World risks second GREAT DYING: Rising temperatures could leave sea creatures unable to breath and wipe out animals on land just like massive volcanic eruptions of 252 million years ago
- The Great Dying was caused by a series of massive volcanic eruptions in Siberia
- Warmer water couldn’t hold enough oxygen for most marine creatures to survive
- Finding has major implications for fate of today’s warming world, say scientists
- Ocean warming could reach 20 per cent of Permian period by 2100, experts say
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An episode of extreme global warming that left ocean animals unable to breathe caused the biggest mass extinction in the Earth’s history, research has shown.
The extinction event at the end of the Permian period 252 million years ago wiped out 96 per cent of all marine species and 70 per cent of land-dwelling vertebrates.
Scientists have linked what has become known as the ‘Great Dying’ with a series of massive volcanic eruptions in Siberia that filled the atmosphere with greenhouse gas.
But precisely what made the oceans so inhospitable to life has remained an unanswered question until now.
Earth could face a similar fate if predictions of runaway climate change in the modern world come true.
Breakthrough: An episode of extreme global warming that left ocean animals unable to breathe caused the biggest mass extinction in the Earth’s history, research has shown
The new study, reported in the journal Science, suggests that 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 per cent of the level experienced in the late Permian by 2100, they point out.
By the year 2300 it could reach between 35 and 50 per cent of the Great Dying extreme.
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Lead researcher Justin Penn, a doctoral student at the University of Washington, said: ‘This study highlights the potential for a mass extinction arising from a similar mechanism under anthropogenic [human caused] climate change.’
Before the Siberian eruptions created a greenhouse-gas planet, the Earth’s oceans had temperatures and oxygen levels similar to those present today.
In a series of computer simulations, the scientists raised greenhouse gases to match conditions during the Great Dying, causing surface ocean temperatures to increase by around 10C.
The model triggered dramatic changes in the oceans, which lost around 80 per cent of their oxygen.
Roughly half the ocean floor, mostly at deeper depths, became completely devoid of the life-sustaining gas.
Epic: Previously experts were undecided about whether lack of oxygen, heat stress, high acidity or poisoning chemicals wiped out life in the oceans at the end of the Permian period
The researchers studied published data on 61 modern marine species including crustaceans, fish, shellfish, corals and sharks, to see how well they could tolerate such conditions.
These findings were incorporated into the model to produce an extinction map.
‘Very few marine organisms stayed in the same habitats they were living in – it was either flee or perish,’ said co-author Dr Curtis Deutsch, also from the University of Washington.
The simulation showed that the hardest hit species were those found far from the tropics and most sensitive to oxygen loss.
Data from the fossil record confirmed that a similar extinction pattern was seen during the Great Dying.
Tropical species already adapted to warm, low-oxygen conditions were better able to find a new home elsewhere. But no such escape route existed for those adapted to cold, oxygen-rich environments.
Previously experts were undecided about whether lack of oxygen, heat stress, high acidity or poisoning chemicals wiped out life in the oceans at the end of the Permian period.
‘This is the first time that we have made a mechanistic prediction about what caused the extinction that can be directly tested with the fossil record, which then allows us to make predictions about the causes of extinction in the future,’ said Mr Penn.
WHAT WAS THE PERMIAN MASS EXTINCTION, KNOWN AS ‘THE GREAT DYING’?
Around 248 million years ago, the Permian period ended and the Triassic period started on Earth.
Marking the boundary between these two geologic eras is the Permian mass extinction, nicknamed ‘The Great Dying’.
This catastrophic event saw almost all life on Earth wiped out.
Scientists believe around 95 per cent of all marine life perished during the mass extinction, and less than a third of life on land survived the event.
In total, it is believed that 90 per cent of all life was wiped out.
All life on Earth today is descended from the roughly ten per cent of animals, plants and microbes that survived the Permian mass extinction.
Previously, it was believed a huge eruption blanketed the Earth in thick smog, blocking the sun’s rays from reaching the planet’s surface.
However, new findings suggest a massive volcanic eruption that ran for almost one million years released a huge reservoir of deadly chemicals into the atmosphere that stripped Earth of its ozone layer.
This eradicated the only protection Earth’s inhabitants had against the sun’s deadly UV rays.
This high-energy form of radiation can cause significant damage to living organisms, causing the death toll to skyrocket.
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