The use of hydraulic fracturing to extract oil and gas from the earth dates back to the 1940s, but only in the past few years has “fracking” become an energy buzzword, alluding primarily to the shale gas boom in the United States and all of the controversy that has accompanied it. Fracking—the high-pressure injection of water, chemicals and sand into shale deposits to release the gas and oil trapped within the rock—in recent years has been combined with horizontal drilling and other improvements in technology to harvest stores of gas and oil that previously were thought commercially unfeasible to access. (See interactive: “Breaking Fuel from the Rock“)

The implications of this sea change are debatable, but the impact is undeniable.