Unabated planetary warming and its ocean structure since 2006

Author
Keywords
Abstract
Increasing heat content of the global ocean dominates the energy imbalance in the climate system1. Here we show that ocean heat gain over the 0\textendash2,000 m layer continued at a rate of 0.4\textendash0.6 W m-2 during 2006\textendash2013. The depth dependence and spatial structure of temperature changes are described on the basis of the Argo Program\textquoterights2 accurate and spatially homogeneous data set, through comparison of three Argo-only analyses. Heat gain was divided equally between upper ocean, 0\textendash500 m and 500\textendash2,000 m components. Surface temperature and upper 100 m heat content tracked interannual El Ni\~no/Southern Oscillation fluctuations3, but were offset by opposing variability from 100\textendash500 m. The net 0\textendash500 m global average temperature warmed by 0.005 \textdegreeC yr-1. Between 500 and 2,000 m steadier warming averaged 0.002 \textdegreeC yr-1 with a broad intermediate-depth maximum between 700 and 1,400 m. Most of the heat gain (67 to 98\%) occurred in the Southern Hemisphere extratropical ocean. Although this hemispheric asymmetry is consistent with inhomogeneity of radiative forcing4 and the greater area of the Southern Hemisphere ocean, ocean dynamics also influence regional patterns of heat gain.
Year of Publication
2015
Journal
Nature Climate Change
Volume
5
Number of Pages
240-245
Date Published
02/2015
ISSN Number
1758-6798
DOI
10.1038/nclimate2513