SWEET: Super-Warm Early Eocene Temperatures and climate: understanding the response of the Earth to high CO2 through integrated modelling and data

SWEET：超温暖的始新世早期温度和气候：通过综合建模和数据了解地球对高二氧化碳的反应

• 批准号: NE/P019331/1
• 负责人: Philip Sexton
• 金额: $ 13.81万
• 依托单位: The Open University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP019331%2F1
• 关键词: SWEET; Super; Warm; Early; Eocene

The Earth's climate is currently changing rapidly, primarily due to emissions of greenhouse gases caused by human industrialisation. These emissions are projected to increase through this century, and under some scenarios atmospheric carbon dioxide (CO2) concentrations could reach more than 1000 parts per million (ppm) by the year 2100, compared with 280 ppm prior to industrialisation. In order to predict the sociological, environmental, and economic impacts of such scenarios, and thus to better prepare for them, the only tool at our disposal is climate modelling. In order to assess our confidence in predictions from climate models, they are routinely tested under conditions of known climate. However, this testing (and associated tuning of the models) is almost exclusively carried out under modern climate conditions, and relative to recently observed climate change, for which CO2 concentrations are less than 400 ppmv. As such, our state-of-the-art climate models have never been tested under the high CO2, super-warm climate conditions to which they are primarily applied, and upon which major policy decisions are made.However, there exist time periods in Earth's deeper past (for example the Eocene, about 50 million years ago) when CO2 concentrations were similar to those expected by the end of this century; but climatological information from these time periods is currently sparse and is associated with large uncertainties, and the exact concentrations of CO2 are only poorly known. Recent changes in our understanding of how the geological record preserves climate signals, and developments in laboratory techniques, mean that for the first time there exists a new and exciting opportunity to remedy this situation and provide a much-needed evaluation of our very latest climate models in a super-warm world.In SWEET, we will apply these emerging techniques, and develop new methodologies and tools, to produce a global dataset of Eocene temperatures. Coupled with new and high-fidelity reconstructions of Eocene CO2 concentrations, and state-of-the-art maps of the 'palaeogeograpy' (continental positions, mountain ranges, ocean depths etc.), we will use this dataset to test a state-of-the art climate model under high atmospheric CO2, Eocene conditions. The model, UKESM, is identical to that being used by the UK Met Office in the international 'CMIP6' project, which itself will be the primary input to the next Intergovernmental Panel on Climate Change (IPCC) assessment report. We will also use our data and additional model simulations (running at high spatial resolution) to investigate the relative importance of the various mechanisms which determine the response of the Earth system to high CO2 and to changes in palaeogeography.A characteristic of SWEET is that we will take full account of uncertainties in the geological data and the modelling, and our model-data comparisons will be underpinned by a statistical framework which incorporates these uncertainties. We will also adopt a 'multi-proxy' approach by using several independent geological archives to reconstruct temperature. For one of these archives, namely the oxygen isotopic composition of the fossilised shells of microscopic marine creatures from the Eocene, we will apply a particularly innovative approach which will enable us to 'resurrect' previously discredited data, by using an extremely fine-scale 'ion probe' to investigate how these isotopic signatures of past climate change are recorded in individual fossils.SWEET has strong links to UK Met Office, and to the international DeepMIP project, which is part of the 'Palaeoclimate Modelling Intercomparison Project', itself part of CMIP6. We expect our results to feed into the next IPCC assessment reports and therefore to ultimately inform policy.

