Evidence of decadal climate prediction skill resulting from changes in anthropogenic forcing

It is argued that simulations of the twentieth century performed with coupled global climate models with specified historical changes in external radiative forcing can be interpreted as climate hindcasts. A simple Bayesian method for postprocessing such simulations is described, which produces probabilistic hindcasts of interdecadal temperature changes on large spatial scales. Hindcasts produced for the last two decades of the twentieth century are shown to be skillful. The suggestion that skillful decadal forecasts can be produced on large regional scales by exploiting the response to anthropogenic forcing provides additional evidence that anthropogenic change in the composition of the atmosphere has influenced the climate. In the absence of large negative volcanic forcing on the climate system (which cannot presently be forecast), it is predicted that the global mean temperature for the decade 2000-09 will lie above the 1970-99 normal with a probability of 0.94. The global mean temperature anomaly for this decade relative to 1970-99 is predicted to be 0.35 degrees C with a 5%-95% confidence range of 0.21 degrees-0.48 degrees C.

有人认为，利用耦合的全球气候模型进行的20世纪模拟（其中外部辐射强迫有特定的历史变化）可被解释为气候后报。文中描述了一种对这类模拟进行后处理的简单贝叶斯方法，该方法可在大空间尺度上生成年代际温度变化的概率性后报。对20世纪最后20年所做的后报显示是有技巧的。通过利用对人为强迫的响应可在大区域尺度上做出有技巧的年代际预测这一观点，为大气成分的人为变化已影响气候提供了额外证据。在气候系统没有大的负火山强迫（目前无法预测）的情况下，预计2000 - 2009年这十年的全球平均温度将高于1970 - 1999年的正常值，概率为0.94。预计这十年相对于1970 - 1999年的全球平均温度异常值为0.35℃，其5% - 95%的置信区间为0.21℃ - 0.48℃。