Almost despite ourselves, we've been becoming more efficient for decades

America's "energy intensity" - the amount of GDP produced per unit of energy used - has been falling steadily since the 1970 oil embargo, and will continue to fall, predicts the US Energy Information Administration. That's their chart, above.

This is a good thing, but it isn't happening by magic; it's a function of technology and choices. We could, and should, choose to make it fall even faster.