"[1] In 2003, the EPA made two determinations:[2] The petitioners were the states of California, Connecticut, Illinois, Maine, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont and Washington, the cities of New York, Baltimore, and Washington, D.C., the territory of American Samoa, and the organizations Center for Biological Diversity, Center for Food Safety, Conservation Law Foundation, Environmental Advocates, Environmental Defense, Friends of the Earth, Greenpeace, International Center for Technology Assessment, National Environmental Trust, Natural Resources Defense Council, Sierra Club, Union of Concerned Scientists, and the U.S. Public Interest Research Group.

Furthermore, the Petitioners filed substantial scientific evidence that the toxicity of carbon dioxide results from high concentrations and that causation of global warming transforms the gas into a pollutant.

Petitioners argued that the use of 'including' automatically means greenhouse gases are part of the first group, 'any air pollution agent' which was not separately defined.

The Petitioners asserted that the EPA Administrator's decision not to regulate carbon dioxide and other greenhouse gases violated the terms of the CAA.

The Supreme Court did not explicitly decide if it is true or untrue that man-made carbon dioxide emissions cause global warming, although high-profile comments by Justices during oral argument are likely to affect the public debate.

[7] The majority cited Justice Holmes' opinion in Georgia v. Tennessee Copper Co. (1907): "The case has been argued largely as if it were one between two private parties; but it is not.

The CAA provides: "The Administrator shall by regulation prescribe (and from time to time revise) in accordance with the provisions of this section, 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 his judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.

"[10] Finally, the Court remanded the case to the EPA, requiring the agency to review its contention that it has discretion in regulating carbon dioxide and other greenhouse gas emissions.

First, the dissent condemns the majority's "special solicitude" conferred to Massachusetts as having no basis in Supreme Court cases dealing with standing.

The dissent compares the majority opinion to "the previous high-water mark of diluted standing requirements," United States v. SCRAP (1973).

Roberts then argues that the alleged injury (i.e., Massachusetts' loss of land because of rising sea levels) is too speculative and without adequate scientific support.

The dissent also finds that even if there is a possibility that the state may lose some land because of global warming, the effect of obliging the EPA to enforce automobile emissions is hypothetical at best.

On February 16, 2010, the states of Alabama, Texas, and Virginia and several other parties sought judicial review of EPA's determination in the U.S. Court of Appeals, District of Columbia Circuit.

[12] The three-judge panel unanimously upheld the EPA's central finding that GHG such as carbon dioxide endanger public health and were likely responsible for the global warming experienced over the past half century.