Estimating saltwater intrusion using remote-sensing datasets and analytical approaches

Coastal regions are home to more than 40% of the world’s population and often depend on fresh groundwater resources to sustain economic, residential, and recreational activities. However, coastal groundwater is under threat from saltwater intrusion (SWI), due in part to rising sea level and climate change. In this work we provide, for the first time, a global assessment of SWI and SWI vulnerability due to regional differences in sea level rise and predicted changes in recharge, leveraging NASA datasets of recharge, seawater density, and IPCC AR6 sea level rise. We show that climate-driven recharge changes drove 45% of watersheds to experience SWI, while SLR drove 92% of watersheds to experience SWI. By synthesizing various global datasets within an analytical framework, the work provides the first step towards evaluating the coastal impacts of saltwater intrusion in a changing climate.