New Method Improves Estimates of Upper-Ocean Warming and Multi-Decadal Sea-Level Rise
Changes in the climate system’s energy budget (the combination of solar radiation and heat in earth systems) are primarily seen in ocean temperatures and the associated contribution of thermal expansion to sea-level rise. However, studying and modeling these phenomena are not simple. There is sparse observational data suggesting large decadal variability in globally averaged ocean heat content but this variability cannot be reproduced in climate models even when volcanic and other climate forcings are included. Also, the sum of observed contributions to ocean thermal expansion does not adequately explain the multi-decadal rise in sea-level. Recent work by SC researcher Peter Gleckler and his colleagues improves estimates of near-global ocean heat content and thermal expansion for the upper portions of the oceans for the period 1950–2003. Using these new estimates, the decadal variability of the climate models with volcanic forcing included now agrees approximately with observations although the modeled multi-decadal trends are smaller than observed. These improved estimates move us one step closer to the development of well-integrated, global climate models needed to understand and predict the current and future climate.
Domingues, C.M., J.A. Church, N.J. White, P. J. Gleckler, S. E. Wijffels, P. M. Barker, and J.R. Dunn. 2008. “Improved estimates of upper-ocean warming and multi-decadal sea-level rise,” Nature 453, DOI: :10.1038/nature07080