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Discussion > Feedbacks and Forcings

Philip

Being condescending is no substitute for being in the right. Instead of playing silly games with me and trying to 'win', why not read Shakun? It would be a much more productive use of your time.

Aug 15, 2012 at 2:46 PM | Unregistered CommenterBBD

BBD
All I see from your 'woodfortrees' graph is a rising trend to ~1880, a falling trend to ~1910, a rising trend to ~1940, a falling (or perhaps level) trend to ~1975 and a rising trend to 2005. Each rising trend appears to start at a slightly higher level than the previous one with the logical explanation being that the earth is still recovering from the Little Ice Age.
Nothing in that graph tells me that CO2 is responsible for anything.
Just for fun I added in the two oceanic oscillation indices. Cracking fit, the AMO. Much better than Mauna Loa CO2 wouldn't you say?
But anyway ... the point here is very much what caused the warm periods because that's what I'm asking you about. I'm not faintly interested in your attempts to sidetrack me by claiming they were "probably not globally synchronous anyway" — another piece of handwaving to avoid addressing the situation.
Arctic Ice, Greenland Ice sheet, permafrost melt, Yeah, yeah, yeah! Heard it all before. None of it empirical evidence of the action of CO2 on anything.
Have you tried reading the 'Moore realist' thread?

The global average temperature has now been flat for the past 15 years, as all the while CO2 emissions have continued to increase. There are only 2 possible explanations for, either there is some equally powerful natural factor that is suppressing the warming that should be caused by CO2, or CO2 is only a minor contributor to warming in the first place.
I don't fancy being the one to tell Patrick Moore he's wrong, but be my guest.
And if you aren't aware of an increasing number of papers casting doubt on the CO2 effect then you haven't been keeping up to date.Try this one
The Radiation Budget of the West African Sahel and its Controls: A Perspective from Observations and Global Climate Models
, Mark A. Miller, Virendra P. Ghate, and Robert K. Zahn. Models getting cloud fedback wrong by anything up to 70 w/m2. Ouch!
Admittedly it's only one year and only one area but, as they say, one brick at a time.

Aug 15, 2012 at 3:58 PM | Registered CommenterMike Jackson

Mike

As usual, you need to stop talking and read back. You just keep skipping along, never taking the time to read and understand what is being said. That is part of the reason these conversations never go anywhere: only one of us is actually developing a coherent argument.

If you were to do make an honest effort to understand, you might begin to see why studies such as the one you link are *irrelevant*. All this obsession with models. I don't think I've mentioned them once on this entire thread. You might also understand why Patrick Moore needs to mug up on stratospheric aerosols, equatorial volcanism since 2000 and Chinese coal burning. Not to mention taking a closer look at the various temperature records over the last 15 years.

You would understand that 'recovery from the LIA' is a nonsense claim because temperatures are *higher now* than *before* the LIA and anyway, there is no ideal climate state to which this 'recovery' leads. You would also understand that there is no known cause for the warming post-1950 other than increasing CO2 forcing, which is real unless you deny the basic physics and only loons do that - and you aren't a loon, are you?

On and on. It's just more of the same old, with no evidence on your part of any willingness to read, think or learn.

Oh, and your graph is illegible. Try this.

Aug 15, 2012 at 4:29 PM | Unregistered CommenterBBD

I read these post's with interest, sometimes even enjoyment. But rarely contribute, as my expertise is in a very different area. But like so many on here, my frustration in the methods used by BBD to divert, obstruct, distract etc. are beyond belief!
Here are a few Latin phrases that refer to what he does:
'Ignoratio elenchi'
'Circulus in demonstrando'
'Cum hoc ergo propter hoc'
'Non Sequitur'

Or, to use words a little more familiar:
Attention-grabber, bait, bluff, commotion, complication, confusion, curve ball, deviation, distraction, distractor, disturbance, diversion, diversionary tactic, dodge the question, false clue, false trail, fool's errand, gimmick, interruption, maneuver, ploy, smoke screen, stratagem, switch, trick, wild-goose chase etc. etc.

It's a shame, because if he were occasionally to get off his 'high horse', he may well prove to be an excelent contributor to these debates, instead of trying to control, and thereby, ruin them. But his tactic does often give us all a good laugh.

