Climate Change Book Reviews - Index

Roy W. Spencer, Climate Confusion: How Global Warming Hysteria Leads to Bad Science, Pandering Politicians and Misguide Policies that Hurt the Poor (Encounter Books New York, 2008)

Roy Spencer is a climate scientist, with a specialty in the analysis of satellite data. He is a scientist who cisputes the consensus view that human emissions of greenhouse gases are causing climate change with the potential for serious consequences for humans. Consequently, the primary reason for reading Spencer's book are his views why the consensus is wrong. Unfortunately, his arguments are unconvincing. That he feels compelled to take gratuitous swipes are at others creates the suspicion that personal issues are at stake.

Spencer is aware that he is perceived by environmentalists as a global warming "skeptic". He also understands that environmentalists typically denigrate "skeptics" by saying that they are influenced by corporate interests opposed to actions that would limit the combustion of carbon dioxide. Early on, he clarifies that he has never been approached by an "energy company" for "skeptic related" services. It is unfortunate that he limited his disclaimer to "approaches" by "energy" companies. There are a variety of corporate interests beyond "energy" companies that have an interest in promoting skepticism of the theory of global warming. These include corporate funded association, lobby groups, think tanks, and non-energy companies such as automakers. Some climate that Spencer does have relationships with some of these entities. This raises doubts about his objectivity and , creating suspicions of his objectivity.

The important aspect of the book is Spencer's views on climate science. His views on matters such as the media, environmentalists, and politicians may be interesting, but Spencer has no particular claim to expertise. Spencer's scientific views are outlined in about 50 pages (out of 182 pages), in three chapters.

The second chapter explains the scientific method. His primary point is that the scientific method does not produce "the truth", and that scientific theories are always subject to further test. He appears to be trying to make the point that we should note take science too seriously. He fails to note the obvious point that some scientific theories are sufficiently relevant that we take them very seriously. Consider medical science and space travel, for example. The question at issue is whether the theories around climate science are sufficiently relevant to take very seriously.

Spencer dismisses most of paleoclimatology, which is based on proxy measurements such as tree rings. His argument is that a scientific interpretation based on proxy measurement cannot be verified. While his argument may makes sense for one proxy measurement of the past, when there are multiple proxy measurementrs all supporting each other and consistent with current observation, the independent proxy measurements support each other, and can be used collectively to support an interpretation of past climates. Spencer's dismissal of paleoclimatology is, in fact, essential for Spencer's later arguments that global warming is not a serious problem.

Chapters 3 and 4 deal respectively with how weather works and how global warming (allegedly)works. These are the most interesting chapters in the book. They present the views of a climate scientist dealing with a subject he knows.

In these chapters, Spencer acknowledges that humans are putting carbon dioxide into the atmosphere, that the carbon dioxide content of the atmosphere is slowly increacing, that the increase not likely the result of natural processes, that some of the carbon dioxide humans are putting in the atmosphere does not stay there and is in fact missing, that carbon dioxide is a greenhouse gas that traps infrared radiation and tries to warm the lower troposphere, and that the globally averaged surface temperature is about 0.6 degrees centrigrade higher than a century ago.

Spencer believes the earth has a thermostatic control system, the essence of which is the precipitation system. The precipitation system affects water vapour in the atmosphere, cloud amounts and air temperatures at various elevations. "When the (climate) system veers too far from normal, complex processes interact in ways that push the system back in the opposite direction." Spencer acknowledges that his hypothesis is "far from being proved", and his acceptance of it has a religious quality.

The primary problem with Spencer's hypothesis is that it ignores the paleoclimatological record. This is a record that Spencer dismissed without much explanation. This record suggests that past climates have not been deviating in a minor way around some benign "normal". The earth has had much warmer and much colder periods, and the current warm period is an historical exception.

Another troubling aspect of Spencer's hypothesis is his inattention to the Earth's positive energy imbalance. Spencer, a specialist in analysing satellite data, knows that the satellite measurements are telling us that the earth has a globally averaged energy imbalance of about 1 watt per metre squared. He dismisses this amount on three counts.

1. Since satellite measurements have started only recently, we do not know how long the imbalance has existed. Spencer is correct about satellite measurement, but paleoclimatology suggests that sea levels have been relatively constant for about 7,000 years. It is unlikely that this would occur with an long term positive energy imbalance.
2. The positive energy imbalance does not necessarily put heat into the atmosphere, causing climate change. Spencer downplays the significance of a positive energy imbalance by suggesting it could simply lead to benign changes in ocean circulation. It is not obvious that changes in ocean circulation are benign, and other possible destinations for the extra energy (warming the ocean surface waters, melting ice) are not necessarily benign, nor is it obvious that these changes will not eventually affect the surface air temperatures.
3. A positive energy imbalance of 1 watt per metre squared is a relatively small percentage of the total energy reaching earth that it is not particularly significant. The best theory for ice ages is based on the work of Milan Milankovitch, who suggested that ice ages were the result of slight changes in earth's energy balance as a result of changes in earth's wobble, tilt, and orbit. The changes were less than 1 watt per metre squared, carried out over a long period of time. If a long term energy changes of 1 watt per metre squared can trigger the onset and disappearance of ice ages, then a short-term positive energy imbalance of 1 watt per metre squared has some significance. Because Spencer's dismissal of the paleoclimatological record is poorly substantiated, his suggestion that a positive energy imbalance of 1 watt per metre squared does not matter is not convincing.

Spencer is critical of climate models for a variety of reasons.

1. Their ability to predict future climates cannot be tested until we get to the future. This is, of course, true for any model.
2. They are based on a lot of assumptions about complex systems. It is not true that there is a full understanding of how all subsystems work (e.g. precipitation, clouds). Even if the subsystems are correct, it is not necessarily true that the subsystems will be integrated in a total system that makes gives an accurate result.
3. The various models treat different subsystems different, yet generally reach the same conclusions.
4. Climate modelers have a vested interest in overstating the accuracy of their modeling to the outside world.
5. There may be significant but unknown natural processes that are not included in models.
6. A lot of climate scientists are skeptical about the accuracy of climate models.

Spencer's points are relevant, but overstate the role of climate modeling in the theory of global warming. The theory of global warming is based on a number of lines of evidence: observations of existing climate systems; physical laws (i.e. theories that have been tested exhaustively without contradition); the study of historical climates; climate modeling to attribute causes of the present and to predict the future. Climate modeling is only one line of evidence. Climate modelling for the purpose of predicting the future is the least compelling line of evidence. As noted above, Spencer dismisses paleoclimatology, and does not not pay much attention to observation.

Spencer's arguments related to climate science are not convincing. Most of Spencer's book deals with issues not related to climate science. On these issues, he has no particular expertise and is even less convincing. His willingness to take gratuitous swipes at the media,, popular science journals, environmentalists, other scientists, science administrators, and politicians raises the question whether personal concerns are involved. Perhaps there are.

In an earlier stage of climate science, Spencer carried out a scientific analysis of satellite data that concluded that the atmosphere was cooling, and not warming, in a manner predicted by climate models. This seemingly contradictory finding led to reviews of the original work. Ultimately, it was concluded that there were errors or oversights in the original work. When the data were corrected, the atmosphere was found to be warming. One wonders what Spencer felt about this episode.

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