Arctic amplification dominated by temperature feedbacks in contemporary climate models

There's a paper in Nurture GeoSci entitled Arctic amplification dominated by temperature feedbacks in contemporary climate models by Felix Pithan & Thorsten Mauritsen (Nature Geoscience (2014) doi:10.1038/ngeo2071). As far as I know the paper is entirely sensible, though I've only read the abstract. From which I quote:

Feedback effects associated with temperature, water vapour and clouds have been suggested to contribute to amplified warming in the Arctic, but the surface albedo feedback—the increase in surface absorption of solar radiation when snow and ice retreat—is often cited as the main contributor... we analyse climate model simulations from the Coupled Model Intercomparison Project Phase 5 archive to quantify the contributions of the various feedbacks. We find that in the simulations, the largest contribution to Arctic amplification comes from a temperature feedbacks: as the surface warms, more energy is radiated back to space in low latitudes, compared with the Arctic... the surface albedo feedback is the second main contributor to Arctic amplification and that other contributions are substantially smaller or even oppose Arctic amplification.

So far, so analysis-of-climate-models. As I've had occasion to say in the past: GCMs can be good tools for studying climate, but alas they are nearly as complicated as the real climate system, so it can often be pretty hard to work out why they are doing something, even if you know that they are doing it.

But if you squint at the paper a bit through "skeptic"-tinted googles, it looks a bit like it is saying that the models have got it wrong, and that something else is the real effect. And this is what NoTricksZone has tricked itself with: the headline there, "Climate Modelers Flub Again…Albedo Not The Number One Arctic Amplifier After All!" says it all. In the comments I'm patiently trying to explain to them what the paper is really saying. There is some hope - there's an update to the post which rather plaintively says the claims made by the authors are based on “model simulations” which you might well have thought was the bleedin' obvious: "Here we analyse climate model simulations from the Coupled Model Intercomparison Project Phase 5 archive to..." is more than just a hint to the wise; although There’s no light the foolish can see better by.

Speaking of which, WUWT falls into the same error. And for a wonder, my comment pointing this out passed moderation. Even more astonishingly, more than one person has, though gritted teeth, admitted that I'm right.

Comments there: NTZ

You haven’t understood the paper. What the paper discusses are the mechanisms for Arctic amplification, as seen in climate models. The models the paper discusses are largely the same as the ones used before. So its not possible for these results to falsify the models, because these results are based on taking the model results at face value.

What you’re missing is the distinction between *understanding* the model results, and the construction of the models.

So “This casts many of the assumptions made in earlier climate models deep into doubt” is entirely wrong. The assumptions made in building the models aren’t challenged at all by this study. What this illustrates is the way the models are so complicated, it can be hard to know exactly why they do things.

FWIW, the idea that ice-albedo feedback isn’t the full answer has been known for some time; e.g.… discusses V A Alexeev et al, Climate Dynamics (2005) , which actually sounds distinctly similar to the new Nature paper.

got the reply:

Not really sure what you’re getting at. Wrong assumptions with right answers still means faulty models.

One thing is clear: 114/117 models have missed the barn so far. Models have been hopelessly inadequate, biased in one direction. In general the paper in my view is rather murky and, should it come out from behind the paywall, it would be interesting to get a closer look at it.

So there's a regrettable failure of understanding, and a not-hard-to-predict attempt to deflect the conversation.

My reply took two attempts to get through:

> Wrong assumptions with right answers still means faulty models

There is no suggestion from the paper in Nature that the assumptions in the models are wrong, or that the models are wrong. The Nature paper presents a new analysis of the models, and that analysis suggests that “the surface albedo feedback… [which] is often cited as the main contributor… is the second main contributor to Arctic amplification”.

> what Spiegel writes

I can find nothing in the English translation of the Spiegel article which supports your assertion. I can see how a rather hasty (and from your point of view, hopeful) reading of the article, or the Nature paper, might suggest that.

I hope you can understand the point I’m trying to make: this doesn’t challenge the assumptions, or the results, of the models at all. It makes no suggestions that the models are in errors. It merely presents a new analysis of the model results.

I don't think I'm getting through.

Comments there: WUWT

My opening bid was:

> climate models need to be reworked

You seem to have made that up. Its not in the paper.

