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

气候变化及其对人类活动的影响是21世纪最重要的全球环境挑战。由氯氟化碳产生的活性氯造成的平流层臭氧消耗是20世纪最重要的问题之一。任何无法解释的气候变化都将导致人们在辩论执行《京都议定书》或其后续议定书的优先事项时，严重丧失对基于科学的建议的信心。由于《蒙特利尔议定书》，预计臭氧消耗的恢复会出现任何莫名其妙的延误，这可能会导致舆论形成者和政策制定者同样失去信心。在这里，我们建议调查南极气候的一个巨大的无法解释的变化和南极臭氧层空洞延迟恢复的强烈可能性，并提供解释。近30年来对流层观测到的最大增温发生在南极冬季的对流层中层。这一最近的发现还无法解释--温室气体增加的计算机模拟显示变暖幅度太小--但最近的研究表明，极地平流层云(PSCs)增加。我们建议检验这一假设，即温室气体增加和PSCs增加共同导致了全球变暖。我们将在将一个全面的PSC增长方案和改进的山上大气波引起的平流层冷点的计算方法插入到主要的英国大气模型中之后，进行一项全面的模拟研究。改进后的模型还将用于预测臭氧空洞的未来演变。在21世纪，氯氟化碳预计将减少。但温室气体将继续增加，这将冷却平流层，从而产生更多的PSC。后一种过程可能会大大推迟臭氧层空洞的预期恢复。这项提议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者与BAS在南极气候归属和宣传方面的专业知识结合在一起，创建了一个特别强大的团队。这项工作应该在南极气候的无法解释的变化引起更广泛的媒体和公众注意之前现在就完成。

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.