It would be hard to overstate the importance of yesterday’s ruling by the Supreme Court that the federal government has the authority to regulate the carbon dioxide and other greenhouse gases produced by motor vehicles.
It is a victory for a world whose environment seems increasingly threatened by climate change. It is a vindication for states like California that chose not to wait for the federal government and acted to limit emissions that contribute to global warming. And it should feed the growing momentum on Capitol Hill for mandatory limits on carbon dioxide, the principal greenhouse gas.
The 5-to-4 ruling was a rebuke to the Bush administration and its passive approach to the warming threat. The ruling does not require the government to regulate greenhouse gases. But it instructs the Environmental Protection Agency to reconsider its refusal to regulate emissions, urges it to pay attention to the scientific evidence and says that if it takes the same stance, it has to come up with better reasons than its current “laundry list” of excuses.
The ruling also demolishes President Bush’s main justification for not acting — his argument that because the Clean Air Act does not specifically mention greenhouse gases, the executive branch has no authority to regulate them. The president has cited other reasons for not acting, including costs. But his narrow reading of the Clean Air Act has always been his ace in the hole.
The court offered a much more “capacious” reading of the act, as Justice John Paul Stevens wrote for the majority. The plaintiffs — 12 states and 13 environmental groups — had argued, and the court agreed, that while the act does not specifically mention greenhouse gases, it gives the federal government clear jurisdiction over “any air pollutant” that may reasonably be anticipated to endanger “public health or welfare.” This interpretation was first set forth by Carol Browner, administrator of the E.P.A. under President Clinton, and remained agency policy until Mr. Bush reversed it in 2001.
The administration had also argued that the states did not have standing to sue on this issue because they could not show that they would be harmed by the government’s failure to regulate greenhouse gases. The court ruled that the states have a strong and legitimate interest in protecting their land and their citizens against the dangers of climate change and thus have standing to sue.
The ruling reinforces state efforts in other ways. California and nearly a dozen other states have adopted their own regulations requiring lower greenhouse gas emissions from cars and trucks. These rules, however, require federal approval, which seemed unlikely as long as the agency could claim that carbon dioxide was not a pollutant — a claim it can no longer make.
The E.P.A. had also argued that reducing emissions would require it to tighten fuel efficiency standards, a job assigned by law to the Department of Transportation. The automakers have made much the same argument against California’s emissions rules. But the court said that the E.P.A. could not shirk its responsibilities just because another department sets mileage standards. The agency is clearly in for some serious soul-searching.
The decision was unnervingly close, and some of the arguments in the dissent, written by Chief Justice John Roberts Jr., were cause for concern — especially his comments about the “complexities” of the science of climate change, which is too close for comfort to the administration’s party line.
Still, the Supreme Court, for the first time, has said that global warming is a real and present danger. This can only encourage those on Capitol Hill and in the states who are growing increasingly impatient for aggressive action.