Paleocene–Eocene thermal maximum

Global warming about 55 million years ago

The Paleocene–Eocene thermal maximum (PETM), alternatively Eocene thermal maximum 1 (ETM1) and formerly known as the Initial Eocene or Late Paleocene thermal maximum, was a geologically brief time interval characterized by a 5–8 °C (9–14 °F) global average temperature rise and massive input of carbon into the ocean and atmosphere. The event began, now formally codified, at the precise time boundary between the Paleocene and Eocene geological epochs. The PETM lasted about 200,000 years, and occurred about 56 million years ago.

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