UCLA: Global Warming
Global warming will negatively impact tropical species, study shows - 5/5/08
Global warming is likely to reduce the health of tropical species, scientists from UCLA and the University of Washington report May 6 in Proceedings of the National Academy of Sciences.
At the same time, a little bit of warming may actually move certain organisms, particularly insects, in the high latitudes closer to their optimal temperature, the researchers say.
"In the tropics, most of the organisms we have studied, from insects to amphibians and reptiles, are already living at their optimal physiological temperatures," said Curtis Deutsch, UCLA assistant professor of atmospheric and oceanic sciences and co-author of the study. "When warming starts, they do less well as they move toward the hottest end of their comfort range. Even a modest increase in temperature appears rather large to them and negatively impacts their population growth rates."
At least for the short term, the impact of global warming will have opposing effects. In the tropics, warming will reduce insects' ability to reproduce; in the high latitudes, the ability of organisms to reproduce will increase slightly, Deutsch said.
Scientists have measured in laboratories how sensitive different species are to changes in temperature. For insects, the data is comprehensive and includes information on how temperature affects the population growth rate for species, Deutsch said. He and his colleagues - who included Joshua Tewksbury, assistant professor of biology at the University of Washington, and Raymond Huey, professor of biology at the University of Washington - studied the data, then went to climate models and analyzed what the predicted temperature change in various regions implied about species' future growth rate.
