Satellite methane detection

In plain language

Methane is a powerful greenhouse gas. Some sites release disproportionately large amounts of it, which ESA calls super-emitters. Oil infrastructure, gas infrastructure, coal mines and landfills are all among the sources that satellite studies have flagged. Satellites that look down at the air above these sites can pick out methane as a faint plume, because the gas absorbs light at particular infrared wavelengths.

Not every satellite sees the same thing. The European Sentinel-5P satellite maps methane across the whole globe each day, but its pixels are about 7 by 5.5 kilometres, so it can show that a plume exists without always pinpointing which facility is leaking. Commercial instruments such as Carbon Mapper's Tanager use much finer ground sampling, around 30 metres in its performance specification.

Technical explanation

Sentinel-5P carries the TROPOMI spectrometer, which measures methane concentrations across the globe each day. Its pixels are about 7 by 5.5 kilometres. Schuit and colleagues (2023) built a two-step machine learning pipeline for this data. A convolutional neural network finds plume-like structures in each scene, and a support vector classifier separates real plumes from retrieval artefacts. The models were trained on pre-2021 data and applied to all 2021 observations. After manual inspection, the authors confirmed 2,974 plumes, with a mean estimated source rate of 44 tonnes per hour and a 5th to 95th percentile range of 8 to 122 tonnes per hour. Attributed shares were 35% urban areas and/or landfills, 24% gas infrastructure, 21% oil infrastructure and 20% coal mines.

Detection limits are stated as probability-of-detection figures under specific conditions, not as a single fixed threshold. Carbon Mapper's Tanager specification gives a 90% probability of detection of 90 to 180 kg of methane per hour, varying with imaging mode, for 3 metres per second wind, a 35 degree solar zenith angle, 25% albedo and 30 metre ground sampling distance. The page is headed 'Detailed Tanager Performance Specifications'. These are vendor figures and have not been independently checked in this profile.

Detection only helps if it leads to action. ESA reports that SRON reviews detections weekly, publishes plume maps online and passes persistent leaks to higher-resolution satellites (ESA, 2023). The sources reviewed for this profile do not give a verified count of leaks repaired after a satellite detection.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Limitations and open problems

• Sentinel-5P's relatively coarse pixels of about 7 by 5.5 kilometres show that a plume is present but make the exact source hard to pin down (ESA, 2023).
• Schuit and colleagues (2023) state that TROPOMI can only be used to pinpoint the largest and most isolated point sources. Smaller or crowded sources need higher-resolution instruments.
• Machine learning detections need checking. The full pipeline reported a precision of 61% to 76% (Schuit and colleagues, 2023).
• Attribution to facilities relies on bottom-up emission inventories, and the authors note that large transient emissions may be misattributed (Schuit and colleagues, 2023).
• Vendor detection limits are probability-of-detection figures under stated conditions and have not been independently checked in this profile.
• The sources reviewed do not give a verified count of leaks repaired after a satellite detection.

Possible future uses

Product concepts: Low-cost methane leak alert sensor for farm sites

Timeline

1. Sept 2023Schuit and colleagues publish a machine learning pipeline for TROPOMI methane plumes, reporting 2,974 confirmed plumes in 2021. Sources: [1]
2. 20 Sept 2023ESA describes SRON's machine learning detection of super-emitter plumes in Sentinel-5P data. Sources: [2]
3. 1 Jul 2025The Environmental Defense Fund announces that MethaneSAT lost contact on 20 June 2025 and is likely not recoverable. Sources: [4]

Futures this could help bring about

How far away?

Finding every methane leak from space

Pilots · 3 of 7 steps done

Related breakthroughs

• Satellite-detected Permian methane leak was reported repaired by its operator (24 Nov 2025)

Glossary

Methane

A powerful greenhouse gas and the main component of natural gas.

Super-emitter

A source that releases a disproportionately large amount of methane compared with other emitters.

Probability of detection

The chance that a plume of a given emission rate is detected under stated conditions, reported at a stated level such as 90% in Carbon Mapper's Tanager specification.

Ground sampling distance

The size on the ground covered by one image pixel. Smaller values allow finer detail.

Sources

1. peer reviewed paper
   Automated detection and monitoring of methane super-emitters using satellite data
   Berend J. Schuit. Atmospheric Chemistry and Physics, Sept 2023. DOI: 10.5194/acp-23-9071-2023. Accessed 21 Oct 2026.
2. news
   Trio of Sentinel satellites map methane super-emitters
   European Space Agency, 20 Sept 2023. Accessed 21 Oct 2026.
3. other
   Carbon Mapper product guide: Detailed Tanager Performance Specifications, Final Operational Orbit
   Carbon Mapper, 7 Oct 2026. Accessed 21 Oct 2026.
4. other
   MethaneSAT Loses Contact with Satellite
   Environmental Defense Fund, 1 Jul 2025. Accessed 21 Oct 2026.

Revision history

3 changes since this profile was created.