Instability of the East Antartic Ice Sheet during the Pliocene warmth?

上新世温暖期间东南南极冰盖不稳定？

• 批准号: NE/H014144/1
• 负责人: Tina Van De Flierdt
• 金额: $ 9.43万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH014144%2F1
• 关键词: Instability; East; Antartic; Ice; Sheet

Warming of the climate system is unequivocal, and evident from observations of increases in global average air and ocean temperatures. Based on projections published in the Nobel Peace Prize winning report of the Intergovernmental Panel on Climate Change in 2007, the Earth's surface is estimated to warm between 1.8 to 4.0 degree Celsius by the end of the century. Already now, we are observing the retreat of mountain glaciers, limited extent of sea ice in the Arctic Ocean, and melting around the edges of the polar ice caps in Greenland and parts of Antarctica. Projected sea level rise by 2100 ranges between 0.2 and 0.6 m. This range however does not include potential contributions from the ice caps, which today tie up a water mass equivalent to about 60-70 m of sea level change. From studying the climate in the past, we know that the polar ice caps can wax and wane with changing climatic conditions. The last time Earth climate was significantly warmer than today, for an extended amount of time, was 4.5 to 3 million years ago, during the time period of the Pliocene. Global temperatures in the warm Pliocene were about 3 degree Celsius higher than today. Sea level estimates for this time range from 5 to 40 m higher than today, with a most commonly used value around 25 m. Such an elevated sea level would not only mean the disappearance of the Greenland and West Antarctic ice sheets, but also instability in parts of the massive East Antarctic ice sheet. Data are however sparse, and models give conflicting results on whether melting only acted on the more vulnerable West Antarctic ice sheet, or also on parts of the large East Antarctic ice sheet. With our project we will try to address exactly this dilemma. We are going to analyse the chemical composition of ice-rafted sediments from the Southern Ocean off East Antarctica. This material was carried to its place of deposition by icebergs, and its geochemical fingerprint contained in mineral grains, allows us to track back the exact area of the continent where the iceberg was coming from. This in turn tells us which part of the ice margin became instable in the past. It is such evidence from the geological record that is vital to test and refine existing climate models. We will investigate which adjustments have to be made to climate models to reproduce our observational data. Once we succeed to produce a better database for understanding ice extent during the Pliocene warmth, and once we have a climate model that matches the observations of the past, we should have higher confidence to use the same type of model to foresee what may happen in the future.

气候系统的变暖是明确的，从全球平均气温和海洋温度上升的观察中可以明显看出。根据2007年获得诺贝尔和平奖的政府间气候变化专门委员会报告中发表的预测，到世纪末，地球表面估计将升温1.8至4.0摄氏度。现在，我们已经观察到高山冰川的退缩，北冰洋海冰的有限范围，以及格陵兰岛和南极洲部分地区极地冰盖边缘的融化。预计到2100年，海平面将上升0.2至0.6米。然而，这一范围不包括冰盖的潜在贡献，冰盖今天束缚了相当于海平面变化约60-70米的水体。从过去的气候研究中，我们知道极地冰盖可以随着气候条件的变化而增减。上一次地球气候比今天明显温暖，持续了很长一段时间，是在450万到300万年前的上新世。在温暖的上新世，全球气温比今天高出约3摄氏度。当时的海平面估计比现在高5至40米，最常用的值约为25米。如此高的海平面不仅意味着格陵兰岛和南极西部冰盖的消失，还意味着南极东部冰盖部分地区的不稳定。然而，数据稀少，模型给出了相互矛盾的结果，即融化是否只作用于更脆弱的南极西部冰盖，还是也作用于南极东部大冰盖的部分地区。在我们的项目中，我们将试图解决这个难题。我们将分析南极洲东部外的南大洋冰筏沉积物的化学成分。这些物质被冰山带到了它的沉积地，它的地球化学指纹包含在矿物颗粒中，使我们能够追踪到冰山来自的大陆的确切区域。这反过来又告诉我们，冰缘的哪一部分在过去变得不稳定。这些来自地质记录的证据对于测试和完善现有的气候模型至关重要。我们将研究必须对气候模型进行哪些调整，以重现我们的观测数据。一旦我们成功地建立了一个更好的数据库来了解上新世温暖时期的冰范围，一旦我们有了一个与过去观测相匹配的气候模型，我们就应该有更高的信心使用同一类型的模型来预测未来可能发生的事情。

项目成果

Wilkes Land Glacial History, Proceedings of the Integrated Ocean Drilling Program

威尔克斯陆地冰川历史，综合海洋钻探计划论文集

• 发表时间: 2011
• 作者: Escutia C

Sea surface temperature control on the distribution of far-traveled Southern Ocean ice-rafted detritus during the Pliocene

• DOI: 10.1002/2014pa002625
• 发表时间: 2014-06-01
• 期刊: PALEOCEANOGRAPHY
• 作者: Cook, C. P.;Hill, D. J.;Gonzales, J. J.
• 通讯作者: Gonzales, J. J.

Developing community-based scientific priorities and new drilling proposals in the southern Indian and southwestern Pacific oceans

在南印度洋和西南太平洋制定基于社区的科学优先事项和新的钻探建议

• DOI: 10.5194/sd-24-61-2018
• 发表时间: 2018
• 期刊: Scientific Drilling
• 影响因子: 1.2
• 作者: McKay R

Pliocene deglacial event timelines and the biogeochemical response offshore Wilkes Subglacial Basin, East Antarctica

• DOI: 10.1016/j.epsl.2018.04.054
• 发表时间: 2018-07-15
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Bertram, Rachel A.;Wilson, David J.;Riesselman, Christina R.
• 通讯作者: Riesselman, Christina R.

Glacial erosion of East Antarctica in the Pliocene: A comparative study of multiple marine sediment provenance tracers

• DOI: 10.1016/j.chemgeo.2017.06.011
• 发表时间: 2017-09
• 期刊: Chemical Geology
• 影响因子: 3.9
• 作者: C. Cook;S. Hemming;T. Flierdt;Elizabeth Pierce Davis;T. Williams;A. L. Galindo;F. Jiménez-Espejo;C. Escutia