Three years of UNEP’s Methane Alert and Response System: achievements, lessons learned, and next steps

Three years have passed since the United Nations Environment Programme’s International Methane Emissions Observatory (IMEO) launched the Methane Alert and Response System (MARS), with one year in a pilot phase (2023) and two years now in nominal operations (2024–present). MARS leverages the capabilities of more than a dozen methane-sensitive satellites to detect emissions worldwide and to drive mitigation actions. Since its launch, MARS has focused on the rapid detection and notification (within 15 days from the observation date) of oil and gas point-source methane emissions. This has resulted in the notification of more than 5,600 plumes from over 1,500 oil and gas point sources across 34 countries, as well as feedback on the cause and current status of emissions from operators and governments for more than 170 sources in 18 countries and the effective mitigation of nearly 25 sources.

While the number of mitigated sources may appear low compared to the number of notifications, feedback received to date from governments and companies indicates that most detected plumes are linked to permitted, short-duration operational events, including planned activities and emergency releases. Other cases involve temporary mitigation measures that do not ensure long-term emission prevention, or mitigation actions requiring substantial economic and logistical efforts, with implementation timelines of several months to years; therefore, they cannot yet be classified as fully mitigated.

In the meantime, engagement with notified countries has increased significantly, with a growing number of formal responses received. This has led to an increasing number of confirmed mitigation cases and is enabling more robust and representative statistics on emission sources, causes, and mitigation status.

In parallel, MARS has also detected and monitored a large number of emissions from the coal, waste, and other sectors over the years, building a multi-sectoral data set with more than 20,000 plumes. Recognizing that mitigation in these other sectors is equally critical, and that satellite data can be a powerful tool to support action, MARS will start notifying emissions in the coal and waste sectors in 2026, adopting different notification approaches depending on the nature and mitigation potential of the source.

In this presentation, we will provide an update on the current status of MARS, highlighting key results and conclusions, as well as lessons learned to date. We will also provide an overview of upcoming measures and new products to be introduced as part of MARS' expansion.