Abrupt climate change
From Wikipedia, the free encyclopedia
Abrupt climate change refers to an event where large and widespread climate change occurs within about five years. A regional drought such as the Dust Bowl of 1932-1938 is the most familiar climate change on this time scale, but the phrase was coined because of worldwide, centuries-long events seen in ice cores of past climate. At least two modes of climate are now recognized: a warm-and-wet climate like today's and a climate that is cooler, drier, windy and dusty. An ice age is often in the latter mode but climate may chatter between the two modes with only minor changes in glaciers, dropping into the dry mode for centuries, popping up into warm-and-wet with only a five year transition, and then crashing back down again after a few more centuries. 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. 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 human population has grown a thousand times since the last major flip; were the transitions spread out over 500 years, civilizations would likely adapt. A five-year transition into worldwide drought would likely produce major wars over remaining resources.
[edit] References
- 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.
