Anthropogenic Forcing of Antarctic Ice Loss (AnthroFAIL)

南极冰损的人为强迫（AnthroFAIL）

• 批准号: NE/X000397/1
• 负责人: Paul Holland
• 金额: $ 63.42万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX000397%2F1
• 关键词: Anthropogenic; Forcing; Antarctic; Ice; Loss

Melting ice caps are widely viewed as illustrative of anthropogenic global warming. The largest ice mass on Earth - Antarctica - is losing ice, and may contribute 1 metre or more to global sea level by 2100. However, it is not clear that this ice loss has been caused by human activities. Instead, this ice sheet may be simply responding to natural variability in the climate system.Antarctic ice loss is primarily caused by increased melting of the ice sheet by the ocean. However, it is not known why this melting has changed. The deep ocean waters melting the West Antarctic Ice Sheet have been buried in the deep ocean for centuries, and have not simply warmed alongside the rest of the climate. Instead, changes in the winds are thought to have altered the transport of these warm waters towards Antarctica.This leads to two main possibilities for why Antarctica is losing ice. Firstly, anthropogenic changes in the winds, caused by greenhouse gases and/or the ozone hole, may have gradually increased the supply of warm water towards the ice sheet. Alternatively, natural variability of the winds may have caused a period of high melting that triggered a self-sustaining ice sheet retreat.It is now urgent that we understand whether human activities have increased the ocean melting of Antarctica. If the ice loss is caused by human activities, we must identify the best strategy for minimising future change. If the ice loss is natural and inevitable, we must prepare for the sea-level rise that will play out over the coming centuries. This project will carefully unpick the contributions of natural and human influences using computer simulations of the ocean surrounding West Antarctica. We will first use historical winds from climate models to drive a set of ocean simulations that comprise our 'best guess' of the real history of ocean melting of Antarctica since 1920, under all natural and human forcings. These simulations will be tested against available historical observations from ships, autonomous vehicles, and ocean sediment cores.Once we have this model history, we will work out how it has been influenced by each of the different forcings. We will perform large sets of ocean simulations with and without human greenhouse gases, the ozone hole, and natural climate variability. These simulations will tell us the contribution of each forcing to the oceanic melting of the West Antarctic Ice Sheet. When we have a good understanding of the role of historical forcings, we will be equipped to assess the impact of future forcings. The ozone hole is expected to recover before 2100, so the question is to what extent future emissions of greenhouse gases will overwhelm this recovery, and continue unchecked thereafter. This research will address the fundamental questions of whether humans have caused Antarctic ice loss, and whether there is anything we can now do about it. The answers to these questions are urgently needed to clarify our options for preventing or adapting to future sea-level rise.

冰盖融化被广泛认为是人类活动导致全球变暖的例证。地球上最大的冰块-南极洲-正在失去冰，到2100年可能使全球海平面上升1米或更多。然而，目前尚不清楚这种冰损失是由人类活动造成的。相反，这些冰盖可能只是对气候系统的自然变化做出的反应。南极冰盖的融化主要是由海洋增加冰盖融化造成的。然而，目前还不知道为什么这种融化发生了变化。几个世纪以来，融化南极西部冰盖的深海沃茨一直埋在深海中，并没有简单地与其他气候一起变暖。相反，风的变化被认为改变了这些温暖的沃茨向南极洲的输送。这导致了南极洲冰层流失的两个主要可能性。首先，由温室气体和/或臭氧洞引起的人为风的变化可能逐渐增加了向冰盖提供的温水。或者，风的自然变化可能导致了一段时间的高度融化，引发了自我维持的冰盖退缩，现在我们迫切需要了解人类活动是否加剧了南极洲的海洋融化。如果冰损失是由人类活动造成的，我们必须确定最佳策略，以尽量减少未来的变化。如果冰的流失是自然的，不可避免的，我们必须为未来几个世纪的海平面上升做好准备。该项目将使用计算机模拟西南极洲周围的海洋，仔细分析自然和人类影响的贡献。我们将首先使用来自气候模型的历史风来驱动一组海洋模拟，这些模拟包括我们对自1920年以来南极洲海洋融化的真实的历史的“最佳猜测”，在所有自然和人类强迫下。这些模拟将与来自船舶、自动驾驶车辆和海洋沉积物岩心的现有历史观测进行测试。一旦我们有了这个模型历史，我们将研究出它如何受到每种不同强迫的影响。我们将在有和没有人类温室气体、臭氧洞和自然气候变化的情况下进行大量的海洋模拟。这些模拟将告诉我们每种作用力对南极西部冰盖海洋融化的贡献。当我们对历史强迫的作用有了很好的理解时，我们将有能力评估未来强迫的影响。预计臭氧空洞将在2100年之前恢复，因此问题是未来温室气体的排放将在多大程度上压倒这种恢复，并在此后继续不受控制。这项研究将解决人类是否造成了南极冰损失的基本问题，以及我们现在是否可以对此做些什么。这些问题的答案迫切需要澄清我们预防或适应未来海平面上升的选择。