Bishop Hill Skeie et al at ESD
Aug 14, 2013 Climate: sensitivity The Skeie et al paper, which helped kick off all the interest in low climate sensitivity when it was still in draft form, is now in open peer review at Earth System Dynamics:
The equilibrium climate sensitivity (ECS) is constrained based on observed near-surface temperature change, changes in ocean heat content (OHC) and detailed radiative forcing (RF) time series from pre-industrial times to 2010 for all main anthropogenic and natural forcing mechanism. The RF time series are linked to the observations of OHC and temperature change through an energy balance model and a stochastic model, using a Bayesian approach to estimate the ECS and other unknown parameters from the data. For the net anthropogenic RF the posterior mean in 2010 is 2.1 W m−2 with a 90% credible interval (C.I.) of 1.3 to 2.8 W m−2, excluding present day total aerosol effects (direct + indirect) stronger than −1.7 W m−2. The posterior mean of the ECS is 1.8 °C with 90% C.I. ranging from 0.9 to 3.2 °C which is tighter than most previously published estimates. We find that using 3 OHC data sets simultaneously substantially narrows the range in ECS, while using only one set and similar time periods can produce comparable results as previously published estimates including the heavy tail in the probability function. The use of additional 10 yr of data for global mean temperature change and ocean heat content data narrow the probability density function of the ECS. In addition when data only until year 2000 is used the estimated mean of ECS is 20% higher. Explicitly accounting for internal variability widens the 90% C.I. for the ECS by 60%, while the mean ECS only becomes slightly higher.
Apparently it was originally submitted to Journal of Climate, so presumably it had the usual rough ride there.
[Updated: I originally thought the paper was in print, but it's actually just open peer review]
Reader Comments (61)
That hum you can hear is 'the Team' getting its smear machine up and running, I wonder if they will break yet another written to publish time record for a paper ‘refuting ‘ this one ?
What worries me is having so little real data that adding a mere 10 years worth to the end can change your results by 20%. That means the next ten years could change the results again, by possibly only a little less, and in either direction.
It's just not a robust result. (and nor is alarmism, of course)
Time to interject my usual claim that the concept of CS is still to be confirmed. I've repeatedly asked for justification, never had a reply. Maybe it's a stupid claim unworthy of answer, but OK, just tell me so, I can take being called stupid.
Second, any figure this lot or any other comes up with is solely the outcome of their assumptions. It is just an exercise in reverse curve-fitting. Take away everything you think you know and whatever is left is the climate sensitivity to CO2. Except it isn't, it is merely the arithmetic total of the unknown unknowns. Routed through a couple of models and a bayesian algorithm. Nonsense on stilts with elevator heels.
Simple, stupid question: If the algorithm was wrong on earlier data, why should it be right with more data?
===============
From the same viewpoint as Rhoda I question this quote:
Do people here really believe they know what all those forcings are, let alone what value they have?
Whatever one decides about the RF of CO2, the 15 year non-rise of global temperatures means that the counter-rise mechanisms must be equal to that RF. When we look at the models, whatever negative forcing existing within the models must add up to that RF.
It can be argued that a simple positive reinforcement of negative forces makes normally immaterial, small cooling influences look like a fundamental large cooling influence. The trouble with this reasoning is that it says we are in a "special" time wrt cooling - otherwise the immateriality of cooling processes is untrue - AND it opens up the door to say that the '75-98 period could also represent a special time in which immaterial, small WARMING influences were in play.
Regardless of how you rationalize the '98-present period, the non-predicted rise in global temperatures weakens the idea that IPCC-type global climate models are accurate enough for global economic and political adjustments.
Well it reads like a load of gobbledy-gook, which I'm sure it is. I'm with Rhoda and Dung. ECS and RF have no scientific meaning and we don't know all the mechanisms.
Bruce Hoult wrote:
"What worries me is having so little real data that adding a mere 10 years worth to the end can change your results by 20%. That means the next ten years could change the results again, by possibly only a little less, and in either direction."
