The State of Massachusetts joined with 11 other states, three cities, a US territory, and numerous environmental groups had sued to force EPA action. Many environmentalists hailed the decision.
"From our perspective, this is a very big victory, particularly with the other signs of momentum we've seen since January – hearings in Congress [and] action taken by California and other states," says Tony Kreindler, spokesman for Environmental Defense. "The flip side is that the court did not say the EPA has to take action on climate change. So nationally, this issue is really up to Congress."
"This is a big victory for planet Earth. And it's a stunning rebuke to the Bush administration," wrote Frank O'Donnell, president of the nonprofit research and advocacy group Clean Air Watch, in an e-mail. "The Supreme Court has confirmed that carbon dioxide can be controlled under the Clean Air Act. That means California and other states have the clear right to limit greenhouse-gas emissions if the Bush administration won't."
Like most environmental groups, industry officials see Monday's court decision as less than definitive. They agree that further action at the lower court level is likely as a result of the Supreme Court's decision. And they also predict that Congress now will play the most important role in deciding how to regulate carbon dioxide, the most important greenhouse gas.
"We tend to assume that the focus of activity on climate change and how CO2 may or not be regulated will be based on Congress's judgments rather than on the EPA's," says Rosario Palmieri, director of energy and resources at the National Association of Manufacturers in Washington.