With the demise of cap-and-trade legislation during the 2010 session of Congress, the climate action spotlight has shifted to the Environmental Protection Agency (EPA) and the Clean Air Act (CAA). But efforts are now underway to revoke the EPA’s authority to regulate greenhouse gas (GHG) emissions.

Clean Air Act

In the aftermath of the first Earth Day in April 1970, Congress passed the Clean Air Act of 1970 and created the EPA to implement the new law. Over the 40 years that the CAA has been in effect, it has yielded dramatic public health and environmental benefits. 

The EPA reports that CAA programs have reduced dangerous air pollutants that cause smog, acid rain, and lead poisoning by 60 percent. This has prevented hundreds of thousands of premature deaths, helped millions avoid developing respiratory ailments and heart disease, and by banning leaded gasoline, greatly reduced the incidence of lowered IQs among children.

Supreme Court Ruling

Despite these gains, concerns about global warming pollution led Massachusetts and eleven other states to sue the EPA over its failure to regulate GHG emissions from the transportation sector. They claimed that human-influenced global climate change was causing adverse effects, such as sea-level rise, to the state of Massachusetts. 

In a 5-4 decision in April 2007, the U.S. Supreme Court ruled that carbon dioxide and other GHGs meet the definition of “air pollutants” under the CAA. The Court required the EPA to determine whether or not GHG emissions from new motor vehicles (the sector cited in the lawsuit) cause or contribute to air pollution that may endanger the public health or welfare.

In 2009, the EPA responded by conducting an extensive examination of the scientific evidence and in December 2009 made a determination — the “endangerment finding” — that GHG concentrations in the atmosphere do threaten the public health and welfare of current and future generations. The EPA also found that GHG emissions from new motor vehicles contribute to the atmospheric concentration of these gases and thus to the threat from climate change.

Once the endangerment finding was released, the EPA moved ahead to finalize proposed GHG emissions standards for light-duty motor vehicles.

The Clean Cars Rule

The EPA partnered with the Department of Transportation (DOT) to issue GHG emissions standards and higher fuel efficiency requirements for passenger cars and light-duty trucks for model years 2012 through 2016. The federal rules mirror California’s Clean Car Standards, also adopted by 13 other states, and set a target of 35.5 miles per gallon for 2016 model-year vehicles. The auto industry supported the new rules, and California agreed to adopt the federal standards.

The EPA and DOT have since proposed emissions and fuel efficiency standards for heavy-duty trucks and buses, beginning in the 2014 model year, and will also set further standards for light-duty vehicles for model years 2017 and beyond.

Stationary Source Regulations

The EPA has also begun phasing in regulations for large stationary sources of GHG emissions. As of January 2, 2011, major new or upgraded facilities that are already subject to CAA permitting requirements for non-GHG pollutants must also implement “best available control technologies” to control GHG emissions. By mid-year, the requirements will extend to other large sources of GHG emissions that were not previously covered by the CAA. These new rules will apply to facilities responsible for nearly 70 percent of GHG emissions from stationary sources.

In addition, the EPA has established a timetable for setting limits on GHG emissions for the two largest sources: power plants and oil refineries. The EPA will propose “performance standards” for new and substantially upgraded power plants by July 2011, with a final rule due in May 2012. Proposed standards for new oil refineries will be issued in December and finalized in November 2012. Rules for existing power plants and refineries will follow in 2015 or 2016. Together, these plants and refineries account for roughly 40 percent of all U.S. GHG emissions.

Challenges to EPA Regulations

Opponents of the new climate change rules are working to block or delay EPA regulation of GHG emissions. Several dozen legal challenges to EPA’s recent actions have been filed by a variety of business and industry groups, several states, and a number of members of Congress.

In Congress, efforts in 2010 to overturn the EPA’s endangerment finding and revoke the EPA’s authority to regulate GHG emissions were not successful, but strong challenges are expected in the new Congress. 

Meanwhile, the EPA maintains that its endangerment finding followed an exhaustive review of the peer-reviewed science and thousands of public comments submitted in an open and transparent process. The agency has also noted that it is committed to proceeding “in a measured and careful way,” soliciting feedback from the business community that “will lead to smart, cost-effective and protective standards that reflect the latest and best information.