A massive release of greenhouse gases, likely triggered by volcanic activity, caused a period of extreme global warming known as the Paleocene-Eocene Thermal Maximum (PETM) about 56 million years ago.
A massive release of greenhouse gases, likely triggered by volcanic activity, caused a period of extreme global warming known as the Paleocene-Eocene Thermal Maximum (PETM) about 56 million years ago. A new study now confirms that the PETM was preceded by a smaller episode of warming and ocean acidification caused by a shorter burst of carbon emissions.
The new findings, published March 16 in Science Advances, indicate that the amount of carbon released into the atmosphere during this precursor event was about the same as the current cumulative carbon emissions from the burning of fossil fuels and other human activities. As a result, the short-lived precursor event represents what might happen if current emissions can be shut down quickly, while the much more extreme global warming of the PETM shows the consequences of continuing to release carbon into the atmosphere at the current rate.
“It was a short-lived burp of carbon equivalent to what we’ve already released from anthropogenic emissions,” said coauthor James Zachos, professor of Earth and planetary sciences and Ida Benson Lynn Chair of Ocean Health at UC Santa Cruz. “If we turned off emissions today, that carbon would eventually get mixed into the deep sea and its signal would disappear, because the deep-sea reservoir is so huge.”
This process would take hundreds of years—a long time by human standards, but short compared to the tens of thousands of years it took for Earth’s climate system to recover from the more extreme PETM.
Read more at: University of California - Santa Cruz
Marine sediments contain the microscopic shells of organisms called foraminifera that lived in the surface waters. The chemical composition of these shells records the environmental conditions in which they formed. (Photo Credit: Marci Robinson/USGS)
