The Harvard Methane Initiative has released a new research brief, summarizing research on satellite-based detection and quantification of methane emissions worldwide.

You may preview and download the brief at the bottom of this page.

Methane is the second-most important greenhouse gas (GHG) after carbon dioxide. Efforts to reduce methane emissions under the Paris Agreement and Global Methane Pledge require nations to set mitigation targets and quantify reductions. However, the methods widely used to report emissions to the United Nations Framework Convention on Climate Change (UNFCCC) are subject to large uncertainties.

The study summarized by this brief uses inverse analysis of satellite observations of atmospheric methane concentrations from the Tropospheric Monitoring Instrument (TROPOMI), together with emissions information from UNFCCC reports and other data sources, to develop optimized estimates of 2023 emissions, at up to 25 km grid resolution, for 161 countries. Results suggest that global anthropogenic emissions are 15% higher than previously reported to the UNFCCC and 32% higher for the oil and gas sector, in particular.

For 44 countries, the new estimates exceed prior national totals reported to the UNFCCC by more than 50%. Emission intensities in the oil and gas sector vary by two orders of magnitude between countries. Sub-Saharan Africa has the highest livestock emissions intensity of any region. Hydroelectric reservoirs, which are generally not included in UNFCCC reporting, are estimated to contribute 6% of anthropogenic methane globally.

Importantly, the analytical framework developed for this study can be used to update country and sector estimates in future years, enabling improved monitoring and reporting of methane trends and more effective implementation of multilateral efforts to reduce global emissions.

Reference to full paper and acknowledgements

A more detailed account of the research on which this brief is based may be found in: James D. East, Daniel J. Jacob, Dylan Jervis, Nicholas Balasus, Lucas A. Estrada, Sarah E. Hancock, Melissa P. Sulprizio, John Thomas, Xiaolin Wang, Zichong Chen, Daniel J. Varon, and John R. Worden. “Worldwide inference of national methane emissions by inversion of satellite observations with UNFCCC prior estimates.” Nature Communications. Vol. 16, Article 11004. December 11, 2025. http://doi.org/10.1038/s41467-025-67122-8.

Results from the analysis, including methane emissions estimates for individual sectors and 161 countries, are available in an interactive online portal developed by John Thomas, one of the co-authors, at https://worldwidemethaneemissions.com.

This work was supported in the framework of UNEP’s International Methane Emissions Observatory (IMEO) and by the NASA Carbon Monitoring System (CMS).

James East and several co-authors are current or former members of the Atmospheric Chemistry Modeling Group led by Professor Daniel Jacob at Harvard University, which receives support from the Harvard Initiative on Reducing Global Methane Emissions, a research cluster of the Salata Institute for Climate and Sustainability at Harvard University.