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WASHINGTON POST ' Book review

What the World Is Coming To

By Michael Ruse, co-editor of the forthcoming "Evolution: The First Four Billion Years"
Thursday, August 7, 2008; C02

THE DOMINANT ANIMAL

Human Evolution and the Environment

By Paul R. Ehrlich and Anne H. Ehrlich

Island Press/Shearwater. 428 pp. $35

Canadians joke that, given their vile winters, they are the only people in the world who welcome global warming. But some things are too serious for humor. The world is in a crisis because of rising temperatures. Climate patterns have been disrupted, with devastating effects on lands near and far. Regions that once produced food in abundance are now arid deserts. Australians, for instance, are starting to realize that their steady succession of droughts may not be a statistical blip but something more serious and permanent. The polar regions north and south are melting and breaking up, leading not just to short-term effects for animals but also to fears of rising ocean levels and the consequent flooding of today's dry land. Miami could find itself the Venice of the future, a city surrounded by waters.

No one has more authority to write on these matters than the husband-and-wife team of Stanford biologists Paul and Anne Ehrlich. For decades now they have been documenting and warning of humans' effects on the environment. Their new book, "The Dominant Animal," continues their chronicle of the damage we have done to our home. And although they write in prose of a high quality that is rare among academics, let alone scientists, gloomy reading is what they offer. But they want to do more than simply wail, Cassandra-like. They also want to dig into how and why we got into the predicament in which we find ourselves.

For the Ehrlichs, human evolution is the cause of our technological triumphs and tragedies. They emphasize that it is a mistake to think, however, that the causes of such evolution can be reduced simplistically to single factors. We must take into account both genetics and culture. The underlying foundation of human thought and behavior may be innate and rooted in our DNA, but the peculiar thing about Homo sapiens is how we lay culture and learning on top of all our biology. A prime example is controlling population growth. As the Ehrlichs point out, from an evolutionary perspective, nothing is more important than having babies. Until fairly recently, human numbers were kept in check by the natural misfortunes that befall almost all animals and plants, such as diseases, predators and food failures. But, thanks to culture, especially in the 20th century, human population exploded: A billion people were added in the two decades from 1950 to 1970. This was a direct function of technological advances, especially pesticides (leading to larger harvests) and antibiotics (leading to fewer deaths from disease).

These huge increases put pressures on people to produce even greater amounts of food, more housing and everything else needed for living. The most rational thing would be for us to notice that life has changed and to restrict our family sizes. But it isn't that simple. The Ehrlichs stress that human evolution at the cultural level is "sticky." We don't just change behaviors, throwing over beliefs, because circumstances are different. Patterns of behavior and thought get engrained and are hard to modify, and there are good biological reasons for this. If something works well over the course of time, then it makes sense that it should be protected against change: Stay with the tried and trusted because on average this will pay off the biggest dividends.

This stickiness has clearly contributed to our ecological crisis. Cultural patterns in such areas as agriculture have led to the great success of humankind, but these same patterns are leading us to strip rain forests and pump out greenhouse gases, leading to today's mess. Getting an understanding of how the interactions of biology and culture affect human behavior is itself reason to read this book.

I wish, however, that the Ehrlichs had made more of their profound insights. The last part of "The Dominant Animal" addresses how we might improve our position, for instance, by eschewing fossil fuels and relying much more on renewable sources of energy. But there is not enough about how we are to overcome our sticky cultural assumptions and do what is in our long-term interest. Houston, for example, recycles less than 3 percent of its waste, whereas San Francisco recycles nearly 70 percent. This is not because the people of Houston are less evolved than the people of San Francisco, but because the infrastructure and incentives are just not there. We need to be discussing how our inclinations to choose the quick and easy fix can be replaced by other cultural imperatives. In wartime, for instance, people can be persuaded to make sacrifices for the sake of the nation. Should we be thinking about a war on environmental destruction?

This is an important book, with much information and some really stimulating ideas. We need to build on these ideas, because the world is in an environmental mess and things are not getting better.

© 2008 The Washington Post Company