A high-resolution gridded inventory of coal mine methane emissions for India and Australia

TL;DR

This paper develops a high-resolution, country-specific methane emission inventory for coal mines in India and Australia, improving spatial accuracy and reducing uncertainty to aid monitoring and mitigation efforts.

Contribution

It presents a novel high-resolution gridded emission inventory for India and Australia, with improved spatial localization and methodology tailored to each country's data.

Findings

India's emissions are about three times lower than global inventories but align with national estimates.

The new dataset shows significant differences in spatial distribution compared to global inventories.

The inventory enhances the accuracy of methane emission estimates for climate and air quality modeling.

Abstract

Coal mines are globally an important source of methane and also one of the largest point sources of methane. We present a high-resolution 0.1deg x 0.1deg bottom-up gridded emission inventory for methane emissions from coal mines in India and Australia, which are among the top five coal-producing countries in 2018. The aim is to reduce the uncertainty in local coal mine methane emissions and to improve the spatial localization to support monitoring and mitigation of these emissions. For India, we improve the spatial allocation of the emissions by identifying the exact location of surface and underground coal mines and we use a tier-2 Intergovernmental Panel on Climate Change (IPCC) methodology to estimate the emissions from each coal mine using country-specific emission factors. For Australia, we estimate the emission for each coal mine by distributing the state-level reported total emissions using proxies of coal production and the coal basin-specific gas content profile of underground mines. Comparison of our total coal mine methane emission from India with existing global inventories showed our estimates are about a factor 3 lower, but well within the range of the national Indian estimate reported to the United Nations framework convention on climate change (UNFCCC). For both countries, the new spatial distribution of the emissions shows a large difference from the global inventories. Our improved emissions dataset will be useful for air quality or climate modeling and while assessing the satellite methane observations.