It's ironic that such a major development on an issue to which I am so attuned would occur while I was on vacation. Somehow, the Supreme Court's landmark decision on regulating greenhouse gases escaped my notice, in the small amount of news I read or watched between stops on our driving vacation out west. But without exaggeration, the Court's ruling in Massachusetts v. Environmental Protection Agency was as important as any in recent years, with the possible exception of the resolution of the 2000 election. By a narrow majority, the justices affirmed that greenhouse gases, including the carbon dioxide given off by every car and fossil fuel power plant--as well as every animal--on the planet, are pollutants. In the process, they have made it much harder for the federal government to continue its current approach to climate change on the basis of incentives and voluntary measures.
I recall my Public Policy professor in business school making quite a point about the number of votes behind a Supreme Court decision, in evaluating the precedent it sets. 5-4 decisions usually set weak precedents, because the shift of a single vote, either through a distinction in circumstances or the retirement of a justice, can undo it the next time a relevant case comes before the court. But in today's political context, that 5-4 looks more like a 7-2 in its likely durability. Had this decision been rendered in 2005, when the Administration and Congress agreed on climate change--and before Hurricane Katrina and "An Inconvenient Truth" raised the public's concern--my main message would have been one of caution. In 2007, however, the stars are lining up for a stronger response on climate change, and the Supreme Court has added its authority to the side of prompt action.
The court's ruling doesn't change my concern that defining CO2 as a pollutant will lead us down the wrong path, but that no longer matters. What counts now is the impact of this decision on US climate policy, and by extension, the global response to climate change. A world in which the US and EU are generally aligned on reducing emissions will look very different from the period that is now drawing to a close. Even developing countries should take notice of the Court's finding, because it implies they will ultimately have to fall into line, as well.
Although this decision may pave the way for action by the states, particularly in forcing the EPA's hand in allowing California and other states to regulate CO2 from automobile tailpipes, the ruling appears much less prescriptive than, say, Brown v. Board of Education or Roe v. Wade. It still remains for the Congress and the White House, whether this one or the next, to map out the actual means of limiting emissions. The biggest long-term impact of this ruling may be in foreclosing many of the legal challenges that will surely follow any such legislation or administrative rule-making.
For the last decade it has looked increasingly likely that the cost of carbon emitted to the atmosphere would not be zero for much longer. Since the 2006 election, that likelihood has increased to a high probability, and with Mass. v. EPA it now looks like a certainty. Based on the views expressed by most of the major candidates for President, by 2009 all three legs of the federal government will agree on the need for urgent action. It now falls to the current Administration to decide whether to work with the Congress to draft climate change legislation that addresses the President's legitimate concerns about international competition and the domestic economy, or to defer action for another two years, setting the stage for tougher regulations, later.