On Wednesday, the Supreme Court heard arguments in Massachusetts v. Environmental Protection Agency, a case analysts say will be the most important environmental decision in years and one that could shape our nation’s approach to global warming well into the future. Massachusetts, 11 other states and numerous environmental groups are suing the EPA for failing to regulate carbon dioxide emissions from cars and trucks.

The 1970 Clean Air Act says that “any physical, chemical, (or) biological … substance or matter which is emitted … into the ambient air” and endangers the public health or welfare is a pollutant, and the states argue that this clearly includes carbon dioxide.

Enough scientific evidence exists to tell us that carbon dioxide, produced by human activities like burning fossil fuels, is contributing to, if not the direct cause of, rising temperatures worldwide in what is called the greenhouse effect. It’s true that we don’t know everything about climate change, but the overwhelming scientific consensus supports this theory. The EPA is responsible for enforcing the Clean Air Act, but with the firm support of the Bush administration, has attempted to dodge this obligation by claiming that scientific evidence is inconclusive, and that the states do not have standing to challenge the EPA because it is unclear whether their welfare is being harmed, even though the Clean Air Act specifically names climate as a part of public welfare.

Under previous administrations the EPA did enforce these very same regulations. Now they are saying they aren’t required to use this authority. Whether climate change is occurring or not – and there is ample evidence to prove it is – the EPA is not doing the job required of it by law.

While carbon dioxide emissions are not the only environmental problem we face today or will soon be forced to face, the Supreme Court would be wise to err on the side of caution and rule against the EPA in this case. Global warming is too serious a problem for the government to stand by and allow “voluntary” regulations any longer.