The biggest mass extinction on Earth happened 252 million years ago because of massive volcanic eruptions that caused catastrophic climate change. As a result, the vast majority of animal species were killed and the planet entered the Age of Dinosaurs. The event led to as much as 97 per cent of species disappearing forever. But, according to researchers of the Chicago Field Museum, the mass extinction took 10 times longer on land than it did on water.
The researchers, who studied fossils of 588 animals alive towards the end of the mass extinction in today’s Karoo Basin in South Africa, found extinctions happened rapidly in the oceans as the volcanic eruptions poured higher levels of carbon dioxide and greenhouse gasses into them. However, life on land underwent a more drawn-out period of extinctions as the changes were slower.
Lead author Pia Viglietti said the researchers found that the marine extinction “may actually be a punctuation” to a longer event on land. To learn what happened to life on land, the researchers examined fossils from 588 four-legged fossil animals that lived at the time of the Permian mass extinction, also known as the period of the Great Dying.
One of the species that helped the scientists reveal the patterns of extinction was Lystrosaurus, a herbivorous mammal that thrived when most other life was struggling. Researchers say it’s not clear exactly why the mass extinction event was slow on land. One possible answeris that climate change on Earth added up over time.
The oceans can absorb a lot of carbon dioxide or rise in temperature, they explained, adding that they focussed on marine extinction because there is a more complete fossil record of life underwater to study. The fossil record gives some idea of what massive biodiversity crises are like. The scientists say their findings can help us understand today’s climate change and habitat destruction events.
The findings have been published in the journal Proceedings of the National Academy of Sciences and can be accessedhere.