Fifty-six million years ago, Earth endured a heat wave that lasted 170,000 years. The event, known as the Paleocene-Eocene Thermal Maximum (PETM), ushered in a wave of evolutionary shifts. New research published in Nature Geoscience suggests a massive belch of carbon from deep below the northern Atlantic Ocean could have played a key role.
“[The PETM] was one of the most extreme global warming events in the recent geologic past,” said Thomas Gernon, a geologist at the University of Southampton. The warm spell raised sea surface temperatures roughly 5°C, acidified the oceans, and wiped out some deep-sea creatures.
What makes the PETM so unusual is its rapid onset, said James Zachos, a paleoceanographer at the University of California, Santa Cruz, who researches the event but was not involved in the new study. “The rate of [carbon] emissions had to be really high—almost the same order of magnitude as fossil fuel emissions.” That suggests multiple sources of carbon, he said.
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Jennifer Schmidt, Eos, 27 July 2022. Full article.
