Methane Emissions Are Higher Than Thought From Gulf of Mexico Drilling

Methane emissions from oil and gas drilling in the Gulf of Mexico are much higher than the United States government has previously estimated, according to a study published Monday in the journal Proceedings of the National Academy of Sciences.

While burning oil and gas for energy releases greenhouse gases, the production of these fuels contributes its own planet-warming emissions. For the study, researchers flew an aircraft over fossil fuel platforms in the Gulf to measure the carbon dioxide and methane released from them. Burning processes during oil and gas production emit carbon dioxide, while leaks and venting—direct release of gas into the atmosphere—emit methane.

Based on the airplane data, the scientists’ estimates of carbon dioxide emissions matched up with those from the government. But they found the average methane emissions are three and 13 times higher than federal and state inventories reported, respectively.

“We don’t know exactly why the methane emissions are higher than what the inventory expects,” Alan M. Gorchov Negron, first author of the new study and a climate scientist at the University of Michigan, tells the New Lede’s Shannon Kelleher. “It’s either because of unknown emissions or unreported emissions.”

The team also calculated the carbon intensity of the region’s oil and gas—or the climate impact per unit of energy provided by the fuel. They found that the carbon intensity of fossil fuels produced in the Gulf of Mexico was double that of official estimates from government agencies, writes Drew Costley of the Associated Press (AP).

“This study represents a novel and thoughtful assessment of the climate impact of oil and gas production in the Gulf of Mexico,” Riley Duren, a research scientist at the University of Arizona who did not contribute to the study, tells the AP.

While the atmosphere has about 200 times more carbon dioxide than methane, the latter is a more potent greenhouse gas. In the first 20 years after it’s released, methane traps 80 times as much heat as carbon dioxide does in the same amount of time. Methane alone has caused about 30 percent of the increase in global temperatures since the Industrial Revolution.

In the study, the researchers found an older type of shallow-water platform often behaves like a “super-emitter,” Negron tells the New Lede. “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.”

Platforms in shallow water had a greater climate impact than platforms in deeper waters, in part due to venting and their tendency to be older and not well maintained.

“The good news is that the bulk of emissions comes from one class of facilities, which means mitigation measures can be more targeted,” Eric A. Kort, a co-author of the study and a climate scientist at the University of Michigan, tells CNN’s Laura Paddison.

The authors note that to reduce emissions, companies could repair deteriorating equipment, plug and abandon poorly maintained infrastructure and burn gases instead of venting them, which would be more efficient.

The most prominent human source of greenhouse gas emissions is burning fossil fuels, and the Gulf of Mexico is the largest offshore oil and gas basin in the United States.

Last week, the Biden administration put millions of acres of Gulf of Mexico water up for auction for oil and gas drilling, writes CNN. Up to ten new lease sales in the Gulf of Mexico are proposed between 2023 and 2028, per the study. These sales, as Negron tells the New Lede, are auctioning off regions of shallow waters.

“It’s very clear from our results that expanding production in shallow waters, the way it’s been done historically, would have disproportionately high climate impacts,” Kort tells the AP.

Will Sullivan | | READ MORE

Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.