Out-of-This-World Methane Detection: Using Satellites to Track Super Emitters

Key Takeaways:

• Methane has a global warming potential about 80 times higher than that of carbon dioxide, making methane emissions an ideal target to slow the rate of climate change.
• A small number of “super-emitter” facilities are responsible for up to 60% of methane emissions in the United States.
• Methane satellites across the globe combine regional mapping with precision imaging to detect plumes, identify leaking facilities, and track emissions over time.
• Investments from states like California are expanding monitoring networks and improving access to methane emissions data.

When it comes to greenhouse gas emissions, carbon dioxide tends to get all the attention—but methane has a warming potential 80 times that of carbon dioxide over a 20-year period. In fact, methane is the second-largest contributor to climate change after carbon dioxide, making it a critical greenhouse gas to address. Approximately 30% of global warming since the Industrial Revolution is attributed to methane. In the last 200 years, atmospheric methane has more than doubled, reaching a high of 1941 parts per billion in October 2024. Although methane’s atmospheric lifespan is shorter than carbon dioxide's (7 to 12 years versus hundreds of years), its greater warming potential leads to more immediate environmental repercussions. Together, methane’s shorter life span and greater potency make methane emissions the ideal target to slow the rate of climate change in the short term. 

Methane emissions caused by human activity—which account for 60% of total methane emissions—come from three primary sources: agriculture (171 metric tons), energy (144 Mt), and waste, particularly landfills (74 Mt). In addition to its climate impacts, methane contributes to ground-level ozone and other air pollution known to worsen respiratory and cardiovascular conditions. In the United States, many large sources of methane, especially oil and gas operations, are located in low-income communities and communities of color, which disproportionally experience the negative health impacts associated with pollution and other environmental hazards.

Methane emissions are also unevenly distributed from source to source. Between 2016 and 2017, NASA’s Jet Propulsion Laboratory found that fewer than 0.2% of oil and gas, manure management, and waste management facilities accounted for more than a third of California’s total methane emissions. Subsequent initiatives by Carbon Mapper have mapped out methane emissions in other regions across the United States and determined that a small fraction of facilities accounted for 20 to 60% of total emissions across multiple economic sectors. 

These super emitters are defined by the Environmental Protection Agency as emitting, either through leaks or deliberate releases, 100 kilograms (220 pounds) or more of methane per hour. These emissions come from a variety of sources, including leaky pipelines, malfunctioning equipment, or deliberate venting in excess of regulatory limits (in the case of oil, gas, and landfill operations). While some emission incidents last for only a few hours or days, many persist for months and even years if they are not detected. Finding and fixing these leaks and malfunctions can rapidly reduce methane emissions. To better pinpoint these emitters, researchers are increasingly turning to satellites.

How Do Methane Satellites Work?

Satellites have changed the way methane is measured. Using imaging spectrometers, satellites can detect methane by identifying its spectral fingerprint in the sunlight that is reflected by Earth’s surface. Just as a prism breaks white light into a rainbow of colors, spectrometers also break light into many wavelengths. Methane absorbs certain infrared wavelengths, creating a signature pattern of light that satellites can detect. Once the light is diffracted into its different wavelengths, the photons of each wavelength are converted into a numeric representation that computers can use to generate an image of a specific methane pattern. By mapping these patterns, satellites can reveal atmospheric methane plumes and even estimate methane emissions.

Methane satellite patterns are quantified and sorted into two types of methane sources: point-source emissions or area emissions. Point-source emissions come from a specific facility or even a specific piece of infrastructure. In contrast, area emissions, sometimes known as dispersed emissions, are scattered across a wider area. Methane satellites can be categorized by whether they detect point-source or area emissions.

Point-source imagers are satellites designed to look at relatively small areas in high detail, acting like a zoom lens. This narrow field of view allows the spectrometers to collect more light per unit of area via sensors, improving sensitivity and allowing them to detect plumes directly over facilities, such as oil and gas infrastructure, landfills, or large feedlots. For example, Carbon Mapper’s first two Tanager satellites can attribute emissions to a specific source within a 50-meter radius. This precision makes point-source imagers ideal for identifying super emitters. They are also an important tool for verifying whether previously-identified leaks have been repaired. 

