reach tens of thousands of birds). They remain amid the ice in order to feed on the rich invertebrate fauna of the shallow sea bottom.

But the effects of warming are worldwide. In general, the north temperate zone has earlier springs, later falls, and more intense rains than 40 or 50 years ago. Summer temperatures in the southern parts of the United States are now 4° F. higher than optimal for seed formation in grains. Increased storminess causes more frequent high tides in the Mediterranean. (More frequent very high tides constitute much of Venice’s flooding problem, not rising sea levels: the level of the Mediterranean is falling because of less water inflow.) There is heavier wave action in the North Atlantic and more frequent and more violent storms in the tropics. Since 1980, 18 new species of warm water fish have been caught off the coast of Cornwall, England. Fish can swim anywhere in the ocean, and thus are a good mark of changes in sea temperature; no new species had been caught off Cornwall between 1940 and 1980. Oceans are rising at about 8 inches per century, partly from thermal expansion of the warmer water, partly from the melting of glaciers and from increased continental drainage. (Continental drainage includes the lowering of water tables for agriculture and construction and the pumping of ancient groundwater not renewed by rain.) Melting of the Greenland ice cap would raise sea levels by about 23 feet, of the West Antarctic ice sheet by 20 feet; or 43 feet total. Such events are becoming more likely. Ice is an excellent insulator and for a long time it was thought glaciers would take thousands of years to melt, since for half the effect of a rise in surface temperature to penetrate 3000 feet down into an ice sheet takes 7000 years, but summer meltwater streams on the ice’s surface drain down through cracks to the bottom of the ice sheet, melting ice as they go. The meltwaters pool at the bottom, lubricate the mass, find an outlet, and help the glacier slide more rapidly towards the sea. Once floating in the sea, ice melts. A rise in sea level of one to three feet in the next 30-40 years no longer looks farfetched. A 33 foot rise in sea level would inundate land with a population of one billion people and much of the world’s most fertile farmland. Three million years ago the temperature was 2° C. to 3º C. higher than now (this much temperature rise is already built into the atmosphere) and sealevel was 75 feet higher. Getting there may take centuries; or it may not. (Since the oceans are not perfectly connected, some places may see more sealevel rise earlier. Meltwater from the Greenland glacier will tend to stay in the North Atlantic for some time. For the first 50-100 years of melting, the sealevel rise along Greenland and the east coast of North America would be 30 times as great as that in the Pacific, that along the European coast 6 times as great. And the strong circumferential currents about Antarctica may prevent Antarctic meltwaters from reaching the rest of the world for centuries.)

Ecological disasters eventually become human disasters. Inuit women who eat a traditional diet of fish, whale blubber, seal meat, birds, berries and caribou, produce breast milk with 10 times the load of chlorinated hydrocarbons (PCBs, DDT, and their metabolites and relatives) than women who live 1000 miles to the south. These materials are implicated in causing cancers and birth defects and suppressing immune systems. Heavy metals, such as mercury, in the milk are also high. Mercury causes impaired neurological development in children. Sources of the chemicals are probably global, but some of the chemicals in the Inuit near Hudson’s Bay have been traced to industrial installations in the state of Alabama. Does this raise a question of liability?

Perhaps Inuit women should no longer nurse their babies. Breast milk helps ward off diabetes and cancer in later life; its fatty acids boost brain growth and its antibodies prime the immune system, so breast-fed babies have fewer infections. Breast-feeding protects the mother from breast and ovarian cancer and reduces her level of stress. But the Inuit are not alone: 10-15% of American women of childbearing age have more mercury in their blood than the Environmental Protection Agency considers safe. The mercury is transferred through the placenta to the fetus, where it affects the development of the brain, kidneys and liver. Approximately 600,000 children a year in the United States are born with unsafe mercury levels. A quarter of all North American women have levels of toxic compounds in their breast milk that would make it unfit for human consumption if it were cow’s milk or apple juice. These include anti-bacterial agents in cleaning compounds, pesticides, chemicals from detergents, from artificial musks in perfumes, from inks, paints, cosmetics and plastics. Most mothers don’t know this. If such mothers nurse their babies, they help purge their bodies of these materials, transmitting 20% of their body burden of fat-soluble chemicals to the (much smaller) child in six months. In a sense, nursing protects female mammals from chemicals in the environment. While the levels of chlorinated hydrocarbons in male seals grow throughout their lives, those in females level off once they reach reproductive age and start transferring the chemicals to their young. Such transfers are already a serious problem in some fish. Small amounts of PCBs, transferred by a female eel to her eggs, are fatal to developing eel embryos. This explains the crash in European eel populations.

