From Stephen Budiansky:
[W]hile population and affluence do increase consumption, technological gains counteract the impact of both. (And as affluence rises, it is also increasingly decoupled from material consumption altogether.)
Of course to concede that technology is often good for the environment runs against the Calvinistic, anti-materialistic strain of the environmental movement a strain that goes back to John Muir and Henry Thoreau at least and which tends to view the planet's ills as at heart a matter of personal guilt to be expiated through renunciation and penance. (A hilarious specimen of this was offered the other day by Prof. Kevin Anderson on Bishop Hill's blog, where he explained earnestly how little he washes himself or his clothing in order to save the planet.) You even used to hear a lot of derisive comments within the environmentalist movement about "technological fixes," as if that were somehow cheating (like buying indulgences).
Per capita comparisons are fine if you want to emphasize the idea that energy use is a personal sin and that industry and commerce either don't exist or are an evil in themselves, chargeable to our individual burden of sins by virtue of our citizenship in a country that is successful at these things. But a more sensible way of looking at it is that energy use is an unavoidable fact of existence and so should be made in a way that produces the greatest buck for the bang.