The scientists who revealed what caused the “greatest crisis in the history of life of Earth”, have called for immediate action to halt the further warming of the planet through human caused climate change.
Oceanographers based in Seattle said the largest mass extinction in the planet’s history – what has been termed the “great dying” – was caused by extreme global warming that saw ocean temperatures rise by as much as 10C around 252m years ago.
The scientists said this resulted in the seas losing as much as 80 per cent of their oxygen. As much as 95 per cent of marine species, and 70 per cent of life on the land, perished as a result.
In an interview with The Independent in their offices at the University of Washington, associate professor Curtis Deutsch and co-author Justin Penn, said the reaction to their paper in Science had been a mixture of excitement and fear – excitement at the discovery and fear of the prescient dangers if people did not act.
“I think this work has identified the leading factor in what led to the largest crisis in the history of life on earth,” said Mr Penn, a doctoral student, asked how he hoped policy makers would respond to the discovery.
Mr Deutsch said the similarities between today and the period when the mass extinction took place were striking, but said society could decide how to act.
“The response to marine ecosystems to climate change can only by countered by slowing the warming,” he said.
“There is no way we can really pull the heat out the ocean or put the oxygen back in…Once that genie is out of the bottle, that’s it.”
“The hopeful message is that despite doing do, it also identifies the solution to that problem – which is the emission of CO2 into the atmosphere. So my hope is we decide to do something about it.”
The scientists based their discovery about the Permian period on computer modelling and calculations that took months. They also made use of information provided by chemical changes in the fossils of eel-like creatures more than 250m years old to show the extent of temperature change.
It had previously been known the mass extinction was triggered after a succession of huge volcanic eruptions in what is now Siberia. While loss of life was linked to a surge in the release of greenhouse gases, it was not previously understood what made the oceans so inimical to life.
“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,” Mr Penn wrote of their discovery, pointing out that the situation they examined 250m years ago, with the presence of increased levels of greenhouse gases and warming oceans, was similar to today.
“Under a business-as-usual emissions scenarios, by 2100 warming in the upper ocean will have approached 20 percent of warming in the late Permian, and by the year 2300 it will reach between 35 and 50 per cent. This study highlights the potential for a mass extinction arising from a similar mechanism under anthropogenic climate change.”
The scientists’ discovery comes as a succession of experts raise warning sounds about the imminent threat presented by climate change, something Donald Trump has called a hoax.
Earlier this year, the UN’s climate science body, the the Intergovernmental Panel on Climate Change (IPCC), said there was barely a dozen years to make massive changes to global energy infrastructure to limit global warming to moderate levels. “There is no documented historic precedent,” the IPPC said.
A report by the US government issued last month said climate change is already having devastating effects, and could cost the economy 10 per cent of GDP by the end of the century. Mr Trump, who withdrew the US from the Paris Accord in one of his first actions as president, said he did not believe the report’s conclusions.