In this case, the Commonwealth of Massachusetts, several other states and certain environmental advocates filed a petition for rulemaking with the Environmental Protection Agency seeking to have EPA regulate carbon dioxide emissions from new passenger cars and light trucks under the Clean Air Act. When EPA declined to make a determination that carbon dioxide emissions "endangered" the environment and refused to issue regulations limiting CO2 emissions, the states and environmental groups initiated legal action to force the EPA to regulate CO2 emissions. EPA declined to regulate such emissions under the Clean Air Act for several reasons, primarily because the agency claimed that the scientific data on the effect of carbon dioxide concentrations on climate are too uncertain to justify action. Other reasons advanced by EPA were that such action could only affect a small fraction of CO2 emissions and therefore can only have a small effect on CO2 concentrations.
The U.S. Court of Appeals for the D.C. Circuit, by a 2 to 1 majority, upheld EPAs decision. This lawsuit is now being appealed to the U.S. Supreme Court. A group of climate change scientists submitted a brief amicus curiae supporting the petition of the Commonwealth of Massachusetts.
Atlantic Legal Foundation filed an amicus brief on behalf of other scientists who, for different reasons, believe the D.C. Circuits decision was correct. Some of the amici believe that the "uncertainty" is overstated and should not inhibit action. The Foundations brief emphasizes other reasons, on which they agree, why the EPAs ultimate decision was correct. Many of the amici note that a single sector of the economy or a region of the world is too small by itself to control the world’s carbon dioxide emissions, but that does not excuse this sector or region from doing its part to solve the problem. Amici therefore feel that the Plaintiff’s petition should not be rejected merely because requiring more efficient transport vehicles in the United States addresses only a small part of the problem; indeed a comprehensive plan may well consist of a number of pieces that address the problem in different ways in different countries.
Petitioners ask EPA to address emissions of CO2 in the same way, and under the same statutory authority, as EPA addresses ordinary pollutants to be reduced as much as possible, whereas the issue here is that concentrations of carbon dioxide in the atmosphere must be managed. The Foundations brief emphasizes that the action sought by petitioners does not address the core problem itself, and therefore does not easily lead to a comprehensive approach. Our brief suggests that emissions of CO2 in one location can be offset by reduction of CO2 in another, a process known as "sequestration." In addition CO2 emissions from combustion of biofuels does not result in a net addition to CO2 in the atmosphere in the way CO2 emissions from combustion of fossil fuels does, making it difficult to regulate CO2 emissions per se.
Atlantic Legals amicus clients are concerned that forcing a particular approach to the problem will perpetuate a way of thinking about potential solutions that is unhelpful. They are also concerned that in the long run this will delay rather than advance a comprehensive solution and be unnecessarily expensive. They believe that a more comprehensive approach is possible by managing all carbon that is present in the Earths surface environment and atmosphere.