Worldwide sea levels have climbed since 1900 by some 1.5 millimeters a year, a pace that is unprecedented in at least 3,000 years and generally attributable to melting ice sheets and glaciers and also the expansion of the oceans as their temperatures warm. Since the middle of the 20th century the rate has gained speed, exceeding 3 millimeters a year since 1992.

In the South the pace has quickened further, jumping from about 1.7 millimeters a year at the turn of the 20th century to at least 8.4 millimeters by 2021, according to a 2023 study published in Nature Communications based on tidal gauge records from throughout the region. In Pensacola, a beachy community on the western side of the Florida Panhandle, the rate soared to roughly 11 millimeters a year by the end of 2021.

In the South the trajectories would fall within and in some places exceed NOAA’s “high” scenario, according to the Nature Communications study. Further acceleration in the region would go as far as to threaten national security and outpace adaptation measures, the report warned.

The data suggest that by 2050 the sea level rise in Florida would correspond with NOAA’s “intermediate,” “intermediate-high” and “high” scenarios, according to the study.