U.S. carbon emissions keep slowly falling, down to levels not seen since 1994, despite a lot more people in this country. I’m probably a bit more skeptical about the long-term sustainability of this than some people for three reasons. First, much of this is based upon the transition from burning coal to burning natural gas. While I’m sure that’s going to be the trend for the foreseeable future, unless we invest heavily in a national infrastructure based around wind and solar energy, eventually it may change back to coal if gas prices go up. Second, the poor economy has played a major role in depressing energy use. That won’t last forever, although given policymakers unwillingness to think about the deeper structural reasons for our economic problems, we probably aren’t seeing a return to 1997 or 2005 anytime soon. Third, I’m not sure whether the continued drop in miles driven by Americans will continue. It’s possible because people in their 20s and 30s are more committed to urban life and eschewing cars like no generation in American history since the car was invented. On the other hand, Americans really like driving and a booming economy might just convince a lot of those people that 3000 square foot houses and SUVs in the suburbs aren’t such a bad thing.
Still, a good sign all in all.