Environmental Impact of The Coal Industry - Greenhouse Gases Emissions

Greenhouse Gases Emissions

The combustion of coal is the largest contributor to the human-made increase of CO₂ in the atmosphere. Electric generation using coal burning produces approximately twice the greenhouse gasses per kilowatt compared to generation using natural gas. About one fourth of the carbon dioxide emitted is absorbed by the oceans, causing a steadily increasing ocean acidification.

Coal mining produces methane, a potent greenhouse gas. Methane is the naturally occurring product of the decay of organic matter as coal deposits are formed with increasing depths of burial, rising temperatures, and rising pressure over geological time. A portion of the methane produced is absorbed by the coal and later released from the coal seam (and surrounding disturbed strata) during the mining process. Methane accounts for 10.5 percent of greenhouse-gas emissions created through human activity. According to the Intergovernmental Panel on Climate Change, methane has a global warming potential 21 times greater than that of carbon dioxide over a 100-year timeline. The process of mining can release pockets of methane. These gases may pose a threat to coal miners, as well as a source of air pollution. This is due to the relaxation of pressure and fracturing of the strata during mining activity, which gives rise to safety concerns for the coal miners if not managed properly. The buildup of pressure in the strata can lead to explosions during (or after) the mining process if prevention methods, such as "methane draining", are not taken.

In 2008 James E. Hansen and Pushker Kharecha published a peer-reviewed scientific study analyzing the effect of a coal phase-out on atmospheric CO₂ levels.Their baseline mitigation scenario was a phaseout of global coal emissions by 2050. Under the Business as Usual scenario, atmospheric CO₂ peaks at 563 parts per million (ppm) in the year 2100. Under the four coal phase-out scenarios, atmospheric CO₂ peaks at 422–446 ppm between 2045 and 2060 and declines thereafter.