A first-of-its-kind survey of the proposed coal mines across the world revealed that they could emit enough methane to match the current CO2 emissions from all of America’s coal plants.
The report from Global Energy Monitor (GEM) surveyed 432 proposed coal mines globally and modelled methane emission estimates at the individual mine level using data on mining depth, coal rank, and production from its newly developed Global Coal Mine Tracker. The study warned that unless controlled, methane emissions from these proposed mines would amount to 13.5 million tonnes (Mt) annually, a 30% increase over current methane emissions.
Methane is the second-biggest contributor to global warming after CO2. It lasts for a shorter duration in the atmosphere, but its warming potential is higher than CO2. It is released during mining from the fractured coal seams.
According to the report, coal mines currently under development would leak 1,135 Mt of annual CO2-equivalent (CO2e) on a 20-year horizon and 378 Mt of annual CO2e on a 100-year horizon. Based on a 20-year horizon, estimated emissions would exceed the annual CO2 emissions from US coal plants (952 Mt in 2019).
The countries with the highest amount of methane emissions (CO2e20) from proposed coal mines include China (572 Mt), Australia (233 Mt), Russia (125 Mt), India (45 Mt), South Africa (34 Mt), the US (28 Mt) and Canada (17 Mt). Proposed coal mines in China, United States, Turkey, Poland, and Uzbekistan could emit 40%–50% of their greenhouse gas emissions in the form of methane, making them among the gassiest proposed coal mines in the world.
Source: Global Coal Mine Tracker
Depending on the methane-to-CO2 equivalency used, coal mine methane is responsible for 7.5% to 20% of a typical mine’s greenhouse gas emissions, for CO2e100 and CO2e20 respectively. However, some mines emit significantly more methane per tonne of coal than others, and for these mines, methane is responsible for 20% to 50% of a mine’s greenhouse gas emissions, for CO2e100 and CO2e20 respectively, the study revealed.
The survey stated the largest potential increase in global coal mine methane emissions comes from 140 new mines currently under development in China. According to US EPA data, operating coal mines in China released 18 million tonnes of methane in 2020. The study estimated that China will emit an additional 6.8 million tonnes of methane per year from these projects, increasing methane emissions by one-third. Shanxi Province was the single largest source of new emissions in the analysis. Coal mines in gassy deposits in Queensland, Australia, and Kemerovo, Russia would also contribute to a large increase in methane emissions from mining activities. Australia has 52 new mines under development and Russia has 55.
State-owned enterprises remain the major sources of proposed coal mine methane, including China Coal, Shandong Energy, Coal India, Shaanxi Coal and Chemical Industry Group. The privately owned Hutton Coal Project, sponsored by Valiant Resources, an independent firm headquartered in Australia, is the single-largest potential methane emitter, according to the analysis.
Ryan Driskell Tate, the author of the study, said: “Coal mine methane has dodged scrutiny for years even though there’s clear evidence it poses a significant climate impact.” If new coal mines are allowed to flourish without mitigation measures in place, then a major source of greenhouse gas will go unrestrained, he added.