New geological research from Utah suggests the end-Permian extinction was mainly caused by burning coal, ignited by magma
Fossil of a Galesaurus, a cynodont that lived during the Permian period. Photograph: Iziko Museum of Natural History |
Scientists have proposed a number of possible culprits responsible for this mass extinction, including an asteroid impact, mercury poisoning, a collapse of the ozone layer, and acid rain. Heavy volcanic activity in Siberia was suspected to play a key role in the end-Permian event.
Recently, geologist Dr Benjamin Burger identified a rock layer in Utah that he believed might have formed during the Permian and subsequent Triassic period that could shed light on the cause of the Great Dying.
Sheep Creek Valley, Utah. Photograph: Benjamin Burger |
Dr Burger’s ‘Rocks of Utah’ episode documenting his investigation of the Permian-Triassic Boundary geologic samples.
Earth turned into a toxic hellscape
Burger’s samples painted a grim picture of Earth’s
environment at the end of the Permian period. A sharp drop in calcium
carbonate levels indicated that the oceans had become acidic. A similar
decline in organic content matched up with the immense loss of life in
the oceans during this period. The presence of pyrite pointed to an
anoxic ocean (without oxygen), meaning the oceans were effectively one
massive dead zone.
The culprit: burning coal
Levels of various metals in the rock samples were critical in identifying the culprit of this mass extinction event. As in end-Permian samples collected from other locations around the world, Burger didn’t find the kinds of rare metals that are associated with asteroid impacts. There simply isn’t evidence that an asteroid struck at the right time to cause the Great Dying.
However, Burger did find high levels of mercury and lead in his samples, coinciding with the end of the Permian period. Mercury has also been identified in end-Permian samples from other sites. Lead and mercury aren’t associated with volcanic ash, but they are a byproduct of burning coal. Burger also identified a shift from heavier carbon-13 to lighter carbon-12; the latter results from burning fossil fuels.
The Permian was the end of the Carboniferous period, which means “coal-bearing.” Many large coal deposits were created in the Carboniferous, including in Asia. Previous research has shown that the Permian mass extinction event didn’t coincide with the start of the Siberian volcanic eruptions and lava flows, but rather 300,000 years later. That’s when the lava began to inject as sheets of magma underground, where Burger’s data suggests it ignited coal deposits.
The coal ignition triggered the series of events that led to Earth’s worst mass extinction. Its sulfur emissions created the acid rain that killed forests. Its carbon emissions acidified the oceans and warmed the planet, killing most marine life. The dead bodies fed bacteria that produced toxic hydrogen sulfide gas, which in turn killed off more species. The warming of the oceans produced a large methane release, which accelerated global warming faster yet. As Burger put it,
Things went from bad to worse, and you can now begin to understand how life nearly died out. Global warming, acid oceans, anoxia, not to mention a toxic atmosphere. We are lucky to be alive at all!Eerie similarities to today
We’ve had less success in tackling carbon dioxide pollution, which continues to rise. As a result, the oceans are becoming increasingly acidic, and temperatures increasingly hot. Scientists today also worry about potentially large releases of methane from the ocean floor and Arctic.
These are some of the similarities between the climate change that nearly wiped out life on Earth 252 million years ago and the climate change today. Both appear to have largely been caused by burning coal. A 2011 study found that over the past 500 years, species are now going extinct at least as fast as they did during the five previous mass extinction events.
It’s enough to make you think; maybe coal isn’t so beautiful and clean after all.
Links
- The Terrifying Phenomenon That Is Pushing Species Towards Extinction
- 'A National Disgrace': Australia's Extinction Crisis Is Unfolding In Plain Sight
- This Is How Your World Could End
- Climate Change Could Wipe Out A Third Of Parasite Species, Study Finds
- When Life on Earth Was Nearly Extinguished
- ‘The Models Are Too Conservative’: Paleontologist Peter Ward on What Past Mass Extinctions Can Teach Us About Climate Change Today
- Burning Fossil Fuels Almost Ended All Life On Earth
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