Bests & Worsts Reviews from Amazon

At first look, this book appears to be a well-documented rebuttal of the claims for man-made global warming. On closer examination, some flaws show up. 1) The main argument for man-made global warming is that CO2 and other greenhouse gases increase global temperatures by well-established physical principles. As far as I can see, Singer and Avery do not even address the physics of greenhouse gases. 2) To generate temperature predictions from these physical principles, climatologists use computer models (Global Circulation Models). Singer and Avery call these "unverified computer models" "so complex and massive that they can only be run on supercomputers" (pp 176-177). It's true that they are complex and massive, but not that they are unverified. Global Circulation Models can't explain local climate - they are not fine-grained enough, and can't explain remote past climate - the models require data inputs that are not available for the remote past. But they can explain and predict average global temperatures, and recent temperature changes are only explained by greenhouse gases. (If you think we shouldn't use atmospheric models, stop looking at weather forecasts - same physics, similar massive computer models, different time scale and geographic scope.) 3) Their opposition to CO2 as an explanation occasionally leads to absurd statements: "The amounts of CO2 already added to the atmosphere must already have 'used up' much - and perhaps most - of CO2's forcing capability" (page 10). This appears to be a reference to the fact that the effect of CO2 on temperature is logarithmic. However, we're nowhere near done with adding CO2 to the atmosphere. Under the most optimistic scenarios, the percentage increase in CO2 in the future will be greater than the percentage increase to date. More importantly, CO2 stays in the atmosphere for about 100 years, and its effects on temperature increase over time, so the impact of CO2 on global temperature is just beginning. 4) As an alternative to man-made global warming, Singer and Avery propose a 1500 year natural cycle. They substantially overstate the evidence for that cycle. They claim a large amount of evidence for the cycle from ice cores, when the only statistically solid evidence is from a Greenland ice core, and then only up to the end of the last ice age. As part of their evidence for the cycle, they cite a paper by Braun et al, whose authors say "that the 1,470-year cycles ended with the Ice Age." (Singer & Avery page 30). 5) Even if a 1500 year cycle exists, it is not an alternative explanation for global warming. At most, it is a partial explanation, and one for which there is no human control. Nothing in Singer and Avery refutes the physics of greenhouse gases or disproves that greenhouse gases are impacting global temperatures. And emission of greenhouse gases is, at least partially, under our control. Disclaimer: I am not a climate scientist. I believe I have that in common with most of the reviewers of this book. If you want to be an informed consumer, I'd strongly encourage you to see what climate scientists think of the book. I think I'm not supposed to put URL's here, so do a web search on "Real Climate." There's lots of discussion on the site on global warming and greenhouse gases. In particular, see an article from 20 Nov 2006 called "Avery and Singer: Unstoppable hot air." When you want a break from the technical details, I'd also recommend "The Sheep Albedo Feedback" from 1 Apr 2007.