Mar 10, 2017

Improved estimates of ocean heat content from 1960 to 2015

by
Lijing Cheng, Kevin E. Trenberth, John Fasullo, Tim Boyer, John Abraham, Jiang Zhu
,
Science Advances

The ocean is the memory of all of the past climate change

Kevin Trenberth, study co-author and senior scientist at the National Center for Atmospheric Research


  • Suggests that since 1960, a staggering 337 zetajoules of energy — that’s 337 followed by 21 zeros — has been added to the ocean in the form of heat. And most of it has occurred since 1980.
  • Provides updated ocean heat content (OHC) estimates with the goal of minimizing associated sampling error
  • Performs a subsample test, in which subsets of data during the data-rich Argo era are colocated with locations of earlier ocean observations, to quantify this error
  • Results provide a new OHC estimate with an unbiased mean sampling error and with variability on decadal and multidecadal time scales (signal) that can be reliably distinguished from sampling error (noise) with signal-to-noise ratios higher than 3
  • Finds that the inferred integrated Earth energy imbalance (EEI) is greater than that reported in previous assessments and is consistent with a reconstruction of the radiative imbalance at the top of atmosphere starting in 1985
  • Finds that changes in OHC are relatively small before about 1980; since then, OHC has increased fairly steadily and, since 1990, has increasingly involved deeper layers of the ocean
  • Finds that OHC changes in six major oceans are reliable on decadal time scales
  • Finds that all ocean basins examined have experienced significant warming since 1998, with the greatest warming in the southern oceans, the tropical/subtropical Pacific Ocean, and the tropical/subtropical Atlantic Ocean