Detection of anthropogenic climate change in the world's oceans

Large-scale increases in the heat content of the world's oceans have been o bserved to occur over the Last 45 years. The horizontal and temporal charac ter of these changes has been closely replicated by the state-of-the-art Pa rallel Climate Model (PCM) forced by observed and estimated anthropogenic g ases. Application of optimal detection methodology shows that the model-pro duced signals are indistinguishable from the observations at the 0.05 confi dence Level. Further, the chances of either the anthropogenic or observed s ignals being produced by the PCM as a result of natural, internal forcing a lone are Less than 5%. This suggests that the observed ocean heat-content c hanges are consistent with those expected from anthropogenic forcing, which broadens the basis for claims that an anthropogenic signal has been detect ed in the global climate system. Additionally, the requirement that modeled ocean heat uptakes match observations puts a strong, new constraint on ant hropogenically forced climate models. It is unknown if the current generati on of climate models, other than the PCM, meet this constraint.