According to an international team of scientists, changes in Earth’s orbit that contributed to warmer conditions may have triggered rapid global warming 56 million years ago, which is considered analogous to today’s climate change.
“The Paleocene-Eocene thermal maximum is the best we have in the geological record for something similar to what we’re experiencing now, and we may encounter climate change in the future,” said Lee Kump, professor of earth sciences at the University of Pennsylvania. . “There is a lot of interest in better deciphering this story, and our work is addressing important questions about what caused this event and the level of carbon emissions.”
The scientists analyzed core samples from the well-preserved PETM record near the Maryland coast using astrochronology, a technique for dating sediments based on orbital patterns that occurred over tens to hundreds of thousands of years, known as Milankovitch cycles.
They found that the shape of Earth’s orbit (eccentricity) and fluctuations in its rotation (precession) contributed to warmer conditions at the start of the PETM, and that these orbital configurations together may have played a role in triggering the event.
“An orbital trigger may have produced a carbon release that caused several degrees of global warming during the PETM, in contrast to the now more popular interpretation that massive volcanism released carbon and triggered the event,” said Kump. Dean of the Faculty of Earth and Mining Sciences.
Findings published in the journal Nature Communication, also showed that the beginning of PETM took about 6000 years. Previous estimates ranged from a few years to tens of thousands of years. According to scientists, time is important in understanding the amount of carbon released into the atmosphere.
“This work allows us to refine our carbon cycle models to better understand how the planet responds to carbon inputs at these timescales and to narrow down the carbon source possibilities that cause PETM,” said Associate Professor Minsong Lee. . He is a former assistant professor of earth sciences at Peking University’s School of Earth and Space Sciences and Penn State, who is the study’s lead author.
Source: Port Altele
