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Discussion > Climate Senstivity and All That

Philip,

I will need to read the references you provided. I quickly scanned the second one; it is on an interesting topic (non-linearity and chaos), and this is indeed a topic that cuts across Dr Koutsoyiannis' work. At a first glance of that paper, there are some things to criticise, but I need to read it in more depth.

It looks interesting, and I will get around to it - perhaps just not today!

Oct 22, 2011 at 2:39 PM | Unregistered CommenterSpence_UK

"I backed away from this thread because I was just getting angry at BBD switching argument every time he was unable to support his position."

You are not the only one with this problem.

Oct 22, 2011 at 2:50 PM | Unregistered CommenterShub

Spence_UK

BBD's claim that low climate sensitivity is rejected from ice ages; so his view must be a strong one that no reasonable scientist would reject. In fact, his position is a minority one that just a few scientists hold.

Name the scientists that currently hold the view that glacial terminations are consistent with a low climate sensitivity. Other than Lindzen and Spencer, that is.

I'm working my way through your confused and confusing comments, but this will do for starters.

Oct 22, 2011 at 7:53 PM | Unregistered CommenterBBD

Let's be clear: BBD is relying on an obscure and little held view of Greenland to support his contention that the ice ages show high climate sensitivity.

No, this is the very latest thinking based on the most recent field work. Only someone determined to misrepresent would make such as statement.

Just to go back to where we started from. BBD argued that the *only* way to explain the ice ages was with a high climate sensitivity. This is a strong claim and requires that all reasonable alternatives be rebutted.

It isn't and they have been. Name the prominent climate scientists who support your view that glacial terminations under Milankovitch forcing are consistent with a low CS.

You are conflating two arguments:

- Did the GIS partly or substantially disappear during the Eeminan?

- Are glacial terminations triggered by very slight changes in RF consistent with a low CS?

(There's a third strand in the muddle, about the Antarctic ice sheet being older than the GIS. Of course it is. This is not in contention, nor is it relevant except that DK uses the Vostok series).

All this generates the confusion in your comments and obscures the lack of a coherent central argument. You disagree wrt Dahl-Jansen but apparently misunderstand what she is saying. Not that it matters as it has no bearing on the CS argument.

You think, per DK, that climate is essentially self-propelling and this somehow trumps the uncontentious statement that:

Small push = large change = high CS

Your view is only held by a handful of contrarians. You are of course entitled to believe whatever you wish, but do not expect others to agree with you. Especially as all the evidence points to a relatively high CS as a necessary condition for glacial terminations initiated by Milankovitch forcing.

The likely explanation is that you do not wish to accept the near-certainty that CO2 emissions are driving recent warming and will continue to do so.

Your tone above is offensive. If you wish to continue this discussion, do so in civil terms or I will not respond. I've had enough of this with Shub.

Oct 22, 2011 at 8:26 PM | Unregistered CommenterBBD

You are not the only one with this problem.

Yeah, I admit I had cut BBD some slack in the past, I didn't realise what a blockhead he/she/it was capable of being. Logic and reason are not BBD's friends, clearly.

Name the scientists that currently hold the view that glacial terminations are consistent with a low climate sensitivity.

And here we go, changing the argument again. Your claim was that we could rule out low climate sensitivity from the ice ages. I'm pointed out a specific example of how a low climate sensitivity is consistent with the interglacials, thus showing that there is a plausible route. To maintain your original claim, you must have a reason why this published viewpoint is incorrect.

I don't know what views other scientists hold because I'm not telepathic. I mean, what a stupid question. Beyond stupidity. So, have you taken opinion polls or surveys on this matter? How do you know they were answered truthfully? Do most scientists even have a view on this topic? Forget this BS, how about: what does the evidence point to? Try thinking for yourself!

No, this is the very latest thinking based on the most recent field work.

You can't explain it, yet you just *know* it is correct.
As I mentioned, (1) it isn't a new idea, it goes back to 1998 and it wasn't well accepted then, and (2) the only "new" thing mentioned so far by Dahl-Jansen is a model rigged to ensure the biggest problem with the claim isn't even addressed because it is assumed away. There may be more, but until you can actually present what that might be, we're wasting our time.

