Abrupt climate change
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Abrupt climate change refers to an event where large and widespread climate change occurs within a short period, perhaps a decade. The phrase was coined because of worldwide, centuries-long events seen in ice cores of past climate. The archetypical such event was the Younger Dryas at the ending of the last ice age, which saw a rapid brief return to glacial conditions. There are also abrupt climate changes with sudden onset and gradual recovery, such as the half-sized event 8,200 years ago associated with a meltwater surge into the Labrador Sea. The best current theory for the triggers of this kind of abrupt climate change is the slowing of the thermohaline circulation (THC) in the North Atlantic caused by freshwater input from the Laurentide ice sheet. Since the ice sheet is no longer present, this same mechanism is unlikely to operate in the near future. About 25 Dansgaard-Oeschger cycles have been identified in the ice core record duing the glacial period over the past 100,000 years.
Other, comparitively small events, such as a regional drought such as the Dust Bowl of 1932-1938 might also be called "rapid climate change".
About 25 such Dansgaard-Oeschger cycles have been identified in the past 100,000 years. The last one was the Younger Dryas which began 12,900 years ago and popped back up into warm-and-wet about 11,600 years ago.
[edit] References
- Dessler, A.E. and Parson, E.A. The Science and Politics of Global Climate Change: A Guide to the Debate. Cambridge University Press, 0-521-53941-2, 2006.
- Alley, Richard (2000). The Two-Mile Time Machine: Ice Cores, Abrupt Climate Change, and Our Future. Princeton University Press.
- Calvin, William H. (2002). A Brain for All Seasons: Human Evolution and Abrupt Climate Change. University of Chicago Press.
- Cox, John D. (2005). Climate Crash: Abrupt Climate Change and What It Means for Our Future. Washington DC: Joseph Henry Press.
- R. B. Alley et al. (2003). "Abrupt Climate Change". Science 299 (5615): 2005-2010. DOI:10.1126/science.1081056.
