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An abrupt climate change occurs when the climate system is forced to transition to a new climate state at a rate that is determined by the climate system energy-balance, and which is more rapid than the rate of change of the external forcing.[1] Past events include the end of the Carboniferous Rainforest Collapse,[2] Younger Dryas,[3] Dansgaard-Oeschger events, Heinrich events and possibly also the Paleocene–Eocene Thermal Maximum.[4] The term is also used within the context of global warming to describe sudden climate change that is detectable over the time-scale of a human lifetime. One proposed cause of such events is feedback loops within the climate system both enhance small perturbations and cause a variety of stable states.[5]

Timescales of events described as 'abrupt' may vary dramatically. Changes recorded in the climate of Greenland at the end of the Younger Dryas, as measured by ice-cores, imply a sudden warming of +Template:Convert/C-change within a timescale of a few years.[6] Other abrupt changes are the +Template:Convert/C-change on Greenland 11,270 years ago[7] or the abrupt +Template:Convert/C-change warming 22,000 years ago on Antarctica.[8] By contrast, the Paleocene-Eocene thermal maximum may have initiated anywhere between a few decades and several thousand years. Finally, Earth Systems models project that under ongoing greenhouse gas emissions as early as 2047, the Earth's near surface temperature could depart from the range of variability in the last 150 years, affecting over 3 billion people and most places of great species diversity on Earth.[9]

ReferencesEdit

  1. Cite error: Invalid <ref> tag; no text was provided for refs named def2
  2. Sahney, S. (2010). "Rainforest collapse triggered Pennsylvanian tetrapod diversification in Euramerica" (PDF). Geology 38 (12): 1079–1082. DOI:10.1130/G31182.1. 
  3. (May 2006) "Geology. Was the Younger Dryas triggered by a flood?". Science 312 (5777): 1146–1148. DOI:10.1126/science.1123253. ISSN 0036-8075. PMID 16728622. 
  4. (2002) Abrupt climate change : inevitable surprises. Washington, D.C.: National Academy Press. ISBN 0-309-07434-7. 
  5. (2004) "Nonlinearities, Feedbacks and Critical Thresholds within the Earth's Climate System" (PDF). Climatic Change 65: 11–00. DOI:10.1023/B:CLIM.0000037493.89489.3f. 
  6. (2005) "A revised +10±4 °C magnitude of the abrupt change in Greenland temperature at the Younger Dryas termination using published GISP2 gas isotope data and air thermal diffusion constants". Quaternary Science Reviews 24 (5–6): 513–9. DOI:10.1016/j.quascirev.2004.10.016. 
  7. (30 April 2008) "4 ± 1.5 °C abrupt warming 11,270 yr ago identified from trapped air in Greenland ice". Earth and Planetary Science Letters 268 (3–4): 397–407. DOI:10.1016/j.epsl.2008.01.032. 
  8. (January 2004) "Abrupt climate change around 22 ka on the Siple Coast of Antarctica". Quaternary Science Reviews 23 (1–2): 7–15. DOI:10.1016/j.quascirev.2003.09.004. 
  9. (2013) "The projected timing of climate departure from recent variability". Nature 502: 183–187. DOI:10.1038/nature12540. PMID 24108050.