In an interview with The New Yorker's Elizabeth Kolbert, Al Gore made an interesting point I hadn't seen elsewhere (it's that last paragraph there):

Once the world makes it clear that we are going to follow a roadmap to a low-carbon economy, the best-managed businesses will seek to race out in front of that emerging trend. Indeed, you’re already seeing a lot of them do exactly that.

And along with legislation and the treaty, there is also the prospective regulation of CO2 by the E.P.A.; the Second Circuit Court of Appeals decision giving a green light to private lawsuits against large CO2 emitters based on tort law; and the prospective requirement to begin, this January 1st, reporting CO2 emissions, a requirement that will cover the emitters of eight-five per cent of the CO2 in the U.S. each year, with the first public release of that annual report coming a year from March.

The last time this kind of reporting mechanism was used, with the toxic reporting initiative, it triggered a mad scramble by the top ten emitters in each city to get off that top ten list.

Just to recap, the EPA finalized its greenhouse-gas reporting rule back in September; it will require the 13,000 or so biggest polluters in the country to start measuring their emissions. The data will become public in 2011. A recent Forbes story noted that some companies are already doing what Gore predicted—finding ways to use energy more prudently and curbing their emissions in order to look better when those reports become public. (What's more, simply by tallying up their emissions, many businesses are discovering just how much energy—and hence money—they're wasting.)

That's not surprising. For years, a lot of companies have tried to foster an eco-friendly image, but now there'll be actual benchmarks to contend with—and greenwashing will be a lot harder to pull off. This sort of voluntary action isn't really a substitute for carbon caps, but it can certainly quicken the rate of change.