A single U.S. shale oil field is responsible for much of the past decade's increase in global atmospheric levels of ethane. Researchers found that the Bakken Formation, an oil and gas field in North Dakota and Montana, is emitting roughly 2% of the globe's ethane, or about 250,000 tons per year.

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A single U.S. shale oil field is responsible for much of the past decade's increase in global atmospheric levels of ethane. Researchers found that the Bakken Formation, an oil and gas field in North Dakota and Montana, is emitting roughly 2% of the globe's ethane, or about 250,000 tons per year.