Lindzen Illusion #7: The Anti-Galileo

Richard Lindzen is one of the most prominent and widely-referenced climate scientist "skeptics".  After all, there is a scientific consensus about anthropogenic global warming, so there are few climate scientist "skeptics" to choose from.  Lindzen has researched climate science for four decades, since the field really began to grow and develop in the early 1970s, has published hundreds of peer-reviewed papers, works at a prominent academic institution (MIT), and has been a "contrarian" for most of his career. 

So his combination of expertise and "skepticism" make Lindzen an appealing figure to "skeptics".  He's even been compared to Galileo quite frequently.  But there's one major difference between Galileo and Lindzen: Galileo was right

Galileo's positions were based on and supported by scientific evidence.  Other scientists at the time also recognized that Galileo was right and supported by the evidence.  In this post we will see that Lindzen, on the other hand, has a history of consistently being wrong on climate issues, and his positions are contradicted by the scientific evidence and observational data.

Lindzen's Evolution

In his 1989 MIT Tech Talk, Lindzen summarized his many climate contrarian positions at the time:

  1. Earth hasn't warmed as much as expected
  2. the surface temperature record is wrong
  3. global warming is not a concern
  4. climate sensitivity is low
  5. the water vapor feedback is negative
  6. the cloud feedback is negative
  7. global warming is just due to internal variability
  8. water vapor is the most important greenhouse gas

Over the years, Lindzen's views have evolved somewhat, and some of these positions have fallen by the wayside.  Let's examine how his 1989 positions compare to his current views, and how they stack up against the observational data.  You would think a scientist's views would match observational reality, but as we will soon see, that's simply not the case for Lindzen.

Earth hasn't warmed as much as expected - this remains one of Lindzen's favorite arguments, which he makes in media articles on an annual basis to this day.  But as we saw in Lindzen Illusion #1, there is simply no truth to this argument.  When we consider all factors, including aerosol cooling and ocean thermal inertia, both of which Lindzen neglects in making this argument, we see that the planet has warmed almost exactly as much as climate models expect.

The surface temperature record is wrong - as we saw in Lindzen Illusion #2, in 1989, Lindzen didn't even put the GISTEMP observed warming trend (0.5 to 0.7°C since 1880) within his range of possible warming trends (-0.2 to +0.4°C since 1880).  As we now know, and as Lindzen would now admit, James Hansen and GISTEMP were right, and Lindzen was wrong.  The surface temperature record was and is accurate.

Global warming is not a concern - this argument is of course fundamental to global warming "skepticism", and thus one which Lindzen continues to subscribe to.  However, it's based on a conglomeration of Lindzen's many other incorrect arguments, and as shown in Lindzen Illusion #3, his arguments against taking action to reduce GHG emissions are based on logical fallacies and a lack of understanding of economics.

Climate sensitivity is low - this continues to be Lindzen's bread and butter argument, but as illustrated in Lindzen Illusion #2, temperature projections using low sensitivity simply don't match the observed warming trend.  Additionally, Lindzen Illusion #1 showed that the warming we've seen so far is inconsistent with low climate sensitivity.  Lindzen Illusion #4 demonstrated that nothing credible we've seen so far suggests sensitivity is nearly as low as Lindzen claims.  His low sensitivity argument seems to be based on little more than his own fundamentally flawed paper.

The water vapor feedback is negative - as we saw in Lindzen Illusion #4, Lindzen argued that water vapor could be a negative feedback due to a drying of the upper atmosphere until the mid-1990s, but had begun to reverse this position by the end of the decade.  Indeed, recent observational evidence has been consistent with the climate model projection of a strongly positive water vapor feedback.

The cloud feedback is negative - Lindzen Illusion #4 also discussed that Lindzen continues to believe the cloud feedback is strongly negative.  However, his "infrared iris" hypothesis has not withstood the test of time, and numerous recent studies have been inconsistent with a strongly negative cloud feedback.

Global warming is just due to internal variability - Lindzen continues to argue that internal variability may account for most of the global warming over the past century.  However, Lindzen Illusion #5 revealed this argument's Achilles heel: the oceans (including the deep layers) are warming too.  If the surface warming were simply due to heat moving around the internal climate system, from oceans to air, then the oceans would be cooling.  Moreover, we saw that Lindzen's argument was based on a misrepresentation of other climate scientists' work.

