UPDATE: This post mistook the upper curve for CO2 in the figure 4 from Callendar’s paper, cropped by the Guy Callendar twitter account. It is actually 5yr smoothed temperature, as pointed out by commenter ‘berniel’ in comments. So the apparent ~2.5yr lag between the upper and lower curve is due to the smoothing of the temperature data. This doesn’t change the fact that CO2 lags temperature at all timescales, but does invalidate the analysis in this article.
Back in 1938, Guy Callendar wrote a paper “The artificial production of CO2 & its influence on temperature”. In it is a figure showing how they both rose in the early C20th. MET office PR man Richard Betts retweeted the Guy Callendar twitter account this morning.
My 1938 paper demonstrated that the Earth had warmed over the previous 50 years & that CO2 was partly responsible pic.twitter.com/AaDoA2oJLD
— Guy Callendar (@GuyCallendar) February 16, 2015
Unlike more modern misrepresentations given by climate scientists, which spuriously splice the instrumental record from 1950 onto ice core records (with a large temporal mismatch), Callendar uses actual empirical measurements of airborne CO2. His data reveals something sceptics have frequently pointed up: Temperature changes lead CO2 changes. Check my annotation to Callendar’s plot below the break.
Note how temperatures start to rise around 1893, but CO2 doesn’t start to rise until a couple of years later. Same thing when temperature starts to rise around 1907. CO2 starts to rise several years later around 1911. Same thing around 1901 when temperature starts to fall. CO2 doesn’t start to fall for several years.
Callendar labels the upper curve “CO2 EFFECT”
Maybe he should have labelled the lower curve “TEMPERATURE CAUSE”
In any case, Callendar’s conclusions are part of the reason he is only rarely wheeled out as a ‘father of AGW theory’. As Jaime summarises in comments:
“small temperature increases” to be expected from the combustion of fossil fuels would be “beneficial to mankind”, aid the growth of plants, extend the northern margin of cultivation and indefinitely “delay the return of deadly glaciers”