As the fourth installment of its kind and the third to be published as a living data collection in the journal Earth System Science Data, the Global Methane Budget 2024 offers a comprehensive analysis of methane trends and their implications for climate change.  With methane being the second biggest human-made contributor to global warming after carbon dioxide, the findings highlight the urgent need for targeted emission reduction strategies.

The rise in methane concentrations in the atmosphere has been particularly alarming in recent years, with higher growth rates than at any other time since reliable measurements began in 1986.

These trends are moving in the opposite direction of what’s needed to maintain a habitable planet and limit global warming below even 2°C.

Methane, which is 28 times more effective at trapping heat than carbon dioxide over a century and 80 times more potent over 20 years, has seen its atmospheric concentration reach 1,923 parts per billion as of 2023.

This level is 2.6 times higher than pre-industrial levels and the highest in at least 800,000 years.

Despite international commitments to reduce methane emissions, including the Global Methane Pledge which aims for a 30% reduction by 2030, current trends are worrying.

Methane emissions from fossil fuels, agriculture and waste management have continued to climb, tracking scenarios that assume minimal climate mitigation efforts. This trajectory is inconsistent with the pledge and reveals a significant gap in our efforts to combat climate change.

The 2024 report highlights that, if the current trends persist, we are unlikely to meet the targets of the Global Methane Pledge. The observed growth in methane emissions follows the Intergovernmental Panel on Climate Change’s most pessimistic greenhouse gas scenarios, which predict global temperatures could rise above 3°C by the century’s end if such trends continue.

Regional hotspots

The report details methane emissions by sector and region, identifying key contributors. The top five emitters of anthropogenic methane in 2022 were China (16%), India (9%), the USA (7%), Brazil (6%), and Russia (5%). Notably, emissions from coal exploitation in China and oil and gas extraction in the Middle East are major contributors.

In contrast, Europe and Australia have seen successful reductions in methane emissions over the past two decades.

Methane emissions from agriculture, including livestock and rice paddies, remain the largest source, accounting for 40% of global anthropogenic emissions. Fossil fuel activities contribute 34%, while waste handling and biomass burning add 19% and 7%, respectively. The growth in emissions from these sectors is primarily due to increased activities in developing regions and intensified exploitation of fossil fuels.

Implications for climate goals and mitigation strategies

Addressing the methane crisis is crucial for achieving climate goals.

Currently, there are no technologies capable of directly removing methane from the atmosphere, making it imperative to reduce emissions at their source. To address this, the report suggests several strategies for reducing methane emissions, particularly in the fossil fuel and waste sectors. These include leak detection and repair, recovery of vented gas, and improved waste management practices.

Although the agriculture sector poses more challenges, measures such as feed changes for livestock and improved manure management offer potential solutions.

Satellites offers a consistent and global view of methane concentrations in the atmosphere and were used by the team for modelling the changing methane emissions, attributed to the main methane sources. These so-called ‘top-down’ estimates were compared to independent ‘bottom-up’ estimates from traditional inventories and derived from land surface models.

ESA’s commitment to tackling methane emissions

To address the rising challenge of methane emissions, ESA is spearheading several initiatives to improve methane monitoring, mitigation and support better methane budget assessments to guide reduction efforts.

The Copernicus Sentinel-5P satellite plays a crucial role in this effort, providing daily global coverage at relatively high-resolution observations of atmospheric methane concentrations, which were used in this study to determine changing emissions in recent years (2018-2023).

Sentinel-5P helps track methane emissions on a global scale, offering critical data for understanding emission sources and verifying the effectiveness of mitigation measures. This satellite data can also help identify methane hotspots, especially as a component of tiered observing approaches to quantify ‘super-emitter’ point sources when combined with data from higher resolution sensors such as GHGSat. 

Developing this tiered observing approach is helping to lower the detection thresholds of methane plumes, enabling detection of smaller sources such as landfills, wetlands and agricultural sources. The ESA SMART-CH4 project is using new point-source data products to better understand regional methane budgets within case study regions and helping to attribute recent trends in methane concentration to specific sectors.

A new ESA project, MEDUSA, targets the growing constellation of methane-observing satellites and retrievals being developed for methane point sources. It will contribute to the maturity and interoperability of these products by assessing the relative merits and limitations of products available, developing a common approach to assess quality, and work on integration approaches across different observing systems.

Another new project launching in early 2025, called AI4CH4, will utilise AI and machine learning to detect methane point sources from satellite imagery, enhancing the ability to monitor and quantify methane emissions. This initiative represents a significant advancement in emission detection technology.

ESA’s Regional Carbon Cycle Assessment and Processes Phase 2 (RECCAP-2) project is supporting improvements to the methane budget assessment through regional case studies, where ‘top-down’ emission estimates are compared and reconciled with transitional inventories.

The project will also explore the use of global Essential Climate Variables (ECVs) in modelling natural sources of methane from wetlands and peatlands, with the aim to reduce uncertainties in methane budgets.

Additionally, the CCI Climate Modelling User Group (CMUG) project is to enhance the modelling of methane emissions from wetlands integrating various ECV datasets to improve emission calculations by constraining them with satellite-observed atmospheric methane concentrations.

Another key ESA initiative, the CCI Greenhouse Gases (GHG) project focuses on creating long-term global climate data records for carbon dioxide and methane. This effort includes deriving surface emission flux estimates of methane using satellite data from Sentinel-5P and GOSAT to improve the accuracy of emission retrievals.

Finally, ESA’s World Emission project integrates satellite data and models to provide global emissions estimates for various trace gases, including methane, through an advanced online system. This platform not only facilitates visualization and analysis but also enables real-time tracking of emission sources and trends.

By combining satellite observations with sophisticated modelling techniques, the system offers detailed insights into methane emissions and their spatial distribution. This comprehensive approach supports policymakers and researchers in assessing emission reduction strategies and monitoring progress toward climate goals, thereby enhancing our ability to address global methane challenges effectively.

Through these and many other projects, ESA is making significant strides in methane monitoring and mitigation, contributing valuable data and insights to the global effort to curb methane emissions and address climate change.