Burning coal may have caused Earth's worst mass extinction
New geological research from Utah suggests that the late Permian extinction was caused primarily by burning coal, inflamed by magma.
So far, Earth has gone through five mass extinction events (scientists are concerned we're on track to unleash a sixth), with the deadliest one occurring 252 million years ago at the end of the Permian geologic period. In this event, coined "The Great Dying", more than 90% of marine species and 70% of terrestrial vertebrate species became extinct. It took about 10 million years of life on Earth to recover from this catastrophic event.
Scientists have proposed a number of possible culprits responsible for this mass extinction, including an asteroid impact, mercury poisoning, the collapse of the ozone layer, and acid rain. High volcanic activity in Siberia is suspected to play a key role in the end-Permian event.
Recently, geologist Dr. Benjamin Burger identified a layer of rock in Utah that he believed could have formed during the Permian and subsequent Triassic period that could shed light on the cause of the Great Death.
During the Permian, the Earth's continents were still combined as a single Pangea, and present-day Utah was on the west coast of the supercontinent. The extreme Permian samples have been collected from rock layers in Asia, near volcanic eruptions, but Utah was on the other side of Pangea. The Burger samples could provide a unique perspective of what was happening on the other side of the world from the eruptions. Burger collected and analyzed samples of the rock layer and documented the entire process in a fascinating video:
Dr. Burger's "Utah Rocks" episode documents his investigation of geological samples from the Permian-Triassic boundary.
Earth turned into a toxic hell
Burger samples painted a bleak picture of Earth's environment at the end of the Permian period. A sharp drop in calcium carbonate levels indicated that the oceans had turned acidic. A similar decrease in organic content coincided 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 a massive dead zone.
The bacteria ate up the excess supply of corpses, producing hydrogen sulfide gas, creating a toxic atmosphere. Hydrogen sulfide oxidizes in the atmosphere to form sulfur dioxide, creating acid rain, which killed much of the plant life on Earth. Elevated levels of barium in the samples are likely to have been transported from the deep ocean by a massive release of methane.
Terrible similarities to today
Scientists are seeing many of the same signs of dangerously rapid climate change today. There is more lighter carbon-12 in the atmosphere because the increase in carbon levels in the atmosphere is entirely due to humans burning fossil fuels. There are a growing number of dead zones in the oceans.
We have had little success in fighting carbon dioxide pollution, which continues to increase. As a result, the oceans become increasingly acidic and the temperatures increasingly hot. Today's scientists are also concerned about potentially large methane releases from the ocean floor and the Arctic.
These are some of the similarities between climate change that nearly wiped out life on Earth 252 million years ago and climate change today. Both appear to have been caused in large part by the burning of coal. A 2011 study found that in the past 500 years, species are going extinct at least as fast as they did during the previous five mass extinction events.
It's enough to make you think.
Original article (in English)