Wednesday, May 14, 2008

Whatever is exactly causing it, there is definitely a problem

Huge study documents changes from climate warming

A series of four photos from 1940, 1982, 1996 and 2005 shows the dramatic retreat of the Chacaltaya glacier in Bolivia.
Intergovernmental Panel on Climate Change
A series of four photos from 1940, 1982, 1996 and 2005 shows the dramatic retreat of the Chacaltaya glacier in Bolivia.

A landmark new climate study released today 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 patterns across Europe, North America and Australia, all in response to rising global temperatures.

While previous studies have looked at single phenomena or smaller areas, this is a new analysis on a continental scale looking at data that had not been previously assembled together in one spot, 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 due to climate change.

"Humans are influencing climate through increasing greenhouse gas emissions, and the warming world is causing impacts on physical and biological systems attributable at the global scale," Rosenzweig says. "These are things that are happening now, not projections of future changes."

The study appears in this week's British scientific journal Nature.

Rosenzweig and her colleagues compiled data on about 28,800 plant and animal systems and 829 physical systems, all of which showed documented changes over the past few decades.

The study found that 95% of the observed physical changes, and 90% of the biological changes, are consistent with what would be expected from warming temperatures.

Some of the physical changes include:

•Melting glaciers on all continents, specifically in Alaska, Peru, and the Alps.

•Earlier break-up and thinning of river and lake ice in Mongolia.

•Declining mountain snowpack in western North America.

•Earlier spring runoff in North America.

Some of the observed effects on living things include:

•Movements of species to higher latitudes and altitudes throughout the Northern Hemisphere.

•Population of emperor penguins has declined by 50% on Antarctic Peninsula.

•Rapid advance of spring arrival of long-distance migratory birds in Europe.

"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. However, scientists reported in the study that "these temperature increases at continental scales cannot be explained by natural climate variations alone."

Rosenzweig says that the 1970 — 2004 time period was selected because it coincides with the rapid recent warming of the planet. During that time, the Earth's temperature rose by about 0.6 degrees F. She points out that a global temperature rise of 3 to 7 degrees by 2100 — as predicted by the Intergovernmental Panel on Climate Change in 2007 — only "heightens the concern of what's happening now."

The data show that changes are most notable in North America, Asia and Europe — mainly because many more studies have been done there, says Rosenzweig.

On the other continents, including South America, Australia and Africa, documentation of changes in physical and biological systems is sparse, although there is strong evidence there of human-influenced warming itself.

The study builds upon the consensus of the IPCC, which in 2007 declared manmade climate warming "likely" to have discernible effects on biological and physical systems.

Original article posted here.

Original article posted here.

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