The attached work should interest you. It shows a rather simple procedure to accurately (standard deviation of differences between calculated and measured temperature anomalies = 0.0634 C) calculate the average global temperature history of the entire 20th century and to the present time using only the time-integral of sunspot count and an assumption of Pacific Decadal Oscillation (PDO) up trend or down trend duration of 32 years and a PDO temperature range of 0.45 C degrees. It assumes no influence from atmospheric carbon dioxide and corroborates previous work.
Dan Pangburn
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