You can convert salt water to fresh water, it is more expensive, but the technology exist. Once fresh water became more rare, there will be people investing in those facilities, much more effective than government can ever get.
In a way wall street is saving us from running out of life sustaining resources, just like how food became so plentiful because of corporations, not the other way around. No one ever complain that we running out of bacons because wall streets are investing in porks.