Calculations by PLASS (1956) indicate that a 10% increase in atmospheric carbon

dioxide would increase the average temperature by 0.36° C. But, amplifying or feed-back processes may exist such that a slight change in the character of the back radiation might have a more pronounced effect. Possible examples are a decrease in albedo of the earth due to melting of ice caps or a rise in water vapor content of the atmosphere (with accompanying increased infrared absorption near the surface) due to increased evaporation with rising temperature.