Human intervention alters natural systems: NASA study

May 15th, 2008 - 4:28 pm ICT by admin  


Washington, May 15 (IANS) Human intervention has caused widespread climatic alterations like permafrost thawing, premature blooming of plants across Europe and declining lakes in Africa, according to a NASA study. Cynthia Rosenzweig of NASA and co-author of the study, said it is the first to co-relate global temperature data sets and observed changes in a broad range of physical and biological systems with humans, climate, and impact.

Rosenzweig and colleagues also found that the link between man-made climate change and observed impact on Earth holds true at the scale of continents, like North America, Europe, and Asia.

To arrive at the link, the authors built and analysed a database of more than 29,000 series bearing on the observed impact on earth’s natural systems. The data were culled from 80 studies, each with at least 20 years of records between 1970 and 2004.

Observed impact included changes to physical systems, such as shrinking glaciers, 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.

Other driving forces, such as land use change from forest to agriculture, were ruled out as having significant influence on the observed impacts.

“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 and in North America, Europe, and Asia.”

The findings of the study have been published in the latest issue of the journal Nature.

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