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« Your taxes at work | Main | Spending cuts »
Sunday
Apr082012

Hide the incline

Willis Eschenbach has been looking at the Shakun et al paper that was the subject of my Greenhouse reversal post a couple of days ago. It looks as if he has found something important:

I leave the readers to consider the fact that for most of the Holocene, eight millennia or so, half a dozen different ice core records say that CO2 levels were rising pretty fast by geological standards … and despite that, the temperatures have been dropping over the last eight millennia …

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Reader Comments (66)

Shakun's Nature trick.

Apr 8, 2012 at 10:55 PM | Registered CommenterPharos

it has all the hallmarks of another data plot where you can draw any conclusion you like from the data...no clear pattern can be ascertained. Rather like the dispute a few months ago about clouds as feedback ior forcing...the agenda-drven side (with fossil fuel funding) will no doubt launch an onslaught in the "peer-reviewed literature".

Apr 8, 2012 at 10:56 PM | Unregistered Commenterdiogenes

You don't get past peer review unless your confirmation bias is robust. Post normal science is very firm on this point.

Apr 8, 2012 at 11:21 PM | Unregistered Commentersimpleseekeraftertruth

Piers Corbyn has produced a short refutation of the Nature paper. Seems the trick is to forget to mention that the Antarctic/southern hemisphere starts warming BEFORE the northern hemisphere warms. That southern HS warming causes the CO2 to rise as it is mostly ocean (unlike the northern HS). By averaging these two warmings they get the mess we've seen which they claim suggests CO2 coinciding with the average rise.
download w2 page pdf: www.weatheraction.com/docs/WANews12No20.pdf

Apr 8, 2012 at 11:23 PM | Unregistered Commenterphilip foster

We all know why it came out. So that at Rio there will be a paper "contradicting" the idea that CO2 follows temperature.

The truth of the paper is entirely irrelevant to that aim.

Apr 9, 2012 at 3:20 AM | Unregistered CommenterMooloo

AR5 is turning climate science into a parody.
============

Apr 9, 2012 at 4:53 AM | Unregistered Commenterkim

Climate "skeptics" have used this exact same strategy to hide the incline in global surface temperatures (here and here and here), lower troposphere temperatures (here), and ocean heat content (here and here). We've found that an effective way to reveal the deception of these arguments is with an animated GIF, comparing the long-term data with the short-term "skeptic" cherrypick. Figure 1 makes this comparison for the global mean sea level data during the satellite radar altimiter record (since 1993) from the University of Colorado. The first frame shows the entire record, the second shows recent periods of flat or declining mean sea level, and the third shows the most recent short-term decline.

Apr 9, 2012 at 5:03 AM | Unregistered CommenterMarry

Eschenbach’s two articles use data display techniques to make an argument a child can follow. (Corbyn’s argument is equally simple) There’s an 8000 year divergence problem, and the authors hide it by cutting off the end of their graph. It’s as simple as that.
Will Nature and RealClimate ignore it? Or propose a defence so complex only they can understand it?
The mainstream journalist who picks up this story can change history. Does he or she exist?

Apr 9, 2012 at 6:20 AM | Unregistered Commentergeoffchambers

Marry, you may be onto something, but your links don't work. Either way it doesn't make the refutations of Shakun et al invalid, so I guess the question to you is, "What's your point?"

Apr 9, 2012 at 6:31 AM | Unregistered Commentergeronimo

Climate "skeptics" have used this exact same strategy to hide ...

Actually they tend to use exactly the opposite strategy. That is when a graph or data is shortened it tends to be only the recent data, not the middle or long term data. Sometimes excessively so, I agree.

But even rock-solid proof that some sceptics have done something wrong is 1) not proof Shakun is right, 2) not proof that all sceptics are wrong, and 3) not proof the world is warmed excessively by carbon dioxide.

Apr 9, 2012 at 6:38 AM | Unregistered CommenterMooloo

Don Easterbrook is also looking at the paper at WUWT. His first part is up there. None of this will stop Shakun at al starring in AR5.

Apr 9, 2012 at 7:44 AM | Unregistered CommenterPhillip Bratby

Stott et. al. 2007 shows that the warming in the deep Southern ocean starts 2 ky before any CO2 increase. The mechanism is the reduction of cloud albedo.

Only after the tropics warm is there any shift in the Northern ice caps during which time the Southern ocean and the tropics are outgasing.

This report is scientific legerdemain of the kind to be expected from the fraudsters who occupy climate science and worthy of Goebbels at his worst..

Apr 9, 2012 at 9:04 AM | Unregistered Commentermydogsgotnonose

Read the Editorial in the copy of Nature this science fiction appears in. In short it's now been proved beyond doubt that temperature follows CO2. No ifs and buts. It looks as though they've found their new "hockeystick", a poster child for AR5?

