Researchers at the University of Pennsylvania examined PETM cores taken off the coast of Maryland. They determined their date using an astronomical technique that calibrates to a time scale related to astronomical phenomena such as Milankovitch cycles. These cycles are periodic changes in three parameters of Earth’s orbit: eccentricity, precession, and ecliptic inclination. The timing of these changes varies, but occasionally they combine and are believed to be the dominant paleoclimate mechanism. Perhaps it was their confluence that caused the ice ages.

From a recent study at Penn State, we learned that changes in the eccentricity and precession of Earth’s orbit favor the emergence of higher temperatures. “This orbital trigger could lead to the release of carbon, causing global warming known as PETM. “We make this theory against the more popular interpretation that the PETM was triggered by violent volcanism,” says Professor Lee Kump.

The analyzes also showed that the initial phase of the warming PETM lasted about 6,000 years. years This value is within current estimates of hundreds to tens of thousands of years. Determining that is important for us to understand how fast global warming occurred during that time. During this 6,000-year period, 10,000 were emitted into the atmosphere. Gigatons of carbon in the form of CO2 and methane, that’s 1.5 gigatons of annual emissions. The average global temperature has increased by about 6 degrees.

“At that time, the level of carbon emissions into the atmosphere was an order of magnitude lower than today. We emit 5 to 10 times more carbon a year than the event that left its permanent imprint on our planet 56 million years ago, Kump adds.

Source:

https://www.nature.com/articles/s41467-022-33390-x