Solving the Oligocene icehouse conundrum

解决渐新世冰室难题

• 批准号: NE/V018388/1
• 负责人: Gordon Inglis
• 金额: $ 58.64万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV018388%2F1
• 关键词: Solving; Oligocene; icehouse; conundrum

Today there is a major ice sheet on Antarctica, but this was not always the case. The Antarctic ice sheet formed around 34 million years ago, ushering in the dawn of the "icehouse world". Over the next 11 million years, the climate swung between cooler and warmer states, with sea level falling and rising as ice sheets grew and collapsed. To simulate changes in sea level and climate of this size, computer models require massive fluctuations in CO2. However, we have no evidence of CO2 change of this magnitude, and little idea of how such changes could be accomplished. Furthermore, the existing CO2 reconstructions from this time interval present another major puzzle, as they show a long-term decrease, which appears to be decoupled from long-term climate. These mysterious interactions between CO2, climate, and ice sheets are the "Oligocene icehouse conundrum" that this project aims to solve.Past changes in climate can be reconstructed using chemical fingerprints in fossil shells of foraminifera - sand-sized organisms that live throughout the ocean - the chemistry of these organisms records the environmental conditions at the time they grew, allowing us to reconstruct how environments have changed in the past. The main reason the climate of the Oligocene (~34-23 million years ago) remains such a mystery is because of a previous lack of sedimentary material containing well-preserved foraminifera from this time interval. Previously acquired records are sparse or biased by poor preservation, leaving us with a limited and confused understanding of how the Oligocene climate system operates. Now, for the first time, we have identified sites with abundant and well-preserved foraminifera, thus overcoming a major obstacle in Oligocene climate reconstruction. We will analyse foraminifera to reconstruct critical aspects of the Oligocene climate, such as the temperature, global ice volume, sea level, ocean acidity (pH), atmospheric carbon dioxide and the strength of the biological pump. These kinds of analyses are increasingly used to help determine both how climate has changed in the past and how it might change in the future, including "climate sensitivity", the amount of warming expected due to rising CO2. We have built a team and strategy that poises the project for success. Principal Investigator (PI) Wade is one of the world's foremost experts on the foraminifera of the Oligocene, and so is perfectly placed to figure out which species best record temperatures and atmospheric CO2. Having identified the best species and sites, we will make the first reconstructions of CO2 from this time using the chemistry of boron. This exciting method has seen extensive development in recent years by Co-PI Rae and Co-Investigator Foster, and we will apply the latest methods to determine past pH and CO2. To explore why CO2 may have changed, we will create new records of the biological pump of carbon to the deep ocean. And to evaluate the impact of CO2 on global climate, we will make new records of temperature, using foraminifera and organic molecules, and sea level, using foraminifera from the sea floor. Armed with these new reconstructions of key components of Oligocene climate, we will use a variety of modelling approaches to integrate and interpret them in a global context. A model of how carbon cycles between different reservoirs will allow us to test mechanisms of CO2 change. Simulations of physical climate and ice sheets will be combined in an exciting new way to explore the stability of major ice sheets. We will transform the understanding of CO2 and climate change in the Oligocene, providing insights into the fundamentals of climate sensitivity and ice sheet stability.The new understanding of Oligocene climate and the carbon cycle that will result from our research will resolve the long-standing Oligocene icehouse conundrum, and improve understanding of climate and ice sheet sensitivity in a warmer world.

