A unified conceptual model of coastal response to accelerating sea level rise, Florida, U.S.A

Abstract

Aggregation of paleo-environmental data derived from geological investigations conducted on the shoreface and inner shelf of Florida's six coastal geomorphic sectors revealed a common and synchronous response to a decelerating rate of Holocene sea level rise: (1) early Holocene overstep and submergence (∼10-5 mm yr^-1), (2) mid-Holocene erosional shoreface retreat (∼2 mm yr^-1), and (3) late Holocene stabilization (<1 mm yr^-1). Linear best-fit analysis of sea level data collected at 14 NOAA tide gauge stations distributed along the entire Florida coast indicates the rate of sea level rise has accelerated from a historical average of 3.1 mm yr^-1 (<1972-2022; range 2.2 to 4.2) to 5.9 mm yr^-1 (1993-2022; range 4.8 to 6.9) and 8.2 mm yr^-1 during the 21st century (2003-2022; range 7.6 to 10.0). The 21st century rates vary between stations, however all fall within the range of values documented during the early Holocene; a time when Florida's coastline was rapidly transgressed. Recent studies have demonstrated that the destabilizing effects of this acceleration on Florida's coastal geomorphology and ecology are already evident. Rates of rise are expected to continue increasing and this will accelerate the pace and scale of landward translation and submergence of Florida's coastal environment.

Keywords: Geochronology; Holocene; Paleo-environments; Sedimentology; Stratigraphy; Tide gauge.