Tuesday, June 24, 2014

Current Weather Extremes Are Not New

. . On January 16'th Judith Curry testified to the COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS OF THE UNITED STATES SENATE reviewing the President’s Climate Action Plan.  http://goo.gl/RrfTiw
. . She is the Chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology and has devoted 30 years to conducting research on topics including climate of the Arctic, the role of clouds and aerosols in the climate system, and the climate dynamics of extreme weather events.  As President of Climate Forecast Applications Network, she worked with decision makers on climate impact assessments, assessing and developing meteorological hazard and climate adaptation strategies, and developing sub-seasonal climate forecasting strategies to support adaptive management.
. . In her testimony she demonstrated that in the U.S., most types of weather extremes were worse in the 1930’s and even in the 1950’s than in the current climate, while the weather was overall more benign in the 1970’s. This sense that extreme weather events are now more frequent and intense is symptomatic of ‘weather amnesia’ prior to 1970. The extremes of the 1930’s and 1950’s are not attributable to greenhouse warming and are associated with natural climate variability (and in the case of the dust bowl drought and heat waves, also to land use practices).
 . . With regards to the impacts of climate change on the continental U.S., the following trends are seen over the past century:
  • declining frequency of wintertime cold extremes
  • declining frequency of drought
  • increasing frequency of heavy rain events
  • increasing sea level rise that is dominated by local factors in many locations 
There is a large component of natural variability seen in the 100+ year data record particularly for drought and heat waves, each of which had maximum extremes during the 1930’s. Sea level rise also shows a maxima during the 1930’s to 1940’s.

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