Saturday, February 25, 2017

Temperature vs Log(CO2)

In an argument discussion on a post from earlier this month, it's suggested to plot temperature vs log2(CO2). Here's that plot:

That's a pretty good linear fit.

(Plotting against log2(CO2/CO21850) shows time in units of CO2-doubling since 1850.)

Data sources:
CDIAC: CO2, 1832-1978
Mauna Loa: CO2, 1959-2016
HadCRUT 4.5: GMST anomalies, 1850-2016

1 comment:

JoeT said...

Thanks for putting this up David. I see you get 2C/doubling. I used Berkeley Earth, Keeling and Law Dome C dating back to 1850 and got 2.2C. As I'm sure you know, you don't even need to divide by log2[CO2_1850] since that only affects the y-intercept and not the slope. The other thing you can see from this is that if you restricted the time interval to say, 1970 to today, the slope would be higher and the fit would be better. The fit isn't as good earlier in time because natural variability played a stronger role. But, my attitude is to use all the data available just to see how far back you might expect feedbacks to kick in. As we know from the works of Jevrejeva, as well as Church, sea level rise dates back to at least the mid 19th century.