Taking the equations from
Radiative forcing - Wikipedia, the free encyclopedia
dF=5.35*Ln(C/Co)
dT = 0.8*dF
dF = change in forcing
C = current concentration CO2 (I'm using 2005) 315ppm
Co = orriginal concentration CO2 (I'm using 1958) 380ppm
dT = change in temperature (using 1958 to 2005) 0.64C
I am hoping they made an actual physical measurement and didn't just run that through a model and call it good. This shows that for a doubling of CO2 we get a change of forcing of 3.39w/m^2, which is different from the IPCC value of 3.7w/m^2.
Using the "measured" value changes the equation to
dF = 4.89 * Ln(C/Co)
Filling in for CO2
dF = 4.89*LN(380/315) = .91w/m^2 for the measured 1958-2005 change in CO2.
That should give us a change in temperature of
dT = .8*0.91 = 0.73C which is 0.09C higher than observed.
Correcting for observed gives us a climate sensitivity of 0.696
Now we can calculate for future warming.
Forcasting a rise to 600pmm.
dF = 4.89*Ln(600/315) = 3.15w/m^2
dT = .696*3.15 = 2.19C
That is assuming all warming is due to CO2 with no influence from the sun.