ESS101C
Prof. Jin-Yi Yu
A 4xCO2 World (50-100 years from now)
qThe 4xCo2 world that may come into existence between 2200 and 2300 would be slowly moving toward condition that exist 50 or more million years ago, when little or no glacial or sea ice was present on Earth, and forests  grew in the higher latitudes of the Arctic.
(from Earth’s Climate: Past and Future)