You disagree wrt Dahl-Jansen but apparently misunderstand what she is saying.

I DON'T KNOW WHAT SHE'S SAYING BECAUSE SHE HASN'T PUBLISHED YET. I suspect you don't know either. The only thing I have to work with is that link which contains no content other than the modelling with the constraint that nobody with a scientific bone in their body should be comfortable with as an explanation. Perhaps there is more, but apparently we don't know that yet, so it isn't worth discussing.

I'm very critical of people who claim to have scientific evidence for something when they rely on the abstract and clearly haven't read the paper. You've actually taken that to a new level - you don't even have an abstract. Are you really not embarrassed by this? At all?

Not that it matters as it has no bearing on the CS argument.

So you've wasted both of our time on a sideshow which was for what - to show that you believe papers that haven't been published, and that you haven't read yet, contain scientific truth? Sheesh.

Your view is only held by a handful of contrarians. You are of course entitled to believe whatever you wish

*facepalm*

This isn't about belief, BBD. It's about a published, scientific case presented in the peer-reviewed literature. It is a complete, coherent argument providing a model (complete with physical justification) of the natural variability of climate which has not been falsified.

This doesn't make it right, but unlike your Dahl-Jansen non-existent paper, there is a case and it is out there, in considerable detail, in the public domain. If you then insist that the glaciations can only be explained by high climate sensitivity, then you HAVE to be able to explain away this published position is wrong. If the best you've got is the hand waving you've posted above, then your original claim was incorrect. And it doesn't matter how many people "believe" it. What matters is the evidence to hand, logic and reason.

Your tone above is offensive.

My tone also becomes offensive when I debate 9/11 troofers, homeopaths and creationists online. I'm afraid I don't suffer fools gladly and you have now clearly crossed the line. You are no longer engaging in rational debate. It is now increasingly clear that your original claim is not supported by any facts or evidence other than apparent telepathic skills enabling you to understand scientific papers that you have not read (and that may not even be written) and your mind reading skills to work out beliefs and viewpoints of other scientists.

If that's the best that you've got, I'm not going to learn anything from this debate and I would fully encourage and support your flounce.

Oct 22, 2011 at 9:17 PM | Unregistered CommenterSpence_UK

"I've had enough of this with Shub."

Oh. come off it dude. You liberally pepper your posts with small jabs all the time. Why don't you go easy on them yourself, and let's press the reset button?

Oct 22, 2011 at 10:37 PM | Unregistered CommenterShub

Spence_UK

We need to review this discussion.

There are two main elements.

(1) The argument that astronomically-paced glacial terminations are strongly suggestive of a relatively high climate sensitivity. Why? Because slight changes in RF over ~2ka ultimately overcome the strongly dominant ice-albedo feedback. If CS is low, this would not be possible.

(2) We disagree about the extent of the GIS during the Eemian. You said:

Do you even realise that Greenland was largely ice free during the Eemian?

This seems increasingly unlikely. If there is an argument here, it is about the relative contribution of the GIS and the WAIS to the 5m Eemian MSL. Of course the geoid affected regional sea level change. That's a valid and interesting point. As is the generally accepted estimate that Eemian GAT was only 1 - 2C higher than at present. But all this has nothing to do with (1).

You have conflated these arguments:

Let's be clear: BBD is relying on an obscure and little held view of Greenland to support his contention that the ice ages show high climate sensitivity.

Your commentary does not address (1). The conflation of the arguments is mistaken and your focus on (2) does nothing to resolve this.

You also simultaneously contradict yourself and refuse to answer a question arising from an earlier comment on this thread:

I don't know what views other scientists hold because I'm not telepathic. I mean, what a stupid question. Beyond stupidity.

But earlier you said:

remember that the reason for this is BBD's claim that low climate sensitivity is rejected from ice ages; so his view must be a strong one that no reasonable scientist would reject. In fact, his position is a minority one that just a few scientists hold.

So, I ask again: pick a few names from the majority that disagree with the view that astronomically paced glacial terminations are consistent with a high climate sensitivity.

You say:

This isn't about belief, BBD. It's about a published, scientific case presented in the peer-reviewed literature. It is a complete, coherent argument providing a model (complete with physical justification) of the natural variability of climate which has not been falsified.

