If Justin hasn’t sated your hunger for blogging about today’s Supreme Court case, check out this series of posts from Jonathan Adler. Lots of good discussion beneath as well.

(NB: below the fold I speak about legal issues, about which my ignorance is boundless. You’ve been warned.)

The case really is fascinating, even apart from my interest in sane climate policy. There are three questions at issue I find particularly juicy:

  • Pollutant: Is CO2 a "pollutant" under the Clean Air Act? Here’s what the act says:
    The term “air pollutant” means any air pollution agent or combination of such agents, including any physical, chemical, biological, radioactive (including source material, special nuclear material, and byproduct material) substance or matter which is emitted into or otherwise enters the ambient air.

    CO2 does not cause direct health effects like smog. It doesn’t “dirty” the air. It doesn’t directly affect particular localities or regions. The causal chain connecting it to ill effects is much longer than for any other substance we consider a pollutant. But it is a chemical, and it is emitted into the ambient air, so …

  • Delegation: Can Congress unwittingly give enormous regulatory power to the EPA? It’s unlikely that Congress even knew what “greenhouse gases” were in 1970. It’s a virtual certainty that no Congresscritter who voted for the act had global warming mitigation in mind. Obviously the concern was with dirty air — smog, mainly. And yet, the act is written in vague, broad language. If we go strictly by the text, there’s nothing to preclude greenhouse gases from qualifying as pollutants. If they qualify, then the scope of the EPA’s regulatory authority will suddenly and vastly expand, as virtually every personal and industrial activity in the developed world generates GHGs. 1970′s Congress will, not by intent but by loose language, have delegated huge power to 2006′s EPA. Should the court take intent and context into mind, or only text?
  • Standing: If the plaintiffs lose the case, this will be where it is lost (in my extremely layman-y layman’s opinion). The question here is twofold: Do the plaintiffs suffer particular harm from GHG emissions? And if so, can EPA regulations reduce that harm? This is where the rubber hits the road, but it’s also where the science is somewhat shaky. I think it will be possible to trace certain harms back to global warming — say, decreased snowpack — but arguing that EPA regulations on car and truck emissions will do anything to meliorate the harm will be … tricky. Again, the causal chains here are long and extremely complex.

One thing Jonathan’s definitely right about: this case isn’t about whether global warming is happening, or whether it’s a bad thing, or whether the U.S. federal gov’t ought to have done something about it. I assume everyone reading this comes down on roughly the same side on those questions. The case is about the language of the CAA and, more broadly, the relationship of the legislative and executive branches.

As I said before, I’m hoping the court deems CO2 a pollutant under the act but doesn’t force EPA to regulate it. That will clear the legal ground for all the state experiments cropping up in California and elsewhere. The feds should just STFU and get out of the way, at least until Gore/Obama/Clinton/McCain/Whoever is president.