Humankind is now consuming natural resources faster than they can be replaced. Researchers at the nonprofit public policy organization Redefining Progress pored over 40 years of data, comparing levels of agriculture, grazing, logging, fishing, and other human demands to the earths regenerative capabilities. In the early 1960s, humans used up 70 percent of the earths productive capacity. By the 1980s, we started to exceed natures annual output. In 1999 we were using 125 percent of capacity. At this rate, says lead researcher Mathis Wackernagel, "we may have to prepare for ecological bankruptcy." Unless, of course, we stop biting the hand that feeds us.