The untimely extinction of the golden toad in a Costa Rican rainforest in the late 1980s just may have been the first in a long list of species driven to extinction by global warming. In the 8 January issue of Nature, a team of researchers concludes that if climate warming proceeds unchecked, 15% to 37% of the 1103 plant and animal species they examined will disappear by 2050.
"Losing all of these species is not absolutely inevitable," says lead author Chris Thomas, a conservation biologist at the University of Leeds, U.K. A substantial number could be saved, Thomas says, by "making the right political and economic decisions."
In a collaborative tour de force, scientists from across the globe came together to collectively analyze how changes in climate may affect various organisms. To predict which creatures are in danger of extinction, the teams used computer modeling and information from the Intergovernmental Panel on Climate Change to compare the way habitats look today with how they may be altered by climate change. They also investigated whether particular species will be able to emigrate if their current territories become unfit.
The authors speculate that many other ecological problems could also erupt from changes in climate. For instance, species that move to a more suitable region or try to make do with their changed environments may have to battle invaders. And some creatures may face serious hurdles because the area between old and new destinations could also be rendered uninhabitable. Butterflies in Britain may be a good example of this, Thomas says. His work shows that many butterfly species that should have moved to more appropriate climates by now have not.
Until now, conservationists have pointed to habitat loss, direct overexploitation, and species invasions as the chief hazards to species survival, says Thomas. But the new study makes it "clear that climate change needs to be ranked among these as a major threat," he says.
The study does a "very nice job" of using different approaches to show that climate change is a dominant force, says Thomas Lovejoy, president of the H. John Heinz III Center for Science, Economics, and the Environment in Washington, D.C. "I think the single most important public policy [issue] here is agreeing on what the limit should be on greenhouse gas concentration," he says. "We've got to come to grips with where to draw the line."