From: NOAA
Published June 20, 2008 10:48 AM
Changing climate will lead to more extreme weather:
Report
The U.S. Climate Change Science Program and the Subcommittee on Global
Change Research today released a scientific assessment that provides the
first comprehensive analysis of observed and projected changes in weather
and climate extremes in North America and U.S. territories. The
Intergovernmental Panel on Climate Change previously evaluated extreme
weather and climate events on a global basis in this same context. However,
there has not been a specific assessment across North America prior to this
report.
Among the major findings reported in this assessment are that droughts,
heavy downpours, excessive heat, and intense hurricanes are likely to become
more commonplace as humans continue to increase the atmospheric
concentrations of heat-trapping greenhouse gases.
The report is based on scientific evidence that a warming world will be
accompanied by changes in the intensity, duration, frequency, and geographic
extent of weather and climate extremes.
"This report addresses one of the most frequently asked questions about
global warming: what will happen to weather and climate extremes? This
synthesis and assessment product examines this question across North America
and concludes that we are now witnessing and will increasingly experience
more extreme weather and climate events," said report co-chair Tom Karl,
Ph.D., director of NOAA’s National Climatic Data Center in Asheville, N.C.
"We will continue to see some of the biggest impacts of global warming
coming from changes in weather and climate extremes,”¯ said report co-chair
Gerry Meehl, Ph.D., of the National Center for Atmospheric Research in
Boulder, Colo. "This report focuses for the first time on changes of
extremes specifically over North America."
The full CCSP 3.3 report, Weather and Climate Extremes in a Changing
Climate, and a summary FAQ brochure are available online.
Global warming of the past 50 years is due primarily to human-induced
increases in heat-trapping gases, according to the report. Many types of
extreme weather and climate event changes have been observed during this
time period and continued changes are projected for this century. Specific
future projections include:
* Abnormally hot days and nights, along with heat waves, are very likely to
become more common. Cold nights are very likely to become less common.
* Sea ice extent is expected to continue to decrease and may even disappear
in the Arctic Ocean in summer in coming decades.
* Precipitation, on average, is likely to be less frequent but more intense.
* Droughts are likely to become more frequent and severe in some regions.
* Hurricanes will likely have increased precipitation and wind.
* The strongest cold-season storms in the Atlantic and Pacific are likely to
produce stronger winds and higher extreme wave heights.
The National Oceanic and Atmospheric Administration, an agency of the U.S.
Commerce Department, is dedicated to enhancing economic security and
national safety through the prediction and research of weather and
climate-related events and information service delivery for transportation,
and by providing environmental stewardship of our nation's coastal and
marine resources.
NOAA plays a key role in the Climate Change Science Program, which is
responsible for coordinating and integrating climate research, observations,
decision support, and communications of 13 federal departments and agencies.
The National Center for Atmospheric Research investigates climate,
weather, and other topics related to the atmosphere. It is sponsored by the
National Science Foundation and managed by a nonprofit consortium of
universities, the University Corporation for
Atmospheric Research.
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