KEY POINTS:
It is billed as one of the most important environmental cases in decades - one that could change America's policy on climate change. At its heart is whether carbon dioxide is a pollutant. At stake is whether the Bush Administration should regulate carbon-dioxide emissions to combat global warming.
Massachusetts v the Environmental Protection Agency (EPA) begins in the US Supreme Court on November 29 - a final destination on a long and winding road dating back to October 1999. The case pits state against state, scientist against scientist, power utility against power utility, environmentalists against the automobile industry, and right wing think tanks against Christians.
That's not all. Native Americans living in Alaska, the Aspen Skiing Company, former Secretary of State Madeleine Albright, former EPA administrators, and the Conference of Mayors are among the diverse group standing up for regulation.
New Zealand gets a mention, thanks to Auckland University's global warming sceptic Chris de Freitas, who, with seven American climate-change sceptics, is arguing against any controls of greenhouse gas emissions.
It's a case that makes for strange bedfellows. Alongside the environmentalists, Entergy, a US$10 billion ($15 billion) a year utility company based in New Orleans, is pro-regulation. Why? Because as America's second-largest nuclear energy generator - producing electricity in a way which does not contribute to global warming - it wouldn't mind seeing restrictions placed on coal-burning utilities that generate lots of carbon dioxide.
Then there's the EPA lining up with big business - the American Petroleum Institute, coal-burning utilities, car dealers and automakers - and asking that its regulatory powers be curbed. Not something you see a regulator do every day.
The legal debate is whether the EPA is shirking its responsibility under the Clean Air Act to set emission standards for "any air pollutant" from motor vehicles which could cause, or contribute to, air pollution. And "which may reasonably be anticipated to endanger public health or welfare".
The EPA says greenhouse gases are outside its gamut. Massachusetts and a long list of co-petitioners argue what comes out of vehicle exhausts - carbon dioxide, methane, nitrous oxide, and hydrofluorocarbons - are air pollutants. And, left unchecked, they will indeed endanger public health and welfare. They cite hundreds of studies linking greenhouse-gas emissions to droughts, flooding and other impacts throughout America.
Environmentalists point out the US is responsible for 25 per cent of global carbon-dioxide emissions and has refused to sign the Kyoto protocol. If the EPA has to recognise carbon dioxide as a pollutant, then it could require more fuel efficiency and fewer emissions in the US transport fleet.
The fleet accounts for about a third of the United States' carbon-dioxide emissions so regulation would make a significant difference to global warming, say the environmentalists. A ruling that carbon dioxide is a pollutant would also pave the way for regulating greenhouse emissions from power plants.
Scientists are central to the fray. A group of 14 - including James Hansen, head of Nasa's Goddard Institute for Space Studies; Nobel prize-winner Sherwood Rowland of the University of California; and David Battisti, a professor of atmospheric sciences at the University of Washington - say the EPA and earlier lower-court rulings have misrepresented scientific findings.
Their brief says a consensus of scientists working on climate change holds that greenhouse gases from mobile and other human-created sources "have already had an effect on the earth's climate and are changing the earth's climate in ways that are significantly increasing the risk of adverse impacts on public welfare".
The scientists point to numerous signs of global warming, including rising global temperatures, plants and animals shifting their range, glaciers and Arctic sea ice in retreat, and rising oceans. They point also to a probability that continued greenhouse-gas emissions "will trigger abrupt climate change surprises that could very rapidly impose large impacts on ecosystems and human societies".
Their brief acknowledges there is no such thing as absolute certainty in climate science, but that is not an excuse for failing to take action when there is a threat of serious damage.
The scientists arguing against regulation are a handful of climate-change sceptics, including Auckland School of Geography and Environmental Science associate professor Chris de Freitas; Patrick Michaels, senior fellow at the Cato Institute; and Sallie Baliunas, senior scientist at the George C. Marshall Institute.
The submission is prepared by the Competitive Enterprise Institute (CEI), a Washington-based conservative think tank.
Their brief to the court says that "substantial scientific uncertainties" around climate risks abound, predicted increases in temperature from climate models are overestimated, and forecasted damage from sea-level rise or health risks from heat waves are exaggerated.
"In short, it is impossible to verify claims that the earth is in the midst of an unprecedented heat wave." The sceptics say the net effect of greenhouse emissions on human health and welfare is unknown.
Oil giant ExxonMobil has funded organisations associated with the sceptical stance. The Cato Institute has received US$90,000 ($136,000) from ExxonMobil since 1998, the Competitive Enterprise Institute (CEI) US$2 million and the George C. Marshall Institute US$630,000. ExxonMobil's funding of research was challenged in July by Britain's science academy, the Royal Society, which charged the world's largest oil company with funding "organisations that have been misinforming the public about the science of climate change".