The mean estimates given for ECS are misleading - the mean is an unsuitable central estimate for skewed distributions. The median is a much more appropriate central estimate. The median estimate for ECS per Skeie's paper is 1.65 C using data up to 2010, and about 1.72 C using data up to 2000. What pushes the mean up 20% is that the probability distribution for ECS becomes much wider and less well constrained when only data only up to 2000 is used, which is to be expected since the signal-to-noise ratio was considerably higher in the 2000s that in previous decades.
IMO the method used is fairly robust, apart from it being a subjective rather than objective Bayesian approach (an objective Bayesian approach uses noninformative priors for the parameters being estimated).
For Rhoda
The hypothesis is that increased CO2 concentration in the earth's atmosphere causes increased temperatures, with the latter proportional to the log of the former. This seems a perfectly respectable hypothesis. You might question whether the tests of the hypothesis so far are valid or propose alternatives (for example that extrapolating from laboratory results to the atmosphere fails because feedback suppresses the increased temps due to CO2 or that it's dwarfed by natural variation) and suggest the effect that such alternatives would have on the calculated sensitivity (for example that it varies wildly or goes negative). You might then conclude that in practice CS is irrelevant or only applies in very restricted and unlikely circumstances but nonetheless it seems unduly harsh to say that the concept is "nonsense on stilts with elevator heels".
Aug 14, 2013 at 5:26 PM | Unregistered CommenterSimon Anthony
"You might then conclude that in practice CS is irrelevant or only applies in very restricted and unlikely circumstances but nonetheless it seems unduly harsh to say that the concept is "nonsense on stilts with elevator heels"."
I don't know Simon, but Rhoda has a point, which is this; if there was such a thing as positive feedback, aka, climate sensitivity, why haven't we seen evidence of it in the paleoclimate records? Temperatures rose during the MWP by 1+C, why didn't it trigger a further rise because of positive feedback/
How about 'Nonsense in tights with a short, slit, skirt'?
=========================
With such wildly different estimates of ECS, I wonder if the whole system is numerically ill-conditioned? Too many variables? Wrong model?
Because there might be such a thing as climate sensitivity and it might be simply about 1C for every doubling of CO2. That's all. There are no feedbacks. So when the temps rose in the MWP for reasons we do not know, they just rose by that much. Then they fell for reasons we also do not know.
This cannot invalidate the concept of climate sensitivity, it just invalidates feedback. If that is what happened - I'm just talking the logic, not necessarily saying this is what happened. But this is why the MWP doesn't invalidate the concept of sensitivity.
I don't really see the problem with the concept. If you accept there is such a thing as a heating effect from CO2, the logical next question is how much, and this is surely all the concept is?
If CS is calculated from running a failed model (and all of the models are failures as we know) then CS is as meaningful as the rest of the model output. i.e. Not meaningful.
This is a form of self-delusion in my view.
> Temperatures rose during the MWP by 1+C, why didn't it trigger a further rise because of positive feedback
Perhaps the 1+C rise included feedback. Without the feedback the rise might have been 0.66.
TerryS:
I keep asking the same question. If a temperature increase causes more water vapour and this leads to more radiative warming, etc. then in theory, that temperature increase could have been triggered by any forcing. It doesn't need to be CO2 that gets it going..
Given that temperatures have been much higher in the past, where was the positive feedback and runaway temperatures?
"With such wildly different estimates of ECS, I wonder if the whole system is numerically ill-conditioned? Too many variables? Wrong model?"
err. No. No. and No.
Would climate sensitivity to CO2 be calculated if temps were now falling? Surely the circular reasoning for the calculation would collapse. And hasn't that collapse already happened due to the current flatlining of temps? Seams to me that it has.
