Deniers R Us – Richard Lindzen

Posted on August 4, 2012

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Richard Lindzen’s Seven Climate Errors

In 1989 Richard Lindzen made seven claims about climate change.  These seven things, he told us, proved that there was nothing to get concerned about with climate change.

Don’t worry, be happy

With three of these seven claims, even Lindzen now admits he was wrong.

Lindzen’s Three Take-Backs

In 1989, Lindzen claimed the surface temperature record was wrong.  He now concedes their accuracy.  Notably, the recent Berkeley BEST study headed by “converted” climate skeptic, the physicist Richard Muller, (and financed with ironic seed-money from oil mega-magnates Koch Brothers), has again confirmed the accuracy of these records.

Lindzen also claimed in 1989 that the effects of water vapour feedback on the climate would be negative, cooling the climate in opposition to the warming effects of CO2. . Consistent observational evidence, however, shows this feedback to be strongly positive—just as climate models predicted.  Lindzen has backed down on this claim.

Lindzen also said that water vapour rather than CO2 was the most important greenhouse gas.  Of course CO2 persists in the atmosphere for hundreds of years and water vapour drops out quite quickly as rain, etc., which Lindzen well knew.  His conclusion was founded on how well he thought each gas trapped energy, that is, on his assessment of their relative potencies as greenhouse gases.

“With CO2 one is talking about three watts per square meter at most,” Lindzen said, “compared to a hundred or more watts per square meter for water.”  He also thought that if you added together the relative greenhouse warming effect of water vapour and clouds they would represent at least 30 times the warming effect of CO2.

Okay (his argument went) while the residence time for water vapour in the atmosphere might be short compared to CO2, it just so potent while it’s up there that it overwhelms the influence of other greenhouse gases including CO2.

Except not really.

Two studies, Lacis et al. (2010) and Schmidt et al. (2010), contradict Lindzen.

Rather than 100 watts per square metre, water vapour actually generates 80.  Lindzen over-estimated water vapour’s potency as a greenhouse gas by 25%.

For CO2, his estimate was low by a factor of ten.  CO2 generates 30 watts per square metre, not three.

So of course he was wrong about clouds and water vapour being 30 times more potent than CO2.  The actual evidence puts the difference as somewhat less than 4 to 1.

Lindzen has abandoned this third talking point as well when discussing climate change.

Lindzen’s 4 Remaining Assertions

Lindzen continues to rely on four of the seven claims he made in 1989.  The remaining claims, taken together, actually represent a broadly consistent pattern of thinking.

The first of these, that climate sensitivity is low, that is, that the effect of adding climate drivers like CO2 to the atmosphere will not bring about the catastrophic rises in temperature that bodies like the IPCC are predicting, fits well with Lindzen’s second surviving claim, that the Earth’s climate has not warmed as much as has been predicted by climate scientists.  Mechanisms like the cooling effects of clouds, the third claim still surviving, would help account for low climate sensitivity.  In fact, as he insists in his fourth claim, what warming we have detected is not real warming at all and can probably be explained by natural variability, the cyclic sloshing of energy out of the oceans and into the atmosphere.

Unfortunately, self-consistency is one of the few scientific virtues of these four remaining theories.

Actually the world is warming exactly as expected.

Lindzen’s assertion that the Earth has not warmed as much as climate models said they would is in fact based on a fundamentally flawed and dishonest way of making the calculations.  Lindzen, in arriving at his own figure, simply makes a raw calculation of the effects of CO2 and other greenhouse gases.  He fails to subtract the well-known countervailing effects of aerosols—pollutants that cool the planet—or to account for the heat storage going on in the oceans.  Aerosols damp down the warming effects of CO2.  The oceans store much of the excess heat pulled into Earth’s climate system by greenhouse gases, with the effect of slowing down overall surface warming.  But that doesn’t mean that the warming is not there, in potentia, waiting to be released over time.

Given these necessary corrections to Lindzen’s calculations, in fact global warming is proceeding exactly as predicted by the IPCC.  The IPCC, unlike Lindzen, didn’t leave aerosols and all the world’s salt seas out of their calculations.

Natural variability doesn’t explain the warming oceans.

Lindzen’s assertion that climate change is down to natural variability fails, because, once again, it doesn’t account for the oceans.  Physics says that if heat flows out of something, then that something gets colder.  If the oceans are a part of a natural cycle which temporarily lifts worldwide surface temperatures by distributing heat from the oceans to the surface, as Lindzen’s natural variability theory suggests, then, after a third of a century of steadily rising surface temperatures worldwide, the oceans which supposedly have shed all of this heat ought to be showing signs of a lot of cooling.  But they’re warming too.  A lot.

In fact, Lindzen’s theory fails hugely on this point, since it fails to account for the vast majority of Earth’s warming—which is accumulating in these same oceans.  The continuing rise in the heat content of the world’s oceans is a complete answer to Lindzen’s argument.

And no, the clouds won’t save us from warming

Lindzen’s thesis that cloud feedbacks would be strongly negative, countering the warming effects of greenhouse gases, has been contradicted by a number of recent studies:  Fu et al. 2001, Hartmann and Michelsen 2002, Lin et al. 2002) Chang and Coakley 2007, Eitzen et al. 2008, Clement et al. 2009, Lauer et al. 2010 and Dessler 2010.  Dessler, while not absolutely ruling out a weak negative feedback from clouds, calculates that the actual climate feedback is much more likely to be positive than negative, warming rather than cooling.

The case for low climate sensitivity hasn’t been made.

Lindzen’s remaining fall-back argument is low climate sensitivity.  If climate sensitivity is low, as he suggests, then we don’t have to worry about the amount of CO2 we are putting into the atmosphere.  The affect of greenhouse gases on the climate won’t be as devastating as all those other legions of climate scientists are predicting, he insists.

Of course his miscalculations about the potency of CO2 as a greenhouse gas, the failure of his hypotheses about the cooling effects of cloud and water vapour feedback, his failure to make the case about a flawed temperature record, his failure to make the case that the climate is not warming—all have, in one way or other, undermined Lindzen’s case for low climate sensitivity.  The fact that he holds on to this assertion when all his other assertions have failed, shows a peculiar stubbornness.

Can Lindzen make a case for low climate sensitivity?  He would have to prove that predictions based on low sensitivity were more accurate than predictions made according to the standard estimates of climate sensitivity generally accepted by mainstream climate scientists.  The following graph plots predictions à la Lindzen against actual measurements of global temperatures.  Included for comparison are predictions made by James Hansen from 1988.

As the graph shows, Hansen’s predictions made on the basis of higher climate sensitivity closely follow reality, the GISTEMP line.  On the other hand, Lindzen’s predictions made on the basis of low climate sensitivity are moving progressively further away from the reality.

Richard Lindzen has consistently fallen short in terms of providing scientific backing for his assertions.  He has had a lifetime of failure, resulting from his consistent backing of scientific ideas simply because they represented an outcome he obviously preferred, for whatever reason.

Lindzen has some need to live in a world in which climate change is not happening.  There are few other explanations available for a career consistently on side of climate change denial, a career of consistent refusal to follow the evidence.

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For a more complete discussion of these issues see  http://www.skepticalscience.com/lindzen-illusion-7-the-anti-galileo.html and associated links.