New research shines a light on two ancient oceanic catastrophes — and hints at apocalyptic futures.
The Permian-Triassic extinction wiped out more animal life in the history of the Earth than any other event. It took place more than 250 million years ago, before the rise of the dinosaurs, was triggered by an epic volcanic eruption in Siberia that spewed greenhouse gases into the atmosphere and raised the planet’s temperature, killing most life in the ocean and land.
Scientists are still working to understand how the eruption led a complete breakdown of the planet’s ecosystem. But a new paper, published in the Proceedings of the National Academy of Sciences, might offer a partial explanation: the global warming and acid rain the eruption caused, according to the researchers, sped up the breakdown of volcanic ash and basalt into harmful chemicals and washed them into the ocean, where they blocked sunlight and acidified the water — leading to the extinction of up to 96 percent of ocean life.
Another paper published in the same journal looks at comparatively recent history — the transitions between chilly and mild climate states known as “Heinrich Stadials,” during which Greenland spits new icebergs into the North Atlantic Ocean.
Those influxes of icebergs, according to a team of Brazilian and American researchers who looked at the chemical composition of stalagmites to estimate ancient rainfalls, was associated with supercharged monsoons with higher precipitation than usual — a result, they suspect of the huge influx of the icebergs’ huge release of melting seawater.