US Bureau of Ocean Energy Management

By Shannon Kelleher

Offshore oil and gas operations in the Gulf of Mexico are releasing far higher quantities of a potent greenhouse gas than regulators have estimated, according to a new study published Monday.

The analysis reveals that the climate change impact of these activities is more than double what official estimates suggest.

The study, published in Proceedings of the National Academy of Sciences, found that 2021 calculations by the Environmental Protection Agency (EPA) – using data from the US Bureau of Ocean Energy Management (BOEM) – correctly estimated carbon dioxide emissions but underestimated methane emissions.

The data, which is based on engineering information, rather than on-site observations, failed to capture methane emissions because an older type of shallow-water platform used in offshore drilling often behaves like a “super-emitter,” leaking large amounts of the greenhouse gas, said Alan Gorchov Negron, a PhD candidate at the University of Michigan and first author of the study. These platforms are central hub gathering and processing facilities, which collect oil and gas through pipelines that extend from smaller nearby platforms.

“They’re a fraction of the platforms in the Gulf of Mexico but they contribute disproportionately to the total methane emissions and total greenhouse gas emissions,” said Negron.

“We don’t know exactly why the methane emissions are higher than what the inventory expects,” he added. “It’s either because of unknown emissions or unreported emissions.

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