A new study "performed by consulting firm Tetra Tech for the Natural Resources Defense Council (NRDC), examined the effects of global warming on water supply and demand in the contiguous United States. The study found that more than 1,100 counties -- one-third of all counties in the lower 48 -- will face higher risks of water shortages by mid-century as the result of global warming. More than 400 of these counties will face extremely high risks of water shortages."
The results for Arizona are shown at right.
The data aren't much different from previous studies but the level of detail is greater.