ABSTRACT

The current Earth’s energy imbalance (EEI) is mostly caused by human activity, and is driving global warming. The EEI represents the most fundamental metric defining the status of global climate change, and can best be estimated mainly from changes in ocean heat content (OHC), complemented by radiation measurements from space. Sustained ocean observations from the Argo array of autonomous profiling floats in the global ocean provide the backbone of new estimates of OHC changes. New estimates of EEI and corresponding rates of change of OHC will be presented. However, we can also do this regionally and therefore provide a commentary on energy flows around the climate system. In particular, new estimates will be shown of the changes in ocean heat transports in the Atlantic Meridional Overturning Circulation (AMOC), which have a profound affect on decadal variability, not only for North America and Europe, but also around the planet. For 2000 through 2013 meridional heat transports in the Atlantic agree well with observational estimates at 26.5°N from the RAPID array but, along with model assessments, suggest that the RAPID assumptions and methodology over-estimate the peak transports by about 0.2 PW. Average peak northward Atlantic Ocean heat transports are 1.1 PW but vary considerably in latitude and time. In addition, these results have no hint of a trend, unlike the RAPID results.

About the Speaker:

Dr. Kevin E. Trenberth is a distinguished senior scientist in the Climate Analysis Section at the National Center for Atmospheric Research. From New Zealand, he obtained his doctorate from Massachusetts Institute of Technology. He has been prominent in most of the Intergovernmental Panel on Climate Change (IPCC) scientific assessments of Climate Change and has also extensively served the World Climate Research Programme (WCRP) in numerous ways, most recently as chair of the WCRP Global Energy and Water Exchanges (GEWEX) project. He has also served on many U.S. national committees. He is a fellow of the American Meteorological Society, the American Association for Advancement of Science, the American Geophysical Union, and an honorary fellow of the Royal Society of New Zealand.