J. Clim. http://doi.org/cr3f (2018)
Much of the global uptake of anthropogenic heat has occurred in the Southern Ocean. Upwelling of cold, deep waters to the surface allows the heat uptake, which is then transported northwards through the overturning circulation. Although this variability in regional heat uptake is known, changes with future warming are unclear.
To address this issue, Jia-Rui Shi and colleagues at the Scripps Institution of Oceanography, University of California San Diego, USA, use nine CMIP5 models to understand the role of GHG and aerosol concentrations on historical and future ocean heat uptake. They find that regional contributions change under a high-emissions scenario: heat uptake in the North Atlantic Ocean (north of 30° N) increases from 6% to 26% of the global total, while the Southern Ocean decreases from 72% to 48%. Although percentage values decline in the Southern Ocean, heat rate gains continue at their current rate.
The authors attribute this change in heat uptake patterns to a decrease in anthropogenic aerosols, which, in combination with increasing GHGs, weaken the overturning circulation and strengthen heat uptake in the North Atlantic. Thus, the North Atlantic is projected to become a major repository of anthropogenic heat alongside the Southern Ocean.