As it happens, Michael Tobis has already taken a look at another very similar construction and identified three deceptions (he kindly called “bugs”) in what is technically correct data.
- different smoothing is used on the two types of data. Temperature is presented in monthly mean whereas CO2 looks to have had the seasonal rise and fall removed. This gives the impression of a steady rise in CO2 in stark contrast to the jitters of temperature.
- the choice of vertical scale dramatically exaggerates the change in CO2. In the last hundred years, CO2 has risen 100ppm, temperature about .8 oC yet this graph puts the same .8 oC of vertical temperature scale against only 35 ppm of vertical CO2 scale, a factor of three times inflation.
- a very short time frame eliminates 90% of the instrumental record and leaves us with much too little temperature data from which to determine a significant trend. Climate is defined as the 30 yr statistics of weather, you can not see a trend in it from 15 years of data.
Michael kindly provides an improved graph with none of those issues.
40 years of data is enough to discern the signal from the noise, the vertical scale of the graph is fair to both data sets and the smoothing is monthly for both. The lie SPPI is trying to pedal, that CO2 and temperature do not correlate, has vanished along with the emperor’s clothes.
Robert Grumbine has an educational post “Does CO2 over the modern instrumental record correlate with Temperature?” Yes, it does.