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  • pat neuman
    May 14, 2008 A new NASA-led study shows that human-caused climate change has impacted a wide range of Earth s natural systems, from permafrost thawing to
    Message 1 of 1 , May 20, 2008
      May 14, 2008

      A new NASA-led study shows that human-caused climate change has
      impacted a wide range of Earth's natural systems, from permafrost
      thawing to plants blooming earlier across Europe to lakes declining in
      productivity in Africa.

      Cynthia Rosenzweig of NASA's Goddard Institute for Space Science in
      New York and scientists at 10 other institutions have linked physical
      and biological impacts since 1970 with rises in temperatures during
      that period. The study, published May 15 in the journal Nature,
      concludes that 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.

      Rosenzweig and colleagues also found that 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.

      To arrive at the link, the authors built and analyzed a database of
      more than 29,000 data series pertaining to observed impacts on Earth's
      natural systems, collected from about 80 studies each with at least 20
      years of records between 1970 and 2004. Observed impacts included
      changes to physical systems, such as glaciers shrinking, permafrost
      melting, and lakes and rivers warming. Impacts also included changes
      to biological systems, such as leaves unfolding and flowers blooming
      earlier in the spring, birds arriving earlier during migration
      periods, and ranges of plant and animal species moving toward the
      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.

      The team conducted a "joint attribution" study in which they showed,
      first, that at the global scale, about 90 percent of observed changes
      in diverse physical and biological systems are consistent with
      warming. Other driving forces, such as land use change from forest to
      agriculture, were ruled out as having significant influence on the
      observed impacts.

      Next, the scientists conducted statistical tests and found that the
      spatial patterns of observed impacts closely match temperature trends
      across the globe, to a degree beyond what can be attributed to natural
      variability. So, the team concluded that observed global-scale impacts
      are very likely due to human-caused warming.

      "Humans are influencing climate through increasing greenhouse gas
      emissions and 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," said Rosenzweig.

      On other continents, including Africa, South America, and Australia,
      documentation of observed changes in physical and biological systems
      is still sparse despite warming trends attributable to human causes.
      The authors concluded that environmental systems on these continents
      need additional research, especially in tropical and subtropical areas
      where there is a lack of impact data and published studies.



      Steve Cole
      Headquarters, Washington

      Leslie McCarthy
      Goddard Institute for Space Studies, N.Y.

      This text is derived from:


      Pat N
      Email: npatnew@...
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