UC Physics Professor Flips: The Conversion of a Climate-Change Skeptic

By | July 31, 2012

RICHARD A. MULLER, professor of physics at the University of California, Berkeley  – 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.

My total turnaround, in such a short time, is the result of careful and objective analysis by the Berkeley Earth Surface Temperature project, which I founded with my daughter Elizabeth. Our 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.

These findings are stronger than those of the Intergovernmental Panel on Climate Change, the United Nations group that defines the scientific and diplomatic consensus on global warming. In its 2007 report, the I.P.C.C. concluded only that most of the warming of the prior 50 years could be attributed to humans. …

What has caused the gradual but systematic rise of two and a half degrees? We tried fitting the shape to simple math functions (exponentials, polynomials), to solar activity and even to rising functions like world population. By far the best match was to the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice.

Just as important, our 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. Although the I.P.C.C. allowed for the possibility that variations in sunlight could have ended the “Little Ice Age,” a period of cooling from the 14th century to about 1850, our data argues strongly that the temperature rise of the past 250 years cannot be attributed to solar changes. This conclusion is, in retrospect, not too surprising; we’ve learned from satellite measurements that solar activity changes the brightness of the sun very little.

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. 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. Adding methane, a second greenhouse gas, to our analysis doesn’t change the results. Moreover, 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. …

via The Conversion of a Climate-Change Skeptic – NYTimes.com.

7 thoughts on “UC Physics Professor Flips: The Conversion of a Climate-Change Skeptic

  1. Fred Killer

    For all we know, we’re helping to return the carbon dioxide levels to their normal historical range.

    What were they like during the reign of the dinosaurs, when trees and other plants were abundant and giving off huge quantities of methane upon decomposition?

    The higher the carbon dioxide level, the better plants thrive. They in turn, produce more oxygen. To try to reduce carbon dioxide levels is suicide (and herbicide, for that matter).

    2.5 degrees in 250 years could be perfectly normal. You’ll find equally compelling evidence that we’re on the brink of a new ice-age.

    1. Xeno Post author

      Extinction is not difficult, in fact, it is quite “normal” …but I like to think of a “normal” Earth as being one that can support the species that invented the word “normal”.

      CO2 reduction is suicide? The opposite, I’d say. Plants did fine with the CO2 levels in the 1600s. Good luck having a normal ice-age with all the CO2 we are spewing… oh, wait, do you live in the UK?

  2. Michael

    “…temperature rise of the past 250 years cannot be attributed to solar changes. This conclusion is, in retrospect, not too surprising; we’ve learned from satellite measurements that solar activity changes the brightness of the sun very little.”

    This is a deliberate and shameful attempt at obfuscation of the data by proffering a misleading conclusion to a generally scientifically-misinformed public. The solar cycles theory has very little to do with changes in solar luminosity and everything to do with changes in solar wind and its effect on receipt of cosmic radiation on the earth. His deliberate misstatement is completely unethical.

    It’s like my trying to disprove that antibiotics work by saying that I have tested milk, a well known antibiotic used extensively in modern medicine, on streptococcal bacteria and it failed to kill them. Therefore, we now know that the theory of antibiotics is completely false. Or that my opponents assert that saws in fact can cut wood. I tested said theory using a pencil, an extremely popular design of wood saw, and completely failed to cut the wood. Therefore the idea that saws cut wood is complete erroneous.

    Shameful.

      1. Michael

        Yes, they do. Thank you for asking.

        Solar activity can be measured from historical records by recorded sunspot activity. Solar wind affects cosmic ray exposure that is experienced on earth, which affects cloud formation. Less solar wind, more cosmic rays received, more clouds, more solar reflection = cooling. More solar wind, less cosmic rays, less cloud formation, less solar reflection = warming. CO2 levels follow temperature changes in ice core records by 200-400 years. Ice core data also gives us other atmospheric data from the past as well (oxygen isotopes, pollen counts) which corroborate this. Although these data are well documented and acknowledged by climate researchers, it is ignored since it would refute anthropogenic global warming theory. We indeed live in interesting times…

        1. Xeno Post author

          Thank you. Interesting times indeed. If you can point me to the data that supports what you are saying, you could change my current view.

      2. Michael

        Any climate publications by Nir J Shaviv or Henrik Svensmark. I teach environmental science and have been an ardent advocate of habitat preservation and restoration for a couple of decades. If I thought that anthropogenic global warming had any credence, I would be all over it. We need to focus all our efforts on habitat preservation and restoration since we are facing the first and only global mass extinction to date caused by humans. That should be a top priority.

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