From Forests to Coal: A Slow Transformation

At the end of the Paleozoic era, when the Earth’s climate was hot and humid, large forests were successively buried, resulting in the formation of coal over millennia. At different stages of development, it takes the form of peat, lignite (brown coal), bituminous coal and finally anthracite. Today, coal is extracted from underground mines or, when it is close to the surface, open-pit mines. Coal is still the main source of energy used for power generation worldwide. (1’20” animated video)