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CO2 and climate change: deciphering the role of the high-latitude oceans

二氧化碳与气候变化：解读高纬度海洋的作用

基本信息

批准号：
MR/W013835/1
负责人：
Graeme MacGilchrist
金额：
$ 118.46万
依托单位：
University of St Andrews
依托单位国家：
英国
项目类别：
Fellowship
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=MR%2FW013835%2F1
关键词：
CO2 climate change deciphering role

项目摘要

With every ton of carbon injected to the atmosphere, humanity makes a commitment to long term changes in climate. The severity of that commitment will depend on how Earth's carbon sinks, that remove carbon from the atmosphere, are themselves altered by the ensuing climatic shifts.The role of the ocean is critical: CO2 dissolves in seawater, allowing the ocean to take up about 30% of the CO2 emitted to date. The future trajectory of atmospheric CO2 - and climate - is thus critically dependent on the behaviour of the ocean CO2 sink.High latitude regions are particularly important, as cooling of surface water allows more CO2 to dissolve (similar to CO2 bubbles in a cold fizzy drink). Cooling also increases density, allowing CO2-laden water to sink and be stored in the ocean's abyss.However, high latitude mixing can also bring CO2 back up to the surface. Depending on the speed at which this CO2 is removed by photosynthesis, and the degree to which it is capped by sea ice, the high latitude oceans may act either as a CO2 source, or a CO2 sink.At present, these processes are not well represented in the computer models used to predict CO2 change in the future. For example, most models misrepresent the seasonal cycle of CO2 uptake and release in the Southern Ocean. They also tend to predict that the ocean will continue to absorb CO2 like a simple sponge, but from the geological record we know that the ocean can switch from a carbon sink to a carbon source with surprising speed.It is therefore critically important that we improve simulation of fundamental processes in the ocean carbon cycle and understand the dynamic ways in which oceanic CO2 has changed in the past and could change in the future. These are the core aims of this proposal.To achieve this, I will harness insights from paleo data alongside new developments in carbon cycle modelling. Pairing these approaches will allow us to answer major questions about Earth's past, such as the causes of ice age CO2 change, and to use paleo observations to help test and improve the oceanographic tools used to predict our future.Firstly, I will examine biases in state-of-the-art carbon cycle models by evaluating how carbon is stored within oceanic layers known as watermasses. Watermass analysis has been one of the most successful tools in oceanography but has been used surprisingly little to study the ocean carbon cycle. It also lends itself well to paleo data, to test how carbon was stored in the ice age ocean.Secondly, I will develop new ways of simulating processes of carbon uptake at high latitudes. The complexity and fine spatial scales involved make this challenging for global models. Here, I will use "idealised" approaches which focus on the most essential processes and regions. Specific targets include the spinning circulation of the North Atlantic and the complex interactions in the Southern Ocean, and these will be compared to records of rapid deglacial CO2 change from these regions. A long term aim is to apply novel mathematical approaches to make a new style of model of global ocean carbon.Thirdly, I will bring together these new insights to create efficient models of the global ocean carbon cycle and its interaction with climate. I will harness them to examine the causes of ice age CO2 change, and trajectories of CO2 uptake in the future.This work will provide oceanographers, climate scientists, and paleoceanographers with a new toolkit for examining major CO2 change. I have positioned myself at the nexus of these fields, and the complementary expertise available at St Andrews, coupled with that of a leading group of project partners, will allow me to undertake the bold, interdisciplinary work needed for a step change in our understanding of the ocean carbon cycle. The reach and impact of this work will be extended directly to policymakers by creation of user-friendly models of future CO2 trajectories and their impact on climate.

