Roy Spencer is one of the few climate contrarians with real credentials. That doesn’t stop him from propagating some real whoppers, however. Here I’ve collected links to critiques of Roy’s work. I’m starting with the posts I’ve made on my blog, including my 3-part review of his new book, The Great Global Warming Blunder: How Mother Nature Fooled the World’s Top Climate Scientists.
Christy and Spencer’s Satellite Temperature Record Mistake
1. Andy Revkin writes about the episode in the New York Times.
Dr. Spencer Goes to Salt Lake City
1. Politicizing Science. Roy Spencer testified before a committee of the Utah House of Representatives. Read all about what he said, and the response of local scientists and politicians.
The Great Global Warming Blunder
1. Roy Spencer’s Great Blunder, Part 1. In his latest book, The Great Global Warming Blunder, Roy Spencer lashes out at the rest of the climate science community for either ignoring or suppressing publication of his research. This research, he claims, virtually proves that the climate models used by the IPCC respond much too sensitively to external “forcing” due to changes in greenhouse gas concentrations, variations in solar radiation, and so on. Instead, Spencer believes most climate change is caused by chaotic, natural variations in cloud cover. He and a colleague published a peer-reviewed paper in which they used a simple climate model to show that these chaotic variations could cause patterns in satellite data that would lead climatologists to believe the climate is significantly more sensitive to external forcing than it really is. Spencer admits, however, that his results may only apply to very short timescales. Since the publication of his book, furthermore, other scientists (including one that initially gave Spencer’s paper a favorable review) have shown that Spencer was only able to obtain this result by assuming unrealistic values for various model parameters.
2. Roy Spencer’s Great Blunder, Part 2. Roy Spencer repeatedly claims that most of the rest of the climate science community deliberately ignores natural sources of climate variation, but then contradicts himself by launching an inept attack on the standard explanation for climate change during the glacial-interglacial cycles of the last million years (i.e., they are initiated by Milankovitch cycles). The problems Spencer identifies are either red herrings or have been resolved, however, and he proposes no other explanation to take the place of the standard one. In fact, climate scientists have used paleoclimate data such as that for the ice ages to show that climate sensitivity is likely to be close to the range the IPCC favors. Therefore, it appears Roy Spencer is the one who wants to sweep established sources of natural climate variation under the rug.
3. Roy Spencer’s Great Blunder, Part 3. Roy Spencer posits that the Pacific Decadal Oscillation (PDO) is linked to chaotic variations in global cloud cover over multi-decadal timescales, and thus has been the major driver of climate change over the 20th century. To test this hypothesis, he fit the output of a simple climate model, driven by the PDO, to temperature anomaly data for the 20th century. He found he could obtain a reasonable fit, but to do so he had to use five (he says four) adjustable parameters. The values he obtained for these parameters fit well with his overall hypothesis, but in fact, other values that are both more physically plausible and go against his hypothesis would give equally good results. Spencer only reported the values that agreed with his hypothesis, however. Roy Spencer has established a clear track record of throwing out acutely insufficient evidence for his ideas, and then complaining that his colleagues are intellectually lazy and biased when they are not immediately convinced.
1. Roy Spencer’s Non-Response. Many of Roy’s readers were asking him to respond to my 3-part review of The Great Global Warming Blunder, which Roy said he wrote because he couldn’t get some of his work published in the peer-reviewed literature. (Due to foul play, naturally.) Now he says he won’t waste time responding to blog critiques, because he’s too busy trying to get his work published in the peer-reviewed literature.
2. Roy Spencer’s Latest Silver Bullet. Roy Spencer has come up with yet another “silver bullet” to show that climate sensitivity is lower than IPCC estimates. I.e., he fits a simple 1-box climate model to the net flux of heat into the upper 700 m of the ocean, and infers a climate sensitivity of only about 1 °C (2x CO2). There are several flaws in his methods–inconsistent initial conditions, failure to use the appropriate data, and failure to account for ocean heating deeper than 700 m. (He fixed the last one in an update.) All of these flaws pushed his model to produce a lower climate sensitivity estimate. When the flaws are corrected, the model estimates climate sensitivities of at least 3 °C, which is the IPCC’s central estimate. In any case, a simple 1-box climate model does not appear to be adequate for this kind of analysis over only a few decades. But while Spencer’s latest effort doesn’t really do any damage to the consensus position, it turns out that it does directly contradict the work he promoted in The Great Global Warming Blunder.
3. Just Put the Model Down, Roy. Roy Spencer’s wild and crazy curve-fitting adventures never seem to end! The following excerpt from my critique says it all. “Well, give me more than 30 parameters, and I can fit a trans-dimensional lizard-goat and make rainbow monkeys shoot out its rear end.”
1. Misdiagnosis of Surface Temperature Feedback (RealClimate.org). Roy Spencer and Danny Braswell published a paper in which they once again botched their statistics in an attempt to show that the climate sensitivities of standard climate models are too high. This created a media bubble, with some media outlets claiming a “gaping hole” had been blown in global warming “alarmism”. Kevin Trenberth and John Fasullo took it apart on the RealClimate blog.
2. Remote Sensing Editor Resigns Over Spencer/Braswell Paper. The editor of S&B’s paper figured out that the criticisms of the paper were devastating, and that S&B had ignored previously published research that they should have addressed in their paper. Given the big media frenzy, the editor decided to resign (probably to save his journal from a reputation for publishing anything submitted.)
3. Roy Spencer Persecuted by Own Data. Roy Spencer’s latest paper, published in Remote Sensing, supposedly “blew a gaping hole” in the standard theory of climate change. A new paper by Andrew Dessler shows that this is just another in a long string of Roy’s faulty claims to prove that climate sensitivity is lower than previously thought. The main problem in all of these attempts has been rampant abuse of statistics. Typically, Roy would brush off such criticisms, relying on the statistical naïveté of his core audience and the media, and claim he is being persecuted by the “IPCC gatekeepers”. In this case, one of Dessler’s figures shows very clearly how Spencer and his co-author Danny Braswell left out of their analysis all the data that didn’t fit with their hypothesis. It’s so clear that even people who don’t know much about statistics can see the problem. There is no running from this one–no claiming that Spencer is being persecuted–unless he wants us to believe he’s being persecuted by his own data.
4. Roy Spencer Responds With More Excuses. Spencer responded to Dessler’s criticisms by misconstruing some of the arguments and sweeping away the statistical concept of “error bars” with a wave of his hand. He also couldn’t understand why he needed to report all that missing data.
5. Remote Sensing Publishes Rebuttal. Remote Sensing published a rebuttal to Spencer and Braswell’s paper. The rebuttal, written by Kevin Trenberth, John Fasullo, and John Abraham, is mostly based on an earlier RealClimate post by Trenberth and Fasullo, but tidied up and updated for publication.