Cal-Adapt logo
Visit our new website at
Banner Image (a California landscape)

Securing an Adequate Water Supply

Continued global warming will increase pressure on California’s water resources, which are already over-stretched by the demands of a growing economy and population. Decreasing snowmelt and spring stream flows coupled with increasing demand for water resulting from both a growing population and hotter climate could lead to increasing water shortages. By the end of the century, if temperatures rise to the medium warming range and precipitation decreases, late spring stream flow could decline by up to 30 percent. Agricultural areas could be hard hit, with California farmers losing as much as 25 percent of the water supply they need.

Water supplies are also at risk from rising sea levels. An influx of saltwater would degrade California’s estuaries, wetlands, and groundwater aquifers. In particular, saltwater intrusion would threaten the quality and reliability of the major state fresh water supply that is pumped from the southern edge of the Sacramento/San Joaquin River Delta. 

Coping with the most severe consequences of global warming would require major changes in water management and allocation systems. As more winter precipitation falls as rain instead of snow, water managers will have to balance the need to fill constructed reservoirs for water supply and the need to maintain reservoir space for winter flood control. Some additional storage could be developed; however, the economic and environmental costs would be high.

Post last edited on: 2011 April 12

Tags: agriculture, precipitation, snow pack, water

Related Interactive Tools:

Snowpack: Decadal Averages Map

Local Climate Snapshots

Precipitation: Decadal Averages Map

Related Articles:


Climate Tools

Data Access



Copyright © 2022 California Energy Commission, All Rights Reserved
State of California, Edmund G. Brown Jr., Governor