Apr 9, 2012 at 9:14 AM | Unregistered Commentergeronimo

You know it really is a layman thing of me to say, but more than any other paper this one has all the hallmarks of really pushing all the bounds of credibility of confirmation bias in the quest for a specific comforting "narrative".

The Corbyn quoted Stieg Alley paper, that highlights an apparently already known about out of phase warming of Southern and Northern hemispheres, is enough to raise huge questions for me about whether the Shakun NH land biased proxies were almost designed for this new story. The big wet CO2 laden Southern Hemisphere with its CO2 leading temperature in the same Antarctic ice bubbles still seens like Occams razor to me.

Apr 9, 2012 at 9:22 AM | Unregistered CommenterThe Leopard In The Basement

Hah, the new narrative has captured me! I meant above:

"The big wet CO2 laden Southern Hemisphere with its temperature leading CO2 in the same Antarctic ice bubbles still seens like Occams razor to me."

Apr 9, 2012 at 9:26 AM | Unregistered CommenterThe Leopard In The Basement

No need to mount a complicated defence.

The transition from glacial to inter-glacial was triggered by the Milankovitch cycles. The increased warming caused out gassing of CO2 from the oceans which added to, and caused most of, the warming by the increased greenhouse effect. The total warming is not possible by changes in the orbital cycle alone.

Shakun et al are not hiding the subsequent rise in CO2. The paper is not aimed at the general public. It is aimed at other scientists. There are innumerable papers detailing subsequent CO2 concentrations that other scientists are well aware of and this paper will be read in the context of that climate science literature.

The Shakun paper shows 2 steep rises in CO2 concentrations totalling ~75 ppm over ~4500 years.

The post-transitional rise in CO2 is ~20 ppm over ~ 11000 years up to modern pre-industrial levels.

Recently we have added over 100 ppm in 150 years!

It's all to to with the RATE of increase, the ability of the carbon cycle to cope with that RATE of increase, and whether there are other drivers/forcings playing a part at the time.

Re. The out of phase warming of Southern and Northern hemispheres.

Shakun et al show this clearly in their Figure 5b. Again this is a well known, and well documented in the literature, effect that climate scientists are fully aware of - the Earth's orbital cycles trigger the initial warming and this is first seen in the higher latitudes. No secret.

Apr 9, 2012 at 9:33 AM | Unregistered Commenteranivegmin

anivegmin

The total warming is not possible by changes in the orbital cycle alone.

That seems a truism that makes me wonder in that case what the new narrative is all about except getting pushed into view of the "general public". Although it is nice to know that the narrative has moved on from "did they ever fit together" winking from Al Gore to its too compicated for you laymen to understand now. Good job ;)

It is the "driving" of warming that is important, no one denies that there must be a contribution of warming from the CO2 in the mix but it seems that the sensitivity of the CO2 effect could be quite low from the temp leading narrative that is shown in the Antarctic bubbles.

It's all to to with the RATE of increase, the ability of the carbon cycle to cope with that RATE of increase, and whether there are other drivers/forcings playing a part at the time.

From the graphs I saw on the Beeb article if you look at the Antarctic temperatures they track CO2 more directly and linearly, at a sharper rate, (and ahead) of CO2, the new narrative world temps struggle to catch up with a smoother and later rise that seems to imply rate is not so important just the level.

Apr 9, 2012 at 9:55 AM | Unregistered CommenterThe Leopard In The Basement

The speed with which shoogly science has been exposed by Eschenbach in his two posts on this paper to date is very encouraging.

The hockey-stick had a much easier time of it for several years - say the 4 to 5 years between MBH paper in 1998 and three events noted in the Hockey Stick Illusion Chapter 3: (i) in 2002, a government leaflet bearing the specious chart appeared in the letter box of one Steve McIntyre who there and then decided to check it out, (ii) in 2003, the Soon & Baliunas paper supporting the existence of the MWP was published, and (iii) an internet forum run by Hans Erren carried a request by him for assistance over several puzzling things about a 1999 update to MBH. By then of course, the political impact of the chart had been achieved - the word Machiavellian springs unbidden to my mind - via the prominence given to it in the Third Assessment Report of 2001, aided by the IPCC's John Houghton sitting in front of a large picture of it as he announced the publication of that report. The impact unfolded over several years. At the end of Chapter 1 of HSI</I>:

'School books told children that the Hockey Stick meant that the world had to change. Politicians told voters that only they could save people from the threat it demonstrated. Insurers, newspapers and magazines, pamphlets and websites were all in thrall to its message; the hockey stick swept all before it.'

