The Sinai baton blue butterfly, with a wingspan no wider than a thumbnail, may seem like an insignificant creature. It lives only on mountainside patches of wild thyme in an arid corner of the Sinai Peninsula in Egypt called Saint Katherine's Protectorate. But a pair of British scientists think it may be the perfect model for how vulnerable animals will go extinct in the face of rising temperatures.
Plants and animals will not dwindle away slowly, say mathematical ecologist Martin Hoyle and biologist Mike James, formerly of the University of Nottingham in England. Instead, they will abruptly wink out of existence when temperatures reach tipping points. They used the butterfly—one of the world's smallest—to test how global warming and other pressures like livestock grazing might cause animal species to go extinct. They projected that small amounts of habitat loss or warming temperatures would have little effect. Even if goats ate up 60 percent of the thyme, the butterflies would be likely to survive. But they found that when average temperatures warmed slightly above a critical threshold, the entire butterfly population would suddenly crash.
Although they limited their study to the butterfly, Hoyle says their work could easily apply to other species. "There is no reason why this kind of thing wouldn't apply to other endangered endemic species" like polar bears, he says. "They don't have anywhere farther north to go."
