Pacific Sea Level Rise Pattern and Global Warming Hiatus

Abstract:

We investigate the linkage between two notable features of climate change and sea level rise during the past decades: a slowdown in global warming (hiatus) and an east-west seesaw pattern of SLR in the Pacific. During the hiatus, the subsurface layer of the Pacific shows significant increase in ocean heat content along with a strong east-west gradient that is reflected in the seesaw pattern of Pacific SLR through the thermosteric effect. Control simulations from 38 climate models indicate that during periods of negative trend in global mean surface temperature (analogous to hiatus decades in a warming world), dynamic sea level increases in the western Pacific and decreases in the eastern Pacific. The opposite occurs during periods of positive temperature trends. Using a regression analysis of the model simulations along with sea-level measurements from satellite altimetry, we find that the recent change in the Pacific Ocean heat storage has suppressed potential surface warming since 1998. Our results suggest that a flip of the Pacific SLR seesaw would imply a resumption of surface warming and SLR acceleration along the U.S. West Coast.