Satellites and AI Track Major Methane Leaks
UNEP's MARS system turns satellite observations into alerts sent to governments and companies so that major methane leaks can be repaired.
A methane leak can remain invisible from the ground while releasing large quantities of gas into the atmosphere hour after hour. Satellites are changing this.
By combining observations with artificial-intelligence tools, the United Nations Environment Programme identifies some major releases and alerts those able to intervene.
On 15 July 2026, UNEP published an assessment of its Methane Alert and Response System, or MARS.
Fully operational since 2024, the system is reported to have contributed to more than 40 mitigation actions worldwide, delivering a climate benefit comparable to the annual emissions of nearly 24 million petrol cars.
Seeing what inventories miss
Methane is the main component of natural gas. It also comes from coal mines, landfills, agriculture and some wetlands. In oil and gas operations, part of the emissions comes from leaks, faulty equipment or exceptionally large one-off releases.
Traditional reporting relies on emission factors, local inspections or annual estimates. These methods are useful, but can miss a brief incident or equipment that deteriorates between inspections.
From space, some instruments scan vast regions and identify abnormal concentrations, while more precise sensors attempt to attribute a plume to a particular site or pipeline.
Artificial intelligence is primarily used to sort a volume of imagery that would be impossible to process manually: detecting plumes, eliminating false signals and prioritising events for verification. An alert is not proof of responsibility.
It must still be checked against weather conditions, field data and information from the operator.
The weak link is human
Countries that have appointed an official contact respond far more often than others.
MARS combines more than 35 satellite instruments, scientific expertise and automated tools. The IEA and the International Methane Emissions Observatory propose a standard procedure:
- An identified contact receives the alert.
- Teams locate the source on the ground.
- The incident is verified with the operator.
- The equipment is repaired.
- Documentation confirms that the release has stopped.
Measurement technology does not reduce emissions by itself. Available teams, a duty to investigate, response deadlines and traceable repairs are all required.
Why target the largest releases
The IEA estimates that fossil fuels account for about 40% of human-caused methane and that a large share could be avoided with technologies already available, sometimes by capturing gas that can then be sold.
In 2025, satellites detected more than 5 million tonnes of methane from very large events in oil and gas operations.
Clouds, snow, terrain, offshore facilities and high latitudes complicate observation. Smaller leaks remain below detection thresholds. A credible strategy combines satellites, aircraft, drones, ground sensors and regular inspections.
UNEP is now extending alerts to coal mines and waste-treatment facilities. Their usefulness will depend on documented responses and verifiable repairs.