Editor's note: The following is a response by climatologist Michael E. Mann to a Q&A article that appeared in the June 2011 issue of Scientific American, which became available to readers in May.

Last month, Scientific American ran a disappointing interview by Michael Lemonick of controversial retired University of California, Berkeley, physics professor Richard Muller.  As an undergraduate physics major at Berkeley in the mid 1980s, I knew about Muller—and his controversial, now generally discarded, theory that a “death star” was responsible for major mass extinctions.  Later, as a graduate student studying climate, I became aware of Muller’s work attempting to overthrow the traditional Earth Orbital theory of the Ice Ages—that, too, didn’t pan out. To be clear, there is nothing wrong in science with putting forth bold hypotheses that ultimately turn out to be wrong. Indeed, science thrives on novel, innovative ideas that—even if ultimately wrong—may lead researchers in productive new directions.

One might hope, however, that a scientist known for big ideas that didn’t stand the test of time might be more circumspect when it comes to his critiques of other scientists. Muller is on record accusing climate scientists at the University of East Anglia Climatic Research Unit of hiding data—a charge that was rejected in three separate investigations. In his interview, Muller even maligned my own work on the “hockey stick” reconstruction of past temperatures. Muller falsely claimed “the hockey-stick chart was in fact incorrect” when in fact the National Academy of Sciences affirmed our findings in a major 2006 report which Nature summarized as ““Academy affirms hockey-stick graph.” Scientific American itself recently ran an article “Novel Analysis Confirms Climate ‘Hockey Stick’ Graph” (November 2009 issue).

Rather than providing a platform for Muller to cast aspersions on other scientists, Lemonick could have sought some introspection from Muller. How, for example, have the lessons learned from his past failures influenced the approach he has taken in his more recent forays into the science of human-caused climate change?

More than anything else, the interview was simply a lost opportunity. Not only can Scientific American do better. It will need to.


Michael E. Mann is a professor in the Departments of Meteorology and Geosciences at Penn State University, and director of the Penn State Earth System Science Center. He is co-author of the book Dire Predictions: Understanding Global Warming.


The views expressed are those of the author and are not necessarily those of Scientific American.