The Integrated Methane Inversion (IMI) is an open-source software tool developed at Harvard University that combines satellite observations with bottom-up information to produce independent, top-down estimates of methane emissions at national, subnational, and sector levels.
How It Works:
- The IMI starts from a country's own Biennial Transparency Report (BTR) inventory as a starting estimate.
- It combines that starting estimate with daily, global observations of atmospheric methane from the TROPOMI satellite instrument (operating since 2018), plus satellite point source data from multiple instruments and weather data to relate emissions to the satellite observations through atmospheric transport.
- IMI thereby adjusts the inventory estimate to match what the satellite actually observes in the atmosphere, producing an accurate emissions estimate with confidence intervals, at 12–25 km resolution.
- In addition to total country-level anthropogenic emission estimates, results are broken out by sector (oil/gas, livestock, landfills, wetlands, rice, coal, wastewater, and more) and reported with spatial distribution.
What Makes It Different:
Unlike point-source satellite products (e.g., GHGSat, Carbon Mapper, IMEO's MARS), which detect and quantify instantaneous emissions from a few large point sources but do not aggregate to comprehensive national totals, the IMI quantifies total annual emissions from all sources across an entire country, giving a complete national picture rather than a partial one. Importantly, the country and sector estimates are obtained using a common methodology worldwide, making them truly comparable. Why It's Trustworthy: The IMI is open-source, applies well-established scientific methods, is fully documented in over 50 peer-reviewed publications, has a wide user community, and is
designed for non-expert use. Its worldwide quantification of anthropogenic methane emissions by country is reported by East et al. (2025) with complete results accessible through an interactive web interface. It complements, rather than replaces, national inventories, using them as its starting point and refining them with independent satellite evidence. And, importantly, because a common methodology is employed for all country estimates, these are numerically comparable.
Supporting National Climate Reporting
The IMI can be a powerful tool in support of major reporting deadlines:
- Biennial Transparency Reports (BTRs), due by the end of 2026, where independent, reliable evidence can strengthen confidence in reported numbers.
- The Second Global Stocktake (2024–2028), where credible, transparent, independently verifiable methane data will be essential to demonstrating collective progress and setting global priorities.