REPLY: It’s an opinion. much like many of your Wikipedia entries – Anthony

since I didn't feel inclined to waste my pearls of wisdom if they were going to be suppressed. But they weren't (indeed, AW replied, I've just noticed that so I've added it in here. He doesn't seem to understand that its not an opinion; this is a matter of the actual statements in the paper), so I replied to "Graeme W" with:

> Much as I hate to agree with Mr. Connolley,

Dr. But apart from that, yes, you’re correct. This is an analysis of model simulations. The article makes no claim at all that the models are flawed, all it is doing is analysing the actual causes of a certain affect *in the models*. The suggestion that “climate models need to be reworked” appears to be an interpolation by our host, possibly based on the post at NTZ, which has made a similar error.


which drew a reply

REPLY: Yet, CMIP5 models still don’t match reality. So yes, they need to be reworked on many levels until they can properly predict climate with accuracy. The dialing in Arctic albedo and feedbacks (plus many other things) aren’t quite there yet. If they were, we’d see better agreement in graphs like this one:…

Unless of course, you’d like to argue that models are “good enough” and need no improvement whatsoever.

So I think the shape of the argument for the defence starts to become clear: ground will shift away from what this article actually says, onto "models aren't perfect", which is dull. I replied (I've corrected the spelling of CMIP here):

That the CMIP simulations aren’t perfect would be agreed by all who work on model development. But that’s not the point here: which is that *this study* provides no evidence for that assertion; its entirely orthogonal to that idea, since its an analysis of model output. I don’t know what you mean by “dialing in Arctic albedo”; that appears to continue your misunderstanding of the paper. The paper isn’t suggesting the models should “dial in” the albedo at all. All its doing is presenting an interpretation of the model results.

which drew in return

REPLY: And you are honing in on a headline, not the body, tough noogies if it upsets you. The fact remains that

1. CMIP Models still have a poor understanding of feedbacks
2. CMIP Models still don’t have a handle on real-world albedo changes
3. CMIPModels aren’t matching reality as measured

Hence, they need to be reworked. I’m not going to change the headline simply because you interpret it in your own special way. Now run along and write up your usual smear.

So, yes, the defence shifts, and he also attempts to use the "headline defence", which is weird, because although headlines in the Meeja are often crap, that's because they're written by subs. In this case, he's written it himself, so "blame the headline" is no defence at all.

> honing in on a headline, not the body

Not at all. Later on you include: "This casts many of the assumptions made in earlier climate models deep into doubt. It’s back to the drawing board (again) for the modelers."

This is as wrong as your headline. As I said, that models can be improved is doubted by none, but what we're talking about here is this study.

> Please provide a clarification which would remove the ambiguity in your post.

Mmmm, this is difficult. (a) and (b) are wrong, because the study doesn't talk about errors in the models. (c) is wrong, because the study isn't really talking about nature very much. I think you're missing the basic point: this study is about the interpretation of model output; its trying to work out what processes in the models are responsible for a certain result in the models. Models are complicated things; its often not at all easy to work out why they do what they do.

(that last abc bit is in response to some drivel by richardscourtney. My response has been disappeared, but Windchasers says much what I would have).


* Harry Potter and the Polar Amplification of Global Warming
* Polar amplification, again - wherein I somewhat prophetically note that People constantly get polar amplification wrong. That post does cast some doubt on the novelty of the Nurture thing, though.

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"> climate models need to be reworked

You seem to have made that up. Its not in the paper.

REPLY: It’s an opinion. much like many of your Wikipedia entries – Anthony"

Very telling response. Anthony thinks his OPINION about what is in the paper is more important than what is ACTUALLY in the paper...

[Yes, odd, or rather not odd. I've now started copying the comments into my post, to save people going to look. My suspicion at this point is that I've outstayed my welcome and am now banned again -W]

Even better: "REPLY: it’s an opinion, are you prepared to argue that models should not be reworked, updated and improved? – Anthony"

So, basically, because models are not perfect, it is ALWAYS acceptable to say that climate models need to be reworked. The following are all accepted (and probably common) phrases in the Watts-household, "Please pass the salt, climate models need to be reworked." "I like ice cream, climate models need to be worked." "Honey, I'm home, climate models need to be reworked!".

Authoritarians like mr.Watts always want definitive instructions for work, so they're inherently incapable of comprehending science, that proceeds through minimizing the errors. They've got no trouble at all taking some 18th century physics and applying it to f.e. automobile tuning, since there are definite formulas which work pretty decently in the system of their choice. It's the difference between modern science and victorian science that might be the source of their confusion about the more complex models, but no doubt there are other reasons (emotional attachments to their tuned automobiles f.e.?) to deny the results of modern climate science. In fact, I think part of J.Currys dichotomial behaviour in the matter is also driven by emotion, thinking of the potential effects of AGW to humankind isn't uplifting, nor promoting thoughts of secure continuation of the lifestyle based on continued growth of economy..

Check out the new headline/intro at NTZ. "A reader points out." Heh.

[Fun! I replied, and I'll paste here to keep it in case it doesn't make it through:

> A reader has pointed out that

Well, you've updated yourself, that's good. I notice though that you can't quite bring yourself to give me credit by name.

