An Ancient Carbon Mystery
Mark Pagani, Ken Caldeira, David Archer, & James C. Zachos
An investigation of the cause of a massive global warming event 55 million years ago.
About 55 million years ago, Earth experienced a period of global warming that lasted ~170,000 years (1). This climate event—the Paleocene-Eocene Thermal Maximum (PETM)—may be the best ancient analog for future increases in atmospheric CO2. But how well do we understand this event?