Our Water Supply, Down the Drain
More people will put a huge strain on our water resources, but another problem comes in something that sounds relatively benign: renewable energy, at least in some forms, such as biofuels. Refining one gallon of ethanol requires four gallons of water. This turns out to be a drop in the bucket compared with how much water it takes to grow enough corn to refine one gallon of ethanol: as much as 2,500 gallons.http://www.washingtonpost.com/wp-dyn/content/article/2009/08/21/AR2009082101773_pf.html