By contrast, area-flux satellites act more like a wide-angle lens, sweeping over broader regions and measuring the average concentration of methane in the atmosphere. Instead of narrow fields of view, these satellites capture hundreds of kilometers at a time. Although they cannot identify the individual infrastructure responsible for methane plumes, area-flux satellites are important for revealing overall methane levels across entire basins or countries. They are also able to revisit locations more frequently than point-source imagers, returning to sites within one to five days and maintaining a consistent methane record. For instance, the European Space Agency’s Sentinel-5P Precursor satellite, equipped with a TROPOMI spectrometer, tracks global daily methane emissions, while the Environmental Defense Fund’s MethaneSat obtained data on oil and gas emissions in the Permian Basin before the organization lost contact with it in June 2025.   

The strength of the current satellite monitoring network lies in how these two types of satellites work together. Area mappers provide big-picture insights and highlight regions where methane emissions are concentrated, while point-source imagers reveal exactly which facilities are responsible for methane plumes. This combined approach allows governments and regulators to prioritize mitigation for the highest-emitting sources and regions. 

Globally, there are now more than 25 active satellites with the ability to monitor methane. This growing network includes large-scale public missions, such as NASA’s EMIT and Germany’s EnMAP, commercial constellations (groups of satellites) operated by private companies like GHGSat, and nonprofit public-private partnerships, including Carbon Mapper’s Tanager-1. These efforts have different approaches to data distribution: government missions typically make data publicly available to researchers, public-private satellites are open-source for non-commercial use, and private satellites require payment to access their data. Together, this ecosystem of satellites combines broad regional coverage with fine detail, with the potential to provide a clearer picture of U.S. and global methane emissions and mitigation opportunities.

Alternative Methods of Measuring Methane

While satellites have transformed methane detection, they are not without limitations, as their sensors detect only large sources of methane. Current satellite technology also struggles with measurements in certain environments, including high and equatorial latitudes, mountainous areas, offshore regions, and places with snow or ice coverage. Since satellites require a clear snapshot to measure methane concentrations, cloud cover and other weather conditions can interfere with their measurements. 

Thus, conventional ground-based and aerial methane detection methods remain necessary to fill data gaps. Handheld, vehicle-mounted, and fixed imaging coupled with handheld sensors can identify large leaks with a high level of accuracy, but only at a limited number of sites due to cost-effectiveness issues. Aircraft equipped with instruments like NASA’s Airborne Visible InfraRed Imaging Spectrometer - Next Generation (AVIRIS-NG) enable larger statewide campaigns. For example, California’s Air Resources Board and Colorado’s Air Pollution Control Division have used aircraft monitoring in the past to target super emitters. While these approaches reveal major leaks, they do not provide continuous monitoring, which leads to a significant underreporting of methane emissions. This is where satellites come in.

Despite their limitations, satellites offer something conventional methods cannot: broad and consistent coverage. As newer satellites include improved sensor technology, they are able to detect methane quantities more accurately, even in difficult environments and weather conditions. These advances position satellites as a critical tool for building a global system of continuous methane monitoring.

California Leading the Way

In 2016, California passed SB 1383, pledging to reduce its methane emissions by 40% from 2013 levels by 2030. To meet the bill’s mandate, California has become the first state in the country to use methane satellite data to target large emitters, building upon previous successes with aerial studies. In March, the state announced its partnership with the nonprofit Carbon Mapper to purchase their high-resolution methane plume data for use in real-time leak detection. The three-year contract, awarded through California’s Satellite Data Purchase Program, is funded by the state’s cap-and-trade program and will allow the state to access data from the Tanager-1 satellite, launched in August 2024. Up to seven more satellites will be deployed through the program in the future.

As part of the program, an additional $5 million in grants was set aside for community engagement. Administered over 36 months, the grant program will support efforts to improve public access to satellite data, design user-friendly dashboards, establish plume notification methods, and provide training resources. The Air Resources Board is also developing a publicly-available dashboard to display plume data as well as updates on actions being taken to address emission sources.

Methane satellites represent a pivotal technology for reducing domestic and global emissions. California is demonstrating the impact of investing in methane monitoring (several super-emitter events have been detected and stopped due to its methane surveys), but realizing the full benefits of this technology will require federal support and international cooperation. Domestically, the federal government has continued to play a critical role by investing in these methane technologies and promoting open access to emissions data, particularly through EPA and NASA research and development initiatives that serve as the backbone for improving satellite technology and integration. Globally, since the launch of the Global Methane Pledge at the 26th annual UN Climate Change Conference (COP26), methane emissions have been a major topic of international climate negotiations. This year’s COP30 presents another key opportunity to address methane at the global level.

Authors: Erin Parker and Isabel Rosario-Montalvo