The problem of methane leaking during oil and gas extraction and transport is well established. But how much of the potent greenhouse gas actually leaks into the atmosphere is disputed. New research in the UK from Princeton and Colorado State University (CSU) scientists shows the leakage rate is 5x higher there than previously estimated, and likely substantially underestimated in other places, too, they say.

The research shows that the emission factors typically used to calculate methane emissions from oil and gas operations are outdated and incomplete. Princeton engineer and environmental policy expert Denise Mauzerall and Stuart Riddick of CSU improved the methodology to account for more realistic environmental conditions and more activities, as when oil rigs are idle but still leak methane. They recalculated emissions and found that the new leakage rates are dramatically larger than what had been reported.

“It is critical to know when, where and how much methane is emitted from each of its sources in order to prioritize emission reductions,” said Mauzerall. “We hope our work will facilitate improved emission estimates and reductions not only from the UK but also from other countries producing methane from oil and gas extraction.”

Cutting methane emissions is one of the prime levers that policymakers now have for slowing the rate of global warming. One hundred fifty countries have signed the new Global Methane Pledge to cut at least 30% of methane emissions by 2030 from 2020 levels.