The chemical industry, like the coal-fired electric power industry, is a cornerstone of the modern world. Many industrial chemicals and metals accumulate in human fatty tissue. These include pesticides, metals from burning coal (such as mercury, cadmium and lead), fire retardants, additives to detergents and plastics, and musk fragrances in perfumes. They accumulate through diet or through exposure to them in air and water. One breathes in waterborn chemicals with the steam of the shower, or absorbs them directly through the skin. The fat of a middle-aged American male contains 177 detectable organochlorines. A small fraction of the population, perhaps 5%, accumulate metals more efficiently and so are more at risk. (Such people, for instance, are probably at risk from mercury amalgam fillings in their teeth.) In general, once exposure to bio-accumulating chemicals ceases, a person sheds half of his load of fat-stored material every seven years. A large fraction comes out in faeces and thus remains in the environment, though bacteria will eventually break down most of the chemicals and immobilize the metals. In the Inuit (as with people in more temperate regions) their diet continues to concentrate these materials, and the metabolites of PCBs in their body fat increase 10 times from age 18 to age 66. Sooner or later, much of this will be expressed in disease. PCBs affect sexual development, among other things. Concentrations of PCBs comparable to those in human breast milk in industrialized countries turn the eggs of red-eared slider turtles from male to female. Polar bears in the Norwegian Arctic, where air pollution from Europe concentrates, develop both male and female genitals. Seals and dolphins in the North Atlantic basin, at the top of fishy food chains that accumulate the rain of chemicals falling on the North Atlantic (and washed into it through rivers) are dying of diseases their depressed immune systems can no longer handle. Several persistent organic pollutants, such as DDT and dioxins and their breakdown products, suppress the immune system. The population of beluga whales in the St. Lawrence estuary has fallen from 30,000 animals to about 30. Originally reduced by hunting, the population hasn’t recovered. The remaining belugas are full of tumors and virtually infertile. Their bodies have among the highest recorded levels of toxic chemicals found in living organisms. (This distinction is shared with the killer whales that eat salmon and seals off the northwest coast of the United States.) Most of these chemicals are industrial and agricultural materials washed into the Great Lakes. The chemicals in the water are taken up by planktonic algae. The algae are eaten by zooplankton, which are eaten by small fish, and eventually concentrated in the larger fish and eels the whales eat. Two toxins found in very high concentrations in the beluga, the insecticides chlordane and toxaphene, have no history of use in the St. Lawrence Basin. However, the St. Lawrence Basin occupies 500,000 square miles, so its waters concentrate airborn chemicals from a wide area. Chlordane and toxaphene probably arrived on the wind from the American South, where they were once used extensively.

One way or another, the environment is implicated in 80% of cancers. Some effects come through choice, as with smoking and diet; and some not, or at least not so obviously. (An example of the nonobvious comes from epigenetic effects on genes. Epigenetic effects involve environmentally mediated changes in genes—through such things as a mother’s diet, or a grandfather’s smoking, or his exposure to the chemicals in smoke—and may skip a generation or continue for several. Things like diet affect the methylation of genes and thus their expression. Epigenetic effects are thought to explain why fathers who started smoking before puberty have prepubertal sons who are heavier than normal; and why women whose grandmothers were short of food between the ages of 9 and 12 live longer. Other such transgenerational effects include the effects of DES, a synthetic estrogen, taken by pregnant women on the reproductive organs of their daughters.) Industrially produced chlorinated hydrocarbons are implicated in many cancers. Now widespread in the environment, chlorinated hydrocarbons are produced naturally by forest fires, volcanoes and some marine algae (traces of halogenated hydrocarbons have been found in the oil of whales killed before such compounds were manufactured), but most of them are produced by people. Some are harmful, some not. (The natural compounds seem to be less harmful.) Some may be involved in epigenetic effects. Many of the several thousand varieties of chlorinated hydrocarbons in the Great Lakes come from the chlorine bleaching of paper. Other chlorinated hydrocarbons include the dry cleaning chemicals and solvents dichloroethylene, trichloroethylene and perchloroethylene, which are found in about a third of American surface waters and also in about a third of American drinking water and in most American processed foods. Polynuclear aromatic hydrocarbons or PAHs are found in the haze of dust, tire dust and unburned gasoline that hangs over freeways in Los Angeles, glinting red in the dusk; PAHs are ubiquitous in lake sediments in North America and Europe; PAHs saturating the air downwind of coal burning power plants cause genetic mutations in mice and birth defects in birds (thus the crossed beaks and other abnormalities in the herring gulls of the lower Great lakes). The nonylphenols used in detergents and in the manufacture of plastics act as hormone mimics; their effect on the developing brains of larval fish has resulted in the fish inhabiting some British rivers being overwhelmingly female; such so-called estrogenic chemicals are also implicated in breast cancers. Nonylphenols leach out of things like plastic toys into human skin and out of food containers into food. They seem to affect larval fish by stimulating an enzyme that converts testosterone to estrogen. (Atrazine, a common herbicide, also an estrogen mimic, may work the same way.) The unpronounceable phthalates are used as plasticisers; phthalates are one of the most abundant industrial chemicals in the environment; some are estrogenic, some carcinogenic.