Aug 15, 2012 at 4:33 PM | Unregistered CommenterG. W.

I think your final comment says it all, BBD.
As well as being patronising and offensive, it demonstrates better than anything I could say or point to a certain overweening self-righteousness.

studies such as the one you link are *irrelevant*.

Patrick Moore needs to mug up on stratospheric aerosols, equatorial volcanism since 2000 and Chinese coal burning

temperatures are *higher now* than *before* the LIA

there is no known cause for the warming post-1950 other than increasing CO2 forcing

It's just more of the same old, with no evidence on your part of any willingness to read, think or learn.

I really did like that one. Pots and kettles came instantly to mind.
Oh, and your graph is illegible
Not when I link to it it isn't. It shows a very close correlation between the AMO and the temperature series, troubling as that might be to you.
As you said to Philip Richens,
Being condescending is no substitute for being in the right.
And I do so agree with you.
My patience is finally exhausted. When backed into a corner you flail as I have just demonstrated. All around you are people casting doubt on CO2 as a prime mover in global warming and you can't even be bothered to go and take a look.
This exchange is at an end.

Aug 15, 2012 at 6:02 PM | Registered CommenterMike Jackson

Mike

This exchange is at an end.

For the reasons given at Aug 15, 2012 at 4:29 PM, it never even started. You are a classic case of denial. Locked in and locked down. What are you so frightened of? Facing the facts?

G.W.

Blah, blah, blah.

Aug 15, 2012 at 6:45 PM | Unregistered CommenterBBD

I've been hunting for days for the source of this quotation and I can't find it. Anyone help?

One of the difficulties in dealing with environmental activists is that it's not enough for them always to be in the right. You have always to be in the wrong.

Aug 15, 2012 at 7:22 PM | Registered CommenterMike Jackson

"...there is no ideal climate state to which this 'recovery' leads"

'no ideal climate state'. Can you explain a little more about this please?

Aug 15, 2012 at 7:28 PM | Registered CommenterPhilip Richens

Philip

There is no ideal climate state = there is no ideal climate state. Equilibrium alters in response to changing forcings.

Aug 15, 2012 at 7:39 PM | Unregistered CommenterBBD

Mike

Sounds like Tom Fuller to me.

Aug 15, 2012 at 7:40 PM | Unregistered CommenterBBD

OK, thanks. I think it might be useful to summarize the main disagreements you and I have noted this time.

1/ Background spectrum: You think that the background spectrum is caused by Milankovitch forcing, whereas I think it is the result of non-linear climate dynamics.
2/ Cloud cover: You think that the amount of cloud cover is determined only by forcing, whereas I think that it is largely controlled by circulation patterns.
3/ Nearly random walks: You think that random walks within the temperature record are not possible because they violate conservation of energy (except at time scales of < 10 days), whereas I think that they occur naturally whenever white noise interacts with a reservoir.
4/ Attribution: You think that modern warming is firmly attributed to increased CO2 levels, whereas I think this remains inconclusive.

Have I understood your positions correctly? Is there anything else I've missed?

There are two other points I raised @ Aug 14, 2012 at 1:42 AM, which I don't believe you picked up on.

A/ Reconstructions of acknowledged forcings are not able to explain the observed millenial scale variability because they do not scale appropriately.
B/ Climate models are found not to exhibit the observed scaling laws over time scales longer than a few decades.

Would you like to express your opinions on these two as well?

Aug 15, 2012 at 8:56 PM | Registered CommenterPhilip Richens

Philip,
Could you please respond to my question from earlier? My sense is that I agree with much of what you have to say.

What I am trying to draw attention to, is the fact that a small change in tilt in degrees, for example, is not really 'small' because the scale at which these things act is planetary. Secondly, 'Milankovitch forcing', if it is said to exist, operates at a time scale of millions of years, which means that 'small' forces can produce large changes, given enough time. Which implies a very low sensitivity rather than a high one. That is not what is said about Milankovitch forcing.

Even in Wunsch's paper, I see use of such terminologies as 'small', 'large', and 'short' etc, when it is clear that such language is somewhat unscientific - ie., conveys subjective quantities.On the other hand, primitive quantification attempts of the forces involved, such as 'W/m2 of forcing' do not capture the variability element and force users into linear, simplistic modes of thinking. That is, it BBD'fies them.

