Saltwater Intrusion Intensifies Coastal Permafrost Thaw

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 unseen unclear due to limited field data the absence models that include salinity-dependent groundwater flow with solute exclusion freeze-thaw dynamics. Here, we develop a numerical model aforementioned processes investigate climate change coastal permafrost. We find lateral thaw depressed freezing temperatures from whereas warming top-down thaw. Under high low scenarios, driven by exceeds warming-driven when normalized influenced surface area. Results highlight an overlooked feedback mechanism between potential implications for infrastructure, ocean-aquifer interactions, carbon mobilization.