UK Contribution to Plio-MIP (Pliocene Modelling Intercomaprison Project)

先进的气候数值模式，通常被称为大气环流模式，正被广泛用于在全球和区域尺度上预测人类引起的气候变化的影响。尽管这些先进的模型在模拟气候变化方面仍然是不完善的工具，因此必须对气候模型的稳健性进行测试，以增加对其预测的信心。气候模型对未来的预测无法直接验证，但科学家可以评估最先进的气候模型重现过去存在的、与今天截然不同的气候状态的能力。自20世纪90年代中期以来，一个名为PMIP（古气候模拟比对项目）的国际项目倡导了对几种气候模式的系统研究，并评估了它们模拟过去发生的大规模气候变化的能力。然而，PMIP还没有研究过地球历史上哪个时期的全球气温比现在高，大气中的二氧化碳（一种温室气体）含量高于工业化前的水平。换句话说，在模拟地球历史上某一时期的气候时，PMIP没有检验各种气候模式的能力，也没有确定气候模式之间的差异，而地球历史上某一时期的气候与预测的未来气候非常相似，这是人类活动造成的结果。该项目将有助于填补这一空白，并使英国能够对一个新项目做出主要贡献，该项目旨在系统地研究地球历史上一个温暖期（上新世中期温暖期，距今约300万年至330万年）的气候模型输出，该项目与本世纪末的气候预测有许多相似之处。最近的政府间气候变化专门委员会（IPCC）第四次评估报告指出，“上新世中期是最近的地质时期，全球平均温度在一段时间内比工业化前的温度高出2至3摄氏度。因此，上新世中期代表了一个在许多方面与模型估计的21世纪晚期地球相似的世界的可接近的例子。”2008年6月，来自全球10个气候模拟小组的代表在纽约会面，讨论并同意将用于上新世中期的新气候模型模拟的细节。该提案概述了英国参与这一激动人心的新国际倡议所需的工作计划和资源。预计这个新项目的结果将被纳入政府间气候变化专门委员会的下一份报告，从而帮助全世界的科学家和政治家了解气候模型在模拟我们星球漫长历史上最后一个持续全球变暖的大时期的能力和差异。

Advanced numerical models of climate, often referred to as General Circulation Models, are being extensively used to predict the impacts of human induced climate change on global and regional scales. Although advanced such models remain imperfect tools with which to simulate climate change, and thus the robustness of climate models must be tested so that confidence in their predictions can be increased. There is no way climate model predictions for the future can directly test, but scientists can evaluate the capability of state of the art climate models to reproduce climate states that existed in the past and that were radically different from those of today. Since the mid 1990's an international programme called PMIP (Palaeoclimate Modelling Intercomparison Project) has championed the systematic study of several climate models and assessed their ability to simulate large changes of climate that occurred in the past. However, PMIP has not studied a period in Earth history that was globally warmer than present-day, and which had higher than pre-industrial levels of carbon dioxide (a greenhouse gas) in the atmosphere. In other words PMIP has not examined the ability of, and determined the differences between, climate models when simulating a period in Earth's history that provides a close analogue to climate as it is predicted to be in the future, as a result of human modification. The project will help fill this gap and enable a leading UK contribution to a new project set up to systematically study climate model outputs for a warm period in Earth history (the mid-Pliocene warm period ca 3 to 3.3 million years before present) which has a number of parallels to climate predictions for the end of this century. The recent Intergovernmental Panel on Climate Change (IPCC) 4th assessment report states that 'the mid-Pliocene is the most recent interval of geological time when mean global temperatures were ~2 to 3 degrees Celsius above pre-industrial temperatures for a sustained period. Therefore, the mid-Pliocene represents an accessible example of a world that is similar in many respects to what models estimate could be the Earth of the late 21st century'. In June 2008 representatives from 10 climate modelling groups worldwide met in New York to discuss and agree the details of new climate model simulations that will be carried out for the mid-Pliocene. This proposal outlines the programme of work and resources necessary to allow the UK to take part in this exciting new international initiative. It is expected that outcomes from this new project will be included in the next Intergovernmental Panel on Climate Change report, thereby helping to inform scientists and politicians worldwide about the ability and differences between climate models in simulating the last great period of sustained global warmth in our planets long history.