Aug 15, 2012 at 9:18 PM | Registered Commentershub

Philip

1/ Background spectrum: You think that the background spectrum is caused by Milankovitch forcing, whereas I think it is the result of non-linear climate dynamics.

- I'm guessing you have Lovejoy & Schertzer's paper on the climate not being what you'd expect in mind here. To be as clear as I can: the evidence for orbital pacing of glacial terminations is too strong to ignore. Whatever internal dynamics are at work, orbital forcing triggers deglaciation. Let's think about the mid-Pleistocene transition. A switch from a 41ka world to a ~100ka word is a switch between the period of obliquity to that of eccentricity, which to me at least is compelling evidence that orbital forcing triggers glacial terminations. Thereafter, synergisitc positive feedbacks take over.

2/ Cloud cover: You think that the amount of cloud cover is determined only by forcing, whereas I think that it is largely controlled by circulation patterns.

Perhaps both are in play, but what we don't have is any evidence that circulation patterns are responsible for (questionable) changes in cloud cover/planetary albedo during the period of satellite observation.

3/ Nearly random walks: You think that random walks within the temperature record are not possible because they violate conservation of energy (except at time scales of < 10 days), whereas I think that they occur naturally whenever white noise interacts with a reservoir.

I think random walks might last longer than a few days, but not more than a year or two. Conservation of energy enforces that (increased OLR = cooling).

4/ Attribution: You think that modern warming is firmly attributed to increased CO2 levels, whereas I think this remains inconclusive.

Really? I didn't know you were agnostic about that. I'm surprised, but it does explain your unwillingness to discuss the elephant.

A/ Reconstructions of acknowledged forcings are not able to explain the observed millenial scale variability because they do not scale appropriately.

- Sounds like a strong argument that we don't yet have the full picture on positive feedbacks.

B/ Climate models are found not to exhibit the observed scaling laws over time scales longer than a few decades.

- You'll have to tell me more about this, but as you'll have noticed, I'm not as hung up on models as most sceptics.

Aug 15, 2012 at 9:49 PM | Unregistered CommenterBBD

- Sounds like a strong argument that we don't yet have the full picture on positive feedbacks.

On which point, I should have mentioned the Lake El'gygytgyn drilling project results. More disquieting mysteries.

Aug 15, 2012 at 10:05 PM | Unregistered CommenterBBD

Shub,

Apologies if it seems like I'm avoiding the issue, this probably reflects how I've come upon the problem and where I feel most confident about it.

1/ My understanding is that the orbital forcings are small and geographically focused, but I don't think this is the key point.
2/ I think the key point is the structure of the spectrum for the ice age temperature record. The spectrum indicates how strong the oscillations are at each different time scale. If the temperature record was a product only of the orbital forcings, then the two would have the same spectrum. If the forcings happened to be a sine-wave, then the temperature spectrum would contain a spike and be zero elsewhere. If the forcings were a sum of sine-waves then the temperature spectrum would contain a series of spikes and be zero elsewhere. But the temperature spectrum is instead a curve approximated by a power law (called the background or continuum), with small superimposed bulges corresponding to the orbital frequencies.

If I've understood you correctly, your concern is to try to match up the estimated orbital forcings with the temperature changes? If so, here are a couple more comments about this.

3/ The climate sensitivity is defined in terms of a linear approximation which probably does not not hold true over these long time-scales. It is however probably valid for short time scales (100 years?), but (according to a number of estimates) low compared to the IPCC central value. Over longer time-scales, there is only a statistical relationship between temperature and forcing - because energy becomes smeared across time by the heat reservoirs within the system (internal variability).
4/ There is a similar issue in matching up the temperature changes in the MWP with the known forcings. If you believe (as many do) that climate sensitivity can be used to calculate between then and now, then the result is a large sensitivity. On the other hand, internal variability should be independent of forcing (at least the forcing that occurs at the same time as the variability). If you accept this, then you can attribute the temperature changes between MWP and now to internal variability and still keep a low sensitivity.

Does this help to answer your question a little bit more? Here is a preprint of a paper, somewhat mathematical but still a good read, that goes into more detail about some of these issues.

