UNECE Guidance To Reduce Emissions Of Methane From Abandoned Coal Mines Will Support Climate Action
Methane is a powerful short-lived climate pollutant. It is also the main precursor of tropospheric ozone (O3). Over a 20-year period, methane’s effect on global warming is 84 times greater than carbon dioxide. Fossil fuel production, including coal mining, accounts for 29% of human-made methane emissions.
Even after coal mines are closed, they continue to emit methane that migrates into the abandoned mine from neighbouring, connected coal deposits. As many countries shift their energy economies away from coal, tackling Abandoned Mine Methane (AMM) emissions will be an important issue. This phenomenon, however, is observed not only in countries where coal production is declining and mines are closing, it is also found in those where coal production continues to play a significant role in the energy mix and closed mines are replaced by new mines. Due to methane’s relatively short 12-year atmospheric lifetime, compared with CO2, taking action now to reduce emissions can have a near-term impact to slow warming.
Methane emissions from closed and closing mines can be substantial and are projected to increase. Estimates of global coal mine methane emissions indicate that AMM represented 17% of the total mine methane emissions in 2010 and forecasts indicate that the proportion may increase to as much as 24% in 2050. To put these numbers in perspective, in 2016, coal mines in the United States alone released 60.5 MMTCO2e of methane, which equals roughly the warming impact caused by 13 million cars.
New methods of assessing emissions, including use of remote sensing, measuring methane concentrations in the atmosphere, pinpointing sources, and estimating based on historical coal production, may help countries identify and inventory methane resources comprehensively. More precise estimates of the cumulative volume of emissions could draw attention to this potentially important energy source and drive policy frameworks that support investment.