Many species of plants and animals will face extinction because they cannot evolve in time to adapt to the rapid onslaught of climate change. The pace of current global warming is simply too quick for natural or evolutionary adaptation.
A study by researchers at the University of Arizona finds that it takes up to a million years for species to evolve to a 1C degree temperature change.
Using data from 540 living species, including amphibians, reptiles,
birds and mammals, [Professor John]Wiens and colleagues compared their rates of evolution with the rates of climate change projected for the end of this century. The results, published online in the journal Ecology Letters,
show that most land animals will not be able to evolve quickly enough
to adapt to the dramatically warmer climate expected by 2100. Many
species face extinction, as a result.
"We found that, on average,
species usually adapt to different climatic conditions at a rate of only
by about 1C per million years," Wiens explained. "But if global
temperatures are going to rise by about four degrees over the next 100
years as predicted by the Intergovernmental Panel on Climate Change, that is where you get a huge difference in rates. What that suggests
overall is that simply evolving to match these conditions may not be an
option for many species."
The study indicates there is simply not
enough time for species to change their morphologies – for example, by
altering their bodies' shapes so they hold less heat – to compensate for
rising heat levels. Too many generations of evolutionary change are
required. Nor is moving habitat an option for many creatures. "Consider a
species living on the top of a mountain," says Wiens. "If it gets too
warm or dry up there, they can't go anywhere."