Skeie et all wrongly claim their sensitivity estimate is based on
They are still not accounting any indirect solar effects so their sensitivity estimate-range is still far too high. Their abstract is not explicit, but it seems that they are using the same RF estimates as the IPCC, just with a little more data. That means the only solar effect they are accounting is the very slight variation in total irradiation but the paleo-evidence shows a much stronger correlation between solar activity and climate than can be accounted for by TSI variation, giving a strong indication that some kind of solar amplifying mechanism is at work. In the scheme of the IPCC and of these Skeie et al., whatever work that amplifying mechanism is doing is getting misattributed to CO2, which was coincidentally correlated with high solar activity over the 20th century.Probably the actual sensitivity is less than one (temperature forcings are damped rather than amplified), but either way, solar effects are likely to outweigh CO2 effects (already indicated by the lack of 21st century warming) and the rational expectation going forward is for cooling, not warming.
A feedback does not have to lead to runaway temperatures.
For example, lets assume a feedback of 0.5 applies so that every 1C increase leads to a positive feedback of 0.5C. You then get:
1 + 0.5 + 0.25 + 0.125 + 0.0625 + 0.03125 + .... = 2
The initial 1C leads to further 0.5C which leads to further 0.25C and so on.
So a positive feedback factor of 0.5 (don't confuse it with sensitivity) would lead to a doubling of the initial temperature rise.
If you assume that there are no feedbacks then the climate sensitivity to CO2 is about 1.2C, with feedback it is ... well that is what most of the argument is about.
At the moment there is no warming and cooling is probably more likely. This throws doubt on the whole warming mechanism and the assumptions that underpin it. Since Climate scientists have no idea why the warming has stopped and no idea what is going to happen next, I see no merit in clinging to aspects of the model. This is another form of cherry picking.
There are probably just two options. If we take the water vapour feedback out of the model does that produce a more realistic result? If not, then the whole concept of GHG radiative warming is suspect and they should scrap it and get back to basics.
Aug 14, 2013 at 4:14 PM | Unregistered Commenter rhoda
You left out one thing. These modelers believe that continuous revision in their highly complicated systems of differential equations will eventually produce a well-confirmed physical hypothesis. This is akin to believing that one can spin straw into gold.
Aug 14, 2013 at 4:14 PM | Unregistered Commenterrhoda
I'm with Rhoda.
Simon Anthony, thanks for the response. The nonsense on stilts comment was meant to refer to the methods used to calculate CS, which invariably require unsustainable assumptions and models. But never mind, they all produce a result because the CS is what's left over. You can't miss.
The concept of CS itself is difficult for me when it is expected to work on a global scale and a centennial timescale. Of course a small change in CO2 will produce a local effect. The problem is in expecting that you can come up with a figure which will be useful over the entire globe for repeated doublings of CO2 no matter what all the other things do. Well, it MIGHT work like that, but I'd say that was an assertion which needs to be tested and justified. Let's assume that water vapour feedback is negative in the tropics and maybe positive at high latitudes while non-operative at the poles at least when it isn't summer. Any global temperature change will alter the extent over which each effect works. That means the first degree will have a different effect than the second or third. Now I could be wrong, but it seems to me hubristic to go straight to the logarithmic relationship seen (but undemonstrable?) in the lab and expect it to apply in the real world.
Aug 14, 2013 at 6:14 PM | Unregistered Commenter michel
One cannot calculate climate sensitivity without knowing exactly what the natural variability of the climmate is at this time. Natural variability is the range of our data. During the last few years of the temperature "plateau," even Alarmists have been appealing to the effects of unknown causes that contribute to natural variability.
Authors who assert that all "all main anthropogenic and natural forcing mechanism(s)" are known might be engaging in irony but more likely they are just confused. The "forcings and feedbacks" calculations involving clouds, water vapor, and other things have not been done and, for that reason, cannot be known.
Aug 14, 2013 at 7:44 PM | Unregistered Commenter rhoda
Wonderfully well said.
