Roy Spencer's stratospheric levels of denial
Paul Braterman is Professor Emeritus in Chemistry, University of North Texas, and Honorary Research Fellow (formerly Reader) at the University of Glasgow. His research has involved topics related to the early Earth and the origins of life, and received support from NSF, NASA, Sandia National Labs, and Scripps Institution of Oceanography. He is now interested in sharing scientific ideas with the widest possible audience, blogs at Primate’s Progress, and is a regular contributor to 3 Quarks Daily, and occasionally to The Conversation, where his articles have received more than a million reads.
When a scientist who has won awards for his work in the field disagrees with his colleagues, we must ask how much attention we should give to his opinion.
The image you’re looking at is copied from the website of Dr Roy Spencer, whose piece was also published by the Cornwall Alliance. Spencer is a Principal Research Scientist at the University of Alabama, Huntsville, was involved in the development of satellite-based atmospheric temperature monitoring technology for which in 1996 he was honoured by the American Meteorological Society, and has received funding from NASA, NOAA, and DOE. Yet here he is using gutter tactics to assert that a piece of significant new work on the mechanism of climate change is part of an alarmist conspiracy, that the conspiracy is failing to persuade, and that the conspirators are now being forced to invoke arguments based on observations of the stratosphere. Who benefits from this conspiracy and why the overwhelming majority of climate scientists have joined it is not clear For what it’s worth, acceptance of the reality of the climate crisis is increasing among Americans, as elsewhere, for reasons that are all too obvious, and the smoke of Canadian forest fires is much more persuasive than the scholarly discussion of the stratosphere that has triggered Spencer’s extraordinary reaction.
What is going on? I’m doing my best here to make sense of what is happening, in terms of the development of the disagreements between Spencer and his scientific colleagues, and Spencer’s own personal beliefs, to the extent that these are public knowledge. This is not an ad hominem attack on Spencer’s scientific output, which has been thoroughly criticised elsewhere, but a good faith attempt to understand how he came to his present position.
In 1990, Spencer and his colleague John Christy reported that their satellite data implied less atmospheric warming than that suggested by ground-based thermometers. This disagreement with the generally accepted view deepened over the following years, with Spencer claiming that everyone else’s work was hopelessly contaminated by failure to account for the effect of clouds and that the generally agreed temperature record was distorted by the urban heat island effect, while downplaying studies that had shown his work to be in error. In 2006, he and the corresponding author of the paper he is now attacking collaborated on a report by the US Government’s Climate Change Science Program. This report identified and corrected errors in the satellite temperature record, so that according to its press release, "There is no longer a discrepancy in the rate of global average temperature increase for the surface compared with higher levels in the atmosphere." The report then drew the inference that "the observed patterns of change over the past 50 years cannot be explained by natural processes alone." According to an eyewitness account, the putting together of the report involved correcting an error in Spencer’s equations, and Spencer seemed unhappy with this.
Spencer has continued to maintain that the consensus view overestimates the amount of global warming, and is one of a handful of scientists who continues to attribute what is happening to changing cloud cover. This of course is an important factor, and it is perhaps natural for Spencer, a meteorologist, to see it as a driver, rejecting the conventional view that while important, it is not a primary cause. In 2008, Spencer wrote Climate Confusion, the first of a series of books in which he defends his view that CO2 is not an important driver of climate change, describes policies aimed at CO2 reduction as “global warming hysteria”, accuses politicians of pandering to special interests, and claims that such policies will harm the poor by restricting economic growth. We should not totally ignore those last two arguments. Biofuel programmes, for example, are beneficial to the US farming lobby but their value in reducing CO2 emissions is hotly contested. And as I was writing this piece, the United Kingdom seemed at one point close to reneging on its commitments to Third World countries, largely as a result of its own poor economic performance. (On the other hand, it is very much the case that the heaviest direct costs of climate change are falling on the poorest countries, thus contributing to the flow of refugees from such countries towards the UK, Europe as a whole, and the US.)
Spencer has come to be closely associated with US conservatism. He has self-published a book on Amazon Kindle in praise of free-market economics, and free-market advocates would rather ignore or deny the damage caused by emissions, since that is an externality built into the true cost, but ignored by the market. He has given testimony to congressional hearings several times, and I should explain to readers outside the US that such hearings are not attempts to discover the truth and influence policy, but political street theatre. In 2010 the right-wing rabble-rouser Rush Limbaugh claimed Spencer as his official climatologist.
Spencer is a member of the advisory board to the Cornwall Alliance for the Stewardship of Creation, where he also has the status of a Senior Scholar. The Cornwall Alliance is a rather unusual organisation, as I have discussed earlier here here and elsewhere. The Alliance derives its deep motivation from its reading of the Bible, interpreting stewardship in terms of the dominion granted (Genesis 1:28) by God to a newly created literal Adam and Eve; see their statement of faith. Its main activity is arguing on scientific grounds against the consensus view that additional fossil fuel use will cause severe environmental damage, and it has direct links to the fossil fuel lobby and its dark funded activities.
The Cornwall connection immediately raises the question of Spencer’s own religious beliefs, which he discussed in a 2014 blog post. There he describes himself as a Bible-believing scientist, but avoids all discussion of evolution and the age of the earth. He tells us that he disagrees on some matters with the position of the Cornwall Alliance, and in particular that he rejects the argument that we are safe from environmental disaster because God is looking after the planet. However, he uses terminology and strawman arguments common in the creationist literature. Thus he attacks the concept of “settled science,” makes the strawman claim that the origin of life is presented as part of settled science, and describes the search by evolutionists (sic) for such a natural origin as “just as religious as the belief in a creator.”