Aug 15, 2012 at 10:40 PM | Registered CommenterPhilip Richens

BBD,

Thanks for the clarifications.

Aug 15, 2012 at 10:41 PM | Registered CommenterPhilip Richens

Philip

No problem. Let's do our best, despite the rather horrible medium of blog comments. Looking at your response to shub, perhaps some cross-purpose argument may be avoided:

Over longer time-scales, there is only a statistical relationship between temperature and forcing - because energy becomes smeared across time by the heat reservoirs within the system (internal variability).

This is not incompatible with an orbital trigger for deglaciation, nor the scientific consensus that CO2 forcing is responsible for modern warming.

Aug 15, 2012 at 11:06 PM | Unregistered CommenterBBD

Nor, now I think of it, the calculation of ECS in HS12, nor that in Annan & Hargreave (2006), nor indeed the consensus (IPCC AR4 WG1) of a most likely value of ~3C to 2xCO2.

Aug 15, 2012 at 11:09 PM | Unregistered CommenterBBD

Philip,
The 'conversation' doesn't proceed very coherently because the participants each pull in different directions centred around the same theme.

Your mission, if you will, of getting BBD to accept that internal variability has a hand in observed changes of any significance will not work because (a) this is BBD you are dealing with, (b) as he says himself - "it all fits", meaning, he uses a construct where the central claim is fixed first and science papers are used to plug holes in the construct.

Your technique of appeasing BBD ("your knowledge is deep") in order to have at least the conversation go fruitfully won't work for the same reason. What BBD hides when he comes to a discussion is how and where he acquired his reading. The standard catechism has a number of holes, so its practitioners acquire a hotch-potch of knives and skillets to throw at questioners (as BBD just did with Mike with the Shakun et al paper, a failure because Shakun et al themselves rely on temperature to explain CO2 rise), and to calm their own mind (that it all 'fits', don't worry). You can derive the standard catechism from the IPCC, you can derive it from Skepticalscience.com, or you can derive it from Hansen. BBD, for a while now, has been deriving it from ss.com and Hansen - he practically doesn't read anything else, other than the references contained within.

The problem for us and this thread (and any similar thread) though lies in the fact that the catechism and its practitioners have no mechanism of admitting outside evidence or findings. They have already closed the circles and explained all changes with their CO2.

The problem/question that concerns us therefore originates in the catechism itself and not in what BBD thinks because he is merely its mouthpiece. So, the Hansen paper has to be examined, and its underlying assumptions - of which there are tonnes - have to be questioned. It is not easy to ferrett out these assumptions as they are numerous, and stated in a very passing manner. A similar exercise is easier with the IPCC, because, they cite references for their claims.

One of the main assumptions in the Hansenko framework is that forces/forcings are quantitatively what we affix them to be. That is, what is termed small, is small, and remains small. If you go back to the previous thread where the whole feedback/forcing argument started, BBD quotes the Hansen graphs as evidence that the climate system is exceptionally sensitive and unstable. That was my interest in pursuing my line of questioning.

My long standing point has been that we ought to give up such terminologies and modes of thinking. One doesn't quantify what one doesn't know. Just give it a name and be done with it.

"The orbital forcing is so small, but yet it causes the whole planet to freeze/warm. How mysterious!!!" I say - please STFU. Even Wunsch uses the same framing (although he is only setting the scene in the introduction):

These changes are so massive, and the Milankovitch forcing so slight (10% spatial redistributions of annual global insolation at periods much shorter than 100 ka), that a number of
interesting hypotheses have been proposedto rationalize the observedshif ts.

My response: Glaciation and deglaciation are "massive" only if one counts such changes to be outside the range of what the climate system is capable swinging between. Yes, it may seem 'massive' to us but given the age of the system and its behaviour within, and our puny abilities of comprehension, it falls within what is 'normal' to it. I have a sense you say the same thing.

In any case, to this end, your answer didn't address the question I try to raise. But nevertheless, thank you for your answer, and the excellent references. :)

Aug 16, 2012 at 1:04 PM | Registered Commentershub

shub

This is weak and self-destructive even by your usual standards:

BBD, for a while now, has been deriving it from ss.com and Hansen - he practically doesn't read anything else, other than the references contained within.

