The U.N. is warning that time is running out to forestall worldwide environmental problems, and it’s already too late to prevent some biodiversity loss and irreversible damage to ecosystems like tropical forests. An end-of-the-century report by the U.N. Environment Program, compiled by experts from more than 100 nations, predicts that a number of “full-scale emergencies” are on the horizon, including severe water shortages and climate change. According to the report, the two major causes of environmental degradation are the poverty of the majority of the world’s inhabitants and excessive consumption by the minority. The report calls on the developed world to cut its use of natural resources by 90 percent to give the rest of the world a chance to emerge from poverty. The report acknowledges some environmental successes, such as the international effort to halt depletion of the ozone layer.