New paper: climate models too sensitive

Climate sensitivity is the key to the AGW conundrum – how much will global temperatures respond to the extra forcing caused by anthropogenic carbon dioxide. If it’s nothing, or a few tenths of a degree, there really isn’t a problem. If it’s six degrees, there’s a problem.

Unsurprisingly, the majority of the consensus climate models indicate high sensitivity, meaning that in the IPCC’s view, it’s a problem that must be tackled.

However, Richard Lindzen and Yong-Sang Choi have prepared a new paper looking at real-world observations in an attempt to pin down climate sensitivity. The abstract contains the following:

We develop a method to distinguish noise in the outgoing radiation as well as radiation changes that are forcing SST [sea surface temperature] changes from those radiation changes that constitute feedbacks to changes in SST. We demonstrate that our new method does moderately well in distinguishing positive from negative feedbacks and in quantifying negative feedbacks. In contrast, we show that simple regression methods used by several existing papers generally exaggerate positive feedbacks and even show positive feedbacks when actual feedbacks are negative.  

And the conclusion states:

Our study also suggests that, in current coupled atmosphere-ocean models, the atmosphere and ocean are too weakly coupled since thermal coupling is inversely proportional to sensitivity (Lindzen and Giannitsis, 1998). It has been noted by Newman et al. (2009) that coupling is crucial to the simulation of phenomena like El Niño. Thus, corrections of the sensitivity of current climate models might well improve the behavior of coupled models, and should be encouraged. It should be noted that there have been independent tests that also suggest sensitivities less than predicted by current models.

Most claims of greater sensitivity are based on the models that we have just shown can be highly misleading on this matter. There have also been attempts to infer sensitivity from paleoclimate data (Hansen et al., 1993), but these are not really tests since the forcing is essentially unknown given major uncertainties in clouds, dust loading and other factors. Finally, we have shown that the attempts to obtain feedbacks from simple regressions of satellite measured outgoing radiation on SST are inappropriate. 

Sensitivity is one of the key areas of climate research. Whether you subscribe to Lindzen and Choi’s view, or the IPCC’s, one thing is certain. The science is most definitely not settled.

Download link here (PDF).


  1. Unfortunately, Lindzen is often dismissed by alarmists, and usually ad hominem in regards to where his funding comes from, rather than the more valid method of actually reviewing his research, which won’t change veracity regardless of how much his funding is, and where it comes from.

    Of course alarmists are ready to believe any scientist that supports AGW theory regardless of how much government funding they receive.

  2. The key line is based on OBSERVATIONS – 0.7 degree warming for a doubling of CO2. The IPCC’s models use guesses.

  3. Simon, you are spot on – the science is far from settled.

    A little know fact is that the IPCC’s computer modelling is only up to 60% accurate, at best. Traditionally, scientists report results at between 95% – 99% confidence levels but where climate change is concerned, up to 60% confidence level is accurate enough and the results are much less likely to be correct than scientific research is generally expected to be. See here and here.

    It’s probably got to do with the fact that current computer models are unable to do: water/ice/snow predictions, water vapor, wind, clouds, ocean oscillations, atmospheric oscillations, ocean currents, polar ice sheets, positive feedback, negative feedback, climate sensitivity, aerosol impacts, submerged volcano impacts, solar/cosmic impacts, monsoons/hurricanes/typhoons, ocean heat, missing heat, missing CO2, minimum surface temperatures, maximum surface temperatures, regional warming/cooling, and of course, global warming. See here.

    So the only thing that is settled is that climate modelling is crap!

  4. the models used are GCM’s. people confuse the “C” in GCM’s for “climate” when in fact the “C” means CIRCULATION along with a heavy dose of ASSumption…

  5. justmeint says:

    talking about being too sensitive…. it reminds me of another article ( ) I read recently which expounded on the fact that far too many medical tests ordered by doctors these days are too sensitive (EG Mamograms and PSA tests) which lead doctors to undertake expensive and not necessary tests, more tests, expensive surgical proceedures and drugs etc.

    The tests they are supposedly running on the climate would also fall into this category me thinks… creating and causing undue worry and concern about something that probably is not going to happen!

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