Johnson said he will solicit public input through an Advance Notice of Proposed Rulemaking as the agency considers the specific effects of climate change and potential regulation of greenhouse gas emissions from stationary and mobile sources under the Clean Air Act.

Representative Edward Markey of Massachusetts, who chairs the House Select Committee on Energy Independence and Global Warming, was particularly frustrated. He views Johnson's notice of rulemaking as another delay tactic as do others who insist global warming is an established fact and needs immediate action.

On April 2, the anniversary of the Supreme Court ruling, Markey says his committee will vote to issue a subpoena for documents from the EPA showing what progress that agency has made in response to the high court's decision.