Unprecedented Continental Drying, Shrinking Freshwater Availability, and Increasing Land Contributions to Sea Level Rise

Abstract:  

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. 75% of the population lives in 106 countries that have been losing freshwater water since 2002. 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 results presented.

Bio:
Dr. Jay Famiglietti is a hydrologist and Global Futures Professor at Arizona State University where he is Director of Science for the Arizona Water Innovation Initiative. He is incoming President-Elect of the American Geophysical Union’s Hydrology Section. Before moving to ASU, Famiglietti was founding Chief Scientist of the Silicon Valley tech startup, Waterplan; he was Executive Director of the Global Institute for Water Security at the University of Saskatchewan; he was Senior Water Scientist at NASA’s Jet Propulsion Laboratory; he was appointed to the California State Water Boards by Governor Jerry Brown; and he held faculty positions at UC Irvine and UT Austin. His research group uses satellites to track how freshwater availability is changing around the globe, and they pioneered the methods to detect groundwater depletion from space. A fellow of the American Geophysical Union, Geological Society of America, and recipient of AGU’s Peter S. Eagleson Hydrological Sciences Award, he is committed to science communication and to multi-sectoral advising on water security issues.