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

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

基本信息

批准号：
NE/P019080/1
负责人：
Tina Van De Flierdt
金额：
$ 18.6万
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：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FP019080%2F1
关键词：
SWEET Super Warm Early Eocene

项目摘要

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.

地球的气候目前正在迅速变化，主要是由于人类工业化造成的温室气体排放。预计这些排放量在本世纪将增加，在某些情况下，到2100年，大气二氧化碳（CO2）浓度可能会达到百万分之1000（ppm）以上，而工业化之前的浓度为280 ppm。为了预测这些情景的社会、环境和经济影响，从而更好地为它们做好准备，我们可以使用的唯一工具就是气候建模。为了评估我们对气候模型预测的信心，我们在已知气候条件下对这些模型进行了例行测试。然而，这一测试（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CO2浓度低于400 ppmv。因此，我们最先进的气候模型从未在高二氧化碳、超暖气候条件下进行过测试，而这些气候条件是它们主要应用的，也是做出重大政策决定的基础。（例如始新世，大约5000万年前），当时二氧化碳浓度与本世纪末的预期浓度相似;但是，这些时期的气候信息目前还很稀少，而且存在很大的不确定性，而且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，实验室技术的发展，意味着第一次存在一个新的令人兴奋的机会来纠正这种情况，并在超暖世界中提供急需的最新气候模型评估。在SWEET中，我们将应用这些新兴技术，并开发新的方法和工具，来制作一个全球始新世温度的数据集。再加上新的和高保真的始新世二氧化碳浓度重建，以及最先进的“古地理”地图（大陆位置，山脉，海洋深度等），我们将使用这个数据集来测试一个最先进的气候模型在高大气CO2，始新世条件下。该模型UKESM与英国气象局在国际“CMIP 6”项目中使用的模型相同，该项目本身将成为下一个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额外的模型模拟（以高空间分辨率运行），以调查决定地球系统对高CO2和古地理变化的反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模拟中的不确定性，我们的模型数据比较将由一个包含这些不确定性的统计框架来支撑。我们亦会采用“多代理”的方法，利用多个独立的地质档案重建温度。对于其中一个档案，即始新世微观海洋生物的贝壳的氧同位素组成，我们将采用一种特别创新的方法，使我们能够“复活”以前不可信的数据，通过使用极细尺度的“离子探针”来调查过去气候变化的这些同位素特征是如何记录在个体化石中的。SWEET与英国气象局有着密切的联系，以及国际DeepMIP项目，该项目是“古气候模拟相互比较项目”的一部分，本身也是CMIP 6的一部分。我们希望我们的研究结果能够纳入IPCC的下一份评估报告，从而最终为政策提供信息。