The Supreme Court, on October 15, 2013, agreed to review the federal government’s power to regulate so-called “greenhouse gases” (GHGs) from stationary sources in an effort to slow climate change.

Some speculate a negative Supreme Court ruling could undermine or even end much of EPA's climate change program

Some speculate a negative Supreme Court ruling could undermine or even end much of EPA’s climate change program

The Court’s pending review will cap six busy years of EPA regulatory actions arising from the Court’s determination in 2007 that GHGs are an “air pollutant” subject to regulation under the Clean Air Act (CAA). Massachusetts v. EPA, 549 U.S. 497 (2007). After issuing an “endangerment finding,” declaring that GHGs may “reasonably be anticipated to endanger public health or welfare,” see 42 U.S.C. § 7521(a)(1), EPA promulgated the Tailpipe Rule, setting GHG emission standards for cars and light trucks. 75 Fed. Reg. 25,324 (May 7, 2010). Once the Tailpipe Rule became effective, GHGs became a “regulated pollutant” under the CAA, which, under longstanding EPA interpretation, required EPA to regulate stationary sources under the Prevention of Significant Deterioration (PSD) and Title V programs. For logistical reasons, EPA initially required permits for only the largest stationary sources, pursuant to the agency’s Timing and Tailoring Rules.

In Coalition for Responsible Regulation v. EPA, 684 F. 3d 102 (D.C. Cir. 2012), various states and industry groups challenged all these regulations and, after the D.C. Circuit sided with EPA on all counts, sought review by the Supreme Court. The high Court accepted six petitions for review of the D.C. Circuit’s decision, consolidating the petitions into single question:

Whether EPA permissibly determined that its regulation of greenhouse gas emissions from new motor vehicles triggered permitting requirements under the Clean Air Act for stationary sources that emit greenhouse gases.

Although the Supreme Court question on review is relatively narrow (in many ways already a victory for EPA), its potential implications are nonetheless broad. If the Court determines EPA’s interpretation of the CAA–that the Tailpipe Rule requires regulation of stationary sources–is unwarranted, such a decision could seriously disrupt, if not terminate, EPA’s planned rulemaking to set GHG performance standards for new and existing power plants.