Researchers at Michigan University and the University of Arizona used a futuristic climate model to successfully invent, the Early Eocene Period’s extreme warming, which is considered to be directly related to the future climate of Earth.
They discovered that the warming rate improved dramatically as the concentrations of carbon dioxide rose, a finding with far-reaching consequences for the future climate of Earth. The scientists reported this in a document published in the Science Advances paper on September 18. Another observation is that the climate of the Early Eocene converted to be more 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 author Jiang Zhu. He is a postdoctoral researcher at the U-M Department of Earth and Environmental Sciences.
Image credit: National climatic data center
“It is a scary observation 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.”
The researchers determined that the substantial increase in climate sensitivity had not been seen in previous attempts to simulate the Early Eocene using similar amounts of carbon dioxide. It is likely due to an improved representation of cloud processes in the climate model they used, the Community Earth System Model version 1.2, or CESM1.2.
The findings of the model, which align with geological proof, indicate that if carbon dioxide levels rise in the atmosphere, extra CO2 increases will have an even more significant climate effect than they would have. This does not mean well for the future of our climate.
Global warming is expected to change the distribution and types of clouds in the Earth’s atmosphere, and clouds can have both warming and cooling effects on the climate. In their simulations of the Early Eocene, researchers found a reduction in cloud coverage and opacity that amplified CO2-induced warming.
The same cloud processes responsible for increased climate sensitivity in the Eocene simulations are active today, according to the researchers.
“Our findings highlight the role of small-scale cloud processes in determining large-scale climate changes and suggest an inherent increase in climate sensitivity with future warming,” said U-M paleoclimate researcher Christopher Poulsen, a co-author of the Science Advances paper.
The Early Eocene, which was roughly 48 million to 56 million years ago, was the warmest period of the past 66 million years. It began with the Paleocene-Eocene Thermal Maximum, which is known as the PETM, the most severe of several short, intensely warm events.
If we don’t restrict greenhouse-gas emissions by the completion of this century, it’s predicted that the concentration of CO2 in Earth’s atmosphere could reach 1,000 parts per million and that’s the same as the level as the early Eocene.
We remain at 415 parts per million which is the highest level ever in human history.
The Eocene Era isn’t the only one in Earth’s history that’s crucial to study to anticipate future climate change better, though. Research published last year suggests that climates like the one during the Pliocene era will become the norm as soon as 2030.
Journal Reference: Science Advances