Then there are the heavy metals. As an anthropologist has pointed out, high lead levels (along with increased fire frequencies, eutrophicated lakes, soils disturbed by cultivation, and early successional forest vegetation) are signs of human occupation. Increasing metal contamination of northern hemisphere lake sediments during the twentieth century has been found wherever studies have been done. Cadmium, used in automobile greases, washes from roadways into rivers; cadmium is used also as a stabiliser in plastics, from which people can absorb it directly. Cadmium is not necessary for life but is implicated in some cancers. Mercury, a nerve toxin, is used as a biocide in paper making (it prevents those dark bacterial streaks I saw in classroom paper as a schoolchild). It is still sent, though much less than formerly, with the wastewater from paper manufacture into waterways, where bacteria convert it to methyl mercury, in which form it enters the food chain and accumulates in fish. (About 90% of mercury can be profitably removed from wastewater streams, the rest not.) The major environmental sources of mercury are the burning of fossil fuels, especially coal, for electricity generation; of gasoline and diesel for transportation; metal smelting; and garbage incineration (the last because of unrecycled mercury batteries in trash). Since the 1970s mercury has been increasing in the atmosphere at 2% a year (so in a few years its concentration will have doubled). Mercury contamination of forest soils is thought to be the reason all species of forest thrushes in North America, except the hermit, are declining. Inactive metallic mercury falling from the air is changed to methyl mercury by bacteria in damp forest soils; biologically active methyl mercury ends up in the invertebrates the thrushes eat.

Industrial chemicals are distributed worldwide by the same processes that distribute the sun’s heat from the tropics to the temperate regions and poles. The earth’s atmosphere insulates the earth and raises its average temperature from -2º F. (earth’s temperature as a radiative black body, determined by its albedo and distance from the sun) to 59º F. (its temperature thanks to the heat absorbing gases in its atmosphere). Air heated by the sun rises at the equator, along with much water vapor (a line of clouds marks its rise along the Intertropical Convergence Zone) and sinks as compressionally heated dry air at about 30º North and South. Thus the deserts that circle the earth at those latitudes. Cooled by radiation to space, air sinks at the poles. The tropical and polar circulations, driven by the relative strength and weakness of sunlight in these places, drive an indirect circulation over the North and South Temperate Zones. The spin of the earth and the placement of oceans and continents drive other, smaller convection cells. Heavy metals, radioactive materials, chlorinated and aromatic hydrocarbons, nitrates and sulfates enter the atmosphere from the stacks of power plants, incinerators, metal smelters, car tailpipes. Pesticides and herbicides evaporate from the fields and forests on which they have been sprayed. Warm, rising air lifted by the sun and given a twist by the earth’s spin carries them poleward, until the air begins to cool and sink, or the materials condense out onto droplets of rain or fog, and are carried downward and deposited on the ground, or in the ocean or rivers. If they settle on water they are absorbed into the thin bioactive skin of the sunlit surface that also contains high concentrations of single-celled organisms (plants, animals, viruses, bacteria). The materials are then incorporated into the food chain, usually by being taken up in cellular fats. As these materials pass up the food chain, their concentrations are biomagnified from 10,000 to 1,000,000 times in living tissue; that is, their concentration in living tissue increases geometrically as one organism eats another; the longer the food chain, the greater the concentration. (So lake trout from lakes with short food chains are safer to eat, and small fish are safer to eat than large ones.) The chemicals are also concentrated by wind patterns, by ocean currents (such as the spinning tropical gyres), in the interface of fresh and salt water, by fish migrations (sockeye salmon, which die after spawning, release the PCBs in their bodies into their natal Alaskan lakes, where they enter the food web), by seabird colonies. The ponds below arctic seabird colonies, fertile oases rich in nitrogen and phosphorus from the birds, and thus with plant and animal life, are also contaminated with the chlorinated hydrocarbons and metals the birds accumulate through eating fish, which they take from far at sea. So the distribution of heavy metals and persistant organic chemicals worldwide becomes surprisingly egalitarian but varies with the terminal location (wet and cold are worse) and the length of the food chain (short is better). Mercury from power plants burning coal ends up in Minnesota walleyes far from any power plant, in concentrations making the fish unsafe to eat, and in the arctic char, whitefish, lake trout and pike of Canada’s Northwest Territories, also far from any power plants. The fish-eating loons of the northeastern United States and Canada, downwind of the continent’s industrial chemistry, are much more contaminated by mercury than those in the center of the continent, or those on the West Coast, an advantage that will disappear as China develops; and, thanks to the thoroughness of atmospheric mixing, DDT sprayed on cotton fields in Brazil ends up in lake trout in Lake Michigan. The United States currently exports several tons per day (9 in 1994) of pesticides whose use is banned here; but the atmosphere returns them to us.

