Worldwide carbon dioxide emissions boomed between 2000 and 2004, a new study shows. Output of the greenhouse gas accelerated by 3.1% each year, compared to a 1.1% rate during the '90s, according to the National Academy of Sciences, faster than all but the most dire forecasts.
Carbon intensity—the amount of energy used to produce each unit of the world's gross domestic product—also increased. India, China and other developing countries bear the brunt of the blame, the report shows: They're industrializing at a rapid clip, but lack clean alternatives to coal. "Putting everyone in hybrid cars isn't going to solve this one," said one researcher.