Global climate change could deal a severe blow to agricultural water supplies, degrade water quality at both estuaries and groundwater aquifers, while threatening the reliability and quality of one of San Diego’s major water sources, according to a report released yesterday.

The California Environmental Protection Agency report, which is based on core research from scientists at Scripps Institution of Oceanography and the University of California, Berkeley, is required every two years by a 2005 executive order from Gov. Arnold Schwarzenegger.

The worst-case scenario: An 8-to 10.5-degree Fahrenheit temperature jump by 2100. If this happens, the report says, cities such as Los Angeles could experience 100 more days annually with temperatures above 90 degrees. The Sierra Nevada spring snow pack, which provides a major source of drinking water in the state, could be reduced as much as 90 percent. The state’s cities could see four-to-six times more heat-related deaths. Sea levels could rise between 22 and 30 inches.

The best-case scenario: A 3-to 5.5-degree jump by 2100. This spells a six-to 14-inch rise in sea levels, a 10-to 30-percent increase in wildfires and twice or three times as many heat-related deaths.

That’s a lot of numbers. The report here spells it out clearly.

Climate change will increase pressure on California already over-stretched water supplies, the report says, and could lead to increasing water shortages. Saltwater could intrude into the Sacramento/San Joaquin River Delta, which serves a major supply of the state’s fresh water. California agriculture – a $30 billion industry – could lose as much as 25 percent of its water supply, the report says.

It reads:

How much snowpack will be lost depends in part on future precipitation patterns … which remain uncertain. However, even under wetter climate projections, the loss of snowpack would pose challenges to water managers, hamper hydropower generation, and nearly eliminate skiing and other snow-related recreational activities.

Some signs are already evident, the report says. Spring flowers are blooming a week or two earlier. Snow pack is melting a week to a month earlier. And those mountainous snow levels are dropping at lower elevations.

We recently wrote about climate change’s potential effects on San Diego’s water supply. Read that story here.

For more climate change info, check out this state website.


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