U.S. Geological Survey (USGS) scientists who study historic climate trends will be presenting new studies at a workshop held in Pacific Grove, California, March 26-29.
The recent six-year-long drought across much of the western United States and the extensive dust bowl of the Great Plains in the 1930s, the subject of John Steinbeck´s "The Grapes of Wrath," are recent examples of droughts that have plagued western North America for centuries. These examples, and the associated costs to society, seem short and insignificant when compared to extensive warm and dry intervals that have been recorded over the past 2,000 years. These include a 16th century megadrought, which affected the culture of central Mexico, an extended period of dry summers which may have led to the abandonment of the Chaco Canyon culture in New Mexico, and a lengthy period between about A.D. 800 and 1350 known as the Medieval Warm Period. USGS scientists use a variety of tools to uncover evidence of these droughts, including tree ring patterns, lake and ocean sediments, geochemistry, and climate modeling. These extended periods of drought are the topic of the 22nd Pacific Climate Workshop (PACLIM) to be held March 26-29, 2006.
Partially organized and funded by the USGS, the conference brings together university and government scientists from around the country for presentations and discussions on various aspects of climate variability, from the impact of the current drought on seasonal snowpack in the Sierra Nevada and the role of sea surface temperature along the California coast, to evidence from tree rings in New Mexico supporting the influence of climate on the migration of Paleo-indian populations across the southwest. Other presentations cover drought and a wide variety of other climate-related topics including the role of climate variability in the types of fish caught in the eastern Pacific, evidence of solar variability from lake sediments, and the influence of volcanic activity on short-term cooling.
USGS scientists will be presenting the results on new analyses of the role of decadal variation in the temperature of the surface waters of the Atlantic and Pacific Oceans (McCabe and others), longer-period variations in water temperature and wind variability in the Gulf of California (Barron and Bukry), aridity patterns derived from microfossils in San Francisco Bay marshes (Starratt), the impacts of atmospheric circulation variability on the climate in Alaska (Anderson), rock glaciers as indicators of climate change in the eastern Sierra Nevada (Millar and others), and the role of climate change in the migration of Native Americans in the southwestern U.S. (Benson).
Highlights of USGS work presented at the Pacific Climate Workshop (PACLIM), Asilomar Conference Center, Pacific Grove, California, March 26-29, 2006, http://wrgis.wr.usgs.gov/wgmt/deserts/paclim/ are as follows:
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