Bequeathing a Ravaged Planet to Future Generations

In 450 million years, there have been five mass extinctions of species around the world. The latest of was 65 million years ago. Now a sixth is underway, caused by human behavior. That's according to the fourth Global Environment Outlook, out today from the United Nations. But despite reporting success in combating ozone loss and chemical air pollution, and saying it did not want to present a "dark and gloomy scenario," the GEO-4 concluded that the human population is now so large there are not enough resources available to sustain it. Andrew Revkin is environment reporter for the New York Times.