Study: Methane leakage 60% higher than EPA estimate

The American oil and gas industry is leaking more methane than the government thinks — much more, a new study says. Since methane is a powerful greenhouse gas, that is bad news for climate change.

The new study, published Thursday in the journal Science, puts the rate of methane emissions from domestic oil and gas operations at 2.3 percent of total production per year, which is 60 percent higher than the current estimate from the Environmental Protection Agency. That might seem like a small fraction of the total, but it represents an estimated 13 million metric tons lost each year, or enough natural gas to fuel 10 million homes.

Thanks to a boom in hydraulic fracturing, natural gas has quickly replaced coal as the leading fuel used by America’s power plants. It has also helped, to some extent, in the fight against climate change: When burned for electricity, natural gas produces about half the carbon dioxide that coal does. The shift from coal to gas has helped lower carbon dioxide emissions from America’s power plants by 27 percent since 2005.

But methane, the main component of natural gas, can warm the planet more than 80 times as much as the same amount of carbon dioxide over a 20-year period if it escapes into the atmosphere before being burned. A study found that natural gas power plants could be worse for climate change than coal plants if their leakage rate rose above 4 percent.

Neither the EPA’s estimates of leakage rates nor the higher estimates in the new study suggest that gas has crossed that threshold. Still, experts said that curbing methane emissions from oil and gas operations could prove an important climate policy.

If there is good news in the report, it is that much of the leakage is fixable at relatively low cost. The lost methane is worth an estimated $2 billion a year.