Interacting ice Sheet and Ocean Tipping - Indicators, Processes, Impacts and Challenges (ISOTIPIC)

该项目的目的是了解控制与海洋和冰盖有关的关键转折点的过程，并评估它们对社会和全球地球系统的潜在影响。要考虑的特定倾覆要素(TES)与大西洋子午线翻转(AMOC)、格陵兰冰盖(GRIS)、南大洋沿岸上升流(SO)和南极冰盖(AIS)有关。这些TES是文献中广泛讨论的TES的相关子集。它们(A)具有相对较长的时间尺度，因此类似的分析方法可能是适当的；(B)可能与倾动级联有关，例如与AIS不稳定和GRIS融水影响AMOC稳定性的大气环流相互作用，以及潜在的两极相互作用；以及(C)分享海平面上升的极其重要的影响。两者的总体目标都是限制已经或可能在未来触发相关排污费的情况；以及处理排污费的长期反应，以评估特别是在哪些情况下排污费真正不可逆转。这些对认识的改进导致在工作包3中确定潜在的预警指标，而工作包4将评估倾倒废物的社会和气候影响，重点是预测的区域海平面上升和全球气候。专题A呼吁确定五个研究问题，所有这些问题都应得到解决。与关键气候TPS相关的全球和区域影响和风险是什么？工作包4侧重于影响，特别是区域海平面上升的关键影响，并与设计风暴潮屏障和制定适应性管理办法的社区建立联系。该工作包还将使用UKESM调查倾倒对全球气候的更广泛影响，例如对季风模式的变化。在最新的ESM中是否有突然变化和TPS的证据？许多当前一代的ESM(特别是在CMIP6中使用的那些)没有包含冰盖TPS的适当耦合，因此我们将使用冰盖模型作为独立的或耦合到区域海洋和大气模型来评估倾倒。这些实验的压力将来自UKESM和更广泛的CMIP6整体。在超过巴黎1.5摄氏度和2摄氏度目标的情况下，TPS的风险有何不同？我们的工作包1和2将确定与冰盖和大西洋经向翻转环流相关的TPS的倾倒阈值，然后将其与巴黎目标联系起来。我们如何为特定的TPS设计最佳预警系统，如大西洋经向翻转环流关闭、冰盖崩溃或森林死亡？我们在工作包3中的方法是测试一系列统计早期预警指标，将它们应用于已知TIP的模型的输出，以确定哪些指标能够预测这种TIP以及在什么时间尺度上。在观察记录中，哪里有证据表明系统弹性发生了变化？在测试了这些指标之后，工作包3将把它们应用于观测记录。

The aim of this project is to understand the processes controlling key tipping points (TPs) associated with the oceans and ice sheets, and assess their potential impacts on society and the global Earth system. The specific Tipping Elements (TEs) to be considered are related to the Atlantic Ocean Meridional Overturning (AMOC), the Greenland ice sheet (GrIS), coastal upwelling in the Southern Ocean (SO) and the Antarctic ice sheet (AIS). These TEs are a coherent subset of the TEs widely discussed in the literature. They (a) share relatively long timescales and therefore similar analysis methodologies are likely to be appropriate; (b) are potentially linked in tipping cascades such as the SO circulation interacting with AIS instability and GrIS meltwater impacting AMOC stability, as well as potential bi-polar interactions; and (c) share the hugely important impact of sea level rise.Work Package 1 focuses on AMOC and GrIS and their interaction; while Work Package 2 focuses on AIS and interactions with the SO. The overall objective in both is to constrain the circumstances under which the relevant TEs either have been or could potentially be triggered in the future; as well as addressing the long-term response of the TE to assess, in particular, under what circumstances the tipping becomes truly irreversible. These improvements in understanding lead into the identification of potential Early Warning indicators in Work Package 3, while Work Package 4 will assess the societal and climatic impacts of tipping focusing on projected regional sea level rise and global climate.The Topic A call identifies five research questions, all of which should be tackled.What are the global and regional impacts and risks associated with key climate TPs? Work Package 4 focuses on impact, in particular the key impact of regional sea level rise with links to the communities designing storm surge barriers and developing adaptive management approaches. This work package will also investigate the wider impacts of tipping on global climate using UKESM, for instance on changing monsoon patterns.Is there evidence for abrupt changes and TPs in the latest ESMs? Many of the current generation of ESMs (in particular those used in CMIP6) do not contain the appropriate coupling for ice sheet TPs so that we will use models of the ice sheets either as standalone or coupled to regional ocean and atmosphere models to assess tipping. Forcing for these experiments will come from both UKESM and the wider CMIP6 ensemble.How do the risks of TPs vary in scenarios that overshoot the Paris 1.5°C and 2°C targets? Our Work Packages 1 and 2 will determine thresholds for tipping for TPs associated with both ice sheets and the Atlantic Meridional Overturning Circulation, which can then be related back to the Paris targets.How do we design the best early warning systems for specific TPs such as Atlantic meridional overturning circulation shutdown, ice-sheet collapse, or forest dieback? Our approach in Work Package 3 is to test a range of statistical early warning indicators by applying them to the outputs of models that are known to tip to determine which indicators are able to predict this tipping and on what timescales.Where is there evidence of changing system resilience in observational records? Having tested these indicators, Work Package 3 will apply them to observational records.