Control of land-ocean temperature contrast by ocean heat uptake

We show that the ratio of observed annual-mean land temperature change to ocean surface temperature change, phi, has remained almost constant during 1955-2003. This is the case, despite most of the heat capacity of the climate system lying in the oceans, and rapid variations in climate forcing. Examining seven General Circulation Models (GCMs), we find land and ocean temperature behavior comparable to observations in six cases. For three models that reproduce observed phi and for which we have data, we find no significant changes in future phi under the SRES A1B scenario. We suggest that variations in land-ocean heat flux primarily balanced by ocean heat uptake are sufficient to maintain constant phi. This flux is present in the six GCMs that resemble observations, suggesting that observed phi may remain constant into the future, even if radiative forcing is markedly different than in the past.