Past greenhouse warming events provide clues to what the future may hold

BOSTON, MA–If carbon dioxide emissions from the burning of fossil fuels continue on a “business-as-usual” trajectory, humans will have added about 5 trillion metric tons of carbon to the atmosphere by the year 2400. A similarly massive release of carbon accompanied an extreme period of global warming 55 million years ago known as the Paleocene-Eocene Thermal Maximum (PETM).

Scientists studying the PETM are piecing together an increasingly detailed picture of its causes and consequences. Their findings describe what may be the best analog in the geologic record for the global changes likely to result from continued carbon dioxide emissions from human activities, according to James Zachos, professor of Earth and planetary sciences at the University of California, Santa Cruz.

“All the evidence points to a massive release of carbon at the PETM, and if you compare it with the projections for anthropogenic carbon emissions, it’s roughly the same amount of carbon,” Zachos said. “The difference is the rate at which it was released–we’re on track to do in a few hundred years what may have taken a few thousand years back then.”

EurekAlert