Attributable impacts from extreme weather events

想象一下，一个恶劣的天气事件发生，对特定地区造成毁灭性的影响。政界人士、灾难应对人员、恢复规划者和记者反复向气候科学家提出的一个问题是，气候变化在引发或影响这一事件中扮演的角色。造成破坏的直接原因是不寻常的天气，但在许多情况下，气候变化将使事件更有可能发生，更严重，或者可能两者兼而有之。在这些情况下，破坏可能部分或主要是由于气候变化。在某些情况下，最糟糕的后果可能是生活在该地区的人的脆弱性，或者是许多不同因素的组合，这些因素将反映过去和当前在不同层面上的决定。了解气候变化是否使这一事件的破坏性更大是重要的。较富裕的国家使世界变暖，但较贫穷的国家经历了一些最具破坏性的后果。国际气候谈判正在讨论“损失和损害”的问题--那些对气候变化负有主要责任的人是否应该以及如何补偿那些经历了最严重后果的人。这个项目将帮助这些讨论，为极端天气事件的后果已经如何改变以及这些后果未来可能如何改变的关键问题提供答案，并将这些事件置于其特定的脆弱性环境中。我们将开发一种新的方法来回答关于极端天气事件的严重性的问题-气候变化如何使特定天气情况的后果变得更糟？如果同样的天气状况发生在100年前的气候中，它的破坏性会不会更小？如果未来天气情况再次发生怎么办？这些都是定义明确的问题，但我们还不能轻易回答它们。例如，我们可能会预计，与100年前发生的同一场风暴相比，今天的强风暴降雨量会更大，这可能会使后果变得更糟。但是，还要下多少雨呢？而且，除了直接的气象后果，对河流流量和人口的影响又是什么？我们还将反过来使用这些概念，将它们应用于几十年前发生的极端事件，以研究它们在当今变暖的世界中的后果有何不同。这个项目将考虑许多不同类型的极端天气事件，包括暴雨、风暴、热浪和干旱，并研究这些天气事件对社会的影响，包括财产损失和洪水。重要的是，我们将确定由于生活在一个更温暖的世界中而造成的特定天气事件的额外影响，直接解决气候变化造成的损失和损害这一关键问题。我们还将建立合理的最坏情况事件的叙述，为适应我们变暖的世界的决策提供信息。

Imagine a severe weather event occurs, causing devastating impacts to a particular region. One question that is repeatedly asked to climate scientists by politicians, disaster responders, recovery planners and journalists is about the role of climate change in causing or affecting the event. The direct cause of the devastation is the unusual weather but, in many cases, climate change will have made the event more likely, more severe, or potentially both. In those cases, the devastation may be partly or even mostly due to the change in climate. In some cases, the worst consequences may be due to the vulnerability of those living in the region, or a combination of many different factors which will reflect past and current decisions on a variety of levels.Understanding whether climate change has made the event more damaging is important. Wealthier nations have caused the world to warm, but poorer nations have experienced some of the most damaging consequences. International climate negotiations are discussing the issue of 'loss and damage' - whether and how those mainly responsible for climate change should compensate those who experience the worst consequences. This project will aid those discussions by providing answers to key questions about how the consequences of extreme weather events have already changed and how those consequences may change further in future, and by placing those events within their specific contexts of vulnerability.We will develop a new methodology to answer questions about the severity of extreme weather events - how have the consequences of a particular weather situation been made worse by climate change? If the same weather situation had occurred in the climate that we had 100years ago, would it have been less damaging? What about if the weather situation happens again in the future? These are well-defined questions, but we cannot easily answer them yet. As an example, we might expect that more rain would fall today in a severe storm than if the same storm had occurred 100 years ago, potentially making the consequences worse. But, how much more rain? And, beyond the direct meteorological consequences, what about the effects on river flows and people? We will also use these same concepts in reverse by applying them to extreme events that occurred several decades ago to examine how their consequences would be different today in a warmer world.This project will consider many different types of extreme weather event, including heavy rainfall, windstorms, heatwaves and droughts, and examine the consequences of those weather events for society, including damage to property and flooding. Importantly, we will identify the additional impacts of a particular weather event which are due to living in a warmer world, directly addressing the critical issue of losses and damages caused by climate change. We will also build narratives of plausible worst-case events to inform decision making on adapting to our warming world.