As carbon dioxide accumulates in the atmosphere, the Earth will get hotter. But exactly how much warming will result from a certain increase in CO2 is under study. The relationship between CO2 and warming, known as climate sensitivity, determines what future we should expect as CO2 levels continue to climb. New research led by the University of Washington analyzes the most recent ice age, when a large swath of North America was covered in ice, to better understand the relationship between CO2 and global temperature. It finds that while most future warming estimates remain unchanged, the absolute worst-case scenario is unlikely. The open-access study was published April 17 in Science Advances. …”This paper allows us to produce more confident predictions because it really brings down the upper end of future warming, and says that the most extreme scenario is less likely,” lead author Vince Cooper, a UW doctoral student in atmospheric sciences said.