Extreme global warming that left ocean animals unable to breathe triggered Earth’s biggest ever mass extinction, according to new research. 
Around 95% of marine species and 70% of life on land was wiped out in the event often referred to as “The Great Dying”, which struck 252 million years ago. Previous studies have linked it with a series of massive volcanic eruptions in Siberia that filled the atmosphere with greenhouse gases.
But precisely what made the oceans so inhospitable to life has remained an unanswered question until now.
The new study, reported in ‘Science’, suggests as temperatures soared, the warmer water could not hold enough oxygen for most marine creatures to survive.
Lessons from the ‘Great Dying’ have major implications for the fate of today’s warming world, say the US scientists. If greenhouse gas emissions continue unchecked, ocean warming could reach 20% of the level experienced in the late Permian by 2100, they point out.
By 2300, it could reach between 35 and 50% of the Great Dying extreme. “This study highlights the potential for a mass extinction arising from a similar mechanism under anthropogenic [human caused] climate change,” said lead researcher Justin Penn.
Before the Siberian eruptions created a greenhousegas planet, the Earth’s oceans had temperatures and oxygen levels similar to those today.
Data from the fossil record confirmed a similar extinction pattern was seen during ‘The Great Dying’.
Tropical species already adapted to warm, low-oxygen conditions were able to find a new home. But no such escape route existed for those adapted to cold, oxygen-rich environments.