The problem with climate change is change. It’s a simple thing, really, but it’s a point sometimes missed. It’s not that it gets warmer or colder or wetter or drier. It’s that it gets different, and the societal systems we’ve put in place to cope with what used to be “normal” become less useful.
A case in point: California. I just ran across this paper from the October Journal of the American Water Resources Association. It’s from a group at UC Davis that ran global 12 climate change scenarios against California water supply models to see what happens as things warm up. As you might expect, the snow melts sooner:
Even most scenarios with increased precipitation result in less available water because of the current storage systems’ inability to catch increased winter streamflow in compensation for reduced summer runoff.
Available water supplies decrease in 9 of the 12 scenarios they looked at. It’s worth noting, too, that in a number of scenarios the Davis team looked at, the decrease in available supply as a result of warming is comparable to the increase in demand from growing population in California. In other words, vulnerability as a result of climate change is comparable in this analysis to vulnerability as a result of societal change.
That’s “Estimated Impacts of Climate Warming on California Water Availability Under Twelve Future Climate Scenarios,” Tingju Zhu, Marion W. Jenkins, and Jay R. Lund, JAWRA, Oct. 2005.