More change has occurred in the environmental movement during the past ten years than in its entire previous history. Its thrust has become less ideological and more pragmatic, less New Age and more scientific. It is increasingly grounded in the databases of atmospheric science and the genetic models of conservation biology. The practice of conservation in particular is now linked to economic development rather than opposed to it, focused on biological diversity rather than just scenic beauty, broadened to save entire ecosystems rather than individual star species such as pandas and bald eagles, and tilted southward to put increasing emphasis on those tropical countries where the most severe environmental problems exist. The next hundred years may well evolve into the century of the environment—during which most societies shift from guns and butter to butter and trees. All this comes not a moment too soon, if we are to save a failing planet.

A decade ago the public image of environmentalism was burdened with what might be called the Greenpeace metaphor. Environmental issues were caricatured as theaters of ideological conflict, where champions of Nature battled champions of Progress. Liberals, in this view, blocked dams in order to save oddly named small fishes, while conservatives heedlessly sacrificed the environment for short-term profit. The dichotomy was far from exact, but like most oversimplifications it held a lot of truth and reflected accurately some of the larger tensions of American life.

Today, to my distress, some conservative writers continue to treat environmentalism with skepticism or outright hostility. They depict it as one more workshop of the left, a means of enlarging government control and the power of the bureaucratic New Class, and a cudgel with which to beat free market economies and press for a restructuring of society—in short, a clever scheme to add the environment and its votaries to the Welfare State.

This is a mistake. The environmental crisis is real. If the heart of the conservation agenda is the preservation of the best in the world in the midst of change, it cannot be limited to institutions, the rule of law, and personal morality, but must also embrace the environment. Conservare is the common stem of conservation and conservatism, and perhaps that ancient link should serve as a signature of the basic principle that humanity does not exist apart from nature and will suffer to the extent that we abuse it.

Growth in scientific knowledge has altered the character of the environmental movement and its relation to political and economic life. A global view now prevails. We no longer see changes as isolated episodes—the pollution of a river here or the extinction of a bird species there. Now we see all of these events as having coalesced into worldwide secular trends. The release of chlorofluorocarbons in the northern hemisphere has opened a hole seven thousand miles away in the stratospheric ozone over Antarctica, admitting higher levels of ultraviolet radiation. This local collapse foreshadows the fate of the global atmosphere) threatening higher levels of skin cancer and disruption of ecosystems worldwide. The consumption of huge quantities of beef and timber in the United States accelerates the deforestation of Latin America, dries its great river basins, ruins its soil, and on a larger scale, raises carbon dioxide levels in the global atmosphere.

The secular trends can be conveniently classified as the four horsemen of the environmental apocalypse: global warming by the greenhouse effect, undeniably coming but at a rate still disputed among atmospheric scientists; ozone depletion, severe and not in dispute; toxic waste accumulation, severe and not in dispute; and mass extinction by habitat destruction, also severe and not in dispute.

Why should these man-induced changes be thought apocalyptic? After all, environmental change is perpetual, and organisms have always adjusted to it in past geological, times. Over millions of years species adapted to alternating climatic warming and cooling, the expansion or shrinkage of continental shelves, the invasion of new competitors and parasites. Those that could not change became extinct, but at such a relatively slow rate that other, better adapted species evolved to replace them. In the midst of endless turnover, the balance of life was sustained. But now the velocity of change is too great for life to handle, and the equilibrium is shattered. The change is the greatest experienced since the end of the Age of Dinosaurs 65 million years ago. It has reached precipitous levels within a single human life span, a mere tick in geological time. Humanity is creating a radical new environment too quickly to allow the adjustment of species, which need thousands to millions of years to accomplish complex genetic adaptations. Most of life is consequently at risk. Our life is at risk.

