Accepted by the Journal of Climate

This paper examines nine analyses of global ocean 0/700m temperature and heat content during the 43-year period of warming, 1960-2002. Among the analyses are two that are independent of any numerical model, six that rely on sequential data assimilation including an ocean general circulation model, and one that uses 4Dvar including an ocean general circulation model and its adjoint. Most analyses show gradual warming of the global ocean with an ensemble trend of 0.77x108 Jm-2/10yr ( = 0.24Wm-2) as the result of rapid warming in the early 1970s and again beginning around 1990. One proposed explanation for these variations is the effect of volcanic eruptions in 1963 and 1982. Examination of this hypothesis suggests that while there is an oceanic signal it is insufficient to explain the observed heat content variations. A second potential cause of decadal variations in global heat content is the uncorrelated contribution of heat content variations in individual ocean basins. The subtropical North Atlantic is warming at twice the global average with accelerated warming in the 1960s and again beginning in the late-1980s and extending through the end of our record. The Barents Sea region of the Arctic Ocean and the Gulf of Mexico also warm, while the western subpolar North Atlantic has cooled. Heat content variability in the North Pacific differs significantly from the North Atlantic. There the spatial and temporal patterns are consistent with the decadal variability previously identified through observational and modeling studies examining SST and surface winds. In the Southern Hemisphere large heat content anomalies are evident and while there is substantial disagreement among analyses on average the band of latitudes 30oS-60oS contribute significantly to the global warming trend. Thus, the uncorrelated contribution