Thursday, June 19, 2008

NOAA: Government admits that man-made climate change is causing extreme weather events and hardships

The United States Climate Change Science Program (of the Department of Commerce, National Oceanic and Atmospheric Administration) has released a detailed report that strongly suggests that extreme weather events, in the United States and elsewhere, are indeed related to global climate change, some of which is likely to result from burning of fossil fuels. The link is here (PDF file, about 10 meg, 164 pages).

The report discusses many observations that ordinary people could make. These include longer growing seasons, fewer and shorter bitterly cold spells, longer spells of extreme heat, and more violent and protracted storms, especially in areas that usually have fewer of them (like the East Coast), as well as Midwest flooding (in 1993 and now 2008) and, of course, Hurricane Katrina in 2005 (and several other huge hurricanes). For example, extreme downpours happen when weather systems “train” along stationary fronts, and these have become more common in recent years.

The report is filled with many colorful charts (enough to please Jake Gyllenhaal’s character in the movie “Rendition”) and photographs. The writing style incorporates a lot of self-annotation, and the tone of the report resembles that of Al Gore’s “An Inconvenient Truth.”

There is a tendency to have less snow in North America in the winters in increasingly warm years, but that trend is not always consistent; the 1990s were a warm decade, but the East Coast had several huge snowstorms (such as in March 1993 and January and February 1996). But the huge snow events probably relate to the size and intensity of low pressure systems tracking far enough east to bring in unusually cold air compared to the general trend for warming; the intensity of the storms may be related to warming.

Sudden, prolonged and extreme droughts in some areas, such as the Southeast in 2007, may cause increasing hardships.

The official description of the report is as follows: “Synthesis and Assessment Product 3.3: CCSP, 2008: Weather and Climate Extremes in a Changing Climate. Regions of Focus: North America, Hawaii, Caribbean, and U.S.; Pacific Islands. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research, edited by and contributions by the following:. Thomas R. Karl, Gerald A. Meehl, Christopher D. Miller, Susan J. Hassol, Anne M. Waple, and William L. Murray, ]. Department of Commerce, NOAA's National Climatic Data Center, Washington, D.C., USA.”

Picture: Strong but brief thunderstorm with rainbow on a day with low humidity; strong sun causes convection into pool of cold air aloft associated with an upper level low to the north.

Update: July 8

Global leaders (in the Group of Eight) today pledged with an unbinding resolution to cut greenhouse gas emissions by 50% by 2050.

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