目前，地球气候正在迅速变化，这主要是由于人类工业化造成的温室气体排放造成的。这些排放量预计将在本世纪增加，在某些情况下，到 2100 年大气二氧化碳 (CO2) 浓度可能达到百万分之 1000 (ppm) 以上，而工业化之前为 280 ppm。为了预测此类情景的社会、环境和经济影响，从而更好地应对这些影响，我们可以使用的唯一工具是气候建模。为了评估我们对气候模型预测的信心，我们会在已知气候条件下对它们进行例行测试。然而，这种测试（以及相关的模型调整）几乎完全是在现代气候条件下进行的，并且是相对于最近观察到的气候变化而言的，其中二氧化碳浓度低于 400 ppmv。因此，我们最先进的气候模型从未在它们主要应用的高二氧化碳、超温暖气候条件下进行过测试，并在此基础上做出了重大政策决定。然而，存在一些时间段地球更深层的过去（例如约 5000 万年前的始新世），当时二氧化碳浓度与本世纪末的预期水平相似；但目前这些时期的气候信息很少，并且存在很大的不确定性，而且人们对二氧化碳的确切浓度知之甚少。最近我们对地质记录如何保存气候信号的理解发生了变化，以及实验室技术的发展，意味着第一次出现了一个新的、令人兴奋的机会来纠正这种情况，并对我们最新的气候模型提供急需的评估在超级温暖的世界中。在 SWEET 中，我们将应用这些新兴技术，并开发新的方法和工具，以生成始新世温度的全球数据集。结合始新世二氧化碳浓度的新的高保真度重建以及最先进的“古地理”地图（大陆位置、山脉、海洋深度等），我们将使用该数据集来测试状态-高大气二氧化碳、始新世条件下最先进的气候模型。该模型 UKESM 与英国气象局在国际“CMIP6”项目中使用的模型相同，该项目本身将成为下一份政府间气候变化专门委员会 (IPCC) 评估报告的主要输入。我们还将使用我们的数据和其他模型模拟（以高空间分辨率运行）来研究决定地球系统对高二氧化碳和古地理变化的响应的各种机制的相对重要性。SWEET 的一个特点是，我们将充分考虑地质数据和建模中的不确定性，并且我们的模型数据比较将以包含这些不确定性的统计框架为基础。我们还将采用“多代理”方法，利用多个独立的地质档案来重建温度。对于其中一个档案，即始新世微观海洋生物化石壳的氧同位素组成，我们将采用一种特别创新的方法，该方法将使我们能够通过使用极其精细的尺度“复活”以前被怀疑的数据。 SWEET 与英国气象局和国际 DeepMIP 项目有着密切的联系，该项目是“古气候模拟比对项目”本身是 CMIP6 的一部分。我们希望我们的结果能够纳入下一份 IPCC 评估报告，从而最终为政策提供信息。

项目成果

Early Eocene Ocean Meridional Overturning Circulation: The Roles of Atmospheric Forcing and Strait Geometry

早始新世海洋经向翻转环流：大气强迫和海峡几何的作用

• DOI: http://dx.10.1029/2021pa004329
• 发表时间: 2022
• 期刊: Paleoceanography and Paleoclimatology
• 影响因子: 3.5
• 作者: Zhang Y

Oxygen rise in the tropical upper ocean during the Paleocene-Eocene Thermal Maximum.

古新世-始新世热最大值期间热带上层海洋的氧气上升。

• DOI: http://dx.10.1126/science.adh4893
• 发表时间: 2024
• 期刊: Science (New York, N.Y.)
• 作者: Moretti S

Proxy evidence for state-dependence of climate sensitivity in the Eocene greenhouse.

始新世温室气候敏感性的状态依赖性的代理证据。

• DOI: http://dx.10.1038/s41467-020-17887-x
• 发表时间: 2020
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Anagnostou E

North Atlantic surface ocean warming and salinization in response to middle Eocene greenhouse warming.

始新世中期温室变暖导致的北大西洋表面海洋变暖和盐化。

• DOI: http://dx.10.1126/sciadv.abq0110
• 发表时间: 2023
• 期刊: Science advances
• 影响因子: 13.6
• 作者: Van Der Ploeg R

Cenozoic evolution of deep ocean temperature from clumped isotope thermometry.

来自聚集同位素测温的深海温度的新生代演化。

• DOI: http://dx.10.1126/science.abk0604
• 发表时间: 2022
• 期刊: Science (New York, N.Y.)
• 作者: Meckler AN