Responding to Satellite Notifications from the Methane Alert and Response System
About this report
In 2023, the International Methane Emissions Observatory launched the Methane Alert and Response System, the first global system to provide free satellite-based alerts on major emission events to governments. Prompt reaction to MARS notifications has led to the successful mitigation of methane leaks in several countries. However, the global response rate to MARS notifications remains relatively low, suggesting that further measures may be required to transform satellite alerts into actionable responses for governments.
The IEA, in collaboration with IMEO, has prepared this technical guidance document to assist governments seeking to improve action on MARS notifications and reduce methane emissions within their territory. The document proposes a five-step sequential process for responding to MARS notifications: (1) receive, assign and classify the notification; (2) notify the operator associated with the emission event; (3) operator responds to the notification; (4) verify the operator’s response and follow-up; and (5) review and document information on the event. It also proposes indicative timelines for acting on such notifications. Recommended timelines vary according to the level of urgency assigned to the event, which is determined by the event’s emission rate and whether the source is recurrent.
The IEA and IMEO are available to provide technical assistance to governments interested in adapting this framework to their jurisdiction’s legal, operational and financial context. Governments interested in implementing this framework within their jurisdiction are encouraged to get in touch with IMEO and the IEA.
Executive summary
In 2023, the United Nations Environment Programme’s (UNEP) International Methane Emissions Observatory (IMEO) introduced the Methane Alert and Response System (MARS), which uses satellite data (coupled with scientific expertise and artificial intelligence) to provide free notifications of large methane emission events to governments and companies.
MARS satellite alerts provide rapid and actionable information that can enable quick mitigation action. Swift action on major leaks or releases detected via MARS can deliver significant benefits for governments, potentially reducing gas waste, boosting sales by domestic companies and improving national energy security while simultaneously decreasing air pollution, minimising local health impacts and increasing productivity. More broadly, it may allow governments to achieve national emissions reduction objectives.
While the response rate to MARS notifications has increased since the system’s introduction in 2023, overall engagement remains low: globally, only around 12% of MARS notifications received a response in 2025. This suggests that further support mechanisms may be needed to ensure satellite alerts translate into effective mitigation responses.
This technical guidance document is designed to assist governments seeking to improve the way they respond to MARS notifications and reduce methane emissions within their territory. It aims to support effective responses to MARS notifications, building on lessons from countries that have successfully responded to and mitigated satellite-detected emission events. The document proposes a five-step sequential process for responding to MARS notifications: (1) receive, assign and classify the notification; (2) notify the operator associated with the emission event; (3) operator responds to the notification; (4) verify the operator’s response and follow-up; and (5) review and document information on the event.
In addition to this five-step process, the framework also proposes indicative timelines for acting on such notifications. These timelines are not intended to be rigid or binding but are instead meant to serve as a guideline for countries seeking to improve action on MARS notifications. Recommended timelines vary according to the level of urgency assigned to the event, which is determined by the event’s emission rate and whether the source is recurrent (with the largest, most frequently detected sources receiving the highest priority).
The framework proposes three distinct urgency levels based on the magnitude and recurrence of emission events, each with its own proposed timeline: urgent (Level 1); fast (Level 2); and regular (Level 3). The recommended timeline to complete all five response steps is 30 days for Level 1, 60 days for Level 2, and 90 days for Level 3. Ideally, any necessary mitigation action should occur within this timeframe (e.g. where the source is readily addressable). If this is not possible due to the complexity of implementing mitigation measures (e.g. cost or safety factors), the operator should develop a plan for implementing such measures, including a timeline for implementation.
|
Response steps |
Level 1 |
Level 2 |
Level 3 |
|
|---|---|---|---|---|
| 1 |
|
24h |
48h |
72h |
| 2 |
|
24h |
48h |
72h |
| 3 |
|
10 days |
20 days |
30 days |
| 4 |
|
10 days |
20 days |
30 days |
| 5 |
|
8 days |
16 days |
24 days |
Note: The timelines outlined in the framework are intended to be ambitious. While some actions may align with standard operator planning windows, recurrent emissions of this magnitude should be treated as emergencies and may necessitate responses outside typical operational procedures. Countries may adapt these timelines to reflect national circumstances and feasibility constraints. However, they are strongly encouraged to recognise the critical nature of such emission events when planning their response.
This framework can potentially serve its function as a non-binding guideline document. However, countries can strengthen the effectiveness of their response processes by ensuring that the MARS focal point and other competent authorities within the relevant jurisdiction have clear legal authority to request operators to take action to address large emission events. This includes the authority to require operators to respond to notifications, provide information on emission events, and implement mitigation measures. Countries should also ensure that the MARS focal point and other competent authorities have adequate resources to implement this plan and follow up on MARS notifications.
Throughout the process, countries should maintain close engagement with UNEP’s IMEO. An open dialogue with IMEO allows countries to obtain targeted information to support the response process. For example, if a country or company implements a mitigation measure in response to a MARS notification, IMEO can provide information on whether the mitigation was successful or not. In addition, there is growing global attention on large emission events, and IMEO publicly releases information on whether MARS notifications received an answer and on whether successful mitigation action was taken. Engaging with IMEO may therefore allow countries to demonstrate credible emissions reduction efforts.
The IEA and IMEO are available to provide technical assistance to governments and companies seeking to improve action on MARS notifications. Governments interested in implementing this framework within their jurisdiction or in understanding the MARS programme more broadly are encouraged to get in touch with IMEO and the IEA at the following email addresses: unep-mars@un.org and iea-methane@iea.org.
Cite report
IEA (2026), Responding to Satellite Notifications from the Methane Alert and Response System, IEA, Paris https://www.iea.org/reports/responding-to-satellite-notifications-from-the-methane-alert-and-response-system, Licence: CC BY 4.0