Professor of Physics at the University of California at Berkeley
Now Pro to the question "Is Human Activity Primarily Responsible for Global Climate Change?"
"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...
Our [Berkeley Earth Surface Temperature project] results show that the average temperature of the earth’s land has risen by two and a half degrees Fahrenheit over the past 250 years, including an increase of one and a half degrees over the most recent 50 years. Moreover, it appears likely that essentially all of this increase results from the human emission of greenhouse gases...
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...
[O]ur record is long enough that we could search for the fingerprint of solar variability, based on the historical record of sunspots. That fingerprint is absent...
How definite is the attribution to humans? The carbon dioxide curve gives a better match than anything else we’ve tried. Its magnitude is consistent with the calculated greenhouse effect — extra warming from trapped heat radiation... our analysis does not depend on large, complex global climate models, the huge computer programs that are notorious for their hidden assumptions and adjustable parameters. Our result is based simply on the close agreement between the shape of the observed temperature rise and the known greenhouse gas increase."
"The Conversion of a Climate-Change Skeptic," www.nytimes.com, July 28, 2012
[Editor's Note: Prior to Richard Muller's July 28, 2012 Pro position above, he held a Not Clearly Pro or Con position as indicated by the Oct. 21, 2011 statement below from "The Case Against Global-Warming Skepticism," available at www.wsj.com.]
"Are you a global warming skeptic? There are plenty of good reasons why you might be....
The temperature-station quality [measuring surface temperature] is largely awful... A careful survey of these stations by a team led by meteorologist Anthony Watts showed that 70% of these stations have such poor siting [locations] that, by the U.S. government's own measure, they result in temperature uncertainties of between two and five degrees Celsius or more...
Using data from all these poor stations, the U.N.'s Intergovernmental Panel on Climate Change estimates an average global 0.64ºC temperature rise in the past 50 years, 'most' of which the IPCC says is due to humans. Yet the margin of error for the stations is at least three times larger than the estimated warming...
We know that cities show anomalous warming, caused by energy use and building materials [known as the urban heat island effect]; asphalt, for instance, absorbs more sunlight than do trees... Could that rise, and increases in other urban areas, have been unreasonably included in the global estimates? That warming may be real, but it has nothing to do with the greenhouse effect and can't be addressed by carbon dioxide reduction...
But now let me explain why you should not be a skeptic, at least not any longer...
We [Berkeley Earth Surface Temperature Project] discovered that about one-third of the world's temperature stations have recorded cooling temperatures, and about two-thirds have recorded warming. The two-to-one ratio reflects global warming. The changes at the locations that showed warming were typically between 1-2ºC, much greater than the IPCC's average of 0.64ºC.
To study urban-heating bias in temperature records, we used satellite determinations that subdivided the world into urban and rural areas. We then conducted a temperature analysis based solely on 'very rural' locations, distant from urban ones. The result showed a temperature increase similar to that found by other groups...
Global warming is real. Perhaps our results will help cool this portion of the climate debate. How much of the warming is due to humans and what will be the likely effects? We made no independent assessment of that."
"The Case Against Global-Warming Skepticism," Wall Street Journal, Oct. 21, 2011
Experts Individuals with PhDs, heads of government, members of federal legislative bodies, and individuals with graduate degrees and significant post-graduate involvement in fields relevant to the study of climate. [Note: Experts definition varies by site.]
Involvement and Affiliations:
Professor of Physics, University of California at Berkeley, 1980-present
Faculty Senior Scientist, Lawrence Berkeley Laboratory, 1979-present
Fellow, California Academy of Arts and Sciences, 1999
Distinguished Teaching Award, University of California at Berkeley, 1999
Member, Board of Advisors, Institute for Nuclear and Particle Astrophysics, 1992-present
Fellow, American Association for the Advancement of Science, 1991
Sponsor, Federation of American Scientists, 1990-present
Fellow, American Physical Society, 1985
Recipient, Science Digest list of 100 Outstanding Scientists Under Age 40, 1984
Recipient, MacArthur Foundation Prize Fellowship, 1982
Associate Professor of Physics, University of California at Berkeley, 1978-1980
Recipient, National Science Foundation Alan T. Waterman Award "for highly original and innovative research which has led to important discoveries and inventions in diverse areas of physics, including astrophysics, radioisotope dating, and optics," 1978
Associate Research Physicist, Joint Appointment at Lawrence Berkeley Laboratory and Space Sciences Laboratory, 1975-1978
Lecturer, Department of Physics, University of California at Berkeley, 1971-1974
Assistant Research Physicist, Space Sciences Laboratory, 1969-1975
PhD, Physics, University of California at Berkeley, 1969