In places like China, with a quarter of the world's population, up to 90% of the fresh water is already polluted, some irretrievably so.
Some 18% of the world population lacks access to potable water, and demand is expected to rise by 40% in the next 20 years.
Aquifers in the US, which took nature millennia to create, are approaching exhaustion. While membrane osmosis technologies exist to convert sea water into fresh, they use ten times more energy than current treatment processes, a real problem if you don't have any, and will easily double the end cost to consumers.
While it may take 16 pounds of grain to produce a pound of beef, it takes a staggering 2,416 gallons of water to do the same.
VIA oilprice.com