Scientific American: The great global cola war has spilled into a new theater of operations: the environment. Hardly a week passes without the two soft-drink behemoths, the Coca-Cola Co. and PepsiCo, announcing new environmental initiatives. Both have launched ambitious water-conservation and recycling drives, and the two are now working feverishly to improve their energy efficiency. Most of what they do saves them money and bolsters their bottom lines. But a recent barrage of press releases from …