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Heat Waves to be More Severe, More Frequent and Longer Lasting w/Global Warming

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  • Mike Neuman
    The article below states that the most severe health impacts from the Chicago heat wave of 1995 was due to the lack of cooling relief several nights in a row.
    Message 1 of 1 , Aug 16, 2004
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      The article below states that the most severe health impacts from the
      Chicago heat wave of 1995 was due to the lack of cooling relief
      several nights in a row. I've also read that very high humidity
      levels (higher heat indexes) had a lot to do with number of heat-
      related deaths from the Chicago 1995 heat wave.
      Future Heat Waves: More Severe, More Frequent, Longer Lasting


      Anatta, NCAR Media Relations

      Jerry Meehl, NCAR

      BOULDER--Heat waves in Chicago, Paris, and elsewhere in North America
      and Europe will become more intense, more frequent, and longer
      lasting in the 21st century, according to a new modeling study by two
      scientists at the National Center for Atmospheric Research (NCAR). In
      the United States, the increase in heat wave severity will be
      greatest in the West and the South. The findings appear in the
      August 13 issue of the journal Science.

      Gerald Meehl and Claudia Tebaldi, both of NCAR, examined Earth's
      future climate using the Parallel Climate Model, developed by NCAR
      and the U.S. Department of Energy (DOE). NCAR's primary sponsor, the
      National Science Foundation, and the DOE funded the study, with
      additional support from NCAR's Weather and Climate Impact

      Model results show that an increase in heat-absorbing greenhouse
      gases intensifies an unusual atmospheric circulation pattern already
      observed during heat waves in Europe and North America. As the
      pattern becomes more pronounced, severe heat waves occur in the
      Mediterranean region and the southern and western United States.
      Other parts of France, Germany, and the Balkans also become more
      susceptible to severe heat waves.

      "It's the extreme weather and climate events that will have some of
      the most severe impacts on human society as the climate changes,"
      says Meehl.

      Heat waves can kill more people in a shorter time than almost any
      other climate event. By a measure of excess death reports, 739 people
      died as a result of Chicago's heat wave July 14-20, 1995. Fifteen
      thousand are estimated to have died from heat in France in August
      2003, along with thousands of farm animals.

      For the study, Meehl and Tebaldi compared present (1961-1990) and
      future (2080-2099) decades to determine how greenhouse gases and
      sulfate aerosols might affect future climate in Europe and the United
      States, focusing on Paris and Chicago. They assumed little in the way
      of policy intervention to slow the buildup of greenhouse gases.

      During the Paris and Chicago heat waves, changes in atmospheric
      pressure produced clear skies and prolonged hot conditions at the
      surface. In the model, similar atmospheric pressure changes are
      enhanced during heat waves in both regions as carbon dioxide
      accumulates in the atmosphere.

      Model Results

      --Heat waves will become more severe

      During the Chicago heat wave, the most severe health impacts resulted
      from the lack of cooling relief several nights in a row, according to
      health experts. In the model, the worst three-day heat waves show a
      rise of more than 3 degrees Celsius (5.4 degrees Fahrenheit) in
      minimum nighttime temperatures in the western and southern United
      States and the Mediterranean region of Europe.

      --They will occur more often

      The average number of heat waves in the Chicago area increases in the
      coming century by 25%, from 1.66 per year to 2.08. In Paris, the
      average number increases 31%, from 1.64 per year to 2.15.

      --They will last longer

      Chicago's present heat waves range from 5.39 to 8.85 days; future
      events increase to between 8.5 and 9.24 days. For Paris, present-day
      heat waves range from 8.33 to 12.69 days; they stretch to between
      11.39 and 17.04 days in future decades.

      Opinions, findings, conclusions, or recommendations expressed in this
      publication are those of the author(s) and do not necessarily reflect
      the views of the National Science Foundation.

      -The End-

      Note to Editors: Reporters may obtain the paper, "More intense, more
      frequent, and longer lasting heat waves in the 21st century," by
      Gerald A. Meehl and Claudia Tebaldi, by calling 1-202-326-6440 or e-
      mailing scipak@...

      Find this press release and images on the Web at
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