Rapid Decadal Acceleration of Sea Level Rise along the U.S. East and Gulf Coasts during 2010-2022 and Its Impact on Hurricane-Induced Storm Surge

Abstract

Sea level rise (SLR) shows important spatiotemporal variability. A better understanding of characteristics and mechanisms of the variability is critical for future SLR projection and coastal preparedness. Here we analyze various observational and modeling data of sea level and its components, atmospheric pressure and winds, and ocean circulation in the North Atlantic. Both the century-long tide gauge data and the more recent altimetry data reveal a rapid decadal acceleration of SLR during 2010-2022 along the U.S. East Coast and the Gulf of Mexico coast. The acceleration is most notable on the Southeast and Gulf Coasts, as quantified by the decadal rise rate, extreme annual sea level departure from the long-term trend, as well as the sea level record-breaking frequency and magnitude. Our analysis suggests that this SLR acceleration is largely a lagged response to the observed slowdown of the Atlantic meridional overturning circulation in 2009-2010. In the North Atlantic, the response is characterized by a large-scale pattern of contrast changes in dynamic sea level between the eastern subpolar gyre and the U.S. Southeast and Gulf Coasts. The latest global climate model generally captures this observed pattern and projects that further increase in greenhouse-gas forcing will modify it over the 21 ^st century. The faster SLR on the Southeast and Gulf Coasts, at a rate of more than 10 mm/year during 2010-2022, coincided with active and even record-breaking North Atlantic hurricane seasons in recent years. As a consequence, the elevated storm surge exacerbated coastal flooding and damages particularly on the Gulf Coast.