The Paleocene-Eocene Thermal Maximum (PETM), which took place some 55.9 million years ago, is the best analogue that we currently have for understanding what might happen if greenhouse gas emissions are not curtailed soon, and according to a new study, the rate of release of carbon dioxide into the atmosphere today is 10 times as fast when compared to the PETM.
“We looked at the PETM because it is thought to be the best ancient analog for future climate change caused by fossil fuel burning,” said Lee R. Kump, professor of geosciences, Penn State, and one of the researchers on the study that has been published in the current issue of the journal Nature Geoscience.
The researchers studied a large sediment core from Spitsbergen, Norway, which was uncovered and curated by a young coal-mining geologist, Malte Jochmann.
“Deep-sea cores usually have from 10 cm to a meter (about 4 inches to 3 feet) of core corresponding to the PETM. The Spitsbergen cores have 150 meters (492 feet) of sediment for the PETM,” said Kump. “We think the Spitsbergen core is relatively complete and shows an interval of about 20,000 years for the injection of carbon dioxide during the PETM.”
From the core and by essentially running a computer model backwards, the researchers were able to set up models to find the proper amounts of greenhouse gases and atmospheric temperature that matched up with the levels of carbon rations observed in the Spitsbergen cores, providing the researchers with an idea of how much carbon was released at what rate and over how long of a period.
The outcome was a warming of from 9 to 16 degrees Fahrenheit and an acidification event in the oceans.
“Rather than the 20,000 years of the PETM which is long enough for ecological systems to adapt, carbon is now being released into the atmosphere at a rate 10 times faster,” said Kump. “It is possible that this is faster than ecosystems can adapt.”