The study, initially completed at MIT, relied on several computer models of economic trends and estimated that if things didn't change much, and humans continued to consume natural resources apace, the world would run out at some point. Oil will peak (some argue it has) before dropping down the other side of the bell curve, yet demand for food and services would only continue to rise. Turner says real-world data from 1970 to 2000 tracks with the study's draconian predictions: "There is a very clear warning bell being rung here. We are not on a sustainable trajectory," he tells Smithsonian.