Bishop may I be the first person on this blog to congratulate the Walworth egg thrower.If ever there was amost deserving candidate for a well targeted egg it is lispy Egg Milliband.
Egg Milliband who forced through the hated Climate Change Act that has puts thousands in fuel poverty and hindered British industry throwing thousands more onto the dole queues.
A concise but penetratingly accurate assessment if I may say so.
Previously I have said that CS is unique among the unverifiable concepts that "climate science" has produced, in that 97% of sceptics also believe in it.
In view of the number of comments above critical of the notion that CS has any validity or meaning, I think I shall have to revise the figure downwards to 96.5% in future.
For Rhoda again
Your doubts about the likelihood of a universal, timeless CS are, I think, well-founded. But I'd have thought you'd be pleased that climate modellers have been so foolish as to think that climate dynamics can be so simplified. As more calculations are done on CS (and, as it's increasingly a public issue, more people will do more elaborate, detailed, local calculations to try to distinguish their work from others') divergences and contradictions will emerge in the value of CS.
If that happened the concept of CS would be discredited as a useful way of modelling the world, which would show that CS was susceptible to scientific test, just not of practical use or relevance.
So I think that the concept of CS is testable but, because I share at least some (and probably most) of your reservations, rather relish the idea of climate scientists continuing to test it as, if our doubts prove correct, they will succeed in thoroughly demolishing its utility.
Rhoda has nailed it pretty well. It seems to me that the climate gurus have to try to regain some of their fast-disappearing credibility. Unfortunately, this alchemical explanation is yet another attempt to appear knowledgeable about a phenomenon that is simply not understood. Detailed knowledge about parts of an open system is not necessarily any guide to overall behaviour.
ZedsDeadBed: you have a point. Personally, I believe that the missing heat is hiding in the depths of the ocean in the crustal subduction zones, right next door to the Tooth Fairy's residence.
Perhaps my responses to ZDB could be re-instated?
Alec Rawls makes an important point. The suspicion has always been that the IPCC bias trivialises solar influence in order to big up CO2 as a driver. We may well see in the coming years if the sun is king after all.
"Explicitly accounting for internal variability widens the 90% C.I. for the ECS by 60%, while the mean ECS only becomes slightly higher."
That gives a 90% C.I. of 0.36C to 4.40C. Such a large interval only precludes the highest sensitivity forecasts of AR4, which are already regarded as excessive. Perhaps the Journal of Climate rejected it because of its lack of precision, and its failure to contribute anything new to the debate.
Australis
Climate is not only a troposphere process. Energy has to flow through the troposphere to reach other parts of the system, but it is not the only relevant part to consider.
Historically we have only been able to record large quantities of temperature data for the troposphere, the surface of the land and the surface of the sea. Those parts of the climate system have a small heat capacity and respond rapidly to changes in energy flow.This is the fast feedback part of the system. In a sense, most of our attention was focused there because the light was better, we had more information.
Mpst of the heat capacity in the system is in slow feedback areas, particularly the bulk volume of the oceans and the ice caps. These respond much more gradually to changes in energy flow because of the large amount of energy needed for even small changes in temperature. It is only since the ARGO float system and the GRACE satellite that we have been able to continuously monitor the deep ocean and the ice caps, and begin to understand their behaviour.
Why are you so keen to concentrate entirely on the fast feedback parts of the climate system and ignore the slow feedback parts?
Further to the post by Australis here is are the definitions given in the UNFCCC
ARTICLE 1:
DEFINITIONS
For the purposes of this Convention:
1. "Adverse effects of climate change" means changes in the physical environment or biota resulting from climate change which have significant deleterious effects on the composition, resilience or productivity of natural and managed ecosystems or on the operation of socio-economic systems or on human health and welfare.
2. "Climate change" means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.
3. "Climate system" means the totality of the atmosphere, hydrosphere, biosphere and geosphere and their interactions.
4. "Emissions" means the release of greenhouse gases and/or their precursors into the atmosphere over a specified area and period of time.
