英国科学家在最新一期《自然·地球科学》杂志上发表论文称，过去一直认为相对稳定的南极东部冰原实际上十分脆弱，500万年前的全球气候变暖曾造成这部分冰原大面积融化，使得海平面上升了将近10米。
为了解古代南极东部冰原的融冰情况，伦敦帝国理工学院的研究人员对取自于南极东部海岸水下3000米海底的泥浆样本进行了化学成分分析。分析结果表明，形成这些泥浆的岩石存在于东部冰原之中，只有冰原融化缩小，这些岩石才会受到侵蚀，进而沉积到海底形成泥浆。而在距今300万年到500万年前，即称为上新世的地质时期，全球气候变暖使得南极东部冰原出现大量融冰，融冰量可使海平面上升近10米。在同一时期，南极西部以及格陵兰岛的部分冰原也因气候变暖而融化。研究人员推测，这一时期全球融冰造成海平面上升了大约20米。
南极东部冰原形成于3400万年前，是地球上最大的冰原，其面积与澳大利亚差不多大小。科学家们过去一直认为，南极东部冰原比南极西部冰原和格陵兰岛冰原都要稳定，但新研究表明，南极东部冰原对于气候变化的敏感程度比科学家原来预想的要大得多。
研究人员指出，在上新世时期，地球大气中二氧化碳的浓度与今天十分相似，而有科学家预计，到本世纪末，全球气温也会与上新世时期的地球温度大体一致。因此，了解上新世冰川的融化情况有助于研究如今全球变暖对海平面波动的影响，这对于全面理解气候变化对地球环境的影响十分重要。（生物谷 Bioon.com）
生物谷推荐的英文摘要
Nature Geoscience doi:10.1038/ngeo1889
Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth
Carys P. Cook, Tina van de Flierdt, Trevor Williams, Sidney R. Hemming, Masao Iwai, Munemasa Kobayashi, Francisco J. Jimenez-Espejo, Carlota Escutia, Jhon Jairo González, Boo-Keun Khim, Robert M. McKay, Sandra Passchier, Steven M. Bohaty, Christina R. Riesselman, Lisa Tauxe, Saiko Sugisaki, Alberto Lopez Galindo, Molly O. Patterson, Francesca Sangiorgi, Elizabeth L. Pierce, Henk Brinkhuis, Adam Klaus, Annick Fehr, James A. P. Bendle, Peter K. Bijl, Stephanie A. Carr, Robert B. Dunbar, José Abel Flores, Travis G. Hayden, Kota Katsuki, Gee Soo Kong, Mutsumi Nakai, Matthew P. Olney, Stephen F. Pekar, Jörg Pross, Ursula Röhl, Toyosaburo Sakai, Prakash K. Shrivastava, Catherine E. Stickley, Shouting Tuo, Kevin Welsh & Masako Yamane
Warm intervals within the Pliocene epoch (5.33–2.58 million years ago) were characterized by global temperatures comparable to those predicted for the end of this century1 and atmospheric CO2 concentrations similar to today2, 3, 4. Estimates for global sea level highstands during these times5 imply possible retreat of the East Antarctic ice sheet, but ice-proximal evidence from the Antarctic margin is scarce. Here we present new data from Pliocene marine sediments recovered offshore of Adélie Land, East Antarctica, that reveal dynamic behaviour of the East Antarctic ice sheet in the vicinity of the low-lying Wilkes Subglacial Basin during times of past climatic warmth. Sedimentary sequences deposited between 5.3 and 3.3 million years ago indicate increases in Southern Ocean surface water productivity, associated with elevated circum-Antarctic temperatures. The geochemical provenance of detrital material deposited during these warm intervals suggests active erosion of continental bedrock from within the Wilkes Subglacial Basin, an area today buried beneath the East Antarctic ice sheet. We interpret this erosion to be associated with retreat of the ice sheet margin several hundreds of kilometres inland and conclude that the East Antarctic ice sheet was sensitive to climatic warmth during the Pliocene.
