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NOAA & NCAR - Two of the nation's premier atmospheric scientists conclude ...

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  • npat1@juno.com
    The study appears December 5 in Science as part of the journal s State of the Planet series. Dec 1, 2003 Press Release 2:00 PM EST No Doubt Human Activity
    Message 1 of 2 , Dec 4, 2003
    • 0 Attachment
      The study appears December 5 in Science as part of the journal's "State
      of the Planet" series.

      Dec 1, 2003 Press Release 2:00 PM EST

      "No Doubt" Human Activity Is Affecting Global Climate, Top Scientists
      Conclude

      BOULDER-Two of the nation's premier atmospheric scientists, after
      reviewing extensive research by their colleagues, say there is no longer
      any doubt that human activities are having measurable-and
      increasing-impacts on global climate. Their study cites atmospheric
      observations and multiple computer models to paint a detailed picture of
      climate changes likely to buffet Earth in coming decades, including
      rising temperatures and an increase in extreme weather events, such as
      flooding and drought. The study appears December 5 in Science as part of
      the journal's "State of the Planet" series.

      The coauthors-Thomas Karl, director of NOAA's National Climatic Data
      Center, and Kevin Trenberth, head of the Climate Analysis Section at the
      National Center for Atmospheric Research (NCAR)-conclude that industrial
      emissions have been the dominant influence on climate change for the past
      50 years, overwhelming natural forces. The most important of these
      emissions is carbon dioxide, a greenhouse gas that traps solar radiation
      and warms the planet.

      "There is no doubt that the composition of the atmosphere is changing
      because of human activities, and today greenhouse gases are the largest
      human influence on global climate," they write. "The likely result is
      more frequent heat waves, droughts, extreme precipitation events, and
      related impacts, e.g., wildfires, heat stress, vegetation changes, and
      sea-level rise which will be regionally dependent."

      Karl and Trenberth estimate that, between 1990 and 2100, there is a 90
      percent probability that global temperatures will rise by 1.7 to 4.9
      degrees Celsius (3.1 to 8.9 degrees Fahrenheit), because of human
      influences on climate. Such warming would have widespread impacts on
      society and the environment, including continued melting of glaciers and
      the great ice sheets of Greenland, inundating the world's coasts. The
      authors base their estimate on computer model experiments by climate
      scientists, observations of atmospheric changes, and recorded climate
      changes over the past century.

      Carbon dioxide levels in the atmosphere have risen by 31 percent since
      preindustrial times, from 280 parts per million by volume (ppmv) to over
      370 ppmv today. Other human activities, such as emissions of sulfate and
      soot particles and the development of urban areas, have significant but
      more localized climate impacts. Such activities may enhance or mask the
      larger-scale warming from greenhouse gases, but not offset it, according
      to the authors.

      If societies could successfully cut emissions and stabilize carbon
      dioxide levels in the atmosphere, temperatures would still increase by an
      estimated 0.5 degree C (0.9 degree F) over a period of decades, Karl and
      Trenberth warn. This is because greenhouse gases are slow to cycle out of
      the atmosphere. "Given what has happened to date and is projected in the
      future, significant further climate change is guaranteed," the authors
      state.

      If current emissions continue, the world would face the fastest rate of
      climate change in at least the last 10,000 years. This could potentially
      alter ocean current circulations and radically change existing climate
      patterns. Moreover, certain natural processes would tend to accelerate
      the warming. For example, as snow cover melts away, the darker land and
      water surface would absorb more solar radiation, further increasing
      temperatures.

      Karl and Trenberth say more research is needed to pin down both the
      global and regional impacts of climate change. Scientists, for example,
      have yet to determine the temperature impacts of increased cloud cover or
      how changes in the atmosphere will influence El Ni�o, the periodic
      warming of Pacific Ocean waters that affects weather patterns throughout
      much of the world. The authors call for multiple computer model studies
      to address the complex aspects of weather and climate. The models must be
      able to integrate all components of Earth's climate system-physical,
      chemical, and biological. This, in turn, will require considerable
      international cooperation and the establishment of a global climate
      monitoring system to collect and analyze data.

      "Climate change is truly a global issue, one that may prove to be
      humanity's greatest challenge," the authors conclude. "It is very
      unlikely to be adequately addressed without greatly improved
      international cooperation and action."

      -The End-

      Contacts:
      Anatta, NCAR
      303-497-8604
      anatta@...
      Cheryl Dybas, NSF
      703-292-7734
      cdybas@...



