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Methane Alert Response System (MARS)

The Methane Alert and Response System (MARS) is the first global satellite observation system that detects, analyses and freely communicates methane emission data.

Source: IMEO

Focus on MARS

What is MARS?

The Methane Alert and Response System was announced at the 27th United Nations Climate Change Conference (COP27) and launched in January 2023 to link methane emissions satellite data to concrete mitigation action.

MARS detects, analyses and quantifies major emissions, notifies countries and companies of emission events and tracks progress of mitigation actions.

Integration

MARS draws data from nearly a dozen satellites and provides them in an accessible and actionable form. MARS leverages the UN Environment Programme's (UNEP) global reach across governments, civil society and the private sector to put accurate emission data in the hands of decision makers and facilities' operators who have the agency to take action.

MARS’s unique value lies in its dual role as a service to support countries and companies to identify emissions reduction opportunities, and as a source of transparent, reliable data for global institutions – including investors, consumers, and civil society organizations – with the influence to drive mitigation across sectors. MARS translates complex data sets from multiple and quickly evolving satellite tools into information that companies and countries can readily use.

Collaboration

IMEO collaborates with a range of institutional partners, including the International Energy Agency, the UNEP-convened Climate and Clean Air Coalition, and the World Bank, research institutes and universities such as Universitat Politècnica de València, Space Research Organisation Netherlands (SRON) and Harvard, national space agencies, the Environmental Defense Fund and the Committee on Earth Observation Satellites (CEOS).

How does MARS detect emissions?

The Methane Alert Response System works by scanning methane emissions data from methane-sensitive satellites, tracing emissions to their source, quantifying emission rates and interpreting the data.

MARS then notifies governments and companies of relevant emissions, providing them the data and insights necessary to help drive concrete mitigation action.

Scale, speed and accuracy

To deliver accurate insights at speed and scale, MARS combines world-leading scientific expertise on methane detection with cutting edge artificial intelligence tools.

IMEO has built and trained custom machine learning models to identify likely methane plumes from satellite images. These models allow scientists to scan locations around the globe for emissions – and analyse thousands of images – in minutes rather than days, enabling quick and powerful analysis at a planetary scale.

From detection to mitigation action

Detection and attribution

MARS draws data from existing global mapping satellites to identify very large methane plumes and methane hotspots. IMEO scientists analyse the plumes and conduct further analysis using higher-resolution satellites and datasets that can help attribute the emission event to a specific facility and operator.

Notification and engagement

The IMEO team works directly to notify companies and governments of large emissions events happening in their operations or jurisdictions. IMEO continues to collect, analyse data and send them new data as it becomes available.

Mitigation action

Notified stakeholders are responsible for determining how best to respond to the emissions. By sharing their actions with IMEO, companies demonstrate their commitment to environmentally responsible operations. As appropriate, MARS partners are available to provide technical assistance to support mitigation actions.

Tracking, learning, collaboration and continuous improvement

IMEO continues to monitor the location of the emission event even after mitigation efforts ended. Data is posted on Eye on Methane 30 days after detection. If a notification was issued and feedback on the plume notification was received from either the operator or the government, the data is posted 30 days after the date of notification. IMEO continuously collaborates across its network of experts to draw lessons from these notified events that can be applied to improve MARS and methane mitigation action.

Power of shared knowledge

Climate action hinges on an open data policy

IMEO believes in the power of shared, transparent knowledge for driving meaningful mitigation action and accountability. Through a comprehensive data-sharing policy, IMEO makes satellite data and metadata available to the public on Eye on Methane 30 days after an emission event is detected. The delay in making data publicly available allows for time to engage governments and companies on emissions events and to identify effective mitigation solutions. All detections are posted on Eye on Methane, including those that did not lead to a notification because they were not attributable, or are older than 15 days.

IMEO also publishes a list of the world's top 50 methane emitters. The list identifies the largest methane-emitting sources globally, based on MARS data. It is designed to assess major sources of methane globally, help prioritize mitigation efforts and track progress over time.

Additionally, IMEO's publishes a monthly response rate by country, which measures the percentage of notified emission sources for which IMEO received feedback from governments or operators compared to the total number of sources notified.

Download the latest MARS snapshot of the world's top 50 methane emitters, country responses and mitigation.

Potential limitations of satellites for methane detection

Satellites hold great potential for methane detection thanks to their global coverage, frequent observation and cost-effectiveness for large-scale monitoring – but they are not a silver bullet and have technical limitations.

Above light and clouds

Methane-sensitive satellites depend on sunlight reflected from the Earth's surface to observe emissions. This means that satellites can only detect methane when sunlight is present and there are no clouds.

Brightness and topography

Moreover, observations over or near water or in snowy areas, in densely forested or complex regions such mountains or cities, and where there is reduced sunlight, like in high northern latitudes, are much more challenging.

Methane concentration

Satellites also have a minimum detection limit, which means they can only detect methane emitted at or above a certain rate - any emissions below this become undetectable.

Introducing the persistency-weighted flux method

A single large leak that lasts only an hour is not the same as a smaller leak that persists for a year. The persistency-weighted flux (PWF) visualization metric is a new way to visualize methane emissions that moves beyond static measurements. The Eye on Methane map now uses persistency-weighted flux for satellite-detected emissions to allow users to quickly identify sources that release emissions consistently over time. More details can be found in our persistency-weighted median flux rate technical note.

Future development and vision

Explore Eye on Methane

So far, the focus of MARS has been on observing methane emissions from the oil and gas sector, so the current distribution of detected events is concentrated in regions with active oil and gas production sites. As Eye on Methane expands into other sectors, such as coal, waste and agriculture, more data will become available for a more complete view of methane emissions.

To learn more about MARS, please visit:

Contact us

For more information, please us an email at unep-mars@un.org