UKESM 1 Year Extension

UKESM 1 年延期

• 批准号: NE/V013203/1
• 负责人: Susan Loughlin
• 金额: $ 0.5万
• 依托单位: British Geological Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV013203%2F1
• 关键词: UKESM; Year; Extension

Global climate change is one of the leading environmental threats facing mankind. To develop appropriate mitigation and adaptation strategies requires accurate projections of the future state of the Earth's climate. To address this, we develop and use Global Climate Models (GCMs) that describe the main physical processes in the coupled climate system. These models are integrated forwards in simulated time, from a pre-industrial period to present-day, forced by observed estimates of key greenhouse gases, aerosols and land-use. The models are then continued into the future forced by a range of greenhouse gas, aerosol and land-use scenarios. Each of the model future climates can then compared to the simulated present-day climates. This analysis results in an ensemble of climate change estimates that can be used to assess the socio-economic and ecological impacts of the simulated changes and aid in the development of mitigation and adaptation policies. GCMs have been further developed into Earth system models (ESMs), as we successfully did in the UKESM LTSM, where UKESM1 was developed from the coupled physical model, HadGEM3-GC3.1. A key difference between ESMs and GCMs is the former include an interactive description of the global carbon cycle supporting the analysis of both physical climate change and potential changes in the efficacy by which anthropogenic emitted CO2 is taken up by natural carbon reservoirs. A reduction in the uptake efficiency of Earth's natural carbon reservoirs may result in a larger fraction of emitted carbon dioxide remaining in the atmosphere to warm the planet. Accurate estimates of the future evolution of both the global climate system and the carbon cycle are therefore crucial for getting a clear picture of the future risks humanity faces, as well as for developing mitigation actions (that typically target the efficacy of carbon uptake) to keep global warming below dangerous levels. To address this need, we developed the 1st UK Earth system model (UKESM1) and ran it for a large suite of experiments in the 6th Coupled Model Intercomparison Project (CMIP6). UKESM1 is the most advanced Earth system model in the world today and as well as a coupled physical climate model, includes interactive treatment of (i) the global carbon cycle and dynamic vegetation, (ii) atmospheric chemistry and aerosols and (iii) models for the Greenland and Antarctic ice sheets. We have run a large (19 member) ensemble of historical simulations with UKESM1 (1850 to 2015) and extended a number of these into the future (2015 to 2100) following 7 different future emission pathways from CMIP6 scenarioMIP. In this extension, we propose a detailed analysis of the UKESM1 historical ensemble and the suite of scenarioMIP projections. Our aims are (i) to better understand what drives observed historical Earth system change and evaluate how well UKESM1 represents these changes, (ii) with the knowledge from (i), analyze simulated Earth system change in the UKESM1 scenarioMIP ensemble, combining this with the CMIP6 multi-model ensemble, to document the range of simulated changes across the coupled Earth system over the coming century. Two primary emphases in this analysis will be; (a) to document and contrast regional changes at different levels of global mean warming (e.g. 2C or 3C) and (b) where possible, to constrain the various coupled feedbacks simulated by UKESM1 that drive the magnitude of future change. In addition, we will continue to provide support to the large UKESM user and model development community and will hold two consultation workshops with (i) UK climate policymakers and (ii) UK climate impacts researchers. In these workshops we will present our findings on predicted future Earth system change and begin a two-way dialogue on how UK Earth system modeling can best support the needs of these two groups, developing future collaborations based on mutual understanding of each group's needs and goals.

全球气候变化是人类面临的主要环境威胁之一。为了制定适当的缓解和适应战略，需要准确预测地球气候的未来状况。为了解决这个问题，我们开发并使用全球气候模型（GCM）来描述耦合气候系统中的主要物理过程。这些模型在模拟时间（从工业化前时期到现在）中进行整合，是通过对主要温室气体、气溶胶和土地利用的观测估计来实现的。然后，在一系列温室气体、气溶胶和土地利用情景的推动下，这些模型将继续延续到未来。然后可以将每个模型的未来气候与模拟的当前气候进行比较。该分析得出了气候变化估计的集合，可用于评估模拟变化的社会经济和生态影响，并帮助制定缓解和适应政策。 GCM 已进一步发展为地球系统模型 (ESM)，正如我们在 UKESM LTSM 中成功所做的那样，其中 UKESM1 是从耦合物理模型 HadGEM3-GC3.1 发展而来的。 ESM 和 GCM 之间的一个关键区别在于，前者包括对全球碳循环的交互式描述，支持对物理气候变化和天然碳库吸收人为排放的二氧化碳的功效的潜在变化的分析。地球天然碳库吸收效率的降低可能会导致大量排放的二氧化碳残留在大气中，从而使地球变暖。因此，准确估计全球气候系统和碳循环的未来演变对于清楚地了解人类面临的未来风险以及制定缓解行动（通常针对碳吸收的效率）至关重要。全球变暖低于危险水平。为了满足这一需求，我们开发了第一个英国地球系统模型 (UKESM1)，并在第六个耦合模型比对项目 (CMIP6) 中进行了大量实验。 UKESM1 是当今世界上最先进的地球系统模型，也是一个耦合的物理气候模型，包括 (i) 全球碳循环和动态植被、(ii) 大气化学和气溶胶以及 (iii) 模型的交互处理格陵兰岛和南极冰盖。我们使用 UKESM1（1850 年至 2015 年）运行了一个大型（19 名成员）历史模拟集合，并根据 CMIP6 情景 MIP 的 7 种不同的未来排放路径将其中的一些扩展到未来（2015 年至 2100 年）。在此扩展中，我们提出了对 UKESM1 历史系综和场景 MIP 投影套件的详细分析。我们的目CMIP6 多模型系综，记录下个世纪耦合地球系统的模拟变化范围。该分析的两个主要重点是： (a) 记录和对比不同全球平均变暖水平（例如 2C 或 3C）的区域变化，以及 (b) 在可能的情况下，限制 UKESM1 模拟的驱动未来变化幅度的各种耦合反馈。此外，我们将继续为大型 UKESM 用户和模型开发社区提供支持，并将与 (i) 英国气候政策制定者和 (ii) 英国气候影响研究人员举办两次咨询研讨会。在这些研讨会中，我们将介绍我们对预测的未来地球系统变化的发现，并开始双向对话，讨论英国地球系统建模如何最好地支持这两个群体的需求，在对每个群体的需求和目标的相互理解的基础上发展未来的合作。