One of the major climate change skeptics, Richard A. Muller, has taken another step in reversing his position. Much of Muller's work has been largely funded by libertarian petrochemical billionaire Charles Koch's foundation, which has consistently supported organizations that deny climate change.
Muller's Berkeley Earth Surface Temperature project has for years questioned the fact of global warming. One of his claims has been that the appearance of warming might come partly from the fact that weather stations are often located in or near cities, where heat from buildings, rooftops, roads and cars can cause artificially high temperatures in the vicinity. But last year, Muller concluded that the Earth has indeed warmed, by about 1.3° F since 1900.
And today, in a New York Times column entitled The Conversion of a Climate-Change Skeptic, he goes a major step further, saying his own studies are confirming not just that the planet is heating up, but that humans are the prime cause:
“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.”
Other scientists hope that this will give conservative members of Congress a face-saving way to change their own positions and start taking action. On his Facebook page, Michael E. Mann, director of the Earth System Science Center at Pennsylvania State University, writes:
There is a certain ironic satisfaction in seeing a study funded by the Koch Brothers – the greatest funders of climate change denial and disinformation on the planet – demonstrate what scientists have known with some degree of confidence for nearly two decades: that the globe is indeed warming, and that this warming can only be explained by human-caused increases in greenhouse gas concentrations. I applaud Muller and his colleagues for acting as any good scientists would, following where their analyses led them, without regard for the possible political repercussions.
Muller's about-face is still evolving quite slowly. He says that polar bears, who are becoming ever more desperate to find seals, are not dying from receding ice. And he writes that "the recent warm spell in the United States happens to be more than offset by cooling elsewhere in the world, so its link to 'global' warming is weaker than tenuous." This is really playing with words, since most scientists are reluctant to ascribe single events to "global warming", talking more about how climate change creates an increasing number of extreme events: hotter in one place, colder in another; wetter here but dryer there; and so on.
But it's an important evolution in one of the icons of climate change denial.