Like many other environmental scientists today, I think the tragedy can be averted, and in a manner that moves us toward a safer and more pleasant existence. It is the essence of the new environmentalism that further economic development need not harm the environment, at least not to anywhere near the degree now prevailing. The exact opposite is the case: intelligent economic development can save the natural environment, and the natural environment can be used to accelerate economic development. The key lies in the preservation and use of wild species and genetic strains, in other words biological diversity. Before exploring how this step can be accomplished, let me explain why biological diversity is the most fragile and in one sense the most valuable part of the environment. The extinction of species is the index of all the other secular changes. And where these processes—global warming, ozone depletion, and toxic pollution—can be reversed, extinction cannot. No species can be called back by a summit conference or Montreal Protocol. Each one is unique, precious, and irreplaceable. It is the terminus of an immense number of mutations, gene recombinations, and episodes of natural selection by which certain sets of genes increased as others declined. Each is prescribed by a genetic code that adapts it exquisitely to a particular part of the environment. Many of the genes vary within the species, so that every individual created by sexual reproduction has its own unique DNA code. A typical eukaryotic organism, such as a flowering plant or a bird (or human being), is prescribed according to species by one billion to ten billion nucleotide pairs, or genetic “letters,” in its DNA. If we could take the DNA double helices from a single cell of house mouse (Mus musculus is a well studied species), stretch them to full length and enlarge them until they were as wide as a piece of wrapping string, they would stretch about nine hundred kilometers, with each inch containing twenty-odd nucleotide pairs or genetic “letters.” The amount of information in the genes of a mouse is about equivalent to that in all 16 editions of the Encyclopaedia Britannica published since 1768.

Without interference from man, species live an average of one to ten million years. How many of these ancient entities are being driven to extinction by human action? We don’t know the absolute number, because the total size of the fauna and flora is not known. With the help of other biologists, I recently estimated that about 1.4 million species have been described to date, that is, given formal names such as Canis familiaris and Homo sapiens. But most specialists on biodiversity today would agree that the actual number is at least ten million, and it could be as high as one hundred million. In other words, the vast majority of kinds of organisms have not even been discovered, much less studied to any extent. The size of the biodiversity is not known even to the nearest order of magnitude! A majority of the species live in tropical forests, which are being reduced by cutting and burning at the rate of 1 percent a year. This destruction alone, if continued unabated, is projected to extinguish over one quarter of all the species of organisms on earth during the next fifty years. This translates to an extinction rate at least ten thousand times that before the coming of man. These estimates help to explain why so many biologists have grown anxious and vocal about the fate of tropical rain forests.

Evolutionary biologists are like art curators watching the Louvre burn down. You may ask why anyone but a few scientists should care about frogs and orchids in faraway tropical countries. Let me peel away the reasons, starting with enlightened self-interest and ending with ethics.

Destroying the habitats where life is richest pollutes the global environment as a whole. Between 2 and 5 percent of the land surface of the world is burned yearly, accounting for 95 percent of all the fires, with the rest coming mostly from lightning. Gases released by the burning, including carbon monoxide and ozone, currently approach the levels generated by the use of fossil fuels. As tropical forests are cleared, they uncover some of the poorest soils in the world, where less than one part in a thousand of nutrients penetrate five centimeters beneath the surface. The situation is radically different from that in the temperate forests, where a large portion of the organic material is invested in the deep leaf litter and humus layers. In tropical forests the material is locked up in the living vegetation and quickly reabsorbed by highly efficient root systems as it decays on the ground surface. When the trees are cut over a wide area, the nutrients bind with aluminum and iron or wash away in the torrential rains. The land becomes a “wet desert,” unable to sustain agriculture or husbandry at a profitable level for more than several years.