随着每一吨碳排放到大气中，人类对气候的长期变化做出了承诺。这一承诺的严重性将取决于地球的碳汇--从大气中清除碳--本身如何被随之而来的气候变化所改变。海洋的作用至关重要：二氧化碳溶解在海水中，使海洋占据了迄今排放的大约30%的二氧化碳。因此，大气二氧化碳的未来轨迹--以及气候--严重依赖于海洋二氧化碳下沉的行为。高纬度地区尤其重要，因为地表水的冷却允许更多的二氧化碳溶解(类似于冷气泡饮料中的二氧化碳气泡)。冷却也会增加密度，使得二氧化碳含量高的水沉入并储存在海洋深处。然而，高纬度的混合也会将二氧化碳带回海面。根据光合作用去除二氧化碳的速度和被海冰覆盖的程度，高纬度海洋可能是二氧化碳的来源，也可能是二氧化碳的汇。目前，用于预测未来二氧化碳变化的计算机模型没有很好地描述这些过程。例如，大多数模型错误地描述了南大洋二氧化碳吸收和释放的季节性周期。他们还倾向于预测，海洋将继续像一块简单的海绵一样吸收二氧化碳，但从地质记录中我们知道，海洋可以以惊人的速度从碳汇转变为碳源。因此，我们必须改进对海洋碳循环基本过程的模拟，并了解海洋二氧化碳过去变化和未来可能变化的动态方式。这些都是这项提议的核心目标。为了实现这一目标，我将利用从古数据中获得的见解，以及碳循环模型的新发展。将这些方法结合起来，将使我们能够回答有关地球过去的主要问题，如冰河时代二氧化碳变化的原因，并利用古观测来帮助测试和改进用于预测我们未来的海洋学工具。首先，我将通过评估碳如何储存在被称为水团的海洋层中来检验最先进的碳循环模型中的偏差。水团分析一直是海洋学中最成功的工具之一，但令人惊讶的是，很少有人将其用于研究海洋碳循环。它也很好地应用于古数据，测试碳是如何储存在冰河时代的海洋中的。其次，我将开发模拟高纬度碳吸收过程的新方法。所涉及的复杂性和精细的空间尺度使这对全球模型来说具有挑战性。在这里，我将使用“理想化”的方法，将重点放在最基本的过程和地区。具体目标包括北大西洋的旋转环流和南大洋的复杂相互作用，这些目标将与这些地区的快速降冰期二氧化碳变化记录进行比较。一个长期的目标是应用新的数学方法来建立一种新型的全球海洋碳模型。第三，我将把这些新的见解结合在一起，创建有效的全球海洋碳循环及其与气候相互作用的模型。我将利用它们来研究冰河时代二氧化碳变化的原因，以及未来二氧化碳吸收的轨迹。这项工作将为海洋学家、气候科学家和古海洋学家提供一个新的工具包，用于研究主要的二氧化碳变化。我把自己定位在这些领域的结合点，圣安德鲁斯大学现有的互补专业知识，加上一个主要项目合作伙伴小组的专业知识，将使我能够开展所需的大胆的跨学科工作，以逐步改变我们对海洋碳循环的理解。这项工作的影响范围和影响将通过创建用户友好的未来二氧化碳轨迹及其对气候影响的模型直接扩展到政策制定者。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Importance of the Antarctic Slope Current in the Southern Ocean Response to Ice Sheet Melt and Wind Stress Change

DOI：
10.1029/2021jc017608
发表时间：
2022-05-01
期刊：
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
影响因子：
3.6
作者：
Beadling, R. L.;Krasting, J. P.;Winton, M.
通讯作者：
Winton, M.

Spatial and Temporal Patterns of Southern Ocean Ventilation

DOI：
10.1029/2023gl106716
发表时间：
2024-02
期刊：
Geophysical Research Letters
影响因子：
5.2
作者：
A. Styles;G. MacGilchrist;Michael J. Bell;David P. Marshall
通讯作者：
A. Styles;G. MacGilchrist;Michael J. Bell;David P. Marshall

Freshwater Displacement Effect on the Weddell Gyre Carbon Budget

淡水置换对威德尔环流碳预算的影响

DOI：
10.1029/2023gl103952
发表时间：
2023
期刊：
Geophysical Research Letters
影响因子：
5.2
作者：
Taylor, Benjamin A.;MacGilchrist, Graeme A.;Mazloff, Matthew R.;Talley, Lynne D.
通讯作者：
Talley, Lynne D.

Ross Gyre variability modulates oceanic heat supply toward the West Antarctic continental shelf

罗斯环流变率调节向南极西部大陆架的海洋热量供应