Well, let us see what advantage they can obtain from Shakun et al.(2012).

Apr 9, 2012 at 10:00 AM | Registered CommenterJohn Shade

anivegmin -
I agree generally with what you write about the way in which the earth exits the glaciated phase, with a relatively small Milankovitch forcing amplified by changes in albedo, dust and greenhouse gases. However, I don't agree that "most of" the temperature change is caused by CO2. Hansen&Sato(2011) claimed only 3 W/m2 for greenhouse gas forcing (going from the LGM to Holocene), compared to 6.5 W/m2 total. Obviously CO2 is only part of the ghg forcing, although if I remember correctly it is the lion's share. However, this is how the editor of Nature puts it: "These observations, together with transient global climate model simulations, suggest that CO2 was a primary driver of global warming during the most recent deglaciation." Unfortunately, I don't have a copy of the paper, so I can't say whether Shakun's evidence overturns the prior assessment.

What I will say is that Shakun's figure 2 which is reproduced in Easterbrook's article on WUWT [I'll refrain from the link in order to avoid delaying this comment] indicates a global temperature change of about 3.5K. Hansen&Sato (2011) suggested that climate sensitivity is 3/4 K/ (W/m2) based on a 5K change; hence using Hansen&Sato's forcing of 6.5 W/m2 with Shakun's temperature change, it would seem that this yields a climate sensitivity of about 1/2 K / (W/m2), or a little under 2 K per CO2 doubling. Interesting.

Apr 9, 2012 at 10:29 AM | Registered CommenterHaroldW

The Leopard In The Basement,

I wasn't completely clear in my previous post.

My comment on the rate of increase followed, and was mostly referring to - "Recently we have added over 100 ppm in 150 years!" and whether the carbon cycle could cope with this rate of increase.

it seems that the sensitivity of the CO2 effect could be quite low from the temp leading narrative that is shown in the Antarctic bubbles.

This is just the Antarctic. Not the whole globe. Why cling to regional data when there is a global study available? Unless of course you want to push a "narrative" that isn't born out by the totality of the evidence.

Yes the level is also important. The increase in CO2 during the transition from glacial to inter-glacial is caused by the warming triggered by orbital variations. Once these variations have stabilised/neutralised, the Earth's natural tendency to find equilibrium in its energy balance takes effect. The slow rise in CO2 of ~20 ppm over the following 11000 years is easily accommodated by the system.

HaroldW,

Yes there are lots of different papers estimating climate sensitivity. These give a range of estimates. It's not a good idea to take one paper in isolation. You have to look at all the literature. The IPCC give a range of 2 - 4.5C with a best estimate of 3C.

Apr 9, 2012 at 11:24 AM | Unregistered Commenteranivegmin

No need to mount a complicated defence.

No, but a defence supported by evidence rather than hand-waving would be a good start. Even the first sentence:

The transition from glacial to inter-glacial was triggered by the Milankovitch cycles.

Is hugely problematic. If you squint at the ice cores, you can "sort-of" convince yourself that the 100kyr inclination is present over the last million years. But that's a problem: the 100kyr inclination should have the smallest effect, but it appears to have the largest effect. This makes no sense.

Furthermore, the pattern of power spectral density in the plots is far more consistent with either a very long time constant autoregressive natural variability or fractal natural variability, i.e. the null hypothesis of natural variability should never have been rejected, nicely explained in this paper by Carl Wunsch:

"Quantitative estimate of the Milankovitch-forced contribution to observed Quaternary climate change", Carl Wunsch, Quaternary Science Reviews 23 (2004) 1001–1012

(I won't link because this comment will go into moderation but it is trivial to find on the web)

Apr 9, 2012 at 11:38 AM | Unregistered CommenterSpence_UK

Yes there are lots of different papers estimating climate sensitivity. These give a range of estimates. It's not a good idea to take one paper in isolation. You have to look at all the literature. The IPCC give a range of 2 - 4.5C with a best estimate of 3C.

This is one area I find really fascinating about climate science.

The IPCC has a number of estimates of climate sensitivity. At the very best most are wildly wrong. Tell me which one you think is right, and defend your choice. Don't give me a range.

The "best estimate" is not 3°. That is what the loons agreed to put forward, to solve the issue of having to actually argue their case separately based on evidence. Because, of course, that would involve them having to break the "consensus" and point out the flaws in the work of the others. It's a political decision, not a scientific one.

Do you think that if CERN and Fermilab disagree on the energy of the Higgs Boson that they will agree to take the average?

