"Models show that even if we take action now to reduce emissions, we will still face serious stresses to water supply in California. Increases in [climate] temperature both decreases water availability while increasing demand. It will no longer just be a battle among the farming industry, the environmental groups and the cities, but those within each interest group will be competing with each other for water." - W. Michael Hanemann, professor of agricultural and resource economics and director of the California Climate Change Center at UC Berkeley

A study from UC Berkeley predicts that California will experience significantly hotter summers throughout this century, thanks to intensifying climate change, with resulting impacts on human health and the availability of water. Warmer temperatures will reduce snow melt from the Sierra snowpack that much of California depends upon for water supplies during hot, dry summers; higher temperatures also mean more evapotranspiration, and moisture-stressed soils and plants. 

And Californians are no strangers to water shortages.

Farmers are already required to cut back on the water used for crops. The San Joaquin-Sacramento Delta, the major water source for two-thirds of the state, is increasingly challenged by its fragile levees and growing demands. By the year 2020, demands on our water supply will result in shortages of six to 14 percent per year.

California has been ordered to wean itself from the excess of 800,000 acre-feet of water over its legal allotment from the Colorado River each year, but we have no viable alternative source. Yet our state acquires new water users at a rate of at least 500,000 people per year through immigration. Continuing our unchecked population growth means accelerating and exacerbating predicted water shortages and demands for water.

While some might argue that Californians have an essentially unlimited supply of water in the vast Pacific Ocean right next door, this is truly a question of “water, water everywhere but not a drop to drink.” Desalinating water is costly and energy intensive – and producing the energy needed to run a reverse osmosis desalination plant, whether from fossil fuels, nuclear power, or renewables, inevitably results in its own environmental impacts.