> as skeptics have long maintained

That's dishonest though. All the "skeptics" do is chant "there is no GW! There is no Arctic amp!" Not a single one of you ever said "albedo [sic] isn't the major driver of Arctic amp".


...more energy is radiated back to space in low latitudes, compared with the Arctic...

Perhaps I'm missing something but isn't this just an expression of the Stefan-Boltzmann Law. The amount of extra energy emitted is smaller in the Arctic per ºC warming simply because temperatures are lower.

[But how the energy moves can be important too. In the tropics, you have a huge Hadley circulation lifting it upwards; near the poles it might struggle to get out. I do confess, I haven't actually read the paper -W]

I am trying to understand why the global warming dissenters are so hung up on the results from the models, this came out during the UK Parliament HoC Energy and Climate Change Committee hearing as well.

Just a convenient red-herring?

In my mind the models are just a tool to help the climate scientists understand the physical processes, and maybe make some general predictions. And if the model includes a stochastic component, no one would expect them to exactly model the physical process.

[If the WUWT and NTZ reactions to this paper are any guide, the reason they're hung up on the models is because they completely fail to understand them. They do know what results the models produce, and they do know they don't like them, but that seems to be about it -W]

Interesting abstract. Correct me if I'm wrong but it seems to saying through analysis that mid-latitudes cool faster than arctic latitudes. It would be interesting to see that interpretation mixed in with the 0-700m ocean temperatures. The paper's model interpretation seems more intuitive if open ocean radiation is different by latitude. It would also interesting to see if antarctic feedbacks differ in magnitude in the model.

By Tim Beatty (not verified) on 05 Feb 2014 #permalink

My last post was about WUWT (and 2 other ostrich blogs) not publishing my neutrally worded comment. I wonder whether that helped your comment getting published. :)

[I saw yours. I think, as someone said at yours, that its a good idea to write these down -W]

By Victor Venema (not verified) on 05 Feb 2014 #permalink

Another climate skirmish.

Seems the Nurture [sic] paper was misterpreted by an overeager side 1. But the glee suggests an equally eager side 2. As does the name calling. And the "aren't perfect" meme.

I'm struck that interpreting the tools warrants an effort equal to a Nurture [sic] paper. Kind of makes you wonder about the kit.

[Science can get complicated. Believe it or not, some people even have trouble understanding GR or QM. Some people would struggle to write out the equations which form the dynamical core of a GCM. Isn't that weird? -W]

But I guess this modern science thingy has different rules than the old science which was so ineffective... oh wait.

The most meaningful climate impact to date is reducing grown men, women (and self proclaimed scientists) to primary school grinder chants and taunts.

I understand that, in the extreme, some leporidae begin referring to themselves in the third person.

I believe the correct Internet-approved response to kdk33's comment is "What is this I don't even".

Science is most complicated when it isn't understood. It tends to be less so once it is figured out.

[Indeed; like GR, or QM, as obvious examples, no? Haven't we, errm, already done this bit? -W]

My point, of course, is that neither side has claim to the moral high ground.

[This is the traditional "false balance" argument. Its a meta-argument; a "oh dear its all too complicated for me"; its what the "skeptics" often retreat to once all their actual arguments have been refuted -W]

The IR spectra of CO2 is a powerful argument. But, AFAICT, all the models are wrong and all on the hot side and that is also a powerful argument. Claims of rampant fraud aren't helpful, but it is naive to ignore the incentives acting on the academics. Scientists are people and skeptics are people and people are known to behave sometimes badly and bad behavior does not correlate with citation counts.

A recent comment noted that engineers tend to be skeptics because they are conservative. The implied logic: conservative leaning engineers can be trusted to build computers, cars, airplanes, highrise buildings, and bridges, but not to objectively assess climate science. And that fairly well pegs the level of discourse on the topic - here and elsewhere.

The question at hand is: what should we do. I tend to think nothing. But thats me.

[I think you should refraim from putting unsupported opinion down; its obviously worthless -W]

A interesting topic for future posts: would 2F warming be good or bad and why.

-W Thank you for the reply,

I don't know what moral high ground has to do with "it's all too complicated for me".

[You lack discrimination. You need to try thinking, and reading, not just writing -W]

I am unaware that the moral highground says anything about the technical argument. Or that it has ever been a "skeptic" argument. You seem confused, so let me try to help you out.

The name calling and gloating and the posting on your blog your clever comments on other blogs so that you and your chums can laugh is all very childish. It is perfectly not technical. It is the same at other venues (I confess to enjoying a bit myself, from time to time). This makes the climate wars amusing and entertaining, but ultimately fruitless.

