Adapting to Sea Level Rise to the Year 2100 and Beyond in the State of Florida, USA: A Regional Approach Based upon Common Vulnerabilities and the Utility of Shared Resources

Abstract:

We simulate the vulnerability of all 35 Florida coastal counties to the ongoing Anthropocene marine transgression unconstrained by the artificial end date of year 2100. Coastal submergence was emulated using a ‘bathtub model’ and rising sea level associated with an atmospheric temperature increase of +1 ^oC to +4 ^oC (see Levermann et al. [1]).

Simulation results are organized into seven regions, each representing an area of common vulnerability characterized in this study as high (9% to 30% land loss), higher (16 to 68% land loss) and highest (48% to 97% land loss). This grouping provides a logical basis for establishing or re-enforcing collaboration based upon a common threat and the utility of shared technical and financial resources.

Our bathtub model assumes Florida terrain is simply submerged as the shoreline migrates across a static landscape without change in the physical and biological materials subject to marine transgression. However, geologic studies of past and present Florida shorelines indicate the rate of rise is as important as the magnitude when predicting coastal response. To determine the utility of the bathtub model as a representative simulation of Florida’s response to future sea level rise, we considered Florida’s coastal response to varying rates of sea level rise over the last 14,000 years. Available data clearly demonstrate predicted rates of sea level rise will result in widespread submergence; the rate of rise will be too fast to be offset by the stabilizing forces of biogenic or physical sediment accumulation. Hence the magnitude of land loss and associated shoreline retreat in each of the seven Florida regions – and likely other coastal zones in the southeast U.S. – will be solely a function of topographic elevation and can therefore be reasonably forecast using a bathtub model.

While our focus is on Florida’s coastal counties, we recognize in some regions the effects of sea level rise will extend further inland. In these areas, the regional boundaries could be expanded to include adjacent non-coastal counties. However, differences in the perception of risk and associated vulnerability between coastal and inland counties may complicate timely collaboration.

References: [1] A. Levermann et al. (2013), The Multi-Millennial Sea-Level Commitment of Global Warming, doi:10.1073/pnas.1219414110.