What are the rural poor to do if they cannot clear the land? The answer lies partly in zoning on a broad scale, while improving agriculture on the arable lands already under cultivation. It also lies in developing new markets for products from wild species. The plants and animals of the forests and other natural habitats are among the most important resources available to mankind, and so far they are the least utilized. In the course of history, for example, people have relied heavily on about twenty crop species, including wheat, rye, millet, and rice. These are mostly the plants that Neolithic man encountered haphazardly at the dawn of agriculture in Mesoamerica, the Fertile crescent, and tropical Asia. Yet there are at least fifty thousand plant species in the world with edible parts, and some of them are demonstrably superior to prevailing crop species. The winged bean (Psophocarpus tetragonolobus) of New Guinea, for example, is a veritable supermarket. The entire plant, including roots, seeds, leaves, stems, and flowers, is palatable, and a coffee-like beverage can be made from its juice. It grows very rapidly, reaching a height of three meters in a few weeks, and has a nutritional value equal to that of soybeans.

The animal equivalent of the winged bean is the giant river turtle Podocnemis expansa of the Amazon River. It can be reared at low cost on rough vegetation in natural and artificial ponds on the river banks. It yields tasty, low-fat meat at 440 times the rate of cattle grown in equivalent areas.

Wild species are a potential cornucopia of new fibers, petroleum substitutes, and pharmaceuticals. The Amazonian babassti palm, Orbignya phalerata, is one of the most productive sources of vegetable oil in the world, a stand of five hundred trees producing about one hundred and twenty-five barrels a year. One in ten plant species contains anticancer substances of at least some degree of potency. A striking success story is the rosy periwinkle, Catharanthus roseus, a native of Madagascar. This inconspicuous little plant yields two alkaloids, vinblastine and vincristine, that effectively cure two of the deadliest forms of cancer, Hodgkin’s disease and acute lymphocyctic leukemia. The U.S. National Cancer Institute is currently screening some ten thousand substances a year from wild plants for activity against other forms of cancer and the AIDS virus.

Not only can species be drawn from natural habitats and cultivated for their products, but the habitats can be converted into extractive reserves from which the products are harvested at minimal expense. A study recently conducted in the Amazonian rain forest near Iquitos, Peru, demonstrated that a greater profit can be made from treating the forest as an extractive reserve, in other words as a source of oil, latex, fruits, and other products, than by cutting it for timber and using the cleared land for ranching or conventional agriculture. And such is the case even though most potentially profitable species in the forest have not yet been identified or studied with a market in mind. Many of the plants and animals do not even bear a scientific name. It is clear that with proper research and capital investment, the fauna and flora of the world can enhance the quality of human life to a hitherto undreamed-of degree.

In conclusion, environmentalism means a great deal more than cleaning air and water, the obvious goals that still dominate public debate. It extends to the fuller use of organisms for the improvement of human existence. The new environmentalism also requires us to address the population problem frontally, without deference to any ideology or religion. The planet cannot sustain the continued growth of a species that already co-opts 40 percent of the sun’s energy available to life. The time has come to begin the discussion of optimal population size, the number of people at equilibrium or near equilibrium that is best for each country in turn. National birth control policies will eventually have to be designed to attain these safer levels, however distasteful this constraint on reproductive freedom may seem. I suspect that the optimum sizes for most countries will prove to be far below those already reached. Yet—how can anyone be certain either way in our present state of ignorance and timidity? Population policy, no less than economic policy, must come to occupy center stage in the years ahead.

Population and environmental policies more rational than those now in existence are crucial to the saving of this planet, which is our home forever. Both pivot on ethics, which turn on our self-image as a species. In an earlier article for Chronicles (April 1990), I suggested the need for “deep history,” which traces not just cultural history of the past ten thousand years, but the far older genetic history that created the brain and sensory apparatus from which culture is built. Humanity is a product of biocultural evolution, a process extending over hundreds of thousands of years. Culture is deeply affected by the results of genetic evolution, while genetically prescribed neurosensory evolution occurs within the arena of culturally transmitted social behavior. Biocultural evolution—deep history—was played out mostly in a natural environment, where technologically primitive people lived amidst a rich fauna and flora, exploring them, using them, and drawing from them the metaphors of art and the totems that mystically reaffirm our kinship to other forms of life. Our roots in the natural environment may be deeper than even dedicated environmentalists have argued. If we cut those roots free in response to a misguided Promethean ethic, it will be at the peril of the human spirit.