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Exhausted and abandoned oil wells in Pennsylvania may be leaking methane, one of the most potent of the greenhouse gases, but are not accounted for in inventories drawn up by the U.S. Environmental Protection Agency.
A recent study by Princeton University environmental researcher Mary Kang found that 19 plugged wells in Pennsylvania are emitting methane in various amounts.
Pennsylvania alone has hundreds of thousands of such wells, and there are many more scattered across the United States, though few if any of them are ever checked to ensure the plugs are working.
The study is the latest conducted during the past three years that suggest crude oil and gas extraction, especially by hydraulic fracturing, or fracking, can be a major source of methane emissions.
Methane is far more potent a greenhouse gas than carbon dioxide and its impact is lasting on the environment, according to Climate Central, a non-profit news organization.
Related Article: Obama’s Climate Plan Is Leaking Methane
Climate Central says methane is about 34 times stronger than carbon dioxide 100 years after it is emitted, and just 20 years later is 86 times stronger. It makes up more than 40 percent of what’s known as “radiative forcing,” a yardstick for climate change that measures how much heat is trapped in the Earth’s atmosphere.
For her study, Kang learned that all 19 wells she tested were emitting methane at various rates. The quantity of the leaked methane was such that if all the abandoned wells in Pennsylvania were leaking in a similar fashion, they could be responsible for between 4 and 13 percent of human-caused methane emissions in the state.
But Kang cautions that it’s too early to draw such conclusions. She says more study is needed to determine how widespread such leaking is and how much methane the plugged wells are emitting.
Robert Jackson, a professor of global environmental change at Duke University, agrees.
“The emissions from single wells were relatively small, but there are hundreds of thousands of such wells in Pennsylvania alone,” he told Climate Central.
Now, Jackson says, the challenge is to test capped wells outside Pennsylvania to get a better idea of the broader threat.
By Andy Tully of Oilprice.com
Andy Tully is a veteran news reporter who is now the news editor for Oilprice.com