Don’t Forget Climate Change: Chapter 3 Richard Lindzen

The story so far, I’m reviewing chapter by chapter a book from a dodgy Australian rightwing think tank on climate change.


Intro, Ch 1, Ch2, …

Chapter 3 is another heavy hitter: Richard Lindzen.

The chapter is better described as disingenuous rather than weirdly misleading like chapters 1 & 2 and it is very much an example of Linden’s position. Lindzen is smart and like a lot of smart people he doesn’t like to be wrong or appear to be wrong. However, he found himself on the wrong side of the climate-change debate and now has to position himself so that he can join in the contrarian fun while avoiding some of the nuttier positions.

He starts by criticising people who accept that climate change is occurring for the way they use language.

“In a further abuse of language, the advocates attempt to rephrase issues in the form of yes-no questions: Does climate change? Is carbon dioxide (CO2) a greenhouse gas? Does adding greenhouse gas cause warming? Can man’s activities cause an increase in greenhouse gases?

Personally, I’d have asked that last question slightly differently as “Has human activity caused an increase in greenhouse gases?”. I think Lindzen would still answer yes. But would others? Linden is giving up yet, though. He goes on to say:

“These yes-no questions are meaningless when it comes to global warming alarm since affirmative answers are still completely consistent with there being no problem whatsoever; crucial to the scientific method are ‘how much’ questions. This is certainly the case for the above questions, where even most sceptics of alarm (including me) will answer yes.”

Lindzen is positioning his argument in a place that is sometimes called Lukewarm. The position of the Lukewarmers is that all the basic principles behind global warming are true (see Lindzen’s list), plus other things such as the temperature record are accurate and climate modelling being feasible. Where the Lukewarmers disagree with the ‘consensus’ position is on an issue that Linden highlights in this chapter.

Climate sensitivity is a key question in the issue of global warming. Put simply, it is the question of how much warming we get if we double the amount of CO2 (and other greenhouse gases) in the atmosphere. The Lukewarm position is that the amount of warming we should get is smaller than currently thought but not zero. If they are right then much of the urgency about climate change is misplaced.

Lindzen describes it like this:
“The term climate sensitivity has come to refer to the equilibrated response of global mean temperature anomaly to a doubling of CO2. Because of the logarithmic dependence of the radiative impact of CO2, it doesn’t matter what the starting value for the doubling is. “

Lindzen points at the instrumental record as evidence that sensitivity is low but concedes that the current belief of many climatologists is that this is misleading. A cooling effect (it is argued) caused by aerosols from industrial processes have a cooling effect which masks some of the warming.

Linden argues otherwise and cites his proposed ‘iris effect’ (R.S. Lindzen, M.D. Chou and A.Y. Hou, “Does the Earth have an adaptive infrared iris?” Bulletin of the American Meteorological Society, Vol. 82 (2001) 417-432) as a possible mechanism that would reduce the positive feedback caused by water vapour. Remember water vapour? This book will flit between authors pointing out what a powerful greenhouse gas water vapour is (to contrast it with the relative puny CO2) and more astute authors trying to find ways in which water vapour isn’t the problem that the hypothesis of anthropogenic global warming says that it is.

But back to the iris effect. The name is a metaphor – in bright light the human iris changes to reduce the amount of light entering the eye. Lindzen does not argue that the atmosphere literally has an iris but rather that increased warmth leads to increased atmospheric water vapour (as in the standard model) but that vapour then impacts on high-level cloud formation which then limits additional warming – particularly in the tropics. In Lindzen’s model, this iris effect is a powerful negative feedback which offsets the positive feedback from water vapour.

There should be a name for this: perhaps “climate sceptical irony”. It afflicts the small number of so-called climate sceptics who make at least semi-serious attempt to engage with the science. The problem they have is that simply dismissing the science of global warming leaves a significant set of residual facts i.e. if anthropogenic global warming isn’t happening then a lot is left inexplicable. Consequently, Lindzen (or somebody like Roy Spencer who doesn’t appear in this book) have to provide their own pet theory to explain the discrepancy. At that point, having exhorted us to be sceptical of scientific evidence and scientific authorities, we are supposed to accept this new theory as clearly correct. The ironic truth of climate scepticism is that it depends so very strongly on credulity. has a lengthy article on Lindzen’s iris effect. It is a hypothesis that was taken credibly and generated interesting lines on inquiry – so it shouldn’t be dismissed out of hand, Lindzen’s work is not crackpottery but that also doesn’t mean it was correct. Remember Patrick Michael’s point in Chapter 2 about the Popper-model of the scientific method? Lindzen’s iris hypothesis met the criteria of a genuine scientific hypothesis in that it implies facts about the world that can be tested by observation. And that is what NASA researchers did and what they found was…the iris hypothesis didn’t match observation. Lindzen has been plugging away ever since and recently there has been at least one ray of hope for the Iris Effect – researcher’s tweaked some aspects of a climate model and found some indication of an iris effect after changing the right parameters. Yeah, but climate models aren’t ‘evidence’ according to Chapter 1.

Lindzen has been plugging away ever since and recently there has been at least one ray of hope for the Iris Effect – researcher’s tweaked some aspects of a climate model and found some indication of an iris effect after changing the right parameters. Yeah, but climate models aren’t ‘evidence’ according to Chapter 1.

Lindzen then goes on to some more standard complaints and oddly devotes a page to a weather map of North America but doesn’t really tie it in with his argument. He complains about claims of extreme weather and then trots out a standard cliche:
“even the term global warming is changed to climate change”
‘Climate Change’ has been a major term for decades – e.g.. the last two letters of the IPCC stand for ‘climate change’ and have never stood for ‘global warming’.

Lindzen then digresses into a short discussion of the Milankovich cycles and then that’s about it.

I feel like the book peaks about here. This was the smartest and most well-argued chapter and yet at best this Lindzen phoning in old arguments.



  1. Mark

    Hmmph, well, this sounds like an improvement on chapter 2’s Adventures in Misleading Graphs at any rate.
    The Iris Effect did sound like a more interesting attempt at critique – I think it’s undeniable that climate is a system that is too complex to ever model with 100% accuracy and there will undoubtedly be these perverse effects in the system (e.g. the aerosol effect you mentioned) so challenging existing models is both valid and a potentially useful contribution. It’s telling that no-one on that side of the debate has made much progress on it though – almost as if the scientific method has tested it and found it wanting.

    Liked by 1 person

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