Do you suggest that Koutsoyiannis has overturned the scientific consensus on climate sensitivity?

Finally, I see that you accuse a respected researcher at the forefront of GIS field work of scientific misconduct:

the only "new" thing mentioned so far by Dahl-Jansen is a model rigged to ensure the biggest problem with the claim isn't even addressed because it is assumed away.

We need to tighten this up.

Oct 22, 2011 at 11:33 PM | Unregistered CommenterBBD

Shub

As usual, you do yourself no favours.

Oct 22, 2011 at 11:36 PM | Unregistered CommenterBBD

Does it ever occur to you that your arguments might rest on your perceptions of ideas like "low", "rapid change", "high sensitivity", "large change"?

Oct 23, 2011 at 1:10 AM | Unregistered CommenterShub

BBD,

You asked for scientists other than Lindzen and Spencer who think glacial terminations are consistent with low sensitivity. I'm not so sure it's reasonable to try to group scientists in such a binary way over this issue.

For example, Chylek and Lomann (2008) do a calculation using Vostok data and arrive at 1.3/2.3 K sensitivity. Does this count as a low estimate? Kohler and company (2009) discuss the calculation in the following terms:-

A recent study (Chylek and Lohmann, 2008a) estimates an aerosol radiation forcing during the LGM to Holocene transition of 3.3 +/- 0.8Wm^2 based on variations in temperature, CO2 and dust in two specific time windows of the Vostok ice core. These conclusions are highly debated (Chylek and Lohmann, 2008b; Ganopolski and Schneider von Deimling, 2008; Hansen et al., 2008; Hargreaves and Annan, 2009), which illustrates that a common understanding is so far missing.

I'd imagine the phrase I've highlighted is an accurate summary of the current position. Kohler et al go on to offer their own estimate:

However, in contrast to the results by Chylek and Lohmann (2008a), our analysis shows that medium values around 2-3 K are more likely and high values also cannot be excluded.


Is this a high or a low estimate? Either way, in other uncertain scientific debates, it might easily be taken as some kind of support for Chylek's position.


I also found the following conference summary from 2008 quite interesting and relevant:-

http://www.geo.ntnu.edu.tw/old%20980202/teacher/%E7%BF%81%E5%8F%94%E5%B9%B3/course/%E6%B0%A3%E5%80%99%E5%AD%B8/Essay03b.pdf

I don't know about you, but my general impression from this is of a group of scientists (more than 120 from 14 countries, apparently) getting together for a lively and no doubt robust discussion about scientific issues where there remains considerable doubt and controversy.

Somewhat OT, but my eye also caught the following comment:-

For example, it was shown that widespread carbon dioxide sequestration is required to stabilize atmospheric levels below 1,000 ppmv.

Bearing in mind the massive likely reserves of fossil fuel, this sounds quite plausible to me. Putting this together with Chylek's "sceptical" sensitivity estimate, it seems obvious to me at least that serious future problems could easily occur, sceptic or not. This is one reason why I personally would still like to see a serious attempt at decarbonisation through use/development of nuclear, gas, desert solar, etc.

Oct 23, 2011 at 11:24 AM | Unregistered CommenterPhilip

Philip

You asked for scientists other than Lindzen and Spencer who think glacial terminations are consistent with low sensitivity. I'm not so sure it's reasonable to try to group scientists in such a binary way over this issue.

Why not? It helps get closer to the likely correct value for CS. Which is widely agreed to be ~3C as an equilibrium response to a doubling of pre-industrial levels of CO2 (or any equivalent increase in RF).

Chylek & Lohmann (2008) has serious flaws which are detailed by Hargreaves & Annan here. As usual, the 'sceptics' make way too much of a single, questionable study:

In a recent paper, Chylek and Lohmann (2008) used data from the Vostok ice core together with simple energy balance arguments to simultaneously estimate both the dust radiative forcing effect and the climate sensitivity, generating surprisingly high and low values for these respective parameters. However, their results depend critically on their selection of single unrepresentative data points from time series which exhibit a large amount of short-term variability, and are highly unstable with respect to other arbitrarily selected data points. When temporal averages are used in accordance with accepted norms within the paleoclimate community, the results obtained are entirely unremarkable and in line with previous analyses.