Water vapor is the most important greenhouse gas - although Lindzen no longer downplays the role of CO2 in the greenhouse effect, he continues to downplay its role as a global temperature driver, and many "skeptics" still argue that water vapor is a far more important greenhouse gas than CO2.  However, as highlighted in Lindzen Illusion #6, two recent NASA GISS studies demonstrated that CO2 plays a far larger role in the greenhouse effect than Lindzen claimed in 1989, and more importantly, is "the principal control knob that governs the temperature of Earth".

In short, of Lindzen's eight 1989 arguments listed above, he has effectively admitted that he was wrong on three points (temperature record accuracy, water vapor feedback, importance of CO2 as a greenhouse gas), but continues to make the other five.  However, none of these remaining five arguments mesh with observational reality.  But a useful question comes to mind, given the frequency with which "skeptic" arguments contradict each other: are these surviving arguments contradictory or self-consistent?

Lindzen's Consistently Cloudy Vision

Lindzen's surviving arguments are: Earth hasn't warmed as much as expected, global warming is not a concern, climate sensitivity is low, the cloud feedback is negative, global warming is just due to internal variability.  And indeed, we can create a consistent depiction of the climate system with these arguments.  

A strongly negative cloud feedback would allow for a low climate sensitivity, which would explain how the large anthropogenic GHG radiative forcing could have a small impact on global temperatures.  If the anthropogenic influence were overestimated, then Earth wouldn't have warmed as much as expected.  But if GHGs aren't driving global warming, there must be another cause.  Lindzen explains the warming through the natural internal variability of the climate system (although as Swanson et al. (2009) note, a climate system with larger internal variability will also tend to be more sensitive to external forcings).  And if the warming is just natural variability, it will soon reverse itself, and thus is of no concern.

So Lindzen does present a mostly coherent, consistent alternative hypothesis to the anthropogenic global warming theory.  There's only one problem: as discussed above, every single one of these arguments is inconsistent with the observational evidence.  You may have also noticed that every single one of Lindzen's positions have underestimated or downplayed anthropogenic global warming, which suggests they may be based on contrarianism rather than scientific evidence.

Lindzen has constructed a house of cards, with his incorrect conclusion (global warming is of no concern) sitting atop a series of incorrect beliefs which are each contradicted by the observational evidence.  Indeed, when asked by then-Senator Al Gore why he believed water vapor and clouds generate a negative feedback in a 1991 Congressional hearing (Page 71), Lindzen responded:

"as far as we can tell every model predicting an excess of 2 degrees [sensitivity to doubled CO2] is predicting more [warming] than we already have seen."

In short, Lindzen's "no concern" argument is based on his "low sensitivity" argument, which is based on his "clouds are a large negative feedback" argument, which is based on his "Earth hasn't warmed as much as expected argument.  It's just one huge chain of wrong arguments based on other wrong arguments, finally leading to a very wrong conclusion.

With this history of being wrong, the comparisons to Galileo seem wholly inappropriate.  There is of course nothing wrong with being occasionally mistaken in science.  The problem arises when a scientist is consistently wrong and fails to learn from the corrections advanced by other scientists or by nature, especially when we're asked to believe that he is right and virtually every other scientific expert is wrong. 

Galileo was not a contrarian who was purely motivated to contradict Catholic beliefs.  Galileo's key feature is that his conclusions were dictated by the scientific evidence.  If anything, Lindzen is the anti-Galileo, as his conclusions seem to be based on pure contrarianism instead of scientific evidence.  Indeed, this seems to be a common feature among self-proclaimed global warming "skeptics", which is likely why Lindzen is held in such high regard despite his dismal climate record.

NOTE: clicking John Cook's snazzy Lindzen Illusions button at the top of the post will take you to our comprehensive Lindzen page (short URL, with tabs for Lindzen's quotes, articles, arguments, our Lindzen blog posts, and relevant external links.  It's identical in format to the Monckton Myths page

Posted by dana1981 on Friday, 13 May, 2011

Creative Commons License The Skeptical Science website by Skeptical Science is licensed under a Creative Commons Attribution 3.0 Unported License.