An international team has discovered hundreds of large bursts of methane from oil and gas production activities across the globe. The bursts account for 10% of global oil and gas methane emissions and are missing from most greenhouse gas emissions inventories.

Carbon Mapper, a nonprofit organization that partners with the University of Arizona to mitigate methane and carbon emissions and accelerate climate conservation, contributed to the study, which is published in the journal Science.

The team performed a systematic analysis of thousands of images produced daily by the European Space Agency satellite mission Sentinel-5P to estimate the amount of methane released into the atmosphere by oil and gas production activities.

Over a two-year period, they detected 1,200 "ultra-emitters" attributed to oil and gas facilities and long major transmission pipelines that sporadically release greater than 25 tons of methane per hour over most of the largest oil and gas basins worldwide.

Together, these facilities represent more than 50% of the total onshore natural gas production. Most of these ultra-emitters were short-lived, and many are likely due to planned maintenance activities.

The study revealed that in total, these unreported ultra-emitters contribute to approximately 10% of all methane emissions from the oil and gas sector across the six major oil and gas producing countries – an incredibly large contribution for such a limited number of events.

"This work confirms what we have only glimpsed in previous studies of individual facilities and regions: that intermittent, large releases of methane from oil and gas operations are common globally and are mostly unreported," said study co-author Riley Duren, a research scientist at UArizona's Arizona Institutes for Resilience and CEO of Carbon Mapper. "In this critical decade for climate action, this underscores the urgent need for persistent global observing systems that can detect, pinpoint and quantify methane emissions at scales relevant to decision making."

These methane sources also represent billions of dollars in subsequent costs when considering their climate impact and natural gas loss. Mitigating these emissions represents the equivalent of taking 20 million vehicles per year off the road. The avoided warming would prevent approximately 1,600 premature deaths annually due to heat exposure.

"To our knowledge, this is the first worldwide study to estimate the amount of methane released into the atmosphere by maintenance operations and accidental releases," said lead study author Thomas Lauvaux, a research scientist at the French Make Our Planet Great Again program at the Laboratoire des Sciences du Climat et de l’Environnement.

"Unreported ultra-emitters explain in part the underestimation in official oil and gas reported emissions by countries as documented by previous studies," Lauvaux said. "The atmospheric monitoring approach enabled by recent satellite missions provides a unique perspective on oil and gas activities, and the potential to mitigate these large releases of methane."

Several recent studies have demonstrated that oil and gas emissions are often underestimated by conventional accounting methods due to the absence of a global monitoring system able to track high emission sources including leaks and planned venting.

The identification and quantification of these sources has significant implications for countries' emissions inventories, as well as global methane emissions estimates, which have risen in international importance with the Global Methane Pledge, which asks countries to join an effort to reduce global methane emissions by at least 30% percent by 2030.

The study concluded that readily available and cost-effective strategies such as enforcing leak detection and repair strategies or reducing venting during routine maintenance and repairs can significantly reduce these ultra-emitters in the near term.

"We find that capturing the methane from these ultra-emitters provides enormous benefits via reduced climate change and improved air quality. Society would come out billions of dollars ahead by eliminating the emissions from these sources," said study co-author Drew Shindell from Duke University. "As the captured methane is a valuable commodity, the companies or countries capturing the wasted gas also typically come out ahead."

The international team also included the analytics firm Kayrros, Duke University's Nicholas School for the Environment, and The Cyprus Institute's Climate and Atmospheric Research Centre.

Carbon Mapper is a nonprofit organization focused on facilitating timely action to mitigate greenhouse gas emissions. Its mission is to fill gaps in the emerging global ecosystem of methane and CO2 monitoring systems by delivering data at facility scale that is precise, timely and accessible to empower science-based decision making and action. The organization is leading the development of the Carbon Mapper constellation of satellites supported by a public-private partnership composed of Planet, NASA's Jet Propulsion Lab, the California Air Resources Board, the University of Arizona, Arizona State University and the Rocky Mountain Institute, with funding from leading philanthropies.