In September Exxon said it was reviewing its funding of groups that deny global warming's dangers. The oil company, which had given the CEI US$270,000 last year, says so far it has donated no money to the institute this year.
The CEI ran ads on US television in May pushing the benefits of carbon dioxide with the catchphrase: "Carbon dioxide: They call it pollution. We call it life."
De Freitas says the link with ExxonMobil via its past funding of the CEI is irrelevant.
"I have received no payment, no gift, no financial support or payment in kind from anyone or any business for my efforts in preparing this brief."
De Freitas says attacking scientists who promote scepticism as agents funded by the fossil-fuel industry follows a logic that implies all funding contaminates all results. "I know some scientists in the US who take money from Exxon and they do very good work."
The EPA's brief to the Supreme Court states: " ... the economic and political significance of greenhouse-gas regulation counsels hesitation in the absence of clear congressional guidance".
The agency, supported by Michigan and eight other states, has long maintained it has no authority under the Clean Air Act to regulate. And the Act's mechanisms are ill-suited to greenhouse gas emissions. It points to congressional policy saying more study and assimilation of data is needed before deciding future legislation or international agreements.
The EPA's foreign policy argument prompted Madeleine Albright to get involved. She is concerned about the EPA's assertion that regulation of motor-vehicle greenhouse gas emissions could "weaken US efforts to persuade key developing countries to reduce the greenhouse-gas intensity of their economies". Albright says withholding domestic regulation to ensure the US Government can bargain with other nations over greenhouse gases is wrong, and is at odds with government policy which does not endorse the use of such leverage.
But the Supreme Court case will address whether the US Administration's decision to rely on voluntary measures to combat climate change are legal under federal clean-air laws. A decision in favour of the EPA could throw into question plans by California and 10 other states to force carmakers to reduce emissions by improving vehicle mileage.
While much of the argument focuses on legal definitions and scientific evidence, there are also signs of a moral imperative at work. The Conference of Mayors, representing more than 1100 cities, stresses the need to take precautionary action - especially when lives are at stake. The brief also emphasises the responsibility of municipal authorities to promote the welfare of their citizens.
Representing a membership of more than 50 million Christians in nearly 140,000 congregations nationwide, the National Council of the Churches of Christ in the USA, says as a source of potential harm, anthropogenic climate change stands out in the history of humanity's affronts to fellow humans and to our environment.
"Followers of the Judeo-Christian tradition are called to be responsible, just stewards of the Earth and the abundant resources that it makes available, today and for future generations." The council's submission to the court says: "We must reduce our contributions to climate change to protect the world entrusted to us."
Timeline
October 1999 - The International Center for Technology Assessment (CTA), joined by 18 other organisations, files its Greenhouse Gas Petition with the EPA seeking the regulation of greenhouse gas emissions from new motor vehicles.
January 2001 - The EPA publishes a notice and request for comments. Almost 50,000 public comments submitted.
December 2002 - CTA, Sierra Club and Greenpeace file a lawsuit against the EPA seeking to compel the agency to answer the Greenhouse Gas Petition.
September 2003 - EPA publishes its notice of denial of the CTA Greenhouse Gas Petition concluding that the Clean Air Act does not authorise EPA to regulate for global climate change purposes.
October 2003 - CTA, Sierra Club, Greenpeace, Center for Biological Diversity, Union of Concerned Scientists, Massachusetts and other states and organisations file a petition for review of the EPA's decision in the US Court of Appeals for the District of Columbia Circuit.
November 2003 - Alliance for Automobile Manufacturers, National Automobile Dealers Association, Michigan and other states, the Utility Air Regulatory Group, the CO2 Litigation Group (includes American Petroleum Institute, the US Chamber of Commerce, and National Association of Manufacturers) move to intervene in the case on the side of the EPA.
July 2005 - Court of Appeals for the District of Columbia Circuit issues a split decision denying petition for review.
December 2005 - Court of Appeals denies petition for rehearing by Massachusetts, and other states.
June 2006 - US Supreme Court grants certiorari to hear Massachusetts v EPA. Oral argument begins November 29.
Online
Supreme Court docket: www.supremecourtus.gov/docket/05-1120.htm
Climate scientists' brief pro regulation: www.climatesciencewatch.org/file-uploads/climate_scientists_brief.pdf
CEI's submission against regulation: www.cei.org/pdf/5572.pdf
Briefs from respondents and petitioners: docs.nrdc.org/globalwarming/default.xdl
www.sierraclub.org/environmentallaw/lawsuits/viewCase.asp?id=316
www.abanet.org/publiced/preview/briefs/nov06.shtml#mass
