Please note: This is a book review. I will neither address the larger issues of global warming nor attempt to defend a position on the issue as a whole. Please read this review as one experienced PhD physicist's evaluation of this particular book.
This book was first published in 2010, and the second edition was published in 2012. The author's central thesis, in his own words, is "that natural cloud variations cause temperature variations, which give the illusion that the climate system is very sensitive to humanity's greenhouse gas emissions." [Preface, Kindle Locations 86-87]. It's at least arguable that this book has played a role in influencing the popular discussion of anthropogenic global warming versus natural climate change. Therefore, the author's ideas are worth consideration.
CONVINCING POINTS. Spencer's book makes some convincing points about the physical processes, data, and calculations related to climate change. Not all of these ideas are original, but they are adequately presented. 1) Climate changes have occurred over the whole of Earth's history through natural processes, that is, over long timescales and without mankind's influence. 2) The most detailed data available for climate study covers the period since modern monitoring methods and satellites have been deployed, a period of 50-100 years. Data at earlier times is less direct and less complete. Even the best modern data cannot measure all aspects of the processes involved in climate change. 3) The most widely used climate modeling employs very large, complex computer models. These computer simulation models are still "models"; they fall short of including all the physical processes involved in determining the climate, and they represent but do not duplicate even those processes that are included in the computer program. The treatment of the behavior and effects of clouds is uncertain in current models. In general, large computer models are not infallible. The models must be constrained by careful comparisons with good, relevant data. 4) In analyzing satellite data, it is inadequate (and can be misleading) to perform a single-variable linear fit to data from a non-linear, complex phenomena such as the amount of cloud cover. Although this is obvious, Spencer spends a great deal of effort making this point and succeeds. 5) The natural processes involved in climate change are not well understood and should receive greater research funding and effort than has been the case. 6) Predicting the future of something as complicated as the climate is difficult and prone to error.
However, as you can tell by my overall rating, I found this book seriously deficient. Here, I will discuss some areas where the book fails, in my opinion.
CONSPIRACY THEORIST. Spencer embeds his scientific insights within a suffocating blanket comprising his conspiracy theory. Climate scientists, journal editors, the IPCC, the media, and politicians are all conspiring, for various reasons against poor Dr. Spencer. Lest you think I am exaggerating, here are a few excerpts expressing his allegations. The IPCC is probably Spencer's primary nemesis, but everybody gets some notice:
"Our most recent paper supporting the theme of this book was peer-reviewed and accepted by top experts in our field, and published in the journal Remote Sensing in 2011. Astonishingly, as a result of that paper being published, the chief editor of Remote Sensing was forced to resign after apparent pressure by an influential "gatekeeper" for the UN's Intergovernmental Panel on Climate Change (IPCC)-even though our paper was never retracted by the journal." [Preface, Kindle Locations 94-97].
"The Keepers of All Climate Knowledge have erected a nearly impenetrable barrier to any new science that does not support the current paradigm of anthropogenic global warming, as defined and guided by those controlling the IPCC process. Published research that should be causing the climate modeling community to sit up and listen is instead being ignored. Groupthink has taken over." [Ch. 5, Intro, Kindle Locations 1363-1365].
"The House of Representatives has already passed cap-and-trade legislation to regulate carbon dioxide emissions by businesses. The EPA may regulate CO2 production now that the Supreme Court has told them to consider it a 'pollutant.'" [Ch. 5, Intro, Kindle Locations 1367-1369].
"I do believe that there is a conspiracy among some politicians and some of the IPCC leaders to get international agreements to regulate greenhouse gas emissions no matter what the science says." [Ch. 5, Sec. 1, Kindle Locations 1387-1389].
Spencer goes completely off the rails in speculating that a clever (hypothetical) whistleblower might meet a sad (and nefarious?) end:
"The story ends with a small obituary in the local newspaper for the prominent, Nobel Peace Prize-sharing scientist who died in a freak accident while filling his hybrid with gas." [Ch. 8, Sec. 3, Kindle Locations 2451-2452].
By this time, Spencer has lost all credibility with me on the subject of how the world (in and beyond physics) works. It was hard to plow through all this muck in the book.
VALID, IMPORTANT SCIENCE? Now, I will put aside the muck and discuss Spencer's main scientific ideas and defense of them.
Spencer goes to considerable length to demonstrate point (4) above, regarding the analysis of satellite data. I am easily convinced on this subject. One glance at Figure 14 is enough to convince me that the data cannot be used to extract a single, linear characterization of the processes involved. However, in case you are too inexpert to understand this point, the author goes on to demonstrate it using a simple model.
Spencer calls his model a "simple climate model". However, I think the "climate" connection is very tenuous. I would characterize it as a simple, ad hoc, non-linear model constructed to show that extracting a physical parameter from the output of a nonlinear process or model can be misleading. His demonstration of this point is technically correct and convincing, if you follow the details.
However, in his next step, he tries to use his simple model to tie together satellite observations and the index for the Pacific Decadal Oscillation (PDO). Here he commits the very blunder he accuses other climate scientists of making: circular reasoning. His simple model contains four parameters; Spencer treats these as arbitrary, curve-fitting parameters. He uses a computer to explore the parameter space covered by his model and selects the solutions he "likes". Let Spencer describe his error in his own words:
"It took only a few minutes to run the 100,000 different combinations of knob settings. Out of all these model simulations, I saved the ones that came close to the observed temperature variations between 1900 and 2000. Then, I averaged all of those thousands of temperature simulations together, which produced the curve labeled 'PDO' in Fig. 25." [Ch. 6, Sec. 3, Kindle Locations 2058-2061].
In short, he chooses, then averages, the results that fit the data and, low and behold, he obtains a (not-very-good) fit to the data. This is just a lot of hand-waving, considering that the observations in Fig. 25 are nearly a straight line, aside from short-time scale fluctuations (which he does not address).
There are other parts of Spencer's technical arguments that I consider questionable. However, the assessment above is sufficient, I think, to discredit the author's science.
MY BOTTOM LINE. "Blunder" is a book that mixes a few interesting thoughts into a mish-mash comprised of paranoia and weak, sloppy (or just plain bad) science. Spencer's book does not convince me of either the conspiracy or the so-called scientific blunder of the IPCC (and most of the rest of the world's "foolish" scientists). Balancing the limited positive content against the extensive negative, I find the balance strongly tipped to the negative. Readers, beware (or skip it).