The Intergovernmental Panel on Climate Change's (IPCC) latest assessment finds that U.S. greenhouse gas emissions have dropped in large part to the use of hydraulic fracturing to produce natural gas: "A key development since AR4 is the rapid deployment of hydraulic‐fracturing and horizontal‐drilling technologies, which has increased and diversified the gas supply and allowed for a more extensive switching of power and heat production from coal to gas (IEA, 2012b); this is an important reason for a reduction of GHG emissions in the United States." (Emphasis is ours.)
If you listen, you can almost hear the gnashing of teeth by our environmentalist friends ...