Apr 9, 2012 at 11:41 AM | Unregistered CommenterMooloo

The problem you have anivegmin is that climate scientists are regarded as activists with computer keyboards by the people on these threads. And with good reason, given the public statements from the climate science community, the inclusion in the IPCC of papers that refuted the MM2003, keeping the hockeystick alive for another few years, the climategate emails, the subsequent whitewashes, the silence of the climate science community when egregious forecasts are made, the outrageously frightening forecasts coming from the climate science community. Did I mention the concerted attempt to deny the MWP in the face of years of scholarship supporting it?

So you see Shakun et al is seen simply as an attempt to "get rid of" the CO2 rises following temperature rises evidence, which of course it is. Of course, CO2 should follow temperature shouldn't it, wouldn't the warming oceans give up their CO2, or have the climate science community now decided to re-write the physics as well?

Apr 9, 2012 at 11:48 AM | Unregistered Commentergeronimo

mooloo
The logic of taking the mean figure for climate sensitivity is a bit like this (take from the CRU entrance exam):
“Phil Jones is placed in the top three in the Olympics Mental Gymnastics event:
What medal did he most probably win?”
Answer: Silver.
(whatever you do, don’t give reasons for your answer)

Apr 9, 2012 at 11:53 AM | Unregistered Commentergeoffchambers

Spence_UK,

Wunsch 2004 is an interesting and much cited paper that raised legitimate concerns. Google gives it as cited by 50. The reason for these 50 citations is that other scientists have read the paper and then gone on to address the problems raised by Wunsch.

http://agwobserver.wordpress.com/2010/01/04/papers-on-the-milankovitch-cycles-and-climate/

The above link gives a list of papers that includes Wunsch 2004 and subsequent papers.

Also of interest are -

www.clim-past.net/2/131/2006/cp-2-131-2006.pdf
http://www.people.fas.harvard.edu/~phuybers/Doc/antarctic_naturegeo2008.pdf

There have been developments in our knowledge and understanding since the Wunsch 2004 paper.

Mooloo,

"At the very best most are wildly wrong." "loons"

I take it you have evidence to back up these scientific statements.

There are uncertainties. We have to deal with uncertainties in life and in science all the time.

geronimo,

You are just spouting a list of blogosphere memes that have no relation to the actual science.

Apr 9, 2012 at 12:37 PM | Unregistered Commenteranivegmin

anivegmin -
Yes, I know that the last published IPCC range was 2-4.5 K per CO2 doubling. But the upper end of that range doesn't make much sense. Most estimates of transient sensitivity are around 2/3 to 3/4 of the equilibrium sensitivity. Say 2/3. A 4.5 K-per-doubling equilibrium sensitivity implies around 3 K-per-doubling transient sensitivity. Over the last 50 years, net forcing changes have increased by perhaps 0.3 of an equivalent CO2 doubling*, yet we've seen only ~0.5 K temperature increase. That's only half of what a 4.5K-per-doubling [equilibrium] sensitivity would imply.

* = Using GISS figures, which have (it seems to me) excessively large negative adjustments for aerosols

It also seems to be the case that the more recent estimates of climate sensitivity are on the low side of that range. The wide distributions which extend out to (and well beyond) 4.5 K per doubling are the result of assumed distributions of unknown values, not constrained by any reasonable prior. I don't know what AR5 will say about this, but it's reasonable to suspect that the range will come down. [My own guess is that 1.5 - 3 K per doubling is about right.]

Apr 9, 2012 at 12:38 PM | Registered CommenterHaroldW

Shakun et al are not hiding the subsequent rise in CO2. The paper is not aimed at the general public.

Then why did they do a press release.? Papers released only for scientists do not get published in the comic that is Nature they get published in their societal journal.

Of course it was meant for the sheeples. It's a useless paper if not.

Apr 9, 2012 at 12:49 PM | Unregistered Commenterstephen richards

anivegmin, in fact neither of those papers address the core questions raised by Dr Wunsch's paper.

I have no doubt that (just in the papers you cite) it is possible to create a model which superficially matches the vostok record. Especially when that model is essentially peak matching, and the authors give themselves freedom to select the location of the peaks by giving themselves a tuning dial - for example, by selecting a single line of latitude (e.g. 65 deg N in the original orbital cycle paper, re-tuned to 77 deg S in Huybers' paper) which allows you to arbitrarily move the peaks to a position of the authors choosing. A p-value which does not account for this is worthless.

Also, the importance of orbital tuning of cores and the inevitable inflation of p-values is almost never discussed. The bottom line is some people have created tunable models which can be made to match the ice ages, but none cross any kind of threshold of strong evidence, and most fail to accommodate any kind of realistic measure of natural variability.

