Mark your calendar: January 1, 2020. ... As this future year unfolds, the gap between how much cocoa the world wants to consume and how much it can produce will swell to 1 million metric tons, according to Mars Inc. and Barry Callebaut AG, the world’s largest chocolate maker. By 2030, the predicted shortfall will grow to 2 million tons. And so on. ... Because of disease, drought, rapacious new markets and the displacement of cacao by more-productive crops such as corn and rubber, demand is expected to outstrip supply by an additional 1 million tons every decade for the foreseeable future. Here, now, as you read these words, the world is running out of chocolate ... Last year, we again consumed more cocoa than we were able to produce. This year, despite an unexpected bumper crop, supply barely kept pace with the recent upswing in demand. From 1993 to 2007, the price of cocoa averaged $1,465 a ton; during the subsequent six years, the average was $2,736 -- an 87 percent increase. ... The world’s most universally delectable treat has begun a journey from being very loved and very common, like beer, to being very loved and a good deal less common, like Bordeaux. Unfortunately, that is the least of the confection’s problems. ... Efforts are under way to make chocolate cheap and abundant -- in the process inadvertently rendering it as tasteless as today’s store-bought tomatoes, yet another food, along with chicken and strawberries, that went from flavorful to forgettable on the road to plenitude.