Update: “Climate Sensitivity Estimates: Heading Down, Way Down?”

A previous post at MasterResource described the findings and implications of a new scientific study published by Richard Lindzen and Yong-Sang Choi, “On the Determination of Climate Feedbacks from ERBE Data” published in Geophysical Research Letters.

Lindzen and Choi’s concluded that climate sensitivity to atmospheric greenhouse gas concentrations is six times less than generally accepted—a conclusion that potentially overturns the current paradigm of scientific thinking.

Their paper is now under careful scrutiny–as it should be. As I wrote:

This is a major paper. And as with most findings with serious repercussions to our scientific understanding, it will doubtlessly be gone over with a fine-toothed comb and subject to various challenges. It is too early to tell whether Lindzen and Choi’s findings will prove to be the end-all-and-be-all in this debate. There are a few issues concerning the quality of the satellite data, how well the results from tropics represent the entire world, the impact that the eruption of Mt Pinatubo may have imparted on the results, and perhaps a couple of other details. But, even if the resolution of these issues bumps up Lindzen and Choi’s original determination of the climate sensitivity a bit, there is still a long way to go before it comes close to the IPCC’s “best estimate” of 3.0°C.

 Now some of the early results are starting to come in.

MasterResource commenter “Rob” initially described some of his concerns with Lindzen and Choi’s conclusions in our original thread, and contacted Dr. Lindzen and other scientists actively working on the climate sensitivity issue to get their response. 

He has reported back last week with some interesting findings, and so we are taking this opportunity to reproduce Rob’s most recent Comment. It contains not only an acknowledgement from Dr. Lindzen that he will look into some of the concerns raised, but also links to more detailed discussions of some of the potential shortcomings in the methodology of Lindzen and Choi. 

It is still too soon to say what will come of all of this, but a good exchange of ideas has begun on this very important topic.

Comment # 22 from Rob from our original thread:

As promised, I contacted Dr. Lindzen himself. To my comments (above) on errors in the Lindzen and Choi paper, he writes :

“I have great respect for people outside this field who bother to seriously examine matters, and we will address your questions explicitly as soon as we can. ”

Now meanwhile, in a separate development, Luboš Motl picked up on my findings and contacted Dr. Roy Spencer for comment :

http://motls.blogspot.com/2009/11/spencer-on-lindzen-choi.html

Dr. Spencer published his own findings of the ERBE data yesterday, which support my criticism of Lindzen and Choi 2009:
http://www.drroyspencer.com/2009/11/some-comments-on-the-lindzen-and-choi-2009-feedback-study/

In this publication, Dr. Spencer essentially points out the same problems that I found in the Lindzen and Choi paper as well :

(1) The ERBE data shows no significant feedback;

(2) The AMIP models that Lindzen used (Graph C above) are not suitable for comparison with ERBE data;

(3) The short term analysis done makes conclusions on climate sensitivity questionable.

More comments are welcome on this and any aspect of climate science; the challenge is to get past ‘consensus’ to science.