I'll link to an conference poster session with a more credible discussion on the roles of natural variability and the orbital cycles in the following comment (it will most likely go into moderation)

Apr 9, 2012 at 1:08 PM | Unregistered CommenterSpence_UK

For a more realistic discussion on natural variability and orbital cycles:

Markonis, Y., D. Koutsoyiannis, and N. Mamassis, Orbital climate theory and Hurst-Kolmogorov dynamics, 11th International Meeting on Statistical Climatology, Edinburgh, International Meetings on Statistical Climatology, University of Edinburgh, 2010.

Link

What we see is a strong influence of 41kyr (as expected, the strongest forcing) and negligible influence from the 100kyr. This explanation is far more satisfying from the perspective of theoretical forcing and highlights the dominance of natural variability in the ice ages of the last 800kyr.

Apr 9, 2012 at 1:12 PM | Unregistered CommenterSpence_UK

"geronimo,

You are just spouting a list of blogosphere memes that have no relation to the actual science."

I stand admonished. Now in the spouting there was a question. Doesn't the physics tell us that the oceans should release CO2 after a rise in temperature? In which case we would expect temperature to precede CO2 and it would be no big deal.

Apr 9, 2012 at 1:22 PM | Unregistered Commentergeronimo

Geronimo: "It looks as though they've found their new "hockeystick", a poster child for AR5?"

At first I thought It looked like a bent paper-clip, but then, if you remember the 'magic eye' 3D illusions that were the rage a few years ago, when you look at Shakun's Fig 1 with cross-eyes you can see a bat flying towards you. So, hockey-stick to bat. Progress. :-)

Interestingly, if you spin the top half anti-clockwise round to the bottom half, there's almost a good 'fit'.

Apr 9, 2012 at 1:22 PM | Unregistered CommenterSnotrocket

anivegmin

Ok fair enough I see now your concerns about rate of increase of CO2 were pertaining to recent times rather than any shown in the Shakun study.

This is just the Antarctic. Not the whole globe. Why cling to regional data when there is a global study available? Unless of course you want to push a "narrative" that isn't born out by the totality of the evidence.

Whose Clinging? I'm staying where I am without any problem - where Al Gore told me to be - with the regional record "did they ever fit together";)

It is the encouragement to move onto a narrow ledge of this new narrative that I am reluctant to do. The Antarctic regional well mixed CO2 is acceptable for being used as the levels that are measured against for both the Antarctic temps and these new world temps - which is fine. However I think I am right in saying that We already know that the Antarctic temps come from the same bubbles the CO2 record come from, and have the chracteristic lead. This new study makes use of Northern Hemisphere proxies that are not so well linked in time to the Antarctic CO2 record, and also have to suffer the hemisphere phase difference issues.

As you say it is not so easy to explain and my problems are just that mine. I still remain unamazed by the persuasiveness of this report. However I think it fulfils the required job that means whenever someone makes the temp lead point in the future, some world weary climate expert can now pat them on the head and tell them a paper in Nature has taken care of that little problem ;)

Apr 9, 2012 at 1:35 PM | Unregistered CommenterThe Leopard In The Basement

I take it back! And sorry to be facetious, but it's not a BAT....it's the 'Shakun Vac'!! (boom tish?)

Apr 9, 2012 at 1:39 PM | Unregistered CommenterSnotrocket

Spence_UK,

Thanks for the link. I have to admit that the technicalities involved here are starting to get a bit beyond my capabilities. However a search on Google Scholar reveals this is an unpublished paper with zero citations. If you think this paper has merit you would need to take it up with experts in the field.

geronimo and The Leopard In The Basement,

The Shakun paper clearly shows a rise in temperature before the increase in CO2.

CO2 can be both a forcing and a feedback.

Apr 9, 2012 at 2:49 PM | Unregistered Commenteranivegmin

However a search on Google Scholar reveals this is an unpublished paper with zero citations.

If you read carefully, it is a summary of a number of peer reviewed papers presented at a respected conference on statistical climatology, with peer reviewed references therein.

Secondly, peer reviewed or not does not confer correctness on a paper, or otherwise. However, it does take some time and effort to understand these things.

The important point is this. Your explanation above hinged on the idea that Milankovitch cycles trigger the ice ages. You present this as fact. As we can see from the peer-reviewed literature, this is far from fact and actually a topic of considerable dispute, with a range of different views, many based on models (with differing tunable parameters, such as the phase of the oscillation), with few taking careful note of the possibility of natural variation being an important factor. Indeed, those that do investigate natural variability as being an important factor, often find they are unable to rule it out or find it to be an important component.

Tuned models are not evidence, merely hypotheses, and sadly many who assess p-values often (1) use a very low standard of 95% confidence (which would not be accepted in many scientific disciplines, e.g. physics, as an acceptable standard of evidence) and (2) fail to account for tuning in their models (phase tuning in particular, but also tuning of the core dates to orbital cycles) and (3) often use simplistic autoregressive models with time constants derived from the data, which will produce a biased, short time constant.

