Washington: The rate at which the planet warms in response to the ongoing buildup of heat-trapping carbon dioxide gas may increase in the future, according to simulations of a comparable warm period over 50 million years ago.
Researchers at the University of Michigan and the University of Arizona in the US used a climate model to successfully simulate — for the first time —the extreme warming of the Early Eocene Period, which is considered an analogue for Earth’s future climate.
The study, published in the journal Science Advances, found that the rate of warming increased dramatically as carbon dioxide levels rose, a finding with far-reaching implications for Earth’s future climate. Another way of stating this result is that the climate of the Early Eocene became increasingly sensitive to additional carbon dioxide as the planet warmed.
“We were surprised that the climate sensitivity increased as much as it did with increasing carbon dioxide levels,” said Jiang Zhu, a postdoctoral researcher at the University of Michigan. “It is a scary finding because it indicates that the temperature response to an increase in carbon dioxide in the future might be larger than the response to the same increase in CO2 now. This is not good news for us,” Zhu said.
The researchers determined that the large increase in climate sensitivity they observed — which had not been seen in previous attempts to simulate the Early Eocene using similar amounts of carbon dioxide — is likely due to an improved representation of cloud processes in the climate model they used.