Extinction risk to plant biodiversity may occur at lower levels of atmospheric CO2 than previously considered

PhysOrg.com: Scientists have traced a sudden collapse in plant biodiversity in ancient Greenland, some 200 million years ago, to a relatively small rise in atmospheric carbon dioxide which caused a rise in the Earth’s temperature. According to the findings published in the leading journal Science, the current estimated levels of atmospheric carbon dioxide which are thought to lead to sudden biodiversity loss may have to be revised downwards.

However, the scientists from University College Dublin, The Smithsonian Institute in Washington DC and Oxford University, have cautioned that their study findings may not have accounted for additional atmospheric gases such as sulphur dioxide which may have emerged from extensive volcanic emissions at the time to also play a role in driving the rise in the Earth’s temperature.

“Examining the 200 million year old fossil leaves from East Greenland, we discovered that the ancient biodiversity crash happened at atmospheric greenhouse gas levels of approximately 900 parts per million,” said Dr Jenny McElwain from the UCD School of Biology and Environmental Science at University College Dublin, Ireland, the lead researcher on the project….

North of Greenland's Kaiser Franz Josef Fjord, near Stensjö Bjerg, shot by Erik, Wikimedia Commons, under the Creative Commons Attribution-ShareAlike 3.0 license.