These topics are all discussed in Wunsch's original paper and none are really satisfactorily addressed in later papers.

This does not mean that Milankovitch cycles are not important; they are one of many plausible hypotheses, for which we do not have sufficient evidence to declare them as fact. It is a red flag to me, when someone invokes them as a cornerstone of a hand-waving explanation of climatic behaviour in the past. This is not how science is done.

Apr 9, 2012 at 3:02 PM | Unregistered CommenterSpence_UK

Apr 9, 2012 at 2:49 PM | anivegmin
Apr 9, 2012 at 3:02 PM | Spence_UK

I've not read the literature on this but surely there must be a massive albedo feedback at some point going from a glacial to interglacial phase. Or is this fully understood already?

Apr 9, 2012 at 3:17 PM | Unregistered CommenterRob Burton

Also wouldn't water vapour rise significantly after a glacial period. I guess you won't find that in a proxy record though? Or is this transition effect fullly understood too?

Apr 9, 2012 at 3:30 PM | Unregistered CommenterRob Burton

@Rob

Yes, the albedo effect of ice is a non-linear coupled feedback dependent upon many things, including (but not limited to!) temperature, precipitation, prevailing wind conditions, ocean currents, etc., etc.

It also has a range of timescales, from monthly (in the case of wind conditions, ocean currents) out to millions of years (e.g. the ice sheets of Antarctica), out to 10s/100s of millions of years (e.g. tectonic plate movements).

Simplification of this down to a single characteristic timescale with linear response dependent only on temperature without strong supporting evidence of such a link would be somewhat hubristic. Therefore, it is safest to capture such interactions with a stochastic model rather than a deterministic model - an approach strongly endorsed by Wunsch in his paper (and only really embraced by the Itia group amongst the papers discussed above).

Apr 9, 2012 at 3:35 PM | Unregistered CommenterSpence_UK

The obvious question:

Did CO2 enhance the warming after the orbital changes?

Or, did the orbital changes increase the amount of H2O in the atmosphere and CO2 is just a response to warming caused by the #1 GHG.

You have to convince me that water vapor never changed after more sunshine started melting the ice sheets.

Ha. What a joke. They didn't even graph the #1 GHG.

Apr 9, 2012 at 3:55 PM | Unregistered CommenterBruce

Of course, the discussion about the cause of the ice ages is really a distraction from the real issue at hand here: the tendency of climate scientists to be selective about what they publish in graphs, etc, to present a tidy narrative. I'm not surprised that activists want to move discussion away from this, which can only be described as a form of spin doctoring.

To be fair, I think sceptics can be just as guilty of this as climate scientists: but only one group gets this accepted into the peer review literature without the bat of an eye from their peers.

Apr 9, 2012 at 5:11 PM | Unregistered CommenterSpence_UK

The 41 ky ice age died out when the Isthmus of Panama formed. ONLY the 100 ky Milankovitch tsi rise is enough to trigger the deep ocean currents which restart the warm part of the bistability. CO2-climate sensitivity is probably net zero and the key factor is a reduction of cloud albedo. ~3.5% reduction of cloud albedo is equivalent to the 2.88 W/m^2 forcing attributable to GHGs from AR4.

Time for the CO2- religion to die out. C'mon Jim Hansen,. ask your followers to drink the Koolade; we're sick and tired of fake physics and wishful thinking by technicians who have never been able to think from first principles/out of their conditioning......:o)

Apr 9, 2012 at 5:29 PM | Unregistered Commentermydogsgotnonose

Apr 9, 2012 at 2:49 PM anivegmin

CO2 can be both a forcing and a feedback.

I'm trying hard to understand statements like this but not getting as far as I'd like, perhaps because of trying to understand in terms of things I know about.

My question: Are the terms forcing and feedback (or other terms with equivalent meaning) used in any other field of science? (in the sense that climate scientists use them)

Is it just me, or are climate scientists making things more complicated than they need be? System modelling, in areas I am familiar with, regards inputs as being independent of what goes on within the system.

Internal variables of the model are simply that - internal variables whose interactions are described by the equations of a mathematical model representing the behaviour of the system but which have no effect on the inputs. Any feedback effects within the model are automatically taken care of.

I found some explanations (below) but I'm struggling to make real sense of them, rather than simply being able to recite the words.
________________________________________________________________________________


[Footnote. Stuff I found but have not really got my head around:

http://www.azimuthproject.org/azimuth/show/Climate+forcing+and+feedback
Forcing denotes an external influence on a characteristic of the climate system. Example: Increased emission from the sun leads to an increase of the temperature.

