(Xinhua)
Updated: 2008-05-15 07:57

WASHINGTON - A new NASA-led study shows human- caused climate change has made an impact on a wide range of Earth' s natural systems, including permafrost thawing, plants blooming earlier across Europe, and lakes declining in productivity in Africa.

Cynthia Rosenzweig of NASA's Goddard Institute for Space Science and scientists at 10 other institutions have linked physical and biological impacts since 1970 with rises in temperatures during that period.

The study, to be published on May 15 in the journal Nature, concludes human-caused warming is resulting in a broad range of impacts across the globe.

"This is the first study to link global temperature data sets, climate model results, and observed changes in a broad range of physical and biological systems to show the link between humans, climate, and impacts," said Rosenzweig, lead author of the study.

Observed impacts included changes to physical systems, such as glaciers shrinking, permafrost melting, and lakes and rivers warming.

Biological systems also were impacted in a variety of ways, such as leaves unfolding and flowers blooming earlier in the spring, birds arriving earlier during migration periods, and plant and animal species moving toward Earth's poles and higher in elevation.

In aquatic environments such as oceans, lakes, and rivers, plankton and fish are shifting from cold-adapted to warm-adapted communities.

Their study indicated that at the global scale, about 90 percent of observed changes in diverse physical and biological systems are consistent with warming.

"Humans are influencing climate through increasing greenhouse gas emissions," Rosenzweig said. "The warming is causing impacts on physical and biological systems that are now attributable at the global scale."

The research team also found the link between human-caused climate change and observed impacts on Earth holds true at the scale of individual continents, particularly in North America, Europe, and Asia.