Spencer is being less than open here. In a more complete statement preserved in the Discovery Institute’s Uncommon Descent archive, he addresses evolution directly, and repeats all the standard arguments against it. Macro evolution has never been observed, and “has virtually no observational evidence to support it.” Moths are still moths. Observed similarities can be as well explained by common design, there are no intermediate fossils connecting amphibians to reptiles, reptiles to birds et cetera, and punctuated equilibrium theory is merely an attempt to explain away the absence of the required evidence. Accepting either evolution or intelligent design is a matter of faith, and both should be discussed in schools. “At the very least, school textbooks should acknowledge that evolution is a theory of origins, it has not been proved, and that many scientists do not accept it.” There is no indication of his beliefs about the age of the Universe. However, both here and in the 2014 blog post he denounces attempts to explain its origin by natural means, claiming that this would violate the laws of thermodynamics. The same argument is made in Whitcomb and Morris’s The Genesis Flood, and repeated in young earth creationist rhetoric.
In the 2014 post, he told us that a scientist’s religious beliefs are irrelevant to judging the quality of the science, while at the same time maintaining that scientists are influenced in their work by their presuppositions. These two statements are not always entirely compatible.
Climatology is very much a case in point. If, for example, Spencer is a young earth creationist (and his choice of arguments, and self-description as “Bible believing,” suggest that this may well be the case), he will automatically reject all the information on climate change amplification that has emerged from the study of the Ice Ages, and if millions of years of variation are shoehorned in his mind into the last few thousand, then it is certainly possible for him to regard present changes as superficial by comparison.
After so long an introduction, analysis of the scientific development that prompted Spencer’s latest post seems almost anticlimactic. Greenhouse gases, as their name implies, reduce the efficiency by which Earth radiates energy into space by virtue of its infrared emissions. An increase in the temperature of the troposphere, the well-mixed lowest level of the atmosphere, combined with stratospheric cooling, is diagnostic of an increased greenhouse effect, since it directly relates temperature increase at low level to a decrease in upwards energy transfer. (The troposphere is the lowest layer of the atmosphere. It is well mixed, and extends from around 6 km above the surface at the poles to 17 km at the equator. The stratosphere is the 50 km or so above that, and shows relatively little mixing between horizontal layers.) For example, if recent warming were simply due to increased solar activity, the stratosphere would have been warmed along with the troposphere, but it wasn’t.
This much is indeed established science. In 1967, Syukuro Manabe and Richard Wetherall calculated the specific changes to be expected with height as the result of increased CO2 . Repeated observations using balloons and satellites, for example here here, have confirmed that such changes are indeed taking place, and Manabe’s work on climate modelling was recognised by a share of the 2021 Nobel Prize in physics.
Of course, it’s a bit more complicated than that. The variation of temperature with height, especially in the lower part of the stratosphere, is also affected by changes in the ozone layer and in particulate content. Moreover, other events such as volcanic eruptions and changes in solar illumination can disrupt the temperature profile, and observations of the signal due to this profile are also contaminated by weather-like random fluctuations (technically known as noise). And as if this were not enough, the noise itself is distorted by the slow responses of the oceans to atmospheric temperature changes. The mathematical methods required to sort out signal from noise under these conditions, so as to specify a fingerprint that would be characteristic of human activity, were developed by Klaus Hasselmann, who with Manabe shared in the 2021 Nobel Prize.
Until recently, unambiguous experimental data were only available for the lower part of the stratosphere. The work described in the paper under discussion, a collaboration involving nine separate investigators and ten different institutions, extends our information to the entire stratosphere. This is important for several reasons. Firstly, the predicted signal of human activity actually increases with height, while the effect of weather-like fluctuations falls away. This leads to an improved signal-to-noise ratio (by a factor of five), greatly enhancing the statistical significance of the findings. Secondly, it is the lower stratosphere that contains the ozone layer, which has of course been changing recently for various reasons, and these changes affect the local temperature profile. This complication is less important at greater heights. Thus the new data enable the most rigorous test to date of Manabe’s predictions, and hence by implication of our intimate understanding of human-caused global warming. There can be few topics more important at present.
And the conclusion is unavoidable even if unsurprising. The planet is heating up, because of our actions.
Except that, with great intellectual agility, Spencer manages to avoid this conclusion, writing
The authors are taking advantage of the public’s lack of knowledge concerning the temperature effect of increasing CO2 in the atmosphere, making it sound like stratospheric cooling is part of the fingerprint of global warming.
It isn’t. Cooling is not warming. [Emphasis in original]
It is hardly taking advantage of the public to publish in PNAS, but let that pass. It gets worse. Spencer claims there is nothing new in the paper, because there have been many earlier accounts of the temperature of the stratosphere. But the whole point of the paper is to extend our earlier knowledge to new heights (ouch! unintended pun, but let it stand.) He refers to Manabe and Wetherall’s seminal theoretical paper (see above), and accepts that its conclusions have been vindicated as regards the stratosphere. Nonetheless, he denies that the work has any real implications for what is happening lower down. But the whole point is that we now have an integrated account of the complete temperature profile of the atmosphere, from ground level to the top of the stratosphere. And he accepts this account (in view of the data in the paper, he could hardly do otherwise) of what is happening in the stratosphere, which doesn’t directly affect us, while arbitrarily rejecting its implications for climate down at the level where we all live, because it’s cloudy and complicated.
I started this piece by asking how much attention we should pay to Spencer’s opinions. I think we have our answer.