1. What authority is given to the EPA by statute? Why does the EPA not want to exercise authority over greenhouse gases?

2. Why does the majority conclude that greenhouse gases are included within that authority?

3. List the arguments the dissent makes against requiring the EPA to take action on greenhouse gases. What do you learn about the role of the issue of global warming in the dissent’s analysis of the case versus the analysis of the majority?

On October 20, 1999, a group of 19 private organizations (Petitioners) filed a rulemaking petition asking the EPA to regulate “greenhouse gas emissions from newmotor vehicles under §202 of the Clean Air Act.” These organizations argued that greenhouse gas emissions have significantly accelerated climate change, and that “carbon dioxide remains the most important contributor to [man-made] forcing of climate change.”

Fifteen months after the petition was filed, the EPA requested public comment on “all the issues raised in [the] petition,” adding a “particular” request for comments on “any scientific, technical, legal, economic or other aspect of these issues that may be relevant to EPA’s consideration of this petition, including whether there was global warming due to carbon emissions.” The EPA received more than 50,000 comments over the next five months.

On September 8, 2003, the EPA entered an order denying the rulemaking petition because (1) the Clean Air Act does not authorize the EPA to issue mandatory regulations to address global climate change; and (2) even if the agency had the authority to set greenhouse gas emission standards, it would be unwise to do so at this time. Massachusetts, other states, and private organizations filed suit, challenging the EPA denial as arbitrary and capricious, violative of the APA, and ultra vires because of statutory mandates for EPA action.

The court of appeals dismissed the appeal from the agency denial and the Supreme Court granted certiorari.

JUDICIAL OPINION

STEVENS, Justice … In concluding that it lacked statutory authority over greenhouse gases, EPA observed that Congress “was well aware of the global climate change issue when it last comprehensively amended the [Clean Air Act] in 1990,” yet it declined to adopt a proposed amendment establishing binding emissions limitations. Congress instead chose to authorize further investigation into climate change. In essence, EPA concluded that climate change was so important that unless Congress spoke with exacting specificity, it could not have meant the agency to address it. According to the climate scientist Michael MacCracken, “qualified scientific experts involved in climate change research” have reached a “strong consensus” that global warming threatens (among other things) a precipitate rise in sea levels by the end of the century.

While it may be true that regulating motor vehicle emissions will not by itself reverse global warming, it by no means follows that we lack jurisdiction to decide whether EPA has a duty to take steps to slow or reduce it. Because of the enormity of the potential consequences associated with man-made climate change, the fact that the effectiveness of a remedy might be delayed during the (relatively short) time it takes for a new motor-vehicle fleet to replace an older one is essentially irrelevant.

We find such action is “… arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” … The first question is whether § 202(a)(1) of the Clean Air Act authorizes EPA to regulate greenhouse gas emissions from new motor vehicles in the event that it forms a “judgment” that such emissions contribute to climate change.

The Clean Air Act’s sweeping definition of “air pollutant” includes “any air pollution agent or combination of such agents, including any physical, chemical … substance or matter which is emitted into or otherwise enters the ambient air…” § 7602(g) (emphasis added). On its face, the definition embraces all airborne compounds of whatever stripe, and underscores that intent through the repeated use of the word “any.” Carbon dioxide, methane, nitrous oxide, and hydrofluorocarbons are without a doubt “physical [and] chemical … substance[s] which [are] emitted into … the ambient air.” The statute is unambiguous. If EPA makes a finding of endangerment, the Clean Air Act requires the agency to regulate emissions of the deleterious pollutant …………………