Making stuff up in an attempt to discredit someone else is a dangerous tactic. People tend to see through it and they will think the less of *you* as a result. It's also somewhat childishly vicious, which will further diminish you in the eyes of others.

a hotch-potch of knives and skillets to throw at questioners (as BBD just did with Mike with the Shakun et al paper

Actually, I linked Shakun for Philip, not Mike. I'm not surprised that you can't get the sciencey stuff straight.

A similar exercise is easier with the IPCC, because, they cite references for their claims.

References for HS12 run from p28 - p32. I haven't counted them exactly, but there are well over a hundred. Also remember that prior to peer review, this study was posted online as a draft for the best part of a year. There has been ample opportunity for anyone - including you - to point out errors to the authors. I know you didn't, which leaves you with exactly nothing further to say, or rather insinuate about HS12. This is a further example of your charmless and self-defeating methods.

Facts matter shub. Even on the internet.

:-)

Aug 16, 2012 at 7:32 PM | Unregistered CommenterBBD

Another way to think about Shub's question might be to ask what would happen if there were no orbital forcings? Huybers and Curry consider this question and here is what they offer:

What would the background continuum look like in the absence of annual or Milankovitch variations? Variations would presumably still exist owing to adjustments in the Equator to pole temperature gradient, providing a background of climate variability upon which variations due to Milankovitch- and annual-period changes are superimposed. [...] Discussion of long-term climate variability is commonly divided between deterministic and stochastic components - often associated with spectral peaks and the continuum, respectively. The analysis presented here indicates that the annual and Milankovitch energy are linked with the continuum, and together represent the climate response to insolation forcing.

Without the orbitals, the variability would not have the same quasi-cyclic behaviour, but it would still exist. How large would it be? Here is another relevant comment from H&C,

Possibly, the climate system has a memory associated with the oceans that causes high-frequency variability to accumulate into progressively larger and longer-period variations, and a Milankovitch-driven low-frequency response that transfers spectral energy toward higher frequencies, possibly involving nonlinear ice-sheet dynamics. These low- and high-frequency temperature responses appear to be of nearly equal magnitude at centennial timescales, midway in log-frequency space between the annual and Milankovitch bands.

As far as I am aware, there are two basic mechanisms of internal variability:-

1/ Redistribution of energy by processing through stores with different thermal properties. This will tend to "clump" variability.
2/ Changes of average albedo and emissivity, caused by processes other than atmospheric temperature change.

The average temperature of the atmosphere depends on the amount of heat energy it contains. Radiative forcing is a measure of how this stored heat energy changes i.e. it is the difference between incoming energy and outgoing. Both 1/ and 2/ create forcings that are not directly associated with orbital, solar or anthropogenic effects. Therefore even if none of the external forcings existed, the existence and size of the observed temperature variability does not mean that measurements of low climate sensitivity must be wrong. This depends on the amount of forcing caused by internal variability. It should be possible to estimate this magnitude.

Aug 17, 2012 at 10:07 AM | Registered CommenterPhilip Richens

Hi Philip

2/ Changes of average albedo and emissivity, caused by processes other than atmospheric temperature change.

What processes other than atmospheric T change affect average albedo and emissivity? I'm not clear how this works but it's late and the in-laws have been here all day and I'm probably missing something obvious.

Aug 17, 2012 at 11:06 PM | Unregistered CommenterBBD

1/ Redistribution of energy by processing through stores with different thermal properties. This will tend to "clump" variability.

What stores other than the ocean? Again, am I missing something here? Sorry.

Aug 17, 2012 at 11:11 PM | Unregistered CommenterBBD

>>> What stores other than the ocean?

Ice is the other significant redistributor of energy.

>>> What processes other than atmospheric T change affect average albedo and emissivity?

Changes in patterns of circulation.

Aug 18, 2012 at 8:13 AM | Registered CommenterPhilip Richens

Changes in patterns of (ocean?) circulation change atmospheric T and emissivity, do they not? Thus invoking conservation of energy.

How much energy do you think is stored in ice compared to the global ocean? Enough to matter in the way you suggest? And how much is lost in phase transitions? Conservation of energy would again seem to be invoked.

Aug 18, 2012 at 7:50 PM | Unregistered CommenterBBD