The planet's 1.5 billion cows are (innocently) an environmental scourge thanks to the copious amounts of horrible greenhouse gases they disgorge. Scientists from Michigan State U have flopped that around, however, and figured out how to turn the resulting manure into something good for the planet: fresh water. By running the poop through a so-called anaerobic digester and reverse osmosis system, they got pure H2O out the other side. The average bovine produces about 10,000 gallons of "raw materials" a year and scientists can transform at least half of that into water (the other half becomes energy and fertilizer). The final product is intended for livestock and not human consumption, but maybe all it needs is some good marketing.