Two primary drivers of average global temperature have been identified. A simple equation, using only them, very accurately explains the reported up and down measurements since before 1900. The coefficient of determination, R2 0.9 (correlation coefficient = 0.95). The equation provides credible estimates back to the low temperatures of the Little Ice Age (1610). The current trend is down. [URL=http://agwunveiled.blogspot.com]]]http://agwunveiled.blogspot.com[/URL]