Not very unsurprisingly. A new paper published in the Climate of the Past Open Access Journal of the European Geosciences Union shows that there is up to a 32 degree variance in the effect of CO2. Yep, that's real precise!
CP - Abstract - Model-dependence of the CO2 threshold for melting the hard Snowball Earth
Here is a blog that runs through the numbers....
Three climate models compared for global temperature claimed to result from 0.2 bar CO2 atmospheric level:
1. Hu et al finds 268K = -5.15C = 22.73F
2. Pierrehumbert et al finds 255K = -18.15C = -.67F
3. Le Hir et al finds (for 50% less CO2 or 0.1 bar) 270K+3K (temp increase claimed for doubled CO2 per IPCC) = 273K = -.15C = 31.73F
THE HOCKEY SCHTICK: Climate Models Differ on CO2 Warming Effect by over 32°F
CP - Abstract - Model-dependence of the CO2 threshold for melting the hard Snowball Earth
Here is a blog that runs through the numbers....
Three climate models compared for global temperature claimed to result from 0.2 bar CO2 atmospheric level:
1. Hu et al finds 268K = -5.15C = 22.73F
2. Pierrehumbert et al finds 255K = -18.15C = -.67F
3. Le Hir et al finds (for 50% less CO2 or 0.1 bar) 270K+3K (temp increase claimed for doubled CO2 per IPCC) = 273K = -.15C = 31.73F
THE HOCKEY SCHTICK: Climate Models Differ on CO2 Warming Effect by over 32°F