NASA predicts 8 degrees of warming in the US by 2100

WUWT
"The interesting part is that they chose the years 1970 to 1999 to calibrate the models. Calibrate them to what? Did they assume the co2 rise during that period was the sole factor driving temperatures across the US and calibrate the rise in temperature based on that correspondence? Did they quantify the role of pollution / aerosol reduction during that period? Changes in multi-decadal oscillations on regional climate? Changes in regional humidity? Was it a global or local model calibration? Why did they end the calibration period at 1999? Why start at 1970? With more data available and no contrasting calibrations provided this looks like a search for a high end projection. Perhaps explanations are provided in the research. Questions abound."