U.S. Supreme Court Considers Case on Greenhouse Gases

December 2006

On November 29, 2006 the United States Supreme Court heard oral arguments on Massachusetts, et. al. v. EPA, et. al., a case that could affect whether the Environmental Protection Agency (EPA) regulates carbon dioxide and other green house gas emissions from motor vehicles pursuant to the Clean Air Act. This case is important to states not only because of its implications for greenhouse gas regulations but also because there are groups of states on either side of the case: twelve states side with the petitioners and ten states side with the respondents.

In 1999 several parties filed a rulemaking petition with the EPA asking it to regulate carbon dioxide, methane, nitrous oxide, and hydroflourocarbons emissions (also known as greenhouse gases) from new motor vehicles under Section 202(a)(1) of the Clean Air Act. Section 202(a)(1) of the Clean Air Act states that EPA shall "prescribe…standards applicable to the emission of any air pollutant from any class or classes of new motor vehicles or new motor vehicle engines, which in [EPA's] judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare."

The EPA denied the petition in 2003 concluding that: the Clean Air Act does not require the EPA to regulate greenhouse gas emissions to address climate change; that carbon dioxide and greenhouse gases are not air pollutants within the meaning of the Clean Air Act; and further, that the provisions in the Clean Air Act dealing with the regulation of new motor vehicles are discretionary rather than mandatory, therefore allowing EPA the discretion not to regulate. The reasoning behind EPA's decision included the scientific uncertainty surrounding climate change and concern that because motor vehicles in the United States represent only a fraction of the global sources of greenhouse gases, regulating them would be an inefficient way to address the problem.

The petitioners, including states, cities, an American territory and several nongovernmental organizations, sought review of the EPA decision in the DC Circuit Court. The court of appeals upheld EPA's decision and the petitioners appealed to the U.S. Supreme Court. The petitioners' main arguments before the Supreme Court are that EPA has the authority to regulate greenhouse gas emissions and it was an error to decide otherwise, and that the EPA used impermissible policy considerations in deciding not to regulate greenhouse gas emissions. EPA's arguments are that the petitioner's lack legal standing to sue, that EPA's decision not to regulate greenhouse gases was reasonable, and that the EPA has the discretionary authority to determine whether or not to regulate greenhouse gases.

Oral Arguments at the Supreme Court

The main issue at oral argument was whether the states have legal standing to sue the EPA for its failure to regulate greenhouse gases. Legal standing has to do with whether the petitioning states have in fact suffered a particular injury that can be remedied through a judicial ruling in their favor. The petitioner states argue that they have standing because they will be injured if the EPA does not regulate greenhouse gases. They contend that left unchecked, greenhouse gas emissions from new motor vehicles will cause global climate change which will trigger rising sea levels reducing states' coastal lands and increasing flooding. The EPA argues that the states cannot show that greenhouse gas regulations of new motor vehicles would actually have a significant enough effect on global warming that harm to the states would be avoided. The greenhouse gas regulations would only address new motor vehicles which account for a very small fraction of global greenhouse gas emissions. The positive effects of regulation could be minimal when compared to increased emissions from other countries. Further, the science is not conclusive enough to demonstrate that harm is inevitable. If the Court determines that the petitioner states do not have standing, then it need not consider any other arguments presented. If the Court concludes that the states do have standing, then it can go on to consider whether or not EPA properly declined to regulate greenhouse gases. The final decision is expected in June 2007.

The state petitioners are Massachusetts, California, Connecticut, Illinois, Maine, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington. The respondent states are Idaho, Michigan, North Dakota, South Dakota, Utah, Alaska, Kansas, Nebraska, Texas, and Ohio.

Air Quality