The participants agreed to an aggregate reduction of 15 percent below 2005 levels by 2020. Not too shabby! (They also acknowledge that "current science suggests that this will require worldwide reductions between 50% and 85% in carbon dioxide emissions from current levels by 2050.")

The WCI's new goal is comparable to the goals that Washington and California have set (1990 levels by 2020), though it's less aggressive than the nonbinding goals set by Oregon and British Columbia (10 percent below 1990 by 2020).

I take WCI's action as great news. But, as in the Northwest, addressing climate change in the West will mean doing something meaningful about transportation emissions. Here's a chart showing fossil-fuel emissions for the U.S. West:

The main difference with Washington's portfolio is that some western states use more CO2-emitting coal power, so transportation shrinks a little bit as a share of total emissions. Still, it's far and away the biggest obstacle to a responsible climate policy.

A couple of footnotes to this post:

The charts in are based on 2003 data and they appear courtesy of über-intern Justin Brant.

The WCI formally includes Arizona, British Columbia, California, Manitoba, New Mexico, Oregon, Utah, and Washington. In addition, there are a number of "observers" who may join in the near future: Colorado, Kansas, Nevada, Ontario, Quebec, Saskatchewan, and Wyoming, plus the Mexican state of Sonora. (I suppose there's a semantic question about whether it can still be the Western Climate Initiative if Quebec joins, which, last time I checked, borders the Atlantic Ocean.)