3C or higher is physically plausible in the light of Milankovitch-paced glacial terminations. Lower estimates are very much harder to reconcile with known paleoclimate behaviour.

Is this a high or a low estimate? Either way, in other uncertain scientific debates, it might easily be taken as some kind of support for Chylek's position.

That is not how I read Kohler's statement. The key words are 'in contrast to the results by Chylek and Lohmann'.

I was very heartened by your last paragraph. You seem to understand that even a low-ish CS still means big trouble ahead. Now that's rare.

Oct 23, 2011 at 1:40 PM | Unregistered CommenterBBD

BBD,

Your argument is seriously flawed. Let me try to describe how:

You are, shall we say, preoccupied with the question of climate sensitivity to a doubling of CO2 mediated increase in forcing.

The 'abrupt change' derivation of climate sensitivity that you employ, to infer a high value, is a *different beast*.

"Small push = large change = high CS" is certainly not universally true of the climte system! How can you derive a baseline high sensitivity from 'sudden' changes' which clearly occur only the confluence of a
number of specific conditions?

Oct 23, 2011 at 2:24 PM | Unregistered CommenterShub

Shub

You don't understand this discussion. Nor will you until you do some reading. Start with H&S11. Also Roe (2006).

Any change in RF can be substituted for CO2. It could be solar. It does not matter. The point is that equilibrium sensitivity to a forcing equivalent to ca 550ppmv CO2 is 3C.

Everything else you say is wrong, rooted as it is in this fundamental misunderstanding.

Oct 23, 2011 at 2:51 PM | Unregistered CommenterBBD

I almost forgot.

Your tag line on your website:

A total distortion of the facts

Too funny.

Oct 23, 2011 at 3:02 PM | Unregistered CommenterBBD

It is you who does not understand.

I know "any change can bring about change in RF blah blah" - you hammed away it for a good length of time already.

Let me rephrase - for your benefit:

You are preoccupied with climate sensitivity. This cannot be inferred from an abrupt change derivation.

Let me illustrate with a short but specific (for our purposes) example: If you are filling a 100mL beaker at 1mL/min, you *do not* infer whether the rate is 'high' or 'low' by making observations at the 99th minute and 100th minute, and noting the state change of the cup.

Like Spence says above, "Try thinking for yourself!". No one needs you to regurgitate the claims and findings of papers you've read. Science, then is reduced to a role-playing game or a baseball card game where people trade stats and trump cards.

Oct 23, 2011 at 4:41 PM | Unregistered CommenterShub

Shub

A total distortion of the facts!

Admit you haven't got a clue and either go away, or do some reading.

Climate sensitivity estimates converge around 3C. You don't like this, but my God you are stuck with it. Adapt or die.

Oct 23, 2011 at 4:54 PM | Unregistered CommenterBBD

Shub

Like Spence says above, "Try thinking for yourself!". No one needs you to regurgitate the claims and findings of papers you've read. Science, then is reduced to a role-playing game or a baseball card game where people trade stats and trump cards.

This is amusing. I especially appreciate the way in which you have broken free from the constraints of reason and observation that bind and blind the so-called experts. Every study is wrong. Every conclusion flawed. Only the mighty intellect of Shub can be trusted on such matters. Everyone else is misguided and stupid. Anyone who resorts to supported argument is just playing Science Top Trumps.

To be fair, although I've come to see you as essentially funny, your astonishing self-belief can sometimes be rather frightening.

Oct 23, 2011 at 5:05 PM | Unregistered CommenterBBD

Why don't you answer the question posed?

Oct 23, 2011 at 6:06 PM | Unregistered CommenterShub

Because it is irrelevant.

Show in what way the analogy (to what?) that you provide is useful in understanding an empirical estimate of CS (eg H&S11).

The fact that you are saying this sort of thing shows that you do not understand the argument.

Asking the wrong question and then insisting on an 'answer' is a well-worn rhetorical device.

Here's a relevant question: why does the entire field of climate science tend towards the view that CS is about 3C? And why should anyone pay any attention to your nay-saying, especially as you do not understand the subject matter?

Oct 23, 2011 at 6:55 PM |