Two years ago, Richard Muller, a star physicist at Berkeley, assembled a team of scientists who had not previously taken public positions on global warming essentially to start from scratch to find answers about climate change. They began a project called Berkeley Earth Surface Temperature (BEST).
With skepticism still prevalent, the team set out to conduct its own research in a manner that would convince the public of its credibility. At the beginning of the project, Professor Muller told me “I honestly don’t know” whether the findings would confirm or contradict the global warming consensus.
Touting its impartiality, BEST has emphasized that its studies would be independent and transparent, and that its findings would be publicly available in both technical terms and in simpler language accessible to the average citizen.
Last October BEST released its initial findings—which were that the earth is indeed warming, by about 0.9°C, since the mid-1950s. Muller wrote in an op-ed in the Wall Street Journal, “When we began our study, we felt that skeptics had raised legitimate issues, and we didn't know what we'd find. Our results turned out to be close to those published by prior groups. We think that means that those groups had truly been very careful in their work, despite their inability to convince some skeptics of that. ” That first report did not draw any conclusions about the causes of the warming.
On Sunday BEST announced a second wave of results. Warming, they say, is caused almost entirely by humans. Their evidence is that a graph of carbon dioxide concentration and volcanic activity is a closer match in pattern than any other potential causes (such as solar activity) to a graph of land average temperature from 1750 to 2011. Downward spikes can be explained by volcanoes which according to BEST “spew particles into the air, which then reflect sunlight and cool the earth for a few years.” A summary of BEST’s results is available on its website. Those who are interested can go to the website and access the raw data used in the charts, as well as look up individual countries and cities to view temperature changes since 1960. The statement that almost all warming is caused by human activity is even stronger than recent reports by the IPCC that only “most” warming is anthropogenic.
Richard Muller said he was surprised by these findings. In the BEST summary he is quoted saying, “I was not expecting this, but as a scientist, I feel it is my duty to let the evidence change my mind.” In a New York Times op-ed, “The Conversion of a Climate-Change Skeptic,” he wrote that BEST kept its research free from the biases of which other climate science has been accused:
We carefully studied issues raised by skeptics: biases from urban heating (we duplicated our results using rural data alone), from data selection (prior groups selected fewer than 20 percent of the available temperature stations; we used virtually 100 percent), from poor station quality (we separately analyzed good stations and poor ones) and from human intervention and data adjustment (our work is completely automated and hands-off). In our papers we demonstrate that none of these potentially troublesome effects unduly biased our conclusions.
According to Muller, however, there are still grounds for doubt:
These facts don’t prove causality and they shouldn’t end skepticism, but they raise the bar: to be considered seriously, an alternative explanation must match the data at least as well as carbon dioxide does.
[...]
It’s a scientist’s duty to be properly skeptical. I still find that much, if not most, of what is attributed to climate change is speculative, exaggerated or just plain wrong. I’ve analyzed some of the most alarmist claims, and my skepticism about them hasn’t changed.
Muller writes that polar bears aren’t dying, the Himalayan glaciers aren’t going to melt away by 2035, and warming isn’t to blame for Hurricane Katrina.
In spite of its seeming balance, however, BEST’s latest has been met with criticism from scientists on both sides of the debate.
While Michael Mann (famous for coining the term “hockey stick,” which he claims climate graphs resemble) agrees with Muller’s findings, he dislikes the assumption that earlier scientists are to blame for failing to convince the public. On Facebook Sunday Mann wrote:
My view is that Muller's efforts to promote himself by belittling the collective efforts of the entire atmospheric/climate research community over several decades, though, really does the scientific community a disservice. Its [sic] great that he's reaffirmed what we already knew. But for him to pretend that we couldn't trust this entire scientific field until Richard Muller put his personal stamp of approval on their conclusions is, in my view, a very dangerously misguided philosophical take on how science works. It seems, in the end--quite sadly--that this is all really about Richard Muller's self-aggrandizement :(
Economics professor Ross McKitrick explains on his website why the BEST papers didn’t pass his standards for peer review in the Journal of Geophysical Research:
I submitted my review just before the end of September 2011, outlining what I saw were serious shortcomings in their methods and arguing that their analysis does not establish valid grounds for the conclusions they assert. I suggested the authors be asked to undertake a major revision.
McKitrick says that the authors went ahead with their October 2011 media blitz even though their research had not yet passed peer review and been accepted for publication. He says the same thing happened with the July 2012 media blitz.
On the blog Watt’s Up With That?, guest author (and private citizen who researches climate change) Willis Eschenbach dismisses the correlation between CO2 and temperature: “that joke has been widely discussed and discounted, even by anthropogenic global warming (AGW) supporters.” The only AGW believer Eschenbach cites, however, is Michael Mann, but he quotes the Facebook comment, which does not discount a link between CO2 and temperature.
Eschenbach provides a chart of his own and argues that seven of the eight major volcanoes since 1750 have in fact occurred in the middle or the end of the fall in temperature they were supposed to have caused.
One disagreement is closer to home for BEST. The climatologist on the team, Judith Curry, is not convinced. BEST already has an explanation on its website:
While Richard Muller and the Berkeley Earth team value the simplicity of the model (indeed, in physics the simple model is generally considered the best), Curry believes that it is overly simplistic and is not convinced. These sorts of disagreements are common among scientists and contribute usefully to advancing science.
On her blog, Curry spells out her disagreements, namely that the BEST authors use models rather than observation in making the connection between carbon dioxide and warming.
“No one that I listen to questions that adding CO2 will warm the earth, all other things being equal,” Curry writes. “The issue is whether anthropogenic activities or natural variability is dominating the climate variability.”
One of the largest donations funding the work of the Berkeley Earth Surface Temperature project came from the Charles G. Koch Charitable Foundation ($150,000). Michael Mann exulted on Facebook, “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.”
Mann cheered Muller and his team for following the science where it led them. If that is really what BEST has done they are indeed to be applauded for their pursuit of scientific truth. Whether this is a model of the integrity of science or the false conversion of a confidence man masquerading as an impartial inquirer is impossible to know right now.
BEST says its next phase of research will measure ocean temperatures and will consider “the implications of our findings.”
Image (of Richard Muller and his daughter Elizabeth Muller): Paul Sakuma/Associated Press
