World's first animals caused global warming
By T.K. Randall
July 3, 2018 · 43 comments
Human activities are not the only cause of climate change. Image Credit: CC BY-SA 3.0 Nobu Tamura
Climate change is not a new thing, as evidenced by global warming that occurred over 500 million years ago.
Back during the Paleozoic era, some of the first animals to have emerged in the world's oceans had begun to break down the organic material found on the seafloor, leading to a rise in carbon dioxide.
This lead to a global warming effect that lasted well over 100 million years.
"Like worms in a garden, tiny creatures on the seabed disturb, mix and recycle dead organic material - a process known as bioturbation," said Professor Tim Lenton from the University of Exeter.
"Because the effect of animals burrowing is so big, you would expect to see big changes in the environment when the whole ocean floor changes from an undisturbed state to a bioturbated state."
Scientists believe that this process may have resulted in several mass extinction events.
"When we ran our model, we were surprised by what we saw," said Dr. Benjamin Mills from the University of Leeds.
"The evolution of these small animals did indeed decrease the oxygen in the ocean and atmosphere, but also increased atmospheric carbon dioxide levels to such an extent that it caused a global warming event."
"We knew that warming occurred at this point in Earth history, but did not realise it could be driven by animals."
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