High Court mulls greenhouse gas regulation

President Bush has rejected calls by environmentalists and some lawmakers in Congress to regulate carbon dioxide, the leading heat-trapping "greenhouse" gas going into the atmosphere. Bush favors voluntary actions and development of new technologies to curtail such emissions.

But a dozen states argued that carbon dioxide and other heat-trapping chemicals from automobile tailpipes should be treated as unhealthy pollutants. They filed a lawsuit in an effort to force the EPA to curtail such emissions just as it does cancer-causing lead and chemicals that produce smog and acid rain.