Why there is so much coal

The Carboniferous produced a disproportionate share of the world's coal, and a widely repeated explanation holds that lignin had evolved but lignin-eating fungi had not, so dead trees simply piled up. A 2016 analysis rejected it: much Carboniferous coal is built from lycopsids, which contained little lignin, and the phylogenetic timing does not fit either. The real cause appears to be tectonic and climatic — vast, persistently waterlogged equatorial basins subsiding at just the right rate.