The U.S. Supreme Court heard arguments on November 29 in an environmental dispute of far-reaching significance.

The case, Massachusetts v. EPA, challenges the Bush administration's refusal, unlike previous administrations, to regulate carbon dioxide and other emissions from cars and trucks.  Eleven other states have joined Massachusetts as plaintiffs.  The states argue that not regulating these emissions will increase global warming.

The Court's ruling will be its first major decision on the issue of global climate change.  It is likely to have an impact on efforts to reduce pollutants from other sources, such as power plants, and on states' efforts to regulate emissions.  The EPA has held up California’s efforts to increase vehicle fuel economy standards for over a year.

Three months ago, I filed a friend of the court brief supporting the states' position that the U.S. Environmental Protection Agency has the authority to regulate motor vehicle pollutants.  I argued that the EPA's interpretations of the Clean Air Act are wrong and have the further negative effect of preempting state efforts to reduce these emissions by local action.  Auto manufacturers have contended in pending cases that the EPA's decision means that states cannot regulate climate change pollutants from motor vehicles.

By failing to protect citizens from the long-term impact of climate change, the EPA is increasing the risk of global warming and its probable impacts – prolonged drought, severe forest fires, warmer temperatures, reduced snow pack, rising sea levels and coastal erosion.

Supreme Court watchers anticipate a closely divided decision that may turn on two questions:  (1) Whether global warming's dangers are sufficiently established by scientific research; and (2) whether U.S. vehicle emissions account for a large enough percentage of all global warming pollutants to make a difference.

Regarding the first question, the Court would have to overlook the findings of the National Academy of Sciences and the strong consensus among environmental scientists to dismiss global warming as a legitimate threat.

On the second question, both sides in this dispute agree that vehicle emissions in the U.S. amount to only 6 percent of total carbon dioxide emissions.  But this isn't an all-or-nothing matter.  As Justice David Souter remarked during oral arguments, the states aren't suggesting they can stop global warming.  Rather, they are asking the federal government to do all it can to help reduce it.

One way or the other, the Court's decision will be a major milestone in our nation's response to the threat of global climate change.

Terry Goddard