Europe isn't as far along as the U.S. in exploiting shale gas, but when it catches up, the impact could be substantial, according to The Economist. "America's shale revolution began 20 years ago, but its impact has been felt only in the past five years," the magazine notes. "Europe's may take just as long. ... But when the fracking begins in earnest, it could turn Europe's energy market on its head, too."