Climate change could hit tropical wildlife hardest

By Deborah Zabarenko, Environment Correspondent

WASHINGTON (Reuters) - Polar bears may have it relatively easy. It's the tropical creatures that could really struggle if the climate warms even a few degrees in places that are already hot, scientists reported on Monday.

That doesn't mean polar bears and other wildlife in the polar regions won't feel the impact of climate change. They probably will, because that is where the warming is expected to be most extreme, as much as 18 degrees F (10 degrees C) by the end of this century.

But there are far fewer species living in the Arctic and Antarctic and in the temperate zones than in the tropics, said Curtis Deutsch of the University of California at Los Angeles.

Many of these tropical creatures are living at the edge of their temperature tolerance already. Even the slight tropical warming predicted by 2100 -- 5.4 degrees F (3 degrees C) -- could push them to the brink, Deutsch said in a telephone interview.

In research published in Proceedings of the National Academy of Sciences, Deutsch and his co-authors investigated what could happen to cold-blooded animals in the tropics over the next 100 years if the predictions of greenhouse warming hold true.

They chose cold-blooded creatures -- mostly insects but also frogs, lizards and turtles -- because warm-blooded animals have other ways of regulating their body temperatures, such as growing a thick coat of fur to guard against cold and shedding when it gets warm.

TROPICAL POPULATION CRASH

Cold-blooded organisms can either seek shade when it's hot or sun themselves when it's cool, but otherwise they are limited, Deutsch said.