"When the facts change, I change my mind. what do you do, sir?" -- John Maynard Keynes.

Richard Muller, founder of The Berkeley Earth Surface Temperature Study, which is funded by the Koch Brothers, now believes global warming is real. Those of us who have believed for years that climate change is happening should welcome our new convert. The planet needs all the help it can get in combating global warming. And Muller changed his mind based on the data and science, with politics not an issue.

Call me a converted skeptic. Three years ago I identified problems in previous climate studies that, in my mind, threw doubt on the very existence of global warming. Last year, following an intensive research effort involving a dozen scientists, I concluded that global warming was real and that the prior estimates of the rate of warming were correct. I’m now going a step further: Humans are almost entirely the cause.