The air in the trophosphere, the lowest level of the atmosphere, mixes in each hemisphere (North and South) on a time scale of a few months. It takes about a year for pollutants to cross the Intertropical Convergence Zone and mix through the atmosphere as a whole, during which time many of them settle out. Thus the egalitarian distribution of manmade chemicals, but with fewer of them in the south, which has less land, less industry and fewer people. Material carried by the atmosphere moves inexorably north (south in the Southern Hemisphere), with an eastward component given it by the earth’s rotation; material that settles on land and is not washed by rain into waterways is re-volatilized by sunlight and continues its journey poleward, perhaps going through several more such settlings and re-volatilizations, during each of which it may be concentrated by rain or snowmelt in waterways, until it settles out on the lichens of the barren lands, and is concentrated in the flesh of the herbivores that graze them (lemmings, musk-ox, caribou), or in the northern oceans, lakes or rivers, and ends up in their fish, birds, whales, seals, and finally in the Inuit. The material may be buried for a time in the Arctic ice. Such scenarios were mostly unimaginable by the scientific community in 1948, when use of DDT and other synthetic chemicals was soaring. (Or were they unimaginable? The dangers of tetra-ethyl lead were well understood in the 1920s, when—thanks to pressure from General Motors and the Standard Oil Company, who had built a factory to produce it—it was introduced into gasoline to raise the octane level. Adding lead to gasoline was cheaper than refining gasoline further. When lead was finally banned from American gasoline in 1996, seven million tons of lead had been deposited into the atmosphere and along American roadsides. Seventy million children had been exposed to high blood levels of lead. As for the effects of coal burning on climate, the possibility of global warming from the burning of fossil fuels had been suggested at the end of the nineteenth century, by a Swedish physical chemist who buried the memory of an unhappy love affair in several years of calculations. But the effect on climate of raising the concentration of carbon dioxide in the atmosphere was thought to be small and slow.) Synthetic chemical production in the United States rose from one billion pounds in 1945 to 400 billion pounds in the 1980s and is higher now. Worldwide production is of course many, many times this.

Market economics always functions against a cultural background. This becomes very clear when one looks at different market-oriented societies. In Norway and Japan, countries with standards of living equal to or greater than that of the United States, the spread of incomes between the lowest and highest paid employees of a company rarely exceeds 10 times. That is, if the minimum wage is $15,000 per year, the head of the firm would earn no more than $150,000. In Sweden the ratio is 13 to 1, in France 15 to 1, in Britain 24 to 1. In the United States in 1980 the average CEO earned 40 times the wage of the average manufacturing employee. Now that CEO earns 475 times the employee’s income. Under current law, much of the CEO’s income is sheltered from taxes. The point is not that the American worker is worth that much less, economically speaking, than an American chief executive officer (such facts are probaby incalculable), but that the public ethos allows chief executive officers to ask that much more, and to pay that much less in monies collected for the public good. In the United States getting rich is considered a right. But how rich? A so-called welfare state that guarantees elderly people a livable income, provides for universal medical care, gives people paid vacations, maternity leave, affordable child-care and long-term unemployment insurance, also buffers itself against economic disaster, by providing a reliable, recession-proof flow of income and purchasing power. Redistributing wealth from the wealthy to those who will spend it guarantees a certain level of consumer spending and thus helps moderate market failure. Skewed income distributions, by limiting consumption, tend to inhibit economic development. This is a problem in parts of Africa, Asia and Latin America and may be becoming one in the United States. A common way to counter the development of extremely skewed distributions of wealth is through inheritance taxes. Andrew Carnegie, a self-made nineteenth-century Scottish-American industrialist, supported the notion of inheritance taxes. Carnegie believed in hierarchical societies, but ones in which the individual’s social position depended on his economic merit, not on inherited power or wealth. Inheritance taxes, by recycling wealth, keep the social order fluid. They also mobilize the movement of money.

Capitalist societies exhibit long-term cycles of growth and decline. For 20% of the history of the United States, the gross domestic product contracted. Markets, constantly evolving, can create massive economic instability. So certain sectors of all market economies are supported by the state. In the United States the list is quite long and includes fossil-fuel energy, war materials, real estate, agriculture, and the production of most virgin materials, such as timber and metal ores. Food, fuel and housing are the few necessary productions of a modern economy. As John Kenneth Galbraith has pointed out, the most long-standing, pure market, that in agricultural commodities, must be regulated to prevent the natural cycle of boom and bust from destroying agricultural producers, with the result of food shortages and high food prices. The cycle is simple. As prices for crops rise, farmers increase production, usually taking out loans to do this. As supplies of farm crops increase, prices fall, making the loans difficult to pay back. Farm profit margins are low, much less than 10% (more like 3%), so small changes in prices can have a big effect on farm profits. Superimposed on such human behaviors are weather conditions, which are not uniform over a growing region and can influence crop yields by 20-30%. Thus a particular farmer can face a poor harvest and low prices, while his neighbors, who have also increased their acreages and also face low prices, have normal yields and are able to remain more or less solvent, at least for a while. As farm income falls, profits drop at local businesses, such as banks, hardware stores, farm equipment dealers, coffee shops, doctors, veterinarians, real estate agents, insurance agencies. If bank loans are unrepayable, farms get auctioned off, real estate values fall, and services supported by property taxes, such as schools and roads, are hurt. After a few years of low prices, farm production drops, shortages develop, prices for crops then rise, the surviving farmers buy up the vacant land and production rises again. Corporations with capital, such as insurance companies, also buy up farms, which leads to land being farmed by tenants rather than owners. One solution to this situation is for the government to buy up surplus crops and store them until the price rises. Another is to support crop prices at the cost of production, no matter how much is produced. This is current U.S. policy. It is not necessarily the best social or environmental solution. While its original purpose was to keep food prices low, it has turned into a support system for corporate farmers. Consistently low, but supported, agricultural prices in the United States, along with greater and greater mechanization and chemical use, and the rising cost of land, have created more and more farm consolidation: larger and larger farms, more corporate farms. Because of the cost of land and of installing drainage, the American Corn Belt has always had a high percentage of its land in absentee owners (about half of cultivated land at the turn of the twentieth century); such owners, along with farmers who rent land, are interested primarily in what they can make off the land in the short run; they are not interested in the future of the landscape. Large farm operations, private or corporate, produce most of the country’s food and receive most of the government support payments. Typically, 20-30% of the income of large farms consists of government payments; if the farm is irrigated, the level of government support is over 90% (mostly in the irrigation infrastructure and the cost of water). Agricultural subsidies in 2000 amounted to half of farm income. Large farms also cause most of the environmental problems of agriculture. A side effect of farm consolidation in the agricultural landscape has been a fall in the rural population, and thus a decline in local economies and in public and private services (schools, stores, medical clinics), and also a widening in the income gap between the relatively well-off corporate farmers and the relatively poor laborers. A poorer population results in a further decline in tax-supported local services, just as the need for such services increases.

