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Saltwater intrusion intensifies coastal permafrost thaw

September 21, 2021

Surface effects of sea-level rise (SLR) in permafrost regions are obvious where increasingly iceless seas erode and inundate coastlines. SLR also drives saltwater intrusion, but subsurface impacts on permafrost-bound coastlines are unseen and unclear due to limited field data and the absence of models that include salinity-dependent groundwater flow with solute exclusion and freeze-thaw dynamics. Here, we develop a numerical model with the aforementioned processes to investigate climate change impacts on coastal permafrost. We find that SLR drives lateral permafrost thaw due to depressed freezing temperatures from saltwater intrusion, whereas warming drives top-down thaw. Under high SLR and low warming scenarios, thaw driven by SLR exceeds warming-driven thaw when normalized to the influenced surface area. Results highlight an overlooked feedback mechanism between SLR and permafrost thaw with potential implications for coastal infrastructure, ocean-aquifer interactions, and carbon mobilization.

Publication Year 2021
Title Saltwater intrusion intensifies coastal permafrost thaw
DOI 10.1029/2021GL094776
Authors Julia Guimond, Aaron Mohammad, Michelle A. Walvoord, Victor F. Bense, Barret L. Kurylyk
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70224590
Record Source USGS Publications Warehouse
USGS Organization WMA - Earth System Processes Division