Global warming of the future is projected by ancient carbon emissions

Mark Pagani Click here for more information.

New Haven, Conn. -- Global warming 55 million years ago suggests a high climate sensitivity to carbon dioxide, according to research led by Mark Pagani, associate professor of geology and geophysics at Yale and published in the December 8 issue of Science.

For some years, scientists have known that a massive release of carbon into the atmosphere caused the ancient global warming event known as the Paleocene-Eocene Thermal Maximum (PETM) that began about 55 million years ago. The geologic record shows that the resulting greenhouse effect heated the planet as a whole by about 9° F (5° C), in less than 10,000 years.

That temperature increase lasted about 170,000 years, altered the world’s rainfall patterns, made the oceans acidic, affected plant and animal life in the seas and on land, and spawned the rise of our modern primate ancestors.

"The PETM is a stunning example of carbon dioxide-induced global warming and stands in contrast to critics who argue that the Earth’s temperature is insensitive to increases in carbon dioxide," said Pagani. "Not only did the Earth warm by at least 9°F (5°C), but it did so during a time when Earth’s average temperature was already 9°F warmer than today."