今天，南极洲有一个主要的冰盖，但并非总是如此。南极冰盖大约在3400万年前形成，迎来了“ Icehouse World”的曙光。在接下来的1100万年中，气候在凉爽和温暖的州之间摇摆，随着冰盖的增长和倒塌，海平面下降并上升。为了模拟这种大小的海平面变化和气候，计算机模型需要在CO2中发生巨大波动。但是，我们没有证据表明二氧化碳变化的大小变化，也没有关于如何实现这种变化的想法。此外，在此时间间隔之后，现有的二氧化碳重建提出了另一个主要难题，因为它们显示出长期降低，这似乎与长期气候相结合。 These mysterious interactions between CO2, climate, and ice sheets are the "Oligocene icehouse conundrum" that this project aims to solve.Past changes in climate can be reconstructed using chemical fingerprints in fossil shells of foraminifera - sand-sized organisms that live throughout the ocean - the chemistry of these organisms records the environmental conditions at the time they grew, allowing us to reconstruct how environments have changed in the 过去的。渐新世的气候（〜34-2300万年前）仍然如此的主要原因是一个谜是因为以前缺乏在此时间间隔以来含有保存完好的有孔虫的沉积材料。以前获得的记录稀疏或偏向不良的保存，使我们对渐新世气候系统的运作方式有限且混乱。现在，我们第一次确定了具有丰富且保存完好的有孔虫的地点，从而克服了渐新世气候重建的主要障碍。我们将分析有孔虫重建渐新世气候的关键方面，例如温度，全球冰，海平面，海洋酸度（pH），大气二氧化碳和生物泵的强度。这些类型的分析越来越多地用于帮助确定过去的气候如何变化以及未来的变化，包括“气候敏感性”，即由于CO2的增加而预期的变暖量。我们建立了一个团队和策略，为成功的项目提供了认可。首席研究员（PI）Wade是世界上最重要的专家之一。确定了最好的物种和地点后，我们将使用Boron的化学从这段时间进行首次重建CO2。近年来，Co-Pi Rae和共同研究器Foster近年来，这种令人兴奋的方法已经广泛发展，我们将采用最新方法来确定过去的pH和CO2。为了探索为什么二氧化碳可能发生了变化，我们将创建碳生物泵的新记录到深海。为了评估二氧化碳对全球气候的影响，我们将使用有孔虫和有机分子以及使用海底的有孔虫来制作新的温度记录，以及海平面。通过这些新的渐新世气候关键组成部分的重建，我们将使用各种建模方法在全球环境中整合和解释它们。一个模型的模型如何在不同储层之间的碳周期使我们能够测试二氧化碳变化的机制。对物理气候和冰盖的模拟将以令人兴奋的新方式组合起来，以探索主要的冰盖的稳定性。我们将改变对渐新世的二氧化碳和气候变化的理解，从而提供对气候敏感性和冰盖稳定性的基本面的见解。对渐新世气候和我们研究所产生的碳周期的新理解将解决长期存在的渐新世冰室结合，并提高对气候和冰纸敏感性在温暖的环境中的理解。

项目成果

Climate Evolution Through the Onset and Intensification of Northern Hemisphere Glaciation

• DOI: 10.1029/2022rg000793
• 发表时间: 2023-07
• 期刊: Reviews of Geophysics
• 影响因子: 25.2
• 作者: E. McClymont;S. L. Ho;H. L. Ford;I. Bailey;M. Berke;C. Bolton;S. Schepper;G. Grant;J. Groeneveld;G. Inglis;C. Karas;M. O. Patterson;G. Swann;K. Thirumalai;S. M. White;M. Alonso-García;P. Anand;B. Hoogakker;K. Littler;B. Petrick;B. Risebrobakken;J. Abell;A. J. Crocker;F. D. Graaf;S. Feakins;J. C. Hargreaves;C. L. Jones;M. Markowska;A. S. Ratnayake;C. Stepanek;D. Tangunan

The PhanSST global database of Phanerozoic sea surface temperature proxy data.

• DOI: 10.1038/s41597-022-01826-0
• 发表时间: 2022-12-06
• 期刊: SCIENTIFIC DATA
• 影响因子: 9.8
• 作者: Judd, Emily J. J.;Tierney, Jessica E. E.;Huber, Brian T. T.;Wing, Scott L. L.;Lunt, Daniel J. J.;Ford, Heather L. L.;Inglis, Gordon N. N.;McClymont, Erin L. L.;O'Brien, Charlotte L. L.;Rattanasriampaipong, Ronnakrit;Si, Weimin;Staitis, Matthew L. L.;Thirumalai, Kaustubh;Anagnostou, Eleni;Cramwinckel, Margot J. J.;Dawson, Robin R. R.;Evans, David;Gray, William R. R.;Grossman, Ethan L. L.;Henehan, Michael J. J.;Hupp, Brittany N. N.;MacLeod, Kenneth G. G.;O'Connor, Lauren K. K.;Montes, Maria Luisa Sanchez;Song, Haijun;Zhang, Yi Ge
• 通讯作者: Zhang, Yi Ge