56 million years ago the climate event, known as the Paleocene-Eocene Thermal Maximum (PETM), warmed the already-hot climate of the time by about 5.6° C due to

56 million years ago the climate event, known as the Paleocene-Eocene Thermal Maximum (PETM), warmed the already-hot climate of the time by about 5.6° C due to a jump in atmospheric CO2.