Sara Menker quit a career in commodities trading to figure out how the global value chain of agriculture works. Her discoveries have led to some startling predictions: "We could have a tipping point in global food and agriculture if surging demand surpasses the agricultural system's structural capacity to produce food," she says. "People could starve and governments may fall." Menker's models predict that this scenario could happen in a decade -- that the world could be short 214 trillion calories per year by 2027. She offers a vision of this impossible world as well as some steps we can take today to avoid it.