What do polar bears and traffic jams have in common? Not much, you might think, but they are inextricably linked, and one could help precipitate the demise of the other. Even though the average polar bear and the average US motorist are not likely to meet any time soon, their interests collide in Washington, in the corridors of the White House.

Carbon emissions from cars and the future of the polar bear have both been subjects of intense legal debate in the past few years. Environmental groups such as the Natural Resources Defense Council (NRDC) and the Center for Biological Diversity have long suggested that the greenhouse gases from one causes global warming that erodes the habitat of the other. Polar bears rely on arctic ice, and global warming caused by greenhouse gases erodes it. They have pressured the US government for years to regulate the emission of greenhouse gases.

The Environmental Protection Agency (EPA) was in favour of the idea in 1998, when the Clinton administration was doing its best to push the Kyoto Accord on climate change through the US legal system. The administration was finding it hard to get the legislative system to accept climate change and do something about it. Already politically crippled by the fallout from his domestic peccadilloes, Clinton did not have the political muscle to push Kyoto through Congress and get the US on board. The agreement lay, signed but unratified for years, and still hasn't been signed.

At the time, the EPA wanted to regulate carbon dioxide emissions, and then it did not. Two EPA chief counsels - Jonathan Cannon and Gary Guzy - both found that the agency could regulate the gas, because it was a pollutant and fell under the scope of the Clean Air Act.

But legal interpretations are one thing, and getting agencies to act on them are another. After the Bush administration came to power, nothing was done, c ausing environmental groups and various states to petition the EPA, forcing it in 2003 to examine the issue for a third time.

In 2003, the EPA's new General Counsel under the Bush administration reversed the previous interpretations of the Clean Air Act, and said that the EPA did not have the right to regulate the gas after all. "An administrative agency properly awaits congressional direction on a fundamental policy issue such as global climate change, instead of searching for new authority in an existing statute that was not designed or enacted to deal with that issue," said Robert Fabricant.

Not happy with that, several states (teaming with environmental lobbyists) made them do it, taking a lawsuit to the Supreme Court. Last year, the same institution that first put the current president in office said that the EPA had to regulate greenhouse gases.

Presumably, that should have been the end of it - but politics is rarely that simple. Getting legislation passed is only one step in pushing through environmental reform.

US agencies are currently being hauled through the courts in multiple lawsuits that all stem from the failure to acknowledge the effects of greenhouse gases in regulation. The NRDC, Center for Biological Diversity and other pressure groups originally sued the US government for not classifying the polar bear as an endangered species. When it finally relented last month, it included a special rule in the decision excluding the consideration of greenhouse gases as a threat to the bears. The same pressure groups are now suing the government to remove the rule.

In the meantime, 12 states want a waiver on federal standards concerning CO2 emissions from cars. The EPA prevented the states, including California, from adopting stricter carbon emissions standards under the Clean Car Program, which would have hit car makers with tougher manufacturing requirements.

"The EPA had 70 to 90 people working on a massive regulatory document to respond to the Supreme Court, but they abandoned course," says Vickie Patton, deputy general counsel for the Environmental Defense Fund.

That response would have been an endangerment finding - a response to the ruling which would have admitted the harmful effects of carbon dioxide. The EPA instead issued an Advance Notice of Proposed Rulemaking (ANPR), which solicits public opinion on the matter for a year. In early April, an environmental coalition including several states filed a petition asking the courts to order the EPA to make a ruling. The court's response is due any time now.

Why is the government dragging its heels on these issues, and fighting so hard to block attempts at regulating greenhouse gases? "The reason that they're trying to shoot down court decisions and the California waiver is because they know that it's a nose under the tent in a big way," says Kert Davies, research director at Greenpeace US. "It is a way to start demonstrating regulatory approaches to CO2. This isn't what they want."

This is the threat that ties together everything from polar bears, through to car emissions and even small engines such as lawnmowers, which are also a contentious issue, unregulated as they are under the Clean Air Act. If the government allows any regulation of greenhouse gases, it opens up the possibility of regulating carbon emissions on a much wider scale, which would have severe ramifications for US society as it operates today. The government said as much, in the special rule that it applied to stop greenhouse gases being factored into the polar bear equation.

Tucked away on page 34 of the document it states that: "Without the requirement of a causal connection between the action under consultation and effects to species, literally every agency action that contributes greenhouse gases to the atmosphere would arguably result in consultation with respect to every listed species or critical habitat that may be affected by climate change. "

According to Kassie Siegel, executive director of the Center for Biodiversity, an aversion to acknowledging the effects of greenhouse gases is also the reason that the US government took so long to release its latest report on the effects of climate change. The report, which was supposed to have been released in 2004 under the Global Change Research Act of 1990, would have updated a previous report produced under the Clinton administration. Pressure groups sued the administration in 2006 to make it release the report.

"It is likely that there has been a substantial human contribution to surface temperature increases in North America", says the report, which cites greenhouse gases as a significant factor, and which also predicts continuing ice shrinkage and rising sea levels. Alaska will be particularly badly hit, it says.

With the release of that report, Siegel says that the administration's platform for denying legal action on climate change is weakening.

"It has acknowledged the science in a legally binding way in these documents, and the next step is going to be moving beyond this administration's opposition to the regulation of greenhouse gas emissions," she says.

At this point, the whole thing may become a moot point. Keith Hay is clean energy advocate at Environment Colorado (one of the states suing the EPA over the California waiver). "The US presidential elections will be completed before the legal case gets solved," he says, pointing out that both candidates have a more sympathetic stance on the environment than the current administration. "So yes, we're suing the EPA to grant the waiver but we’re most likely to see a change in EPA status by seeing a change in US president."

Unfortunately, when correctly manipulated by those wanting to prevent change, the legal system can move even slower than the ecosystem does - and for groups set on reducing carbon emissions, this administration's stance on global warming has probably done all the damage it can.

For environmentalists, the next administration will be a crucial one. With leading NASA climate scientist Jim Hanson moving the desired target for CO2 levels from 450 to 350ppm (they're currently in the mid-380s), there is little time to lose, says Davies: "Scientists say that if we don’t have a clear drop in emissions by 2015, it's game over. "