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    Global climate change

    Changes in Atmospheric Temperature clearly related to Human Activities

    11/30/2012, 5:18:55 AM

    By comparing nearly two dozen computer simulations to actual satellite observations going back to 1979, scientists from the Lawrence Livermore National Laboratory and others have shown that tropospheric and stratospheric temperature changes are clearly related to human activities.

    The troposphere is the lowest portion of earth's atmosphere. The stratosphere is right above the troposphere, generally between 6 and 30 miles above earth's surface.

    Key excerpts from the Lawrence Livermore National Laboratory news release.....

    In both satellite observations and the computer model simulations of historical climate change, the lower stratosphere cools markedly over the past 33 years. This cooling is primarily a response to the human-caused depletion of stratospheric ozone. The observations and model simulations also show a common pattern of large-scale warming of the lower troposphere, with largest warming over the Arctic, and muted warming (or even cooling) over Antarctica. Tropospheric warming is mainly driven by human-caused increases in well-mixed greenhouse gases.

    Temperature trend of the lower stratosphere since 1979. Courtesy Remote Sensing Systems.


    Temperature trend of the lower troposphere since 1979. Courtesy Remote Sensing Systems.


    "It's very unlikely that purely natural causes can explain these distinctive patterns of temperature change," said Laboratory atmospheric scientist Benjamin Santer, who is lead author of the paper appearing in the Nov. 29 online edition of the journal, Proceedings of the National Academy of Sciences. "No known mode of natural climate variability can cause sustained, global-scale warming of the troposphere and cooling of the lower stratosphere."

    These particular climate model simulations will play a key part of the upcoming 5th assessment of the Intergovernmental Panel on Climate Change (IPCC), which is due out in 2014.

    The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com


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    Global climate change