When UC Berkeley researcher and physics professor Richard Muller published the results of a climate change study in a New York Times Op-Ed piece on July 28 before submitting them to journal review, he incited a controversy in the science community.

The results — which were published by the Berkeley Earth Surface Temperature Project which Muller and his daughter, Elizabeth, founded — show that the Earth’s temperature has risen 2.5 degrees Fahrenheit over the last 250 years, with 1.5 of those degrees rising in the most recent 50 years. The study matched this increase with the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice.

Together, according to Muller, these two sets of data point conclusively to human release of greenhouse gasses into the atmosphere as the reason for climate change.

Muller also stated in his article that Berkeley Earth’s findings were “stronger than those of the Intergovernmental Panel on Climate Change,” which is the United Nations group that defines the scientific and diplomatic consensus on global warming, and added that he expects the temperature to continue to rise.

“Because we were able to get the temperature all the way back to (the year) 1753, we could look for the fingerprints of the various causes,” Muller said.  “We could look at volcanoes, ocean currents, solar variation and greenhouse gasses, and the match to the greenhouse gasses was so close that I had to conclude that they were essentially responsible for all of the global warming.”

What has caught the attention of the greater climate change science community is not Muller’s findings, which are consistent with research that has been accumulating for nearly half a century, but that Muller chose to release the results of the study in The New York Times, rather than through the traditional process of submitting the information to a science journal for peer review.

Benjamin Santer, a climate researcher at the Lawrence Livermore National Laboratory, was one of the first to speak out against Muller’s article and told the Los Angeles Times that he “found it troubling that Muller claimed such definitive results without his work undergoing peer review.” Santer is out of the state and could not be reached for comment, but Santer’s Program for Climate Model Diagnosis and Intercomparison Director Karl Taylor agreed with this view.

“The research in this area has been going on for a long time, and scientists have looked at it very carefully and came to very careful conclusions before,” Taylor said. “It’s a little troubling that supposedly some evidence has come to light that hasn’t yet been peer reviewed.”

Elizabeth Muller, co-founder and executive director of Berkeley Earth Surface Temperature, responded to these claims and said the information published in the New York Times article was worthy of immediate publication.

“The journal system takes a long time, and we felt that these findings were too important to keep from the public for another year,” she said. “We’re all talking about policy changes about global warming, and we were somewhat skeptical, so we felt that our simplicity of our new model made it much more convincing.”

Richard Muller’s research is also a marked departure from his previous opinions on climate change, as he was formerly among the skeptics who doubted its existence. The Charles Koch Foundation, responsible for funding a portion of the project, has likewise been linked to groups that have contested climate change in the past.

“They only accounted for one-sixth of our funding, and they wanted us to do good science,” Muller said. “They never gave us any indication of what they wanted us to find because they understand that science doesn’t work that way.”

The findings were released online in an effort to practice “traditional peer review,” according to Richard Muller, who asserts that all information was distributed to scientists both publicly and privately.

“We are the most transparent group,” he said. “The peer review system is (that) you present public talks, publish your work, and you solicit criticism. We’ve gone through all of those, and we’re getting much better information from other people who’ve read the paper than through the preprint approach.”