Santa Barbara built a desalination plant in 1991, then the rains hit, and they mothballed it in 1992, now they are reopening it and Carlsbad is building the largest desalination plant in the Western hemisphere.
In 2011 the United States, along with Saudi Arabia, the United Arab Emirates, and Spain was among the top 4 markets for desalinated water, it isnt like we dont know about it, or wont incorporate it as the market dictates.
Despite these hurdles, however, the United States ranks fourth among markets for desalinated water behind Saudi Arabia, the United Arab Emirates, and Spain, according to an International Desalination Association presentation from 2011.
http://www.bna.com/us-desalination-industry-n17179876105/
If we could make the ice caps melt more, than that would have to produce more evaporation and rain I would think...
Thanks for the info and the link.