You cite an paper with predictions, dated 2004. In 2008, researchers from Scripps Institute in San Diego (some of the same researchers) published a report in Science that they had already measured declining snowpack over the past 50 years.
Other research as found the same thing. More precipitation is falling as rain, and warmer temperatures are causing faster melt. So more is running off in Spring and summer and less water is available in fall.
This means two things: more years with spring floods, more years with fall droughts. How will the state adapt? That is a very good question. The climate changes in the Southwest combined with population growth continues to put stress on the Colorado River (which does not reach the ocean -- its water is 100?laimed as is).
This will put more political pressure on a plan to transport more water from Northern California. Should such a plan pass, California tax payers will have to shoulder the expense of building a vast new water infrastruction to transport water -- given the current debt, this will certainly require new taxes on California. Ideally some of the cost could be raised by ending water subsidies and allowing the cost of water to increase to market rates for all users. The cost of water is certain to rise for Californians regardless of the exact funding plan.
Adding to the political mess and cost, is that the most efficient means to transport water is to intercept water headed to the San Francisco Bay. You might recall that in 1982 voters rejected the Peripheral Canal -- Southern Ca voters rejected it because they did not want tax payers to subsidize the big agribusiness, Nothern Ca voters rejected it by more than 90?ecause of the environmental damage it would do to the bay and because they did not want to subsidize the SoCal lifestyle. These issues still exist, and the low fall runoff will make the SF Bay even more sensitive.
The cost to California taxpayers will be huge. Get ready for expensive water folks. There will adaptation by home owners, business and agriculture. There will be changes in the crops grown and the processes to grow them. The green vegetables grown now in the Imperial Valley using subsidized water will have to be imported from elsewhere. Agriculture jobs will go elsewhere, food cost will increase, water will be less available and more expensive. Oh, and Spring flood damage will be more expensive and more common.
And some people want to do nothing because they think doing something will cost them.