Methane is responsible for around 30% of the rise in global temperatures since the Industrial Revolution, and rapid and sustained reductions in methane emissions are key to limiting near-term warming and improving air quality.

Two key characteristics determine the impact of different greenhouse gases on the climate: the length of time they remain in the atmosphere and their ability to absorb energy. Methane has a much shorter atmospheric lifetime than carbon dioxide (CO₂) – around 12 years compared with centuries – but absorbs much more energy while it exists in the atmosphere.

Methane also affects air quality because it can lead to ground level (tropospheric) ozone, a dangerous pollutant. Methane leaks can also pose explosion hazards.

There are large differences between data based on measurement campaigns and scientific studies, and the emissions levels reported by official public bodies, such as to the UN Framework Convention on Climate Change (UNFCCC), which rarely make use of direct measurements. This mismatch exists at both global and national levels and for all sources of emissions. Many official greenhouse gas submissions to the UNFCCC have not been updated for years, and, even for those that have, many of these inventories are not yet accurate enough to provide a clear picture of emissions.  

Methane emissions can be estimated in a number of ways. Bottom-up approaches can use activity data (e.g., the number of facilities or the extent of operations) multiplied by standardised emission factors (e.g., default values or leak rates for particular types of equipment). Top-down methods tend to measure atmospheric methane concentrations, normally by airborne or satellite sensors, to infer emission releases.

Estimates are subject to significant uncertainty over the magnitude of emissions sources and their variability. Some of the largest emitting events are the result of accidents and unpredictable process failures and these might contribute a large level of emissions from oil and gas operations, but these are often not included in bottom-up inventories. Tried and tested approaches are already available for lowering methane emissions, but better and more transparent data will help to facilitate targeted action.

Advances in monitoring technologies, notably from satellites, have been a key to boosting our understanding of the level and nature of methane emissions. Current satellites and data processing techniques can be used to detect and quantify total emissions from major leaks over a large area, down to small leaks at the facility level. They also enable regional estimates of total methane emissions over longer periods of time.

New satellites are being developed that will provide higher resolution, greater coverage, and have more sensitive detection thresholds. These include instruments such as GHGSat, EnMAP, Carbon Mapper, SBG, CHIME and EMIT and MethaneSAT that aim to deliver high-resolution images for selected high-priority areas. These will improve methane quantification capabilities, raise public awareness and support regulatory oversight.

Satellite technologies are not perfect. They can struggle to provide readings in many environments such as offshore areas, mountain ranges, snowy or ice-covered regions, and at high latitudes. Satellites are also impaired by cloud cover, even if only a portion of the monitored area is covered, limiting the number of days when detections can be made. For example, countries with dense forests or in equatorial regions, such as Nigeria or Venezuela, are very often cloudy, hindering observation efforts.

Data from the European Space Agency satellite Sentinel-5P, processed by the earth analytics firm Kayrros, indicates that during 2022 there were around 70 countries where methane emissions from oil and gas operations could have been detected for at least 15 days. Large emission events were observed in 20 of these countries in 2022. Coverage tended to be best in the Middle East, parts of Central Asia and Australia, where it was possible to make a direct observation every 3-5 days. On the remaining days, cloud coverage or other interference prevented observations from taking place. Accounting for the level of satellite coverage, observed very large leaks are estimated to have emitted around 3 Mt of methane from oil and gas operations in 2022 (6% of our estimate of oil and gas emissions in the 20 countries where events were detected).

New technology development has allowed satellites to detect methane emissions in offshore areas for the first time in 2022, but this has not yet become part of routine monitoring efforts, and there is still a high degree of uncertainty over estimates derived from satellite readings of emissions from offshore events. Emissions from the Nord Stream pipeline explosion were one of the first offshore leaks to be quantified using satellite data. A working paper from the International Methane Emissions Observatory estimates emissions from this event were between 75 and 230 thousand tonnes of methane.

Satellites are also uncovering large methane emissions from coal mines, with several detections in Russia, the United States and other coal producing regions. Sentinel-5P detected around 0.2 Mt of emissions from such events in 2022 (2% of our estimate of coal mine methane emissions in the seven countries where events were detected) and more than 1 500 methane emissions events were observed at coal mines by GHGSat (GHGSat can detect events larger than around 100 kg per hour while Sentinel-5P can detect emissions events larger than around 5 tonnes per hour). High-resolution satellites are also beginning to provide new insights on other potential sources of emissions with around 10 leaks detected at LNG liquefaction facilities in 2022.

Other detection and measurement campaigns will remain vital, and the optimal system will combine satellite measurements with drone-based and other aerial surveys, ground-based sensors and surveys, and continuous monitoring devices. Reporting and verification procedures and systems are also essential.

A detailed picture of methane emissions is necessary to design policy tools that can drive deeper cuts in an efficient manner through market-based instruments, performance standards and trade measures. Robust monitoring, reporting and verification can also facilitate the work of regulators in verifying compliance and in tracking progress against reduction targets; it can support regulatory development; and enable other stakeholders to engage with methane mitigation efforts.

The IEA produces and publishes country-level estimates for energy-related methane emissions and abatement options as part of our IEA Global Methane Tracker. This data tool also includes the latest emissions estimates from non-energy sectors – waste and agriculture – based on publicly available data sources, to provide a fuller picture of methane sources from human activity.

Our estimates are regularly updated using the best available data on fossil fuel operations, country- and production-specific emissions intensities, measurement campaigns and large emissions events detected by satellites. We also work with IMEO to ensure our estimates reflect the latest findings from measurement-based, peer-reviewed studies. Recent studies are improving our understanding of methane emissions from LNG supply, biogas production, incomplete-combustion in flares, the sources of oil and gas methane, different sectors in China, oil and gas emissions in Canada and the United States, and coal facilities in Australia and many other regions.

With fossil fuels, methane emissions can occur at any point during production, processing and transport. In addition to these emissions, we include emissions from the end use of coal, oil products and natural gas in the Global Methane Tracker (3 Mt or 3% of energy-related methane). This estimate is based on the emissions factors published by the Intergovernmental Panel on Climate Change for energy consumption in homes, industries and in the transport sector. Some measurement campaigns have suggested that these emissions factors could significantly underestimate actual emissions across different end-use environments, including in industry, cities and households. These are areas with very high levels of uncertainty and our estimates will continue to be updated as the evidence base grows.

Emissions from abandoned coal mines and oil and gas wells are not included in the Global Methane Tracker. Existing measurements cover a limited number of facilities and regions, and reliable data on abandoned mines and wells is not available for most countries. These sources could, nonetheless, represent significant levels of emissions. The U.S. Environmental Protection Agency indicates they are responsible for close to 5% of energy-related methane in the United States; and a recent study estimated that abandoned mines could account for almost one fifth of methane emissions from worldwide coal production.

The IEA Global Methane Tracker 2023 is our best attempt to reconcile existing information and produce a consistent set of country-level estimates. Further details on the methods used can be found in the Global Methane Tracker Documentation. We recognise these estimates do not represent the last word. We welcome all feedback based on measurement campaigns and robust data sources that can further refine our estimates. Relevant reports or scientific studies can be shared with IEA analysts by email at MethaneTracker@iea.org.