The so-called Permian Extinction or Great Dying was the largest cataclysm that affected life on our Earth by 4.5 billion years. In total, there have been five major extinction events in the past 450-600 million years, including an asteroid attack 66 million years ago. But the Permian event takes the crown, and until recently it wasn’t clear what caused the mass extinction.
The extinction occurred about 250 million years ago, at the end of the Permian period.
Scientists have proposed multiple scenarios: volcanic eruptions, asteroid attacks or climate change.
One theory, in particular, proposed that an eruption of the Siberian Traps – a volcanic region in northern Russia – was responsible for the disruption of the planet’s climate.
Researchers from Japan, the United States and China now believe the mass extinction was driven by volcanic activity and climate change, after all.
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The researchers presented their findings in the peer-reviewed journal Geology.
The study focused on two specific eruptive events: one that has so far escaped scientists and one responsible for killing swaths of marine and terrestrial life.
According to principal investigator Kunio Kaiho, a professor emeritus at Tohoku University in Japan, the study examined rock samples from southern China and Italy.
The researchers analyzed the organic compounds and mercury contained in the samples and found that the rocks were marked with two coronene-mercury enrichments.
These chemical compounds have been linked to an initial ecological disturbance and subsequent mass extinction.
Professor Kaiho said: ‘We believe this is the product of large volcanic eruptions because the coronene anomaly was formed by abnormal high-temperature combustion.
“High temperature magma or asteroid / comet impacts can make such coronene enrichment.”
Coronene is a condensed polycyclic aromatic hydrocarbon (PAH), which requires more energy to transform than other PAHs.
This suggests that high-temperature volcanism was responsible for hydrocarbon enrichment in sedimentary rocks.
The research, led by Dr Hana Jurikova of GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, found that volcanic eruptions filled the skies with large amounts of carbon dioxide, triggering extreme global warming and acidification of the oceans.
Dr Jurikova said: ‘We are dealing with a cascading catastrophe where the increase of carbon dioxide in the atmosphere triggered a chain of events that subsequently extinguished almost all life in the seas.
“Ancient volcanic eruptions of this type are not directly comparable to anthropogenic carbon emissions, and indeed all modern fossil fuel reserves are too insufficient to release as much carbon dioxide in hundreds of years, let alone thousands of years as has been released. 252 million years ago.
“But it is surprising that humanity’s carbon dioxide emission rate is currently 14 times higher than the annual emission rate at the time that marked the largest biological catastrophe in Earth’s history.”