A leading climate-change denier switches, says earth is warming and humans are the main cause

In what is being described as both "a bombshell" and "a man-bites-dog" story, a leading skeptic of climate change has dramatically reversed his position after a study he conducted with money from an even larger critic of climate science, the Charles G. Koch Charitable Foundation. On the opinion pages of The New York Times, Richard Muller, left, is unequivocal about his new position: "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."

He continues: "The careful analysis by our team is laid out in five scientific papers now online at BerkeleyEarth.org. That site also shows our chart of temperature from 1753 to the present, with its clear fingerprint of volcanoes and carbon dioxide, but containing no component that matches solar activity. Four of our papers have undergone extensive scrutiny by the scientific community, and the newest, a paper with the analysis of the human component, is now posted, along with the data and computer programs used. Such transparency is the heart of the scientific method; if you find our conclusions implausible, tell us of any errors of data or analysis." Muller's opinion page piece is here.

Michael E. Mann, director of the Earth System Science Center at Penn State, said Muller’s conversion might help shape the thinking of the "reasonable middle" of the population "who are genuinely confused and have been honestly taken in" by attacks on climate science. The Los Angeles Times's Neela Banerjee writes that Koch Foundation spokeswoman Tonya Mullins said the support her foundation provided, along with others, had no bearing on results of the research. "Our grants are designed to promote independent research; as such, recipients hold full control over their findings," Mullins said in an email. "In this support, we strive to benefit society by promoting discovery and informing public policy."