This week an interesting paper was published in Geophysical Research Letters by climate modelers at the National Center for Atmospheric Research. They estimated future temperature changes if the atmospheric concentration of carbon dioxide (CO2) were held constant at current levels (well, actually 2000 levels). The results are shown in Figure 1.
Figure 1. Global average temperature change projected from 16 different climate models for the 21st century if atmospheric CO2 levels are held constant at the year 2000 levels.