A Little Common Sense Is Not Out of Place, Even in Climatology — Why MIT’s Global Warming Contrarian, Dr. Richard S. Lindzen, Is Probably Wrong

© 2012 Peter Free

 

09 May 2012

 

 

Citation — to pertinent New York Times article that discusses Dr. Lindzen’s climate-contrarian idea

 

Justin Gillis, Clouds’ Effect on Climate Change Is Last Bastion for Dissenters, New York Times (30 April 2012)

 

 

Citation — to the Climate Progress blog entry on the same subject

 

Joe Romm, ‘Hug The Monster’: Why So Many Climate Scientists Have Stopped Downplaying the Climate Threat, Climate Progress (07 May 2012)

 

 

What this essay is about — common scientific sense and probabilities

 

Anthropogenic climate warming deniers have reportedly seized on contrarian MIT atmosphere researcher Richard Linzdzen’s thinking that decreased tropical cloud cover — resulting in increased infrared radiation to space — will cool the planet enough to offset the warming effect of human-increased greenhouse gases.

 

Dr. Lindzen’s thinking is probably (but not certainly) incorrect, not only because the scientific consensus is that his research is flawed, but because he seems to be missing the overarching perspective that scientifically-derived common sense would provide.

 

Before addressing Lindzen’s decreased tropical cloud hypothesis, let’s establish a broadly applicable analytical framework.

 

 

An analytical aid — the Precautionary Principle — why has this received so little explicit attention in the climate debate?

 

Climate change is a prime example of a situation in which the Precautionary Principle could be used to rationally frame the debate regarding what to do in the face of uncertainty.

 

Note

I have addressed the Precautionary Principle before:

 

here — (where I defined it and discussed the overlooked potential utility it might have held in preventing the Deepwater Horizon oil spill disaster)

 

and

 

here — (in possibly tedious length, in regard to the United Kingdom’s botched attempt, beginning in November 1986, to deal with the public health uncertainties that newly discovered mad cow disease had raised in the United Kingdom).

 

Properly used, the Precautionary Principle forces us to rationally discuss:

 

society’s goals;

 

the economic and social costs of non-action, partial action, and complete action;

 

and

 

the likelihood that the mechanisms we choose will actually work in achieving our chosen social goals.

 

 

The essential question in climate change is whether we should act now in preparing for potentially catastrophic outcomes — not whether apparently important elements of anthropogenic global warming can be proven beyond all doubt

 

The “to act” or “not to act” cost-benefit climate questions are not particularly difficult to analyze.  This is true, even in the face of scientific uncertainties about the scope and effect of probably coming developments.

 

Probabilities rule, just as they do everywhere else in science.

 

Yet, probabilistic thinking seems to go missing, just as soon as the debate leaves the science community and enters the political one.

 

 

Here are a handful of ordinary questions that should (but do not) characterize the climate change discussion

 

Cost-benefit questions raised by global warming exactly parallel those that routinely crop up in our day-to-day lives:

 

Is the phenomenon arguably real?

 

Does existing evidence show changes that could go in a potentially harmful direction?

 

How probable is it that an undesirable outcome would occur?

 

What is the severity range of the potentially bad outcome?

 

How catastrophic would it be, if even a low probability disaster eventually occurred?

 

Are there potentially workable remedies that could realistically prevent or ameliorate undesirable developments?

 

How much would it cost to:

 

(a) prevent undesirable change from occurring (probable or not)

 

or

 

(b) fix its effects, once it had occurred?

 

And, given these weighted costs and benefits, what (if anything) should we do now to mitigate, or budget for, probably harmful future phenomena?

 

 

Back to Richard Lindzen’s contrarian reduced tropical cloud theory

 

Because cost-benefit analysis is about (i) probabilities, and (ii) our willingness to tolerate low-chance catastrophes, roughly estimating the chances of “this and that” occurring is important for society.  This is so, even when scientific uncertainties remain significant.

 

This is where I take issue with Dr. Lindzen’s idea that decreasing tropical cloud cover will offset human-caused warming.

 

What is the probability that his hypothesis is true enough to count on in our calculations?  Near zero.

 

Why?

 

My answer depends on a (paraphrased) principle that the now deceased Professor Ernie Rost told his University of Colorado at Boulder physics class years ago:

 

Look at your answer to see whether its units and magnitude make ballpark sense, given the problem you are trying to solve.

 

Dr. Lindzen’s hypothesis fails this common sense magnitude test.  And it fails the equally common sense “what has happened in the past” review.

 

His conclusion implies that the planet has an in-built equilibrium system that keeps climatic conditions within the comparatively comfortable range they frequent today.  His solution also implies a connection between anthropogenically originated greenhouse gases and an automatically induced, warmth-offsetting decrease in tropical cloud cover.

 

But both these implications are preponderantly not true, based on climate research that has looked back thousands and millions of years.

 

Those findings indicate that the climate has, in fact, cycled rather dramatically through uncomfortable (for us) conditions.  And, in virtually each case, scientists have been able to tentatively point to causative mechanisms that tilted the warm-cold balance one way or another.

 

If Dr. Lindzen is correct that the generation of greenhouse gases prompts the offsetting contribution of cooling cloud cover, why did previous greenhouse gas-caused warmings occur?  What is present now that was not present then?

 

And why does Professor Lindzen think that the comparative magnitude of the decreased cloud cover will approximate the magnitude of the increase in greenhouse gases?  (This is the common sense magnitude question that Ernie Rost told us to examine in physics class.)

 

Dr. Lindzen’s only answer can be that the planet is insensitive to greenhouse gases.  But, again, the geological and paleoclimatological evidence appear to indicate that he is most probably wrong.

 

Although Professor Lindzen could (hypothetically) argue that the planet does indeed express a very wide-ranging climatic equilibrium — otherwise we would not be here — that is not the same as saying that conditions have always been as narrowly and comfortably pegged as they were during 20th Century.

 

Consequently, his implication that human contributions to global warming will be conveniently cancelled out (planet-wide) by decreased tropical cloud cover seems to be much less probabalistically plausible than the reverse (and scientifically prevalent) hypothesis.

 

 

The moral? — Common scientific sense can reduce highly questionable arguments to the low probability status that they deserve

 

If we can now dispose of Dr. Lindzen’s (probably) low probability argument — can we finally embark on a nuanced discussion of global warming and what (if anything) to do about it?