Feedback denotes the reaction of the (climate) system to the forcing which, in return, leads to a change in the forcings. Example: a change in the Earth’s temperature may cause effects that lead to more radiation being absorbed or emitted. This then creates further changes in the Earth’s temperature.

http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/214.htm#611
"The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropo-spheric temperatures and state held fixed at the unperturbed values". ]

Apr 9, 2012 at 8:59 PM | Registered CommenterMartin A

anivegmin

"At the very best most are wildly wrong." "loons"

I take it you have evidence to back up these scientific statements.

Do I have evidence that the "climate sensitivity" to CO2 cannot be both 2° and 4.5°? No, I have no scientific paper, peer reviewed, that says that it cannot be one thing, and also another wildly different thing.

Do you ask physicists seeking the mass of the Higgs Boson for papers describing how it can only have one mass and not a couple?

There are uncertainties. We have to deal with uncertainties in life and in science all the time.

My point is that the IPCC are not dealing with uncertainties, they are merely pretending that averaging them out makes them go away.

You can't deal with uncertainties this way. You cannot say that you have proof that the climate sensitivity is 3° by pointing to one study that shows it is 2° and another that shows it is 4.5° unless the errors given by those studies are +/-1.5° (so, in other words, they are wild guesses in the first place). Every study that does not show the IPCC mandated 3° within its uncertainty range is therefore wrong and of no use at all to the IPCC.

Which causes another problem, which is why are so many of the results wrong? If there is this magical "climate sensitivity" why can we not find the result to a reasonable degree of accuracy? Are all the papers just wrong then, trying too hard to find what is not there in the data?

There is, however, no major disagreement at the IPCC about dong what they all must know is an inappropriate average, because they are not interested in finding the actual climate sensitivity. What they need is a scary number for CO2 doubling, not an accurate one. 3° works fine for them, whether it is right or not. What they are not interested in is taking apart each of the studies to actively examine which ones are valid. That would destroy the consensus and might yield an entirely inappropriate (but correct) result that was too low for their purposes.

Apr 9, 2012 at 10:26 PM | Unregistered CommenterMooloo

The publications at Principia Scientific International show why carbon dioxide has absolutely no effect on climate, so sensitivity is zero. See, for example, my peer-reviewed paper Radiated Energy and the Second Law of Thermodynamics on the site.

I am proud to be an active member of PSI and, as such, I am in daily email contact with many of these main stream scientists, including professors and PhD's in various disciplines such as physics, applied mathematics, chemistry, climatology and astro physics. The numbers are approaching 40, including well known new members just announced.

What I write are not just my theories. We are all in agreement that standard physics and empirical results back us up.

Apr 9, 2012 at 10:37 PM | Unregistered CommenterDoug Cotton

The Holocene equates with the current interglacial, which started c. 12,000 BP years ago, ie about 10,000 BC, with optimum temperature reached about 8000 BP and it seems to be generally accepted that the relatively rapid transition from full glaciation to the interglacial started in the Antarctic and lasted +/-1500 years. Previous interglacials have rarely exceeded the length of the Holocene interglacial, while the glaciations, which last around 100,000 years, have generally become increasingly severe during their duration and also each successive glaciation more severe than the last.

The impact on primitive humans in the last full glacial (Weichsel) is speculative at best but, with thick ice sheets extending into the northern temperate zones, can be assumed to have been devastating; challenging at the very least.

Since we remain subject to the same remorseless natural forces which will inevitably bring a return to another full glacial in the geologically imminent future, it seems inconceivable to me that the primary focus of climate science is on putative anthropogenic warming, with seemingly no effort or interest in fully understanding the far more potent natural causes of the glacial cyclicity and determining just how long we have to prepare for the consequences for another full glaciation.

I really do not understand why anyone embarking on a career in climate science can ignore it. Yet it seems they do.

Apr 9, 2012 at 10:51 PM | Unregistered CommenterPharos

Mooloo, re sensitivity:

The UN need to justify their AGW policy on the grounds that it is necessary to avert disaster, and will be effective in doing so.

If climate sensitivity is too low, policy is not necessary; if it's too high, policy cannot be effective.

It so happens that 3.3ºC is 'just right' on both counts. What luck!

Apr 10, 2012 at 1:17 AM | Unregistered CommenterJake Haye

Apr 9, 2012 at 10:51 PM | Pharos

"I really do not understand why anyone embarking on a career in climate science can ignore it. Yet it seems they do."

Massively agree Pharos. I'm fascinated by the glacial/interglacial transition and Earth history in general that we don't understand (It is a large very multidisciplinary scientific and more recently historic area) but unfortunately didn't get to study it in my postgrad Meteorology days. Surely there are so many really quite small areas that could be turned into fascinating Phds.

