Coal
Climate change

The largest and most long-term effect of coal use is the release of carbon dioxide, a greenhouse gas that causes climate change. Coal-fired power plants were the single largest contributor to the growth in global CO emissions in 2018, 40% of the total fossil fuel emissions, and more than a quarter of total emissions. Coal mining can emit methane, another greenhouse gas.

In 2016 world gross carbon dioxide emissions from coal usage were 14.5 gigatonnes. For every megawatt-hour generated, coal-fired electric power generation emits around a tonne of carbon dioxide, which is double the approximately 500 kg of carbon dioxide released by a natural gas -fired electric plant. In 2013, the head of the UN climate agency advised that most of the world's coal reserves should be left in the ground to avoid catastrophic global warming. To keep global warming below 1.5 °C or 2 °C hundreds, or possibly thousands, of coal-fired power plants will need to be retired early.
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