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    • patneuman2000
      Dec 1, 2003 Press Release 2:00 PM EST No Doubt Human Activity Is Affecting Global Climate, Top Scientists Conclude BOULDER-Two of the nation s premier
      Message 2 of 2 , Dec 15, 2004
      • 0 Attachment
        Dec 1, 2003 Press Release 2:00 PM EST

        "No Doubt" Human Activity Is Affecting Global Climate, Top Scientists
        Conclude

        BOULDER-Two of the nation's premier atmospheric scientists, after
        reviewing extensive research by their colleagues, say there is no
        longer any doubt that human activities are having measurable-and
        increasing-impacts on global climate. Their study cites atmospheric
        observations and multiple computer models to paint a detailed picture
        of climate changes likely to buffet Earth in coming decades, including
        rising temperatures and an increase in extreme weather events, such as
        flooding and drought. The study appears December 5 in Science as part
        of the journal's "State of the Planet" series.

        The coauthors-Thomas Karl, director of NOAA's National Climatic Data
        Center, and Kevin Trenberth, head of the Climate Analysis Section at
        the National Center for Atmospheric Research (NCAR)-conclude that
        industrial emissions have been the dominant influence on climate
        change for the past 50 years, overwhelming natural forces. The most
        important of these emissions is carbon dioxide, a greenhouse gas that
        traps solar radiation and warms the planet.

        "There is no doubt that the composition of the atmosphere is changing
        because of human activities, and today greenhouse gases are the
        largest human influence on global climate," they write. "The likely
        result is more frequent heat waves, droughts, extreme precipitation
        events, and related impacts, e.g., wildfires, heat stress, vegetation
        changes, and sea-level rise which will be regionally dependent."

        Karl and Trenberth estimate that, between 1990 and 2100, there is a 90
        percent probability that global temperatures will rise by 1.7 to 4.9
        degrees Celsius (3.1 to 8.9 degrees Fahrenheit), because of human
        influences on climate. Such warming would have widespread impacts on
        society and the environment, including continued melting of glaciers
        and the great ice sheets of Greenland, inundating the world's coasts.
        The authors base their estimate on computer model experiments by
        climate scientists, observations of atmospheric changes, and recorded
        climate changes over the past century.

        Carbon dioxide levels in the atmosphere have risen by 31 percent since
        preindustrial times, from 280 parts per million by volume (ppmv) to
        over 370 ppmv today. Other human activities, such as emissions of
        sulfate and soot particles and the development of urban areas, have
        significant but more localized climate impacts. Such activities may
        enhance or mask the larger-scale warming from greenhouse gases, but
        not offset it, according to the authors.

        If societies could successfully cut emissions and stabilize carbon
        dioxide levels in the atmosphere, temperatures would still increase by
        an estimated 0.5 degree C (0.9 degree F) over a period of decades,
        Karl and Trenberth warn. This is because greenhouse gases are slow to
        cycle out of the atmosphere. "Given what has happened to date and is
        projected in the future, significant further climate change is
        guaranteed," the authors state.

        If current emissions continue, the world would face the fastest rate
        of climate change in at least the last 10,000 years. This could
        potentially alter ocean current circulations and radically change
        existing climate patterns. Moreover, certain natural processes would
        tend to accelerate the warming. For example, as snow cover melts away,
        the darker land and water surface would absorb more solar radiation,
        further increasing temperatures.

        Karl and Trenberth say more research is needed to pin down both the
        global and regional impacts of climate change. Scientists, for
        example, have yet to determine the temperature impacts of increased
        cloud cover or how changes in the atmosphere will influence El Niño,
        the periodic warming of Pacific Ocean waters that affects weather
        patterns throughout much of the world. The authors call for multiple
        computer model studies to address the complex aspects of weather and
        climate. The models must be able to integrate all components of
        Earth's climate system-physical, chemical, and biological. This, in
        turn, will require considerable international cooperation and the
        establishment of a global climate monitoring system to collect and
        analyze data.

        "Climate change is truly a global issue, one that may prove to be
        humanity's greatest challenge," the authors conclude. "It is very
        unlikely to be adequately addressed without greatly improved
        international cooperation and action."

        -The End-

        Contacts:
        Anatta, NCAR
        303-497-8604
        anatta@u...
        Cheryl Dybas, NSF
        703-292-7734
        cdybas@n...
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