This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers have conducted the largest-ever controlled test of space-based methane monitoring, finding that dedicated methane sensors correctly detected nearly all methane plumes released on clear days. Published Oct. 14 in Nature, the results provide a benchmark for satellite systems increasingly used by regulators, environmental groups and companies to detect leaks and identify super-emitters of the planet-warming gas.
"There has been significant skepticism over the years about whether methane tracking really works because it's a challenging technical problem to detect the gas from space," said senior study author Adam Brandt, a professor of energy science and engineering in the Stanford Doerr School of Sustainability. "Our results should give regulators, policymakers, producers of methane and the general public a lot of confidence moving forward." Together with Ph.D. student and lead author Frances Reuland, Brandt and collaborators timed 481 methane releases at a Stanford research site in Casa Grande, Arizona, to overpasses by 11 government, nonprofit and commercial satellites throughout 2025. Fifteen research teams from corporations, nonprofits, government agencies and academia across nine countries independently analyzed the observations, assessing whether each satellite image showed a methane plume and, if so, how much methane was released.
The study authors compared the resulting estimates with the known releases. Instruments designed specifically for methane monitoring produced the best detection rates, correctly identifying the presence of 92%–100% of test plumes. Most estimates based on these observations were up to 50% higher or lower than actual emission amounts, but the over- and underestimates roughly balanced out on average.
That makes the estimates reliable enough to flag large leaks for follow-up, inform governments' regional greenhouse gas emissions inventories and assess the relative emissions intensity of different oil and gas regions, the authors said. "In many cases, the detection is the important part," said Brandt. "As long as you know approximately how big it is, then you still know you need to go fix it." Under ideal conditions, with few clouds and moderate wind, these instruments reliably detected plumes when methane flowed at rates down to about 50–200 kilograms per hour, depending on the system.
This emission rate is close to the threshold of 100 kilograms per hour that triggers reviews under some state and national "super-emitter" programs. "These results were great to see, and we hope they build confidence in this field overall," said Reuland, who is a member of Brandt's lab and a Ph.D. student in energy science and engineering in the Doerr School of Sustainability. Satellite-based monitoring systems detect methane using infrared light reflected off Earth's surface.
That reliance on reflected sunlight means even the dedicated instruments aboard GHGSat and Tanager-1 satellites struggled to detect methane plumes through clouds. "This poses problems in some key methane-emitting regions," the authors write, "including tropical oil and gas producers Nigeria and Venezuela, as well as cold, cloudy climates like Canada and Russia." More research is needed, they added, to understand how these satellite systems and algorithms work over nondesert terrains, across various weather conditions and over open water. Discover the latest in science, tech, and space with over 100,000 subscribers who rely on Phys.org for daily insights. d research that matter—daily or weekly.
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