There’s more bad news about the environmental consequences of hydraulic fracturing or “fracking” in order to access greater quantities of natural gas. A new study finds that the process of injecting high-pressure water, sand and chemicals into wells to force the natural gas out of shale formations deep underground results in a high level of methane emissions—a potent greenhouse gas. In fact, the study published in Climatic Change Letters on April 14, revealed that fracking has a more damaging global warming impact than coal or oil. Methane is more than 20 times as potent as carbon dioxide as a greenhouse gas, and natural gas is mostly made up of methane.
During hydraulic fracturing, the study found that “3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the lifetime of the well. These methane emissions are at least 30% more than and perhaps more than twice as great as those from conventional gas.” Because methane acts more immediately in driving global warming—and stays in the atmosphere just 11-12 years—the short-term picture for shale-gas extraction via fracking is particularly damaging. Over a 20-year time period, the study found, the ecological footprint for shale gas extraction is anywhere from 20% to more than twice the level of environmental damage as coal. Over a 100-year period, the two fuels would be comparable in terms of their global warming impact.
Methane escapes during hydraulic fracturing at a number of points during the process. It’s present with the flow-back fluids—the fluids that return after the injection of water and chemicals to fracture the rock and access the gas. Methane is also emitted during “drill-out,” when more drilling releases the gas for production. (Conventional gas drilling has no flow-back or drill out.) There are also “fugitive emissions” at a well site over its lifetime, the result of routine venting and equipment leaks, as well as emissions during processing, transport, storage and distribution.
And as damaging as methane is in terms of exacerbating global warming, increased reliance on fracking to extract natural gas reserves leaves a toxic legacy on land, too—specifically as a result of the proprietary chemical mixtures used to fracture the rock. An April 2011 report from the United States House of Representatives Committee on Energy and Commerce asked the 14 leading oil and gas companies to “disclose the types and volumes of the hydraulic fracturing products they used in their fluids between 2005 and 2009 and the chemical contents of those products.” Of the 750 chemicals in more than 2,500 hydraulic fracturing products that were used, the report notes, 29 are known or possible human carcinogens regulated under the Safe Water Drinking Act or listed as hazardous air pollutants under the Clean Air Act. Benzene—a known human carcinogen—along with the toxins toluene, xylene and ethylbenzene appeared in 60 of the hydraulic fracturing products used. The report found that “The hydraulic fracturing companies injected 11.4 million gallons of products containing at least one” of these chemicals over the five years in question. Many other chemicals used could not be identified according to company claims.
With growing concern about the dangers of fracking—and growing demand for more U.S.-based oil—environmental activists are taking up the challenge. Those who oppose fracking for health and environmental concerns even have a special name: fractivists. And the Sierra Club’s Activist Network has a hydrofracking team.