Arguments have wrapped up in the Supreme Court for today. Here’s a transcript (PDF). SCOTUSblog has good analysis here. Roger Pielke Jr. has some commentary here. Jonathan Adler reacts here. You can watch a webcast of a panel of experts discussing the case at Georgetown here.
As I suspected, the central issue was standing. Mass. and the other states have to show not only that they will be harmed by global warming, but that EPA regulations of U.S. car and truck tailpipe emissions — 6% of total global emissions — would measurably reduce the harm.
As much as I hate agreeing with Roger, I think he’s right: it’s scientifically impossible to show that a 6% (likely lower) reduction in global GHG emissions will have measurable effects on the damage to Mass. Arguments otherwise are going to play on the scientific ignorance of the judges.
Lyle Denniston at SCOTUSblog thinks the standing issue will split the court: Stephen G. Breyer, Ruth Bader Ginsburg, David H. Souter, and John Paul Stevens will support the petitioners’ standing; Chief Justice John G. Roberts, Jr., Samuel A. Alito, Jr., Antonin Scalia, and (presumably) Clarence Thomas will oppose. The deciding vote — not for the last time with this court — will go to Anthony M. Kennedy. Denniston thinks he’s favorably inclined.
If they get standing, I don’t see how they’ll lose. But it’s still an open question whether they’ll get it.