Tuesday, July 17, 2012

The Great American Drought: Climate Change? The New Dust Bowl?

It’s difficult to deny that large areas of the US are undergoing drought conditions at the moment. But should we be assuming that this is a portent of climate change? Or even that it is a harbinger of a new Dust Bowl, as in the 1930? We cannot completely rule out either of those possibilities but the correct answers as yet are no and no.
That there are drought conditions in many places is not in doubt:
In a monthly report to be released Monday, the National Climatic Data Center is expected to announce that this year’s drought now ranks among the ten largest drought areas in the past century.
Preliminary data computed from the Palmer Drought Severity Index shows that 54.6 percent of the contiguous 48 states was in drought at the end of June, the highest percentage since December 1956, and the sixth-highest peak percentage on record.
Monday’s State of the Climate drought report from NCDC is expected to show that since 1895, only the extraordinary droughts of the 1930s and 1950s have covered more land area than the current drought.
Note that we’ve only really had accurate rainfall and drought measurements for much of the US since that 1895 date. So, leaving aside specific years and looking at groupings, we’ve got the third worst drought conditions in just over a century. No, this isn’t to be ascribed to climate change then, obviously. As I say, it could be of course, but the prima facie answer is that it is not. For we’ve had it worse, twice, before in periods when we really were not worried about anthropogenically caused climate change. Occam’s Razor would so far lead us to the thought that it’s just one of those things that happens in a the normal variations of something like weather.

Read more: http://www.forbes.com/sites/timworstall/2012/07/16/the-great-american-drought-climate-change-the-new-dust-bowl/

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