Professor Chris Poulsen from Department of Earth and Environmental Sciences said: “Some of the newest models used to make future predictions may be too sensitive to increases in atmospheric carbon dioxide and thus predict too much warming.”
Professor Poulsen and two of his colleagues used the CESM2 model to simulate temperatures during a period known as the Early Eocene 50 million years ago.
Fossil evidence from the Early Eocene suggests rainforests were thriving across the tropical regions of the New World.
However, the CESM2 model predicted land temperatures at the time exceeded 55C.
The temperatures appear to contradict the fossil record because photosynthesis slows down at temperatures above 40C.