Apr 9, 2012 at 5:11 PM | Spence_UK

"Of course, the discussion about the cause of the ice ages is really a distraction from the real issue at hand here:"

I agree here to but I'm actually interested in discussing science but not politics/religion that this quickly descends to. I'm not saying the politics is not important (it really is, and I do care strongly about things like energy policy) but I don't think discussions on that in a blog get anywhere as they really are opinion. I guess direct (political) action is the way forward here. Scientific opinion is right or wrong at the end of the day/decade/century.... so is much simpler, and I like simple/straightforward.

Apr 10, 2012 at 4:29 AM | Unregistered CommenterRob Burton

Mooloo: 'Are all the papers just wrong then, trying too hard to find what is not there in the data?'

There’s no experimental proof of any CO2-AGW. You can explain warming that has occurred, now reversing, by other means. What's more, climate science has made a cardinal error since Aarhenius of failing to take into account Gibbs’ 'Principle of Indistinguishability', which is that no statistical entity in physics remembers its history. Now I know empirical scientists aren't taught such stuff, but the failure to know it means they taint science by making falsifiable claims.

When a GHG molecule absorbs an IR photon it joins an assembly of such molecules already excited thermally [~5% of CO2 at room temperature]. Climate science claims and teaches apparently that in the ~1 microsecond before the molecule ejects the photon, it dissipates the energy by ~1000 collisions so the energy is thermalised. Not true because that fails to take account of the PoI.

Once an already excited molecule ejects a photon in a random direction, almost instantaneous pseudo-scattering, Local Thermodynamic Equilibrium is restored. The recent experiment by Nasif Nahle where he showed that CO2 in a thin Mylar balloon did not warm in the way it does in the PET or glass bottle, apparently proves there is little if any direct thermalisation [the warming in the other containers is probably at the walls].

So, my current thinking is that the whole atmosphere operates as a continuum: an energy quantum absorbed near the Earth’s surface is absorbed at near the speed of light at heterogeneous interfaces: clouds, bare aerosols, the Earth’s surface, or heads off to space. So the warming is at clouds mainly which may explain Miskolczi’s experimental proof of constant IR optical depth independent of [CO2] [there is no warming at the Earth's surface because that effect is part of Prevost Exchange].

Therefore, unless it does not assume direct thermalisation, one must consign every climate science claim of net CO2-AGW to the dustbin of scientific history. Sorry, but we are talking science here not dogma.

Apr 10, 2012 at 9:07 AM | Unregistered Commentermydogsgotnonose

Looking at their own supplementary data the proxy temperature is far from homogeneous, so their global 'stacked' temperature can only be estimated after a good deal of homogenization and model inputs. That is far from a solid reference as the Nature editorial suggests. In fact, it is highly questionable.

I have put a figure with several of the proxy temperature data and the CO2 estimates from Epica Dome C (CO2 on the left Y-axis) at this link: http://img13.imageshack.us/img13/8874/shakumtempco2.gif
The anomaly is calculated as departure from the mean value of the time series between 0 and -22000 years,
all temperature values are from their supplementary material, CO2 EDC data from ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/edc-co2-2008.txt

The figure shows quite a lot of discrepancy among temperature records.
CO2 seems to rise before temperature, but time response is very different at -17000 and at -12000.
There is an steady increase in CO2 from -6000 to present, while temperatures are relatively flat.
At -14000 years, CO2 remains at the same level for 2000 years while temperature drops almost 20C in Greenland, it drops about 3 degrees in Southern Europe and it raises in Alaska.

In a summary, paleo-stuff does not seem to be a very solid piece of evidence in general.

Apr 10, 2012 at 12:47 PM | Registered CommenterPatagon

To a layman, a feature of the Vostok Ice Core Data Plot is that the behaviour of CO2 after the last interglacial peak, 8,000yBP give or take, is that it continued to increase after temperatures began to drop. This is different from CO2 behaviour after the three previous interglacial peaks, where CO2 followed temperatures down, with a lag of 800y, give or take. It seems difficult to link this to human activity, since human population levels were so low around 7,000yBP - although I believe one UK Arctic Survey scientist has suggested, pretty improbably, that human-caused deforestation may have already begun to be significant by that time. Until we have an explanation for this feature, I do not believe that our understanding of climate science is sufficient to make confident forecasts.
There do seem to have been step-changes to the climate cycle at much earlier times, indicated by sediment core observations - for example significant changes to time between interglacial peaks. I don't know if there is any suggestion that these can be explained by the pattern of Milankovich cycles - or whether the change in CO2 behaviour represents a similarly explicable step-change?

Apr 10, 2012 at 11:51 PM | Unregistered CommenterJohnH

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