Unprecedented continental drying, shrinking freshwater availability, and increasing land contributions to sea level rise

Changes in terrestrial water storage (TWS) are a critical indicator of freshwater availability. We use NASA GRACE/ GRACE-FO data to show that the continents have undergone unprecedented TWS loss since 2002. Areas experiencing drying increased by twice the size of California annually, creating mega-drying regions across the Northern Hemisphere. While most of the world's dry/wet areas continue to get drier/wetter, dry areas are now drying faster than wet areas are wetting. Changes in TWS are driven by high-latitude water losses, intense Central American/ European droughts, and groundwater depletion, which accounts for 68% of TWS loss over non-glaciated continental regions. Continental drying is having profound global impacts. Since 2002, 75% of the population lives in 101 countries that have been losing freshwater. Furthermore, the continents now contribute more freshwater to sea level rise than the ice sheets, and drying regions now contribute more than land glaciers and ice caps. Urgent action is required to prepare for the major impacts of these results.

Hrishikesh A. Chandanpurkar, James S. Famiglietti, Kaushik Gopalan, David N. Wiese, Yoshihide Wada, Kaoru Kakinuma, John T. Reager, Fan Zhang