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

• 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

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.

每吨碳注入大气中，人类致力于长期变化的气候变化。这种承诺的严重程度将取决于地球的碳下沉（从大气中去除碳的碳下沉）本身会因随之而来的气候变化而改变。海洋的作用至关重要：二氧化碳溶解在海水中，使海洋迄今为止占据了约30％的二氧化碳。因此，大气二氧化碳和气候的未来轨迹严重取决于海洋二氧化碳的行为。高纬度区域尤为重要，因为地表水的冷却使更多的二氧化碳可以溶解（类似于冷泡沫中的二氧化碳气泡）。冷却还会增加密度，使含二氧化碳的水沉没并存储在海洋的深渊中。根据光合作用的速度以及海冰封顶的程度，高纬度海洋可以用作二氧化碳源或二氧化碳源。例如，大多数模型歪曲了二氧化碳吸收和在南大洋中释放的季节性周期。他们还倾向于预测，海洋将继续像简单的海绵一样吸收二氧化碳，但是从地质记录来看，我们知道海洋可以以惊人的速度切换到碳源。因此，至关重要的是，重要的是，重要的是，我们至关重要的是，我们要改善对海洋碳循环的基本过程的模拟并了解过去和过去的海洋二氧化碳在过去和未来会发生变化的动态方式。这些是该提案的核心目的。为了实现这一目标，我将利用古数据的见解，以及碳循环建模的新发展。配对这些方法将使我们能够回答有关地球过去的主要问题，例如冰期二氧化碳变化的原因，并使用古观测来帮助测试和改善用于预测未来的海洋学工具。首先，我将通过评估碳存储如何存储在已知水质的海洋层中，以研究最先进的碳循环模型。水质分析一直是海洋学中最成功的工具之一，但令人惊讶的是研究海洋碳循环。它也很好地适合古数据，以测试碳在冰河时代的海洋中的存储方式。第二，我将开发出模拟高纬度碳吸收过程的新方法。涉及的复杂性和精细的空间尺度使得全球模型具有挑战性。在这里，我将使用“理想化的”方法，这些方法侧重于最重要的过程和地区。具体的目标包括北大西洋的旋转循环以及南大洋中的复杂相互作用，这些相互作用将与这些区域的快速冰期二氧化碳变化的记录进行比较。一个长期的目的是应用新颖的数学方法来制定全球海洋碳模型的新样式。三分之一，我将汇总这些新的见解，以创建全球海洋碳循环的有效模型及其与气候的相互作用。我将利用他们检查冰期二氧化碳变化的原因，并在将来摄入二氧化碳的轨迹。这项工作将为海洋学家，气候科学家和古稳态人员提供新的工具包，以检查主要的二氧化碳变化。我将自己定位在这些领域的联系中，圣安德鲁斯提供的补充专业知识，再加上领先的项目合作伙伴组的补充专业知识，将使我能够从事对海洋碳周期的理解所需的大胆，跨学科的工作。这项工作的影响力和影响将通过创建未来CO2轨迹的用户友好模型及其对气候的影响，直接扩展到决策者。

项目成果

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

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.

Enhanced subglacial discharge from Antarctica during meltwater pulse 1A.

• DOI: 10.1038/s41467-023-42974-0
• 发表时间: 2023-11-13
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Li, Tao;Robinson, Laura F.;Macgilchrist, Graeme A.;Chen, Tianyu;Stewart, Joseph A.;Burke, Andrea;Wang, Maoyu;Li, Gaojun;Chen, Jun;Rae, James W. B.
• 通讯作者: Rae, James W. B.

Potential Predictability of the Spring Bloom in the Southern Ocean Sea Ice Zone

南大洋海冰区春季水华的潜在可预测性

• DOI: 10.1029/2023gl105139
• 发表时间: 2023
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Buchovecky B