Most developed societies support the price of agricultural commodities and regulate production. In France, agricultural policy is seen both as supporting the food supply and as supporting the late-medieval French agricultural landscape: the appearance and the taste of the land (in wine, honey, salt, butter) some Frenchmen call the soul of France. The French developed methods of replanting hedgerows in Normandy, for instance. Hedgerows are useful as windbrakes in that windy land, and important as habitat for birds, small mammals, pollinators and other invertebrates. The hedgerows had been removed to make the fields larger and easier to work with modern equipment. Restoring them restores the landscape. Similar small-scale agricultural operations are supported all over France. These include sheepherders, wheat farmers, small wine-makers. Shepherds still follow herds of sheep grazing along the sides of country roads, or in the grassy wastelands near new housing projects. Such government subsidies represent social as much as economic choices. If the United States made similar choices, instead of the ones it now does, it would support biologically appropriate agriculture, distribute income more thoroughly, substitute photo-voltaic and wind power for coal and establish universal health care. The natural landscape would be allowed to recover. One could call the American economy still colonial, in that (in large measure) we trade agricultural and forest products for manufactured goods and oil. The rate of erosion from agricultural land in the United States is 10 to 15 times the background geological rate. Cutover timberland also erodes. The soil and nutrients lost from the land end up in rivers and the sea, shortening the life of dams, making clean water more expensive and eliminating native fisheries. Supporting better agricultural practice, treating abandoned or polluted lands as a resource, redistributing income and developing small-scale renewable energy would lead to an economic boom. As a candidate for election in 1996 suggested, a one-time tax of 15% on the net worth of all Americans worth $30 million or more would raise enough money to pay off the national debt. The money now paid in interest would be freed up to be used elsewhere; and the rich would make their money back in three years.

Economics also functions against a biological background. Plants change levels of atmospheric gases, modify nutrient cycles, engage in chemical warfare, promote (or suppress) wildfires, create shade, alter the temperature and humidity near the ground. Bacteria change the planet through photosynthesis, decomposition, respiration, nutrient cycling and fixation, by initiating processes that allow other organisms to colonize new environments. Fossil fuels, limestone and phosphate deposits, soils, sedimentary iron deposits, the amount of carbon dioxide in the atmosphere, the presence of oxygen—all are signs of life. Photosynthetic cyanobacteria began to oxygenate the atmosphere about 2.7 billion years ago. Iron precipitated out of the anoxic seas; was uplifted over hundreds of millions of years; and weathered of impurities to form concentrated iron ore, or hematite. Oxidation of the iron helped absorb some of the extra oxygen, which was poisonous to much of existing life. Such life, adapted to a world without oxygen, retreated underground, and new life arose. Modern ecosystems, with flowering plants, pollinators and mammals, began during the Jurassic Period 150 million years ago, when the level of oxygen in the atmosphere was close to 12%. Oxygen levels started rising in the middle of the Cretaceous Period about 100 million years ago during a burst of plant growth (never reached again), and reached the modern level of 21% perhaps 50 million years ago. Lower levels would make it hard for large mammals, which have less efficient lungs than dinosaurs and birds, to survive. Dips in the level of atmospheric oxygen correspond to major episodes of extinction. During this time, the stage was set for our cooler glacial world by the evolution, 390 million years ago, of root systems in plants. Roots secrete carbon dioxide into the soil, where it reacts with soil minerals, breaking them down and making them available to plants, and locking much of the carbon up in the process. The death of roots also adds carbon to the soil. Soil storage of carbon may have resulted in a 45% drop in atmospheric carbon dioxide and a slow planetary cooling (reinforced by the absorption of more carbon dioxide by the cooling ocean; much carbon dioxide was also locked up as coal and oil).

