It depends on how much gas leaks into the atmosphere during the fracking process. Eduardo Porter points out that one “study last year suggested that replacing coal with gas would reduce greenhouse gas emissions only as long as the leakage of methane into the air from gas production did not exceed 3.6 percent”:
Different groups of researchers have come up with vastly different estimates of leakage, from around 2 percent to a whopping rate of 9 percent, found in a recent analysis of a gas field in Utah. Ms. Brantley suggests that the National Science Foundation underwrite an exhaustive study that could bring some clarity to the issue. But will it have the money? Sequestration just cut some $350 million from its budget for 2013.
The Dish 