The acidification of the Earth’s oceans, which climate scientists warn is a dangerous effect of continued carbon emissions, was behind a mass extinction event 66 million years ago, according to a new study.
Small-shelled marine organisms survived the meteorite that struck the Earth and wiped out the dinosaurs, according to researchers at the GFZ geosciences research center in Potsdam, Germany, but the subsequent sharp drop in pH levels in the ocean caused the marine life to go extinct.
“We show ocean acidification can precipitate ecological collapse,” Michael Henehan, who led the study, told The Guardian.
Researchers examined shell fossils in sediment dating back to the time period just after the meteorite struck the planet, which showed that the oceans’ pH dropped by about 0.25 units in the 100 to 1,000 years after the strike.
“In the boundary clay, we managed to capture them just limping on past the asteroid impact,” Henehan said.
But, the newspaper reported, “It was the knock-on effects of acidification and other stresses, such as the ‘nuclear winter’ that followed the impact, that finally drove these foraminifera to extinction.”
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“We have been warned,” climate campaigner Ed Matthew tweeted with a link to the research, which was published in the Proceedings of the National Academy of Sciences.
Climate change is making the oceans more acidic. This vital scientific research shows that it was an acidic ocean following the asteroid strike 65m years ago that caused 75% of ocean life to become extinct. We have been warned https://t.co/PYiE8V2CM3
— Ed Matthew (@Ed_Matthew1) October 21, 2019
Today, climate scientists warn that the continued burning of oil, gas, and coal is causing ocean acidification that, left unchecked, could cause a pH drop of 0.4 units.
If policymakers are able to help limit the warming of the globe to two degrees Celsius by ordering that fossil fuels be left in the ground and shifting to a renewable energy economy, the ocean’s pH level could drop just 0.15 units.
“If 0.25 was enough to precipitate a mass extinction, we should be worried,” Henahan told The Guardian.
As Common Dreams reported in July, MIT researchers also recently turned their attention to ocean acidification as well. The researchers released data showing that today’s carbon levels could be fast approaching a tipping point threshold that could trigger extreme ocean acidification similar to the kind that contributed to the Permian–Triassic mass extinction, which occurred about 250 million years ago.