Mass melting of the West Antarctic Ice Sheet, leading to a multi-metre rise in global mean sea levels during a period known as the Last Interglacial (129,000-116,000 years in the past), took less than 2˚C of ocean warming, finds new paleoclimate study : science
Fifty years in the past, it was speculated that the marine-based West Antarctic Ice Sheet is weak to warming and will have melted in the previous. Testing this speculation has proved difficult due to the problem of growing in situ data of ice sheet and environmental change spanning heat intervals. We current a multiproxy document that means loss of the West Antarctic Ice Sheet during the Last Interglacial (129,000 to 116,000 y in the past), related to ocean warming and the launch of greenhouse fuel methane from marine sediments. Our ice sheet modeling predicts that Antarctica could have contributed a number of meters to global sea stage right now, suggesting that this ice sheet lies shut to a “tipping point” below projected warming.
The future response of the Antarctic ice sheet to rising temperatures stays extremely unsure. A helpful period for assessing the sensitivity of Antarctica to warming is the Last Interglacial (LIG) (129 to 116 ky), which skilled hotter polar temperatures and better global mean sea stage (GMSL) (+6 to 9 m) relative to current day. LIG sea stage can’t be totally defined by Greenland Ice Sheet soften (∼2 m), ocean thermal growth, and melting mountain glaciers (∼1 m), suggesting substantial Antarctic mass loss was initiated by warming of Southern Ocean waters, ensuing from a weakening Atlantic meridional overturning circulation in response to North Atlantic floor freshening. Here, we report a blue-ice document of ice sheet and environmental change from the Weddell Sea Embayment at the periphery of the marine-based West Antarctic Ice Sheet (WAIS), which is underlain by main methane hydrate reserves. Constrained by a widespread volcanic horizon and supported by historical microbial DNA analyses, we offer proof for substantial mass loss throughout the Weddell Sea Embayment during the LIG, more than likely pushed by ocean warming and related to destabilization of subglacial hydrates. Ice sheet modeling helps this interpretation and means that millennial-scale warming of the Southern Ocean may have triggered a multimeter rise in global sea levels. Our information point out that Antarctica is very weak to projected will increase in ocean temperatures and will drive ice–local weather feedbacks that additional amplify warming.