“Great Dying” is Lurking

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% of all marine species and 70% 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.

Earth could face a similar fate if predictions of runaway climate change in the modern world come true.

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% of the level experienced in the late Permian by 2100, they point out.

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% of their oxygen.

The researchers studied published data on 61 modern marine species including crustaceans, fish, shellfish, and corals, to see how well they could tolerate such conditions.

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.

  • Source: Daily Mail

 

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