Scientists found that the evolution of world’s first animals caused global warming, more than 500 million years ago.
The research, published in Nature Communications, is from the Universities of Exeter, Leeds and Antwerp, and the Vrije Universiteit Brussel.
Some 520-540 million years ago, animal life evolved in the ocean and began breaking down organic material on the seafloor, leading to more carbon dioxide and less oxygen in the atmosphere.
In the 100 million years that followed, conditions for these earliest animals became much harsher, as ocean oxygen levels fell and carbon dioxide caused global warming.
Professor Tim Lenton, from the University of Exeter, explains:
“Like worms in a garden, tiny creatures on the seabed disturb, mix and recycle dead organic material – a process known as bioturbation.
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.”
Professor Filip Meysman, from the University of Antwerp, said:
“We did indeed see a decrease in oxygen levels in the ocean around 520 million years ago.
But evidence from the rock record showed sediment was only a little disturbed.”
source University of Exeter