This is the ineluctable background of modern life. But economics focuses relentlessly on the human world. Economics assumes that the natural world can be ordered according to market needs and within market time-scales. It assumes that biological goods, such as forests, fish and beach-front property, can be consumed as fast as the market allows, at neglible economic or human cost: wild fish, salamanders, semi-palmated plovers, and other organisms of little economic value, pay the cost. Forests and mangrove swamps are exchangeable for hot dogs and dollar bills. Once a given resource has been exploited, the profits, if any, are invested in other enterprises. Most people don’t lose: wild salmon runs are replaced by farmed salmon; the profits from logging redwoods are invested in setting up web pages. Individuals such as fisherman and loggers may lose, but that is part of the creative destruction of capitalism; they can get other jobs; and the economy as a whole gains. As natural wealth disappears, the creation of wealth depends more and more on human manipulation. The exploitation of natural resources may remain high or even rise, their lower value per acre (as in second-growth timber), or lower unit value (the declining percent of metal in an ore) compensated for by larger machines, shorter rotation times, and greater use of fossil fuel energy. Oil and coal became cheaper and cheaper during the twentieth century thanks to increasing mechanization and ever-increasing use of those (ever cheaper) fossil fuels: a helpful upward spiral. In this abundant world, energy costs, even of energy-producing devices, didn’t really matter. When oil was abundant and accessible, oil production consumed only 2% of the energy the oil contained. Most other energy resources (coal, tar sands, photo-voltaics) require several times that energy investment and, partly because of this, will require a far larger energy infrastructure. (A 1970’s criticism of nuclear power plants was that more energy went into building them than they would ever produce; this turned out to be not quite true.)

Some sectors of the economy, such as the service sector, are less dependent on natural resources. The medical industry (15% of the United States’ economy) or the educational industry (another good-sized chunk) are examples of wealth-creating industries that don’t require such high levels of resource exploitation per unit of output; at any rate less than mining, logging, metal smelting or agriculture. Of course, modern physicians and teachers depend on the already high level of resource exploitation that the society itself requires (some of that mining, logging and agriculture). Computer software development is an almost purely intellectual effort, but behind it lie customers and computers, power plants, chip manufacturing facilities, heated or air-conditioned buildings, trucks, tremendous quantities of polluted groundwater. In 20 years computers have risen to consume 10% of the American electricity supply. In no time the person at the desk becomes part of the whole petrochemical stream.

Our world is constantly recreated by living things. Climate is partly regulated by the amount of carbon dioxide in the atmosphere and thus by the storage of carbon in vegetation, soils, peat bogs and carbonate rocks. Plants absorb carbon dioxide from the air, turn some of it into plant tissue and pump some of it into soils, where it is absorbed by the breakdown of rocks into useful plant nutrients (so-called, in-place weathering). Soil invertebrates, bacteria and fungi immobilize the carbon left behind in dying plant roots. (A considerable percent of the fine roots of trees and perennial grasses die and regrow every year.) Physical processes in the oceans would precipitate out absorbed carbon dioxide as calcium carbonate (limestone), but living things do it first, so limestone is mostly formed of shells and corals. Uplifted limestones from the sea form 10% of continental crusts. One day, as the earth’s continental crusts are slowly recycled, they will be subducted into the earth’s fiery mantle and their vaporized carbon returned to the atmosphere through volcanoes. Fossil fuels are probably the product of one major past storage event of tens of millions of years duration during a warm wet period especially favorable to vegetation. (Coal certainly is; some writers claim oil and gas are not, but are continually regenerated from inorganic matter by physical processes in the earth’s mantle.) At present, peat bogs and grasslands are both better than forests at long term storage of carbon and tropical forests are better than temperate ones.

The main absorption band of carbon dioxide corresponds with the earth’s peak thermal emissions, which explains its role as a greenhouse gas. Carbon dioxide levels in the atmosphere have been declining for tens of millions of years, and as a result, the earth has been slowly cooling, despite the increasing radiance of the sun. (The increasing radiance of the sun is a very long-term process.) A cooler climate tends to be a drier one, because less water evaporates from the oceans, and so declining carbon dioxide levels favor grasslands over forests, which need more moisture. The rise of carbon-storing grasslands and grazers over the last several million years has corresponded with our cooler glacial ages and, by absorbing more carbon dioxide into the soil, creates a positive feedback for a cooling earth. Some writers argue that under present planetary conditions, carbon dioxide (and the related gas methane, which oxidizes to it) acts as a natural thermostat. Carbon dioxide is stored as a gas in the atmosphere, as a weak solution of carbonic acid in the oceans, as clathrate hydrates near the poles, as carbonate minerals in the earth’s crust, in oil and natural gas. Cooling of the earth causes the reactions that store carbon dioxide in the oceans and soil to slow down, thus moderating the cooling. Continuing volcanic activity releases carbon dioxide from fossil fuels, carbonate minerals and other sources, slowly rewarming the earth. But under current planetary conditions carbon storage slowly increases overall, so the activity of the thermostat is superimposed on the slow cooling of the last several millions of years.

Besides carbon dioxide and oxygen (whose level is maintained by photosynthesis, largely of cyanobacteria and blue-green algae, but also by higher plants), gases of biological origin in the atmosphere include methane, nitrous oxide, and dimethyl sulfide. All are produced by bacteria or algae; methane and nitrous oxide are heat-absorbing gases that work at different wavebands than carbon dioxide; dimethyl sulfide, produced by marine organisms, is important in cloud formation (as are bacteria, which use the atmosphere for dispersal, and whose DNA is found in rain and snow); clouds are also important in regulating climate. (Such facts are taken by some to support the argument that earth’s climate is, within limits, self-regulating.) Without life, the composition of the atmosphere would be very different: the amount of carbon dioxide would be much greater, the turnover of nitrogen gas 10 to 20 times slower, the amount of oxygen very small. Atmospheric methane would not vary with the expansion and contraction of termite habitat or of methane-producing tropical wetlands (whose size is controlled by the strengths of summer monsoons, those a function of plate tectonics, ice cover in the Arctic, ocean currents, earth’s orbital cycles, and the intensity of the summer sun.)

