With the climate policy discussion now settling into lines of cap & trade vs. carbon tax, and allocation vs. auction, it has implicitly moved beyond the top-down, command-and-control models favored by early plans (and in particular the multi-pollutant, "4P" bills).
This market focus is a good thing, on balance. What isn't good is that it's only being applied to greenhouse gas pollution. Our existing air pollution laws create disincentives to GHG reduction. Modernization of these (non-carbon) pollution laws may be the single most important thing the federal government can do to lower GHG emissions. As we head out of the harbor, it's time to haul up the anchor.
Relevant history
The Clean Air Act, coupled with New Source Review, has dramatically lowered SOx, NOx, and particulate emissions. It has also substantially increased GHG emissions. The reasons why are three-fold:
1. The rules were set on a so-called "input basis." Come under a certain parts-per-million of exhaust and you are OK. Exceed it and you're in violation.
This has the perverse effect of discouraging energy efficiency: if I lower absolute pollution (tons/yr) by 40% and cut fuel use by 50%, I have reduced the flow of fuel and combustion air by more than I've reduced pollution (e.g., the "millions" in the parts-per-million formulation). Thus my ppm actually increases and I can't get a permit anymore.