A global coal mine methane tracker to highlight inventory gaps and target mitigation

Methane (CH₄) is a key short-lived climate forcer, yet robust monitoring of its anthropogenic sources remains limited by inconsistent national reporting and incomplete inventories, especially from coal mining. Global anthropogenic CH₄ emissions are about 369 million tonnes per year, of which coal mine methane (CMM) contributes roughly 40 million tonnes per year, which is comparable to emissions from the gas sector. In 2023 only 15% of coal production reported annual CMM emissions in national greenhouse gas inventories and this limits the scientific basis for monitoring and verification of progress towards the Global Methane Pledge and the Paris Climate Agreement.

We present Ember’s Coal Mine Methane Data Tracker as a new open, global, evidence based dataset for understanding CMM emissions, reporting quality and methane targets. The Data Tracker compiles and harmonises national greenhouse gas inventory submissions to the United Nations Framework Convention on Climate Change (UNFCCC). It integrates these data with historic coal production statistics from the US Energy Information Administration (EIA), International Energy Agency (IEA) coal production forecasts and independent emission estimates (IEA Methane Tracker, Global Energy Monitor (GEM) Global Coal Mine Tracker).

To reconstruct national emissions from 1990 onwards, we calculate country and year specific CH₄ emission intensities wherever both reported emissions and coal production exist. Emission intensity is defined as CH₄ emissions (in kilotonnes) per million tonnes of coal produced. This approach also enables consistent comparison of reported emissions across countries and over time.

We fill gaps in the intensity time series using values from neighbouring years so that each country has a continuous record. We then multiply these completed intensity series by observed production to estimate unreported emissions. Ember’s gap filled series indicates that global active CMM emissions exceeded 34 million tonnes in 2023, whereas official UNFCCC inventories reported only 4.62 million tonnes, less than 14% of the inferred total. For 2024, the latest compilation of submissions implies 34.5 million tonnes of reported CMM, with underreporting of up to 21.2 million tonnes when compared with independent datasets.

We introduce a quantitative confidence score from 0 to 6 for each country’s reported CMM emissions, combining recency of UNFCCC reporting, consistency with independent estimates from both top down and bottom up approaches, and methodological robustness. Applied to major producers, this score shows that most large coal producing countries fall in the low-to-moderate confidence range, with only a small number, such as Poland (score 5), achieving higher confidence in their reported CMM inventories. 

By providing a transparent, harmonised framework for CMM monitoring, we demonstrate that systematic underreporting pervades national inventories. This gap is driven by widespread reliance on low tier IPCC methods, with 86% of reported CMM emissions relying on emission factors rather than direct measurement. Our quantitative confidence score (ranging from 0 to 6) highlights this reliance, showing that low scoring countries correlate directly with significant underestimation. This evidence necessitates the need for transparent, measurement based Monitoring, Reporting and Verification (MRV) frameworks to establish the rigorous CH₄ accounting required by global climate commitments.