Roy Spenser offers a climate model based on natural forcings from the the Pacific Decadal Oscillation (PDO), Atlantic Multi-decadal Oscillation (AMO), and the the Southern Oscillation Index (SOI) (a measure of El Nino and La Nina activity). The correlation he obtains to the post 1975 warming is truly remarkable.
What impresses me is that he trains the model in a flat temperature period and it nevertheless predicts the observed warming. This correlation, though, begs the question of whether there isn’t some other ultimate factor responsible for the variation in the indicies used and temperature – solar forcing perhaps? Hat Tip: Watt’s Up With That