30 Years of Global Warming Has Altered the Planet

"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," said lead author Cynthia Rosenzweig, a scientist at the NASA Goddard Institute for Space Studies and the Columbia Center for Climate Systems Research.

Both research centers are affiliates of The Earth Institute at Columbia University in New York.

Rosenzweig and researchers from 10 other institutions around the world analyzed data from published papers on 829 physical systems and some 28,800 plant and animal systems, back to 1970.

Migrating birds like these geese are affected by climate warming. (Photo courtesy FreeFoto.com)

Their analysis of revealed a picture of changes on continental scales, while previous studies had looked mainly at single phenomena, or at smaller areas.

Scientists are recording earlier leafing of trees and plants over many regions; movements of species to higher latitudes and altitudes in the northern hemisphere; changes in long distance bird migrations in Europe, North America and Australia.

In physical systems, 95 percent of observed changes are consistent with warming trends.

These include wastage of glaciers on all continents; melting permafrost; earlier spring river runoff; and warming of water bodies.

Among living creatures inhabiting such systems, 90 percent of changes are consistent with warming, the researchers found.

In the oceans, they are observing the shifting of the plankton and fish from cold-adapted to warm-adapted communities.

"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," said coauthor David Karoly, a climate scientist at the University of Melbourne in Victoria, Australia.

"This was possible only through the combined efforts of our multi-disciplinary team, which examined observed changes in many different systems around the globe, as well as global climate model simulations of temperature changes," he said.

Creeping desert sands invade once fertile land. (Photo courtesyUnited Nations University)

Their work builds upon the consensus of the Intergovernmental Panel on Climate Change, which in 2007 declared climate warming caused by human activities "likely" to affect biological and physical systems. This report was approved by consensus of 113 countries, including the United States, after a line-byline review.

The data showing the patterns of change are strongest in North America, Asia and Europe - mainly because far more studies have been done there, said Rosenzweig.

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

The authors say that there is an urgent need to study these environmental systems, especially in tropical and subtropical areas.

The study, "Attributing physical and biological impacts to anthropogenic climate change," appears in the May 15 issue of the scientific journal "Nature."

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