The particular state of our world is maintained by its ecosystem services. The living world’s influence on climate (a sort of regulation) is its most dramatic ecosystem service. Others include maintaining the natural water cycle (regulating the heights of ground water tables and floods; to some extent, regulating the amount of rainfall); cleaning the air and water (forests filter the air passing through them; most ecosystems scavenge nutrients and toxic chemicals from water passing through them and influence its temperature, its siltiness, its chemistry, its rate of flow); maintaining the relative composition of the gases in the atmosphere (such as oxygen and carbon dioxide); creating and maintaining soils (the structure, water-holding capacity, and nutrient levels of soils are all functions of the living things in them as much as of their mineral composition and their location in the landscape); the cycling of nutrients essential for life, including human life, among the atmosphere, the oceans, plants, animals and soils; detoxifying pollutants (the workers here include the many organisms of decay, including those micro-organisms that can reduce human hormones and chlorinated hydrocarbons to more benign chemicals); on a smaller scale, pollination of plants and the regulation of plant and animal populations. The yearly value of such services has been put between $3 trillion and $33 trillion dollars (the latter about equal to the world’s gross domestic product, the former—given a yield of 5%—implying an investment of around $60 trillion). While such calculations are economically useful, ecosystem services are essentially irreplaceable. Both estimates are likely way too low. We can’t create systems that perform the services natural ones perform. Even on small scales, as in space ships or sewage treatment plants, this is difficult. Partly this is because of their size (and therefore their cost, both in wealth and in energy consumption) and partly because we don’t understand how the systems work.

We all share in our effects on the natural world. Any permanent human settlement changes plant cover and the local water cycle, and modern settlements require energy use and chemical output far above those of a few centuries or a few decades back. The footprint of a modern person—the acreage of farm, forestland, mines, manufacturing plants, roads, oil wells, waste dumps needed to sustain his or her life—is much larger, about 24 acres for the average American. Our combined demand requires more land than the United States contains. Is this necessary? Certainly not for human life. The energy use of a hunter-gatherer society, which is mostly food, plus some fuelwood, is little more than their caloric requirements, about 2000 kilocalories per person per day, all of it recyclable. Agriculturalists, who often grow a surplus of food, and also may use draft animals, irrigation water, and derive power from wind and water, use between 5 and 10 times as much, 10,000 to 20,000 kilocalories per person per day. While such societies are sun-powered and potentially sustainable, they may not be so in practice. (They may overcut their forests or overexploit their soils.) Industrial peoples of the nineteenth century with their railroads, steam engines, piped water and gas light, used about 70,000 kilocalories per person per day, much of it from coal, a fossil fuel, that is, a fuel whose energy comes from stored solar energy; burning a fossil fuel returns its carbon to the atmosphere from which it came, in general at a rate too fast for the land and oceans to absorb and neutralize. Late twentieth-century people in the developed world, with their automobiles, large houses, electric lights, airplanes, televisions and computers use about 120,000 kilocalories per person per day, or 60 times that of hunter-gatherers, and twice that of industrial populations in the nineteenth century. North Americans use twice that; but live no better than Europeans. The difference is thought to be partly extravagance (bigger cars, larger, warmer houses, a larger military establishment), partly more energy-intensive industries, and partly North America itself, with its more extreme climates and longer driving distances. The footprint of the developed world, if applied to a population of 6 billion, is not sustainable: that many people living a western life would require several earths. Astronauts, because of the energy demands of escaping earth’s gravitational pull (and those of recreating earth in space), use 2.7 million kilocalories per person per day. Most of the energy used by the developed world comes from the combustion of fossil fuels.

Fuel use is not the only way to measure the environmental impact of a society; synthetic chemical production and patterns of human settlement are others. The size of the American corn crop is a measure of the environmental impact of American agriculture. (The picture is one of relentless growth: corn yields are up 31% since 1995, 72% since 1975, that is from about 4 billion bushels in 1970 to 10 billion in 2000, largely because of genetic improvements, even as the land planted to corn shrank; each bushel requires 1.25 quarts of oil and one or more bushels of eroded topsoil to grow.) However extraction and combustion of fossil fuels constitute one of the most important causes of land degradation and water pollution, as well as a leading source of man-made greenhouse gases. Compared to natural energy fluxes on earth, human fossil fuel use is small, amounting to .11 calories per square meter per day. Input from the sun is 4900 calories per square meter per day, primary production by plants 7.8 calories, weather 100 calories. The outsize effect of fossil fuel use on natural systems derives from several factors. Water use by electric power plants constitutes the largest use after irrigation. While it is not a consumptive use like irrigation (water is pumped through the plants to cool them), it warms rivers and changes their flow regimes, simplifies their flora and fauna, and ruins their fisheries. (New plants can cut water use by 90%, at a small increase in the cost of power.) Obtaining fossil fuels takes up land for wells, roads, mines and pipelines and through spills or disposal of wastes, contaminates land and water. Burning them puts the products of combustion into the atmosphere: carbon dioxide (the gas of global warming), heavy metals like arsenic and mercury, dioxins and other hydrocarbons, sulfur, and radioactive materials. The heavy metals, sulfur, and radioactive materials are natural contaminants of the fuels. While arsenic, lead, mercury and radioactive elements are present in small concentrations in the natural environment, current man-made fluxes of them are comparable to, often greater than, the natural ones. For instance, the flux of mercury produced by people is 10 times the natural flux.

