Meltwater pulse 1A

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Image showing sea level change during the end of the last glacial period. Meltwater pulse 1A is indicated.

Meltwater pulse 1A was a considerable post-glacial sea level rise of about 20 m in less than 500 years,[1] perhaps just 200 years.[2]

Period[edit]

The meltwater event occurred in a period of rapid climate change when the Holocene glacial retreat was going on during the end of the last ice age. Several researchers have narrowed the period of the pulse to between 13,000 and 14,600 years ago.[3]

The pulse is framed historically between the Bølling-Allerød (B-A) interstadial and the Antarctic Cold Reversal/Older Dryas events.[4]

Mechanism[edit]

Computer modelling, published in 2012, suggests that the collapse of the ice-sheet saddle between Canada and Greenland can explain the meltwater pulse.[5] A 2014 study that examined dust released from melting icebergs onto the seabed of the Southern Ocean suggests a significant meltwater contribution from a collapse of Antarctic ice sheets.[6]

Whether the pulse originated in the North or South, the event probably relates to the North Atlantic Deep Water thermohaline circulation which transports heat between the North Atlantic and the South Pacific.[4] At different times research supported the pulse originating in the north or south but it is certain there was some component from both,[4] and perhaps the majority coming from the north.[7]

Sea level[edit]

The sea level is estimated to have risen at a rate of 37 to 65mm/yr - the pulse was much larger than current sea level rise, which has been judged to be in the region of 2[8] to 3mm/yr.[9]

References[edit]

  1. ^ Webster, Jody; et al. (February 23, 2004). "Drowning of the -150 m reef off Hawaii: A casualty of global meltwater pulse 1A?". Geology and GSA Today (The Geological Society of America, Inc.). pp. 249–252. Retrieved 2009-12-08. 
  2. ^ Stanford, Jennifer D.; Rohling, Eelco J.; Hunter, Sally E.; Roberts, Andrew P.; Rasmussen, Sune O.; Bard, Edouard; McManus, Jerry; Fairbanks, Richard G. (9 December 2006). "Timing of meltwater pulse 1a and climate responses to meltwater injections". Paleoceanography (American Geophysical Union) 21 (4): 4103. Bibcode:2006PalOc..21.4103S. doi:10.1029/2006PA001340. 
  3. ^ Gornitz, Vivien (2009). Encyclopedia of paleoclimatology and ancient environments. Springer. p. 890 (Table S1). ISBN 978-1-4020-4551-6. 
  4. ^ a b c Weaver, Andrew; Saenko, Oleg; Clark, Peter; Mitrovica, Jerry (14 March 2003). "Meltwater Pulse 1A from Antarctica as trigger of the Bølling-Allerød Warm Interval". Science 299 (5613): 1709–1713. Bibcode:2003Sci...299.1709W. doi:10.1126/science.1081002. PMID 12637739. Retrieved 2009-12-08. 
  5. ^ Gregoire, Lauren (11 July 2012). "Deglacial rapid sea level rises caused by ice-sheet saddle collapses". Nature (Nature Publishing Group, a division of Macmillan Publishers Limited.) 487 (7406): 219–222. Bibcode:2012Natur.487..219G. doi:10.1038/nature11257. 
  6. ^ Weber, Clark, Kuhn, Timmermann (5 June 2014). "Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation". Nature (Nature Publishing Group) 510 (7503): 134–138. doi:10.1038/nature13397. 
  7. ^ Peltier, W.R. (26 April 2005). "On the hemispheric origins of meltwater pulse 1a". Quaternary Science Reviews (Elsevier Ltd.) 24 (14–15): 1655–1671. Bibcode:2005QSRv...24.1655P. doi:10.1016/j.quascirev.2004.06.023. 
  8. ^ Chambers, D. P.; Ries, J. C.; Urban, T. J. (2003). "Calibration and Verification of Jason-1 Using Global Along-Track Residuals with TOPEX". Marine Geodesy 26 (3): 305. doi:10.1080/714044523. 
  9. ^ Bindoff, NL et al. "Observations: Oceanic Climate Change and Sea Level". Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press 

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