Modelling the effects of realistic polar stratospheric clouds on past climate and future ozone

气候变化及其与人类活动的关系是21世纪最重要的全球环境挑战。由氟氯化碳中的活性氯引起的平流层臭氧损耗是20世纪最重要的问题之一。在讨论实施《京都议定书》或其后续议定书的优先事项时，任何无法解释的气候变化都将导致对基于科学的建议的信心严重丧失。由于《蒙特利尔议定书》的缘故，预计臭氧损耗的恢复会出现任何无法解释的延误，这可能导致舆论形成者和决策者同样丧失信心。在这里，我们建议研究南极气候的一个巨大的无法解释的变化和南极臭氧空洞延迟恢复的可能性，并提供解释。近30年来对流层观测到的最大变暖发生在南极冬季对流层中部。这一最近的发现还无法解释——计算机模拟显示温室气体增加的变暖幅度太小——但最近的研究表明极地平流层云（PSCs）增加了。我们提议检验温室气体和psc增加共同导致变暖的假设。我们将在英国首要的大气模型中插入一个全面的PSC增长方案，以及一个由山区上空大气波引起的平流层冷点的改进计算后，进行一次彻底的建模研究。改进后的模式还将用于预测臭氧空洞的未来演变。预计在21世纪，氟氯化碳将会减少。但是温室气体将继续增加，这将起到冷却平流层的作用，从而产生更多的psc。后一种过程可能会大大推迟预期的臭氧空洞的恢复。该提案将利兹大学和剑桥大学在PSC和大气化学建模方面的世界领先地位与BAS在南极气候归因和宣传方面的专业知识结合起来，创建了一个异常强大的团队。这项工作应该在南极气候无法解释的变化引起更广泛的媒体和公众的注意之前完成。

Climate change and its attribution to human activity is the most important global environmental challenge of the 21st Century. Stratospheric ozone depletion due to reactive chlorine from CFCs was one of the most important of the 20th Century. Any unexplained climate change would lead to severe loss of confidence in science-based advice when priorities for implementing the Kyoto Protocol or its successors are being debated. Any unexplained delay in the recovery of ozone depletion, expected because of the Montreal Protocol, could lead to similar loss of confidence by opinion formers and policy makers. Here we propose to investigate a large unexplained change in Antarctic climate and a strong possibility of delayed recovery of the Antarctic ozone hole, and proffer explanations. The largest warming observed in the troposphere in the last 30 years occurred in the mid- troposphere in Antarctic winter. This recent discovery cannot yet be explained - computer modelling with increased greenhouse gases shows too small a warming - but recent work has implicated increased Polar Stratospheric Clouds (PSCs). We propose to test the hypothesis that a combination of increased greenhouse gases and increased PSCs has caused the warming. We would conduct a thorough modelling study, after inserting a comprehensive PSC growth scheme, and an improved calculation of the stratospheric cold points induced by atmospheric waves above mountains, into the premier UK atmospheric model. The improved model will also be used to forecast the future evolution of the ozone hole. During the 21st Century, CFCs are expected to reduce. But greenhouse gases will continue to increase, which will act to cool the stratosphere and so produce more PSCs. This latter process may significantly delay the expected recovery of the ozone hole. This proposal combines world leaders in PSC and atmospheric chemistry modelling at Leeds and Cambridge Universities with BAS expertise in Antarctic climate attribution and publicity, to create an exceptionally strong team. This work should be done now before the unexplained change in Antarctic climate comes to the attention of the wider media and public.