Climatic responses to tropical sea surface temperature changes on a "greenhouse" Earth

The uncertainty associated with tropical sea surface temperatures (SSTs) du ring past "greenhouse" climates may have important and unaccounted for effe cts. We explore early Paleogene climatic sensitivity to changes in tropical -subtropical SSTs with a general circulation model. We demonstrate that tro pical SST changes have local and far-field climatic effects, underscoring t heir importance in understanding greenhouse climates. The responses of wind s, upwelling, and surface water balance to tropical SST changes are substan tial. Our results indicate that current tropical SST reconstructions may ha ve a significant cool bias despite corrections and that the existence of ho t (>30 degrees C) tropical SSTs may be realistic for greenhouse climate int ervals, including the Eocene.