11/21/2008 05:12 am ET | Updated May 25, 2011

Update: Obama Adviser Says 'Yes' - What Sayest McCain?

Back in July I posed a question to the presidential candidates: will our next president follow the Supreme Court's directive to regulate carbon dioxide (CO2) emissions through the authority of the Clean Air Act? At last, we have an answer from one candidate, which begs a response from his opponent.

Obama would direct EPA to regulate greenhouse gases under the Clean Air Act, his adviser has said; what would McCain do?
In 2007 the Supreme Court ruled that the Environmental Protection Agency could only avoid regulating greenhouse gases if it finds "... that greenhouse gases do not contribute to climate change or if it provides some reasonable explanation" (see complete ruling [pdf]). While President Bush has softened his position on climate change in the last year of his presidency, he has not directed EPA to take any action. This could change in the next presidency.

Jason Grumet, Barack Obama's energy advisor, said in an interview last week that, as president, Obama would order EPA to develop rules to regulate CO2 pollution from power plants and industry via the Clean Air Act. By taking this route to regulate and curb greenhouse gases, Obama would be able to avoid the inevitable delays that a comprehensive climate bill wending its way through Congress would bring. John McCain has yet to weigh in on whether he would use the Clean Air Act to regulate greenhouse gases.

Dr. Bill Chameides is a member of the National Academy of Sciences and the dean of the Nicholas School of the Environment at Duke University. He blogs regularly at