Forget the zombie apocalypse: Imagine a worldwide cocoa deficit. Chocolate consumption outpaced production by 70,000 metric tons in 2013, and the gap could increase to one million tons by 2020. Farms are stretched, partly because Theobroma cacao — whose beans make chocolate — is a slow-producing crop that’s tough to improve. Growers are investing in new higher-production strains that won’t sacrifice flavor. But if that doesn’t work, it’ll mean smaller, more expensive bars. Chocoholics, stock up while you can.