Climate vs. Climate Alarm

This is the title of a 2011 talk by Richard Lindzen.

RL's conclusion is that the Climate Alarmists are wrong.

Here are some excerpts from the talk.
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The public perception of the climate problem is somewhat schizophrenic. On the one hand, the problem is perceived to be so complex that it cannot be approached without massive computer programs. On the other hand, the physics is claimed to be so basic that the dire conclusions commonly presented are considered to be self-evident.

Consistent with this situation, climate has become a field where there is a distinct separation of theory and modeling. Commonly, in fluid mechanics, theory provides useful constraints and tests when applied to modeling results. This has been notably absent in current work on climate.

In this talk, I will try to show how the greenhouse effect actually works using relatively simple basic concepts. We will see that the greenhouse effect, itself, presents little cause for alarm from increasing levels of CO2 since the effect is modest. Concern is associated with the matter of feedbacks that, in models, lead to amplified responses to CO2. Considerations of basic physics (as opposed to simply intercomparing models) suggests that current concerns are likely to be exaggerated. A variety of independent arguments all lead to the same conclusion.

All attempts to estimate how the climate responds to increasing CO2 depend on how the climate greenhouse actually works. Despite the concerns with the greenhouse effect that have dominated environmental thinking for almost a quarter of a century, the understanding of the effect is far from widespread. Part of the reason is that the popular depiction of the effect as resulting from an infrared ‘blanket’ is seriously misleading, and, as a result, much of the opposition that focuses purely on the radiation is similarly incorrect. The following description is, itself, somewhat oversimplified; however, it is probably adequate for understanding the underlying physics.

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As we have seen, the simple existence of the greenhouse effect is neither new nor a cause for alarm. The critical issue is one of feedbacks. This is not a technical detail; it is central, and there is ample reason (as we have already seen) to think that current models are substantially exaggerating the feedbacks.

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I hope that what has been shown demonstrates that increasing CO2 and greenhouse warming are not at all indicative of alarm, and that there is ample evidence that the system is not particularly sensitive. Moreover, the high sensitivity of some current models would render the stability of the earth over 4.5 billion years dubious. Engineers have long recognized this and generally avoid feedback factors greater than about 0.1.