A Hot Topic

In "Heatstroke," an ecologist argues that we need to rethink conservation in the age of global warming.

Heatstroke

By Anthony D. Barnosky

Island Press. 269 pp. $26.95

Ecosystem: It has long been a sacred word in environmental science. How best to preserve nature in the face of human population growth and habitat loss? Tempted though we may be to think "save the gorilla" or "save the whale," we must instead think "save the ecosystem" and protect a stable community of plants and animals. Now along comes ecologist Anthony D. Barnosky to say, "Think again."

Barnosky likes ecosystems just as much as the next scientist, but in "Heatstroke: Nature in an Age of Global Warming," he argues brilliantly that conservation biology can no longer focus on saving them. The reason is simple: Thanks to global warming, the ecosystem we work to save today will have a different climate tomorrow. This means that many species will face extinction (or at least serious loss of genetic diversity), even if the land around them is protected from the logger's chainsaw and the developer's backhoe.

Already, warming and drying have killed big herbivores such as antelope in South Africa. In Yellowstone National Park, the whitebark pine is declining, affecting animals from grizzly bears to red squirrels. Northern states are becoming increasingly southern in climate: For plants, Barnosky tells us, living in Maryland today is like living in Virginia was in 1970.

Like all complex systems, the Earth tends toward a stable state; it's not easy to change Nature. But once a fundamental shift in climate has occurred, Barnosky warns, it will be very hard to change back. "Heatstroke" begins with an assumption that the "if" questions about global warming have been answered, so on we march toward ways of coping. Most innovative is Barnosky's proposal for wildland reserves, where ecological interactions rather than stable communities would be protected. Because of global warming, in wildland reserves "our children will not see the same species that we see," but immersion in true wilderness will still be possible. May it be so.

-- Barbara J. King