The analysis at Reference 1 presents a method and equation that accurately calculates average global temperatures since 1895 without considering any influence from change to the level of carbon dioxide or any other greenhouse gas in the atmosphere. The coefficient of determination, R2, for that calculation is 0.8686 (all of those digits are as calculated and are shown only to reveal the tiny differences between calculated values.
There is no presumption that real-world precision is this close) which means that the equation explains 86.86% of the measured average global temperature (agt) anomalies.
This is far better than has been achieved by any Global Climate Model. The agt anomaly identified in Ref 1 as a prediction is more correctly called a calculation up to the present and a projection (for the condition of no sunspots) thereafter.
The present paper includes a determination of the contribution that added atmospheric CO2 makes to average global temperature. It is a refinement of the previous work which was presented in Ref 1. The present work produced the rather startling discovery that, although assuming no effect of added atmospheric CO2 produced an excellent correlation with measured agt, when a significant contribution from added atmospheric CO2 is
included, an excellent correlation was also produced, in fact, a tiny bit better.
Click to download "Effect of Change to Atmospheric CO2 Level on Average Global Temperature"
by Dan Pangburn