Environmental meltdown altering life cycles
By Doyle Rice
USA Today
A landmark climate study out yesterday reports that global warming is already changing the life cycles of thousands of animals and plants — as well as hundreds of physical systems — worldwide.
It documents rapid glacier melts in North America, South America and Europe; trees and plants sprouting leaves much earlier in the spring in Europe, Asia and North America; permafrost melting in Asia; and changes in bird migration across Europe, North America and Australia, all in response to rising global temperatures.
While most previous studies have looked at a single phenomenon or smaller areas, this analysis examines data on a continental scale, says lead author Cynthia Rosenzweig, a scientist at NASA's Goddard Institute for Space Studies in New York.
By analyzing data from each of the Earth's seven continents and the oceans, the study paints a clear picture of a world that's been undergoing rapid transformation in just the past few decades.
"These are things that are happening now, not projections of future changes," she says.
In the study in this week's journal Nature, Rosenzweig and her colleagues compiled data on about 28,800 plant and animal systems and 829 physical systems, in all of which changes have been documented over the past few decades.
The study found that 95 percent of the observed physical changes and 90 percent of the biological changes are consistent with warming.
Some of the physical changes noted:
Some of the observed effects on living things:
"It was a real challenge to separate the influence of human-caused temperature increases from natural climate variations or other confounding factors, such as land-use changes or pollution," says study co-author David Karoly, a climate scientist at the University of Melbourne in Victoria, Australia.
But scientists said in the study that "these temperature increases at continental scales cannot be explained by natural climate variations alone."
However, Pat Michaels, a senior fellow in environmental studies at the Cato Institute in Washington, D.C., says that the study "is a retrospective study, with very little to say prospectively, given the unevenness of global warming."
Michaels says that there has been no significant warming since 1997, and that a recent study, also published in Nature, found that global warming isn't likely to get started again for at least another 10 years.
"I think the problem with this study is not in matching the past with the changes, but in projecting the future," Michaels says.
The data showed the most notable changes in North America, Asia and Europe mainly because many more studies have been done there, says Rosenzweig.
