INTRIGUED: INvestigating The Role of the North Pacific In Glacial and Deglacial CO2 and Climate

感兴趣：研究北太平洋在冰期和冰消期二氧化碳和气候中的作用

基本信息

批准号：
NE/N011716/1
负责人：
James Rae
金额：
$ 64.46万
依托单位：
University of St Andrews
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FN011716%2F1
关键词：
INTRIGUED INvestigating Role North Pacific

项目摘要

The geological record offers an invaluable window into the different ways earth's climate can operate. The most recent large-scale changes in earth's climate, prior to modern climate change, were the Pleistocene glacial cycles, which feature growth and disintegration of large ice sheets, rapid shifts in major rain belts, and abrupt changes in ocean circulation. Changes in atmospheric CO2 concentrations, reconstructed from air bubbles in ice cores, are intimately linked with these ice age climate events. Indeed the close coupling of CO2 and temperature over glacial-interglacial cycles has become an iconic image in climate science, a poster child for the importance of CO2 in climate, and the natural template against which to compare current man-made CO2 rise. However despite the high profile of glacial-interglacial CO2 change, we still don't fully understand its cause. The leading hypotheses for glacial CO2 change involve increased CO2 uptake by the ocean during ice ages, which is vented to the atmosphere during deglaciation. However despite decades of work these hypotheses have had few direct tests, due to a lack of data on CO2 storage in the glacial ocean. One of the most glaring holes in our understanding of ice age CO2 and climate change is the behaviour of the Pacific. This basin contains half of global ocean volume, and ~30 times more CO2 than the atmosphere, and so its behaviour will have global impact. It has also recently been suggested that the North Pacific may play an active role in deglacial CO2 rise, with local deep water formation helping to release CO2 from the deep ocean to the atmosphere. If correct, this hypothesis provides a new view of Earth's climate system, with deep water able to form in each high latitude basin in the recent past, and the North Pacific potentially playing a pivotal role in deglaciation. However few data exist to test either the long-standing ideas on the Pacific's role in glacial CO2 storage, nor the more recent hypothesis that North Pacific deep water contributed to rapid deglacial CO2 rise. Given the size of the Pacific CO2 reservoir, our lack of knowledge on its behaviour is a major barrier to a full understanding of glacial-interglacial CO2 change and the climate of the ice ages. This proposal aims to transform our understanding of ice age CO2 and climate change, by investigating how the deep North Pacific stored CO2 during ice ages, and released it back to the atmosphere during deglaciations. We will use cutting-edge geochemical measurements of boron isotopes in microfossil shells (which record the behaviour of CO2 in seawater) and radiocarbon (which records how recently deep waters left the surface ocean), on recently collected samples from deep ocean sediment cores. By comparing these new records to other published data, we will be able to distinguish between different mechanisms of CO2 storage in the deep Pacific, and to test the extent of North Pacific deep water formation and CO2 release during the last deglaciation. We will also improve the techniques used to make boron isotope measurements, and add new constraints on the relationship between boron isotopes and seawater CO2 chemistry, which will help other groups using this technique to study CO2 change. To help us understand more about the mechanisms of changes in CO2 and ocean circulation, and provide synergy with scientists in other related disciplines, we will compare our data to results from earth system models, and collaborate with experts on nutrient cycling and climate dynamics. Our project will ultimately improve understanding of CO2 exchange between the ocean and the atmosphere, which is an important factor for predicting the path of future climate change.

地质记录为地球气候运作的不同方式提供了一个宝贵的窗口。在现代气候变化之前，地球气候的最新大规模变化是更新世冰川循环，它们具有大型冰盖的生长和瓦解，主要雨带的快速变化以及海洋循环的突然变化。大气二氧化碳浓度的变化与这些冰河时代气候事件密切相关，从气泡中重建了大气中的二氧化碳浓度。实际上，在冰川科学中，二氧化碳和温度的紧密耦合已成为气候科学中的标志性图像，是二氧化碳在气候中重要性的海报孩子，以及比较当前人造二氧化碳升高的自然模板。然而，尽管冰川间 - 冰2的变化很高，但我们仍然不完全理解它的原因。冰期二氧化碳变化的主要假设涉及在冰河时期内海洋吸收的二氧化碳吸收增加，该海洋在脱气过程中被排出至大气。然而，尽管缺乏冰期海洋中的二氧化碳存储数据，但这些假设几乎没有直接测试。我们对冰河时代二氧化碳和气候变化的理解中最明显的洞之一是太平洋的行为。该盆地含有全球海洋量的一半，二氧化碳是大气的30倍，因此其行为将产生全球影响。最近还有人提出，北太平洋可能在冰冰二氧化碳的上升中发挥积极作用，局部深水形成有助于将二氧化碳从深海释放到大气层。如果正确的话，该假设提供了地球气候系统的新观点，最近的每个高纬度盆地都可以形成深水，而北太平洋则可能在脱气中发挥关键作用。然而，很少有数据可以测试有关太平洋在冰川二氧化碳存储中的作用的长期观念，也很少有关于北太平洋深水导致快速冰期二氧化碳升高的最新假设。鉴于太平洋二氧化碳储层的大小，我们对其行为的缺乏知识是完全了解冰川间 - 冰川二氧化碳变化和冰河气候的主要障碍。该提案旨在通过调查北太平洋在冰河时代储存二氧化碳的方式，并将其释放回冰期期间的大气中，从而改变我们对冰河时代二氧化碳和气候变化的理解。我们将使用微化石壳中的硼同位素（记录海水中二氧化碳的行为）和放射性碳（记录最近深水离开地面海洋）的最先进的地球化学测量。通过将这些新记录与其他已发表的数据进行比较，我们将能够区分深太平洋中的二氧化碳存储机制，并测试上次回发展期间北太平洋深水形成和二氧化碳释放的程度。我们还将改善用于进行硼同位素测量的技术，并对硼同位素和海水CO2化学之间的关系增加新的限制，这将帮助使用该技术研究CO2变化的其他组。为了帮助我们更多地了解二氧化碳和海洋循环变化的机制，并与其他相关学科的科学家提供协同作用，我们将将数据与地球系统模型的结果进行比较，并与营养循环和气候动态的专家合作。我们的项目最终将提高人们对海洋与大气之间的二氧化碳交流的理解，这是预测未来气候变化道路的重要因素。