It is the production of carbon dioxide by the burning of fossil fuels whose effects may turn out to be the most dramatic, and perhaps the most catastrophic, for us. Carbon dioxide from the clearing of woodland, the cultivation of soil, and the burning of fossil fuels has apparently reversed the slow fall in the atmospheric concentration of this gas during the last several million years. Sunlight falls through the earth’s atmosphere with little absorption (a little is absorbed as heat) to strike the earth, where it is absorbed or reflected. When reflected (re-radiated) from the earth as infrared radiation (radiant energy of a different wavelength), it is captured by several gases in the atmosphere, including carbon dioxide, methane, nitrous oxide, and water vapor. Water vapor is the most abundant and most important greenhouse gas. By capturing a small amount of additional heat, man-made carbon dioxide raises the temperature of the atmosphere and increases the evaporation of water vapor from the oceans; this creates a positive feedback that raises the temperature of the atmosphere further; the climate warms. Since the ability of the atmosphere to hold water vapor increases rapidly with temperature, a small rise in temperature caused by carbon dioxide can end up having a large effect on atmospheric temperature.

The gases that absorb visible or infra-red radiation are not the only factors that influence the earth’s balance between incoming and outgoing solar radiation. The amount of dust in the atmosphere, clouds, the reflectivity of the earth’s surface (that is, whether it tends to reflect or absorb sunlight: ice reflects light, water absorbs it) also alter that balance, warming or cooling the planet. The global temperature is currently up 0.74º C. (1.33ºF.) from the pre-industrial level, though it is now thought that the pre-industrial level had been raised slightly above the “natural” level by human influences beginning several thousand years ago, including forest clearance for agriculture and wet rice cultivation (rice paddies produce methane). Clearing forests and cultivating soils releases carbon dioxide that would otherwise be stored. To keep global warming below 2º C. (considered a “safe“ level) carbon dioxide in the atmosphere must stay below 450 parts per million; this corresponds to an average carbon emission of half a ton of carbon dioxide per person per year. (2º C. is still a level at which the permafrost boundary will move 400 to 600 kilometers north and sea level rise several feet. Current measurements of methane released from thawing permafrost, and of carbon released from peat bogs, implies we are already at an unsafe level of warming.) A person in India currently produces 0.3 tons, an American 6 tons, a European 2 tons. Thus stabilising the climate implies large cuts in carbon dioxide emissions in developed countries, as countries like China and India develop; 70% in Europe, 90% in North America. This is not necessarily a disaster. Carbon dioxide from stationary sources (such as power plants) can be immobilized, at costs estimated at 2 to 4 cents per kilowatt hour, or 10-20% of current electricity costs. This would come to about $15 a month on the average American bill. (What we would do with a several billion tons a year of magnesium carbonate blocks is another matter.) Norwegian offshore oil and gas production is currently taxed at $38 per metric ton for the carbon dioxide associated with the burning of the fuels; to avoid this tax the state oil company reinjects the carbon dioxide stripped from its gas wells into salt formations under the North Sea. Renewable sources of energy work; and efficiency gains in the use of energy of far greater than 50% are possible, probably 1000% in the case of cars. The French and Japanese in the early 1960s supported themselves on energy usage one-seventh that of the United States today. They certainly lived modern lives (they made better movies), and because of tremendous increases in energy efficiency to date would lead even better ones on the same amount of energy today. By that measure the world today produces enough energy; the problem, as with food, is one of distribution. Even lower energy consumptions than those of France or Japan in the 1960s will support societies with low infant mortality, high life expectancies, varied diets, good medical care, and good educational opportunity. People in the Indian state of Kerala are said to live such lives on per capita incomes of less than $400 a year. (Since other writers claim that an adequate diet, that is, one that allows full expression of one’s genetic potential for growth, arrives only during the early stages of modernization, at per capita incomes of about $4000 a year, ten times that in Kerala, one must wonder at such claims.)

The direction of market-ruled societies is upward; their purpose is growth; their citizens constantly strive to increase their incomes. The notion of constant material improvement in human life is recent, probably foolish, and undoubtedly unsustainable. What is clear is that our current way of increasing our wealth is too much for the biological world to bear. All high civilizations fail; and their people die or disperse to lead simpler lives. (Four to six million people disappeared when the Maya collapsed.) In the past such failures have occurred when climates changed, rains failed, trade routes disappeared, soils grew less fertile. Since people took up agriculture and began to settle in villages 10,000 years ago, societies have created wealth from the extraction of virgin resources and the clearing of new land. For the most part, such societies occupied relatively small areas of the earth and used relatively small amounts of easily available natural resources (timber, soil, coal, copper, iron ore). While all societies fail in the end, none will take as much of the world with them as we will.