Last week's Supreme Court ruling on Massachusetts versus EPA was a landmark victory for Planet Earth, but there's still much work to be done. The ruling doesn't demand any specific action - it just sets the stage for future rulings. Case in point: California’s petition to EPA to use its own, stricter emissions standards rather than federal emissions standards.

In light of this ruling, will the EPA grant California’s petition? On April 5^th, a couple of news outlets reported that EPA had approved California's request. Unfortunately, they got it wrong. EPA simply agreed to take the next to step in considering the California waiver - holding public hearings. We won’t know for months how EPA will rule.

Here's some background. In recognition of California’s role as a leader in air quality protection, the Clean Air Act allows California, upon the approval of the EPA, to make their own standards more stringent than the federal government’s. It also allows other states with air quality problems to opt for California's standards rather than the federal standards.

In 2002, California passed a law, introduced by Assembly member Fran Pavley, that would limit greenhouse gas emissions from cars. Standards to implement the law were finalized in 2004 by the California Air Resources Board, and in 2005 California petitioned EPA for a waiver so it could proceed with them. Subsequently, 11 other states indicated their intention to follow the Pavley standards.

EPA waited to rule on California's waiver request pending the outcome of Massachusetts versus EPA. Would the Supreme Court allow EPA to deny the waiver petition by claiming it didn't have the authority to regulate greenhouse gas emissions? On April 2, 2007, the EPA got its answer: No. The Supreme Court said that, far from having no authority, EPA has a duty to regulate greenhouse gas pollution. But we don’t know what EPA will do in response.

In the meantime, discussions on climate change legislation continue in Congress. Like I said, there's a lot of work ahead.