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Around 252 million years ago, more than 90 per cent of all life was wiped out from Earth. This mass extinction ended the Permian geological period and was known as the Great Dying. It was one of the five global catastrophic events in Earth’s history and worse than the extinction event that killed all dinosaurs 65 million years ago.

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A massive heating event has been cited as the most logical explanation for it to date. A volcanic activity in the Siberian Traps released carbon dioxide and this led to a sudden warming of the planet. The vast area was about the size of Australia and the emissions resulted in higher temperatures, acid rain and ocean acidification.

Now, according to new research published Thursday in the journal Science, a mega El Niño effect is what likely led to that mass extinction 252 million years ago. 

This one was more intense and prolonged than the one humans witness today. 

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“What we’re showing is that it was a climate-based extinction crisis. It wasn’t just the warming, it’s how the climate responded,” study co-author, Paul Wignall, a professor of paleoenvironments at the University of Leeds in the United Kingdom, said.

“If the conditions were bad but constant, life could have evolved to cope with it. But the fact is, it kept lurching from one extreme to the other over the decades.”

To understand the Great Dying, researchers built a computer model of the global climate during the close of the Permian Period. It showed that a rise in global temperatures led the El Niño events to grow in magnitude and length.

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Earth started witnessing extreme weather conditions, with mass flooding for a period of time followed by scorching droughts and so on. This caused wildfires which killed all types of species across the globe and continued for around 100,000 years.

El Niño originated in Panthalassic Ocean

El Niño is a climate pattern that originates in the Pacific and affects the entire planet. It affects wind patterns and ocean currents and typically lasts between nine and 18 months, occurring every two to seven years. However, during the warmest phases of the extinction event, it would have stretched for 10 years, Alex Farnsworth, a senior research associate at the UK’s University of Bristol and the study’s joint lead author, said.

It must have originated in the Panthalassic Ocean, which was much larger than the Pacific and so could hold more heat. This in turn made the El Niño effects much stronger and longer.

He maintains that volcanic activity also played a role but wasn't enough to cause a mass extinction of that scale. Similar incidents had happened earlier as well but never triggered a mass extinction.

“It’s volcanism that was the main culprit here, but it had a feedback mechanism on ocean dynamics that led to these much stronger El Niños starting to develop and then (the two things) play in concert,” Wignall said.

This explanation seems plausible considering extinctions started on land before they occurred in the ocean, the study said. “Whilst the oceans were initially shielded from the temperature rises, the mega-El Nino’s caused temperatures on land to exceed most species thermal tolerances at rates so rapid that they could not adapt in time,” co-lead author Yadong Sun, a researcher at China University of Geosciences in Wuhan, said in a press release.