Projections of Arctic Coastal Erosion Rates in CMIP6 Climate Scenarios

Abstract:

Arctic coastlines respond directly to climate change. Land surface warming, permafrost thaw, and sea-ice loss increase the vulnerability of Arctic coasts to thermoabrasive erosion. The erosion of permafrost releases organic carbon to the ocean and atmosphere, which potentially contributes to further climate warming, and adds to the permafrost-carbon feedback. Earth System models (ESMs) do not generally represent Arctic coastal erosion and cannot, therefore, properly quantify its relationship with climate change. Here, we use long-term mean erosion rate estimates from the Arctic Coastal Dynamics database (Lantuit et al. 2012) and climate reanalyses to develop a semi-empirical model for Arctic coastal erosion. Our model accounts for Arctic-mean thermal and mechanical forcings as the main temporal drivers of coastal erosion rates, and considers local environmental and morphological variables (e.g. wave energy and ground-ice content) to represent their spatial variability. We use simulations from the Max Planck Institute Earth System Model (MPI-ESM) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to calculate Arctic coastal erosion rates in historical and future climate scenarios. This is a first step towards representing Arctic coastal erosion in the MPI-ESM, and quantifying its effect on the global carbon budget.

References

Lantuit, H. et al. (2012) The Arctic Coastal Dynamics Database: A New Classification Scheme and Statistics on Arctic Permafrost Coastlines. Estuaries and Coasts 35, 383–400 doi.org/10.1007/s12237-010-9362-6