Hydrological intensification is poised to increase uncertainty for water resources management
Abstract
Increased global temperature intensifies the hydrological cycle via increases in the fluxes of water to and from the terrestrial surface, resulting in a simultaneous increase in the occurrence of heavy precipitation surplus events [precipitation reference evapotranspiration (ETo)] and the length of time between meaningful precipitation (dry spells; ETo precipitation). Here, we examine projected changes in hydrologic intensification and its role on increasing uncertainty in water resources planning and management. We force a GCM ensemble and emission scenarios from Phase Six of the Coupled Model Intercomparison Project (CMIP6) through a new framework that quantifies the dynamics of juxtaposed precipitation surpluses and dry spells while also accounting for expected plant responses to rising CO2 and vapor pressure deficit (VPD). The magnitude of precipitation surplus events is projected to get larger (18.5% increase for the end of the 21st century compared to the 1950-1980 baseline) and the duration between them longer (9.6% increase), resulting in an intensification of the hydrologic cycle. The juxtaposition in wet and dry extremes will stress existing infrastructure in the worlds major river basins, where over one-third of the years during the 2080s will be categorized as hydrologically intense, leading to conditions unanticipated in current water resource management. Basins with large reservoir capacity have significant populations, considerable irrigated farmland, and threatened and endangered aquatic species, yet are also projected to have a larger number hydrologically intense years than basins with less reservoir capacity. Managing water for water users will become increasingly contentious and thus incorporating flexibility into water management will be paramount.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMGC23D..07F