Climate Fact: Drought Trends
As Earth warms, the water cycle intensifies. While this means more total rainfall for some regions, it also means that more rainfall comes in the form of heavy and extreme events and periods between rainfall events become longer. Longer periods without rain and higher temperatures lead to losses of soil moisture; if drying of the soil continues for long enough, droughts occur. Since the 1950′s, some areas of the United States, including most of the Northeast and Midwest, have been experiencing drought conditions less frequently. Other areas, including most of the West and Southeast, have been experiencing drought conditions more often.
To see how drought frequency has changed in your local area since the 1950′s, visit http://www.earthgauge.net/climate-facts-image-library#3. This image is featured in the “Global Climate Change Impacts in the United States” report recently published by the U.S. Global Change Research Program. The image was originally created as part of an ongoing analysis of drought trends by Guttman and Quayle (see citation below). The image is in the public domain.
Seasons: Summer, Fall
Sources: Global Climate Change Impacts in the United States, Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson,(eds.). Cambridge University Press, 2009 and Guttman, NB and Quayle, RG. “A historical perspective of U.S. climate divisions.” Bulletin of the American Meteorological Society 77 (1996): 293-303. Operational practices described in this paper continue.
