U.S. Government Scientists Chime In

Lisa MooreThis post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense Fund.

IPCC scientists have been saying for years that man-made global warming is likely to increase extreme weather events. A new report ("Weather and Climate Extremes in a Changing Climate") from U.S. government scientists confirms these findings, and focuses specifically on the U.S.

It’s certainly timely, considering the devastating floods in the Midwest.

The report describes how U.S. weather is becoming more extreme, and links much of this change to human-induced global warming:

  • "[M]ost of North America has been experiencing more unusually hot days and nights"
  • "Heavy downpours have become more frequent and intense"
  • "Droughts are becoming more severe in some regions"

And what do they say about the future? According to model projections under a business-as-usual scenario:

  • "A day so hot that it is currently experienced once every 20 years would occur every other year or more by the end of the century."
  • Extreme downpours "that occur on average every 20 years in the present climate would, for example, occur once every 4-6 years for Northeast North America."
  • "[W]ith continued global warming, heat waves and heavy downpours are very likely to further increase in frequency and intensity. Substantial areas of North America are likely to have more frequent droughts of greater severity. Hurricane wind speeds, rainfall intensity, and storm surge levels are likely to increase. The strongest cold season storms are likely to become more frequent, with stronger winds and more extreme wave heights."
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  1. mikes
    Posted June 23, 2008 at 3:32 pm | Permalink

    Except that the Midwest floods have nothing to do with “Global Warming”

    And, most of the conclusions in the report have no basis in peer-reviewed research:

    And, on the 20th Anniversary of Jim Hansen’s original testimony to Congress, world temperatures are cooler than on the day he testified:

  2. fred1
    Posted June 24, 2008 at 8:09 am | Permalink

    And simple thermodynamics as it relates to extreme wx events shows that most storm systems in the mid latitudes are strengthened by the temperature differences between air masses….in other words, warm air masses from the subtropical areas colliding with colder air masses from the northern mid latitude areas. this is what has been happening in the Midwest where you have had an unusually cool spring. this cool air is still in place interacting with warmer air from the Gulf of Mexico. throw in the jet stream and you have increased storms.

    in summary, the global cooling we are currently experiencing is playing a major role in causing the extreme weather, due to higher differentials between hot and cold. Global warming, which would typically occur in the mid to upper latitudes (we all know the tropics don’t really get warmer during global warming periods), would cause a decrease in the regional temperature differentials that drive intense weather fronts and systems.

    in this case too bad we are not experiencing global warming since that would help to minimize the extreme events in the midwest. we need to blame the current global cooling trend as a main culprit for these events.

    i don’t understand why all these “scientists” don’t admit that..