Another interesting topic for a future post: What would -W have us all do to lower CO2 and why.

kdk33 - You conflate many things in your posts and few of the thought streams are fleshed out fully enough to give a reasonable rebuttal.

For example,"A recent comment noted that engineers tend to be skeptics because they are conservative. The implied logic: conservative leaning engineers can be trusted to build computers, cars, airplanes, highrise buildings, and bridges, but not to objectively assess climate science. And that fairly well pegs the level of discourse on the topic – here and elsewhere.

Now, a hundred dozen different public opinion surveys will provide evidence that conservatives and liberals views on climate change, global warming, AGW, whatever significantly differ. The commenter only recites the anecdotal experience that most people that frequent climate science blogs would agree with - that the most insistent and delusional cockamamie ideas often come from engineers. They have enough intelligence to devise truly ingenious ways to 'explain' anything - except it's usually nothing more than mathturbation because they don't want to take the time to actually study the science.

Is this a fair and accurate portrait of engineers? Probably not. But the vocal ones that get noticed ruin it for all of the others (one bad apple, etc). Of course Engineers are likely to be more economically conservative than the population as a whole, but on a host of other issues they're likely to be more liberal. The dichotomy of the effects of higher education and higher income.

At the level of national engineering societies a quick and hardly exhaustive Google search finds these statements in support of the theory of climate change:
American Society of Civil Engineers
International Council of Academies of Engineering and Technological Sciences
Chartered Institution of Building Services Engineers

More important, we trust them to build things they've been *trained* to understand. We also *want* them to be conservative when our life may depend on their dcalculations. But we no more expect an aeronautical engineer to build a skyrise than we do a civil engineer to design an airplane -regardless they be conservative or liberal. So, the idea that we trust an aeronautical engineer to design an airplane, but can't trust his opinion on climate science is hardly irrational - in fact we shouldn't accept his opinion as 'expert' opinion on anything other than his area of expertise.

"And that fairly well pegs the level of discourse on the topic – here and elsewhere."

Really, Tamino gives virtual classes in statistics for free while taking apart denier memes. Eli Rabbett has walked through various aspects of atmospheric chemistry. WC has real insights to GCMs because he's *actually* worked with them. At Neven's new scientific papers are eagerly awaited, discussed, compared to previous works and an entire cottage industry of new arctic graphs has sprung up. Any thoughts of equivalence to WUWT or Goddard's or similar sites is delusional.

By Kevin O'Neill (not verified) on 08 Feb 2014 #permalink

[Sorry, you're too far off topic and too fact-free. Moved to the Burrow; you may feel free to continue the discussion there -W]

[Ditto. This isn't a free-fire zone -W]

[Meh, sorry. But I don't want this to turn into bickering, and I do want to be even handed. So do feel free to continue over at the burrow -W]

By Mal Adapted (not verified) on 08 Feb 2014 #permalink

Yeah, you're right, sorry. Too easy a target anyway.

By Mal Adapted (not verified) on 08 Feb 2014 #permalink

After a high minimum,

though probably not hit peak yet and of course there are other measures:…
could be a record warm average temperature north of 80N in the coldest month, February. Might this cause the volume gain to be rather low?

I am always a little uncertain about temperatures - is it more a case of thin ice causes warm temperatures than warm temperatures slowing ice growth? Maybe that is just Autumn and early winter. When ice thickness is approaching equilibrium thickness in late winter, might high temperatures be a sign of high ocean upward heat flux and is that likely to continue (even if only following a year with higher ice volume since the minimum than the last couple of years)?

Feedback models are based on wrong assumptions. The greenhouse radiative forcing conjecture starts with an assumption that there would be isothermal conditions [... Drivel copied to the burrow -W]

By Visiting Physicist (not verified) on 15 Feb 2014 #permalink

"Need I say more about this ludicrous travesty of physics?"

Your "ludicrous" example is actually reasonably close to reality at night, when the sun is no longer directly warming the ground. Deserts cool much more rapidly at night than humid areas do.

For example, I routinely camp in desert conditions where 70-90F temps during the day are the norm, with nighttime temps often falling below freezing. I've also camped in south Florida where daytime temps are in the low 80s or so, humidity very high, and nighttime temps drop no more than 10-15 degrees.

"Need I say more about this ludicrous travesty of physics?"

I'd be somewhat surprised if an entire subfield of physics is actually based upon a presumed violation of the 2nd law of thermodynamics. I think it's going to take more than a random post by a random blogger on the internet to convince myself, not to mention mainstream physicists, of this amazing and mind-blowing fact that has escaped all others for over a century.

Good luck, though. I'm sure you'll receive a kind welcome at WUWT …

[Try search for VS, you'll find him in the usual places. I'm afraid I burrowed his comment -W]