Coal ash cause of Permian extinction
The mass Permian extinction 250 million years ago is frequently blamed on volcanoes. But a new study shows that what may have really tipped the climate was the volcanic release of massive amounts of combusted coal –Â similar to modern day coal ash from coal-fired power plants. If so, modern day climate change hasn’t been the first time that burning coal was to blame.
The extinction of that era wiped out some 90 percent of marine species, one of the largest extinction events in history. Scientists led by the Geological Survey of Canada, Stephen Grasby, found deposits of carbon on Permian-aged rocks in the Canadian high Arctic dated to just before extinction rates began to spike.
They now believe that the eruption of volcanoes in Siberia (known as the Siberian Traps) led to the massive combustion of carbon from underlying coal beds that smoldered after the initial blasts. Plumes of combusted coal particles, or fly ash, spread to the Canadian Arctic and settled out into marine ecosystems, where it’s known to be particularly toxic and the cause of anoxic conditions that inhibit photosynthesis. On a global level, a similar effect may have occurred as ocean conditions altered to a point that they could no longer support marine life.
The study is the first to pin the Permian extinction on burning coal as a new source of contamination, on top of the likely spike in global atmospheric greenhouse gas levels. Once source — the combustion of coal — can work on several levels to undermine the conditions that support life, indicating that the atmosphere is just one of a possible number of conditions that contribute to climate change.