Spring 2007-12 U.S. Supreme Court issues important decision on global climate change

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Number 67
Spring 2007

U.S. Supreme Court issues important decision on global climate change

The stage is set for the United States to finally address climate change. And the U.S. Supreme Court is making sure that the Environmental Protection Agency steps up to the plate (or at least explain its reasoning behind a decision not to).

On April 2, 2007, the Court found that the federal agency charged with protection of the environment has authority under the Clean Air Act to regulate greenhouse gas emissions from new motor vehicles, a decision that has far-reaching impacts for regulated industries.

In Massachusetts v. EPA, 2007 U.S. LEXIS 3785, the majority of the justices held that EPA can regulate carbon dioxide and other greenhouse gases from new motor vehicles through application of the broad statutory definition of the term "air pollutant." Environmental groups, joined by the Commonwealth of Massachusetts and other states, sued EPA over the agency's refusal to regulate CO2 and other greenhouse gases from new vehicles and engines. EPA claimed that it lacked authority, and that, even if it had that authority, it was inappropriate to use it given the uncertainties of the science of climate change.

Court decision

The Court disagreed and, in a strongly worded opinion, held that EPA has the authority to regulate the gases. The justices sent the case back to EPA, so that the agency consider promulgating regulations. EPA must now decide whether these gases contribute to climate change and, if so, either act to regulate their emission by new vehicles, or expressly articulate a policy argument supported by the Clean Air Act to avoid their promulgation.

On the coattails of rising scientific evidence and worldwide public awareness of the global warming phenomenon, the Court found a link between increased CO2 levels attributed to vehicle use and rising global temperatures, resulting in increased sea levels and the loss of shorelines in coastal states, including Massachusetts. Thus, the Court found that controlling greenhouse gases from vehicles would reduce the risks associated with climate change; although it conceded that its decision would not reverse global warming by itself.


Unintended consequences of the Court's action-and its acceptance of the available science behind global warming-include the triggering of Congressional action in the form of climate change legislation to guide EPA's upcoming regulatory efforts, and individual state action from proactive states pushing their own more stringent regulatory initiatives to fight global warming.

© 2007 Goldman Antonetti & Cordova, LLC