Ocean Science

Heating the Deep Ocean

See allHide authors and affiliations

Science  19 Jul 2013:
Vol. 341, Issue 6143, pp. 216-217
DOI: 10.1126/science.341.6143.216-e

As greenhouse gas concentrations in the atmosphere increase, the resulting heat warms not only the atmosphere but also the oceans. However, temperature increases at the sea surface and in the upper ∼700 m of the oceans stalled in the 2000s. Recent modeling and observational studies have suggested that the deep ocean has taken up the heat, particularly at depths between 700 and 2000 m. However, regular, spatially homogenous ocean temperature data are only available since 2003 from the Argo ocean observing system, complicating comparison with earlier data sets. Balmaseda et al. used a new observation-based reanalysis of the ocean to investigate how the heat content has changed over the period from 1958 to 2009. They provide evidence for an overall warming trend, punctuated by cooling episodes that can be attributed to volcanic eruptions. The massive 1997–1998 El Niño event also had a noticeable cooling impact. In the past decade, the deep ocean has continued to warm, whereas temperatures in the upper 300 m have stabilized; the ocean as a whole has continued to warm at an increasing rate. The qualitative warming patterns persisted when Argo data were removed. The authors attribute the changing heat distribution to changes in surface winds, particularly an intensification of the trade winds in subtropical gyres.

Geophys. Res. Lett. 40, 1754 (2013).

Navigate This Article