Saving the World Might Mean Accepting Slower Growth

Economists teach us that resources don't just run out. As something becomes scarcer, its price rises, triggering a search for new supplies or the discovery of substitutes. We've seen it happen over the past two decades in the oil market, as dwindling reserves triggered the U.S. boom in oil derived from shale. Unexpectedly, the U.S. has surpassed even Russia and Saudi Arabia as the world leader in crude oil production.

Even so, the shale boom is already petering out, as we've nearly tapped most of the easily extracted oil, a comprehensive new study suggests. Huge investments and the drilling of nearly 10,000 new wells every year are now required to keep production at current levels. We're putting in ever more energy for every barrel we get out.