5. "Greenhouse gases" means those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and re-emit infrared radiation.
6. "Regional economic integration organization" means an organization constituted by sovereign States of a given region which has competence in respect of matters governed by this Convention or its protocols and has been duly authorized, in accordance with its internal procedures, to sign, ratify, accept, approve or accede to the instruments concerned.
7. "Reservoir" means a component or components of the climate system where a greenhouse gas or a precursor of a greenhouse gas is stored.
8. "Sink" means any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere.
9. "Source" means any process or activity which releases a greenhouse gas, an aerosol or a precursor of a greenhouse gas into the atmosphere.
http://unfccc.int/essential_background/convention/background/items/2536.php
Entropic Man effectively defines "climate" as being any energy flow we might be able to monitor.
There has been a vigorous worldwide debate regarding climate change science and policy since the issues were defined by the 1992 Rio Earth Conference (and the IPCC's FAR). It has serious purpose and is not just an academic debate where definitions might be abandoned or replaced at will.
An observed 100-year warming trend in the atmosphere has been attributed to anthropogenic greenhouse gases on the basis that no other known forcing can produce such a trend.
There is no similar long-term warming trend in the oceans. As Entropic man points out, monitoring of ocean heat content is in its infancy. The ARGO float program is a great advance but it does not measure changes at all levels and will be unable to produce any confident 30-year trend line until the 2030s at best.
Ocean temperature trends are off-topic. It is difficult to avoid the conclusion that 15 years of atmospheric temperature standstill have driven some diehards to attempt a "bait and switch". See http://www.quadrant.org.au/blogs/doomed-planet/2013/03/the-climate-commission-plumbs-new-depths
Troll comments and numerous follow-ups removed as per usual. Please DNFTT.
Simon - Would you care to give the barest outline of how the concept of CS might be tested, ideally with the outcome of the test being available during the lifetime of anyone who is alive today?
BTW - I have a secret algorithm for predicting the outcome of tossing a coin (heads/tails). My tests of the algorithm to date suggest that its accuracy in predicting the outcome of a coin toss is close to 50%. I hope that your test for CS will result in a higher level of confidence in CS predictions than for my coin toss algorithm.
"the suspicion has always been that the IPCC bias trivialises solar influence in order to big up
CO2 as a driver."
No real suspicion, more a fact based on quote from IPCC authors.
" This paper re-enforces the
fact that the warming in the last 20
to 40 years can't have been caused
by solar activity"
http://news.bbc.co.uk/2/hi/6290228.stm
The 'feedback' is from 1981_Hansen_etal.pdf. They implied that if you take out all ghgs the position of the -18 deg C composite IR emitter in radiative equilibrium with space coincides with the Earth's surface, therefore the ghe = 15 - (-18) =33 K. This claims the ghe is from lapse rate heating. Balderdash.
No clouds or ice mean you increase the SW heating of the surface by 43% in which case the new mean temperature for radiative equilibrium with Space = 4 - 5 deg C, ghe = ~ 11 K.
The feedback is imaginary because the models are calibrated to 33 K not 11. Time for this junk science to end.
Aug 14, 2013 at 11:04 PM | Pharos
...
The IPCC was never constituted to examine anything other than the influence of CO2 ... this CO2 fixation of the IPCC and its sycophants must supported at all costs ... it's the vibe, it's Mabo, it's the Constitution (its an Australian thing) ... Ah! it's the IPCC's Constitution that supports the hypothesis and the hypothesis that supports to sycophants of the IPCC.
I am with Theo Goodwin, Rhoda and Schrodinger's Cat on this, and have in the past made many comments upon the present impossibility to make any assessment of climate sensitivity (which is how the real world responds to an increase in CO2, not upon its theoretical in lab qualities).
Recently, over at WUWT, I made the following comment (which is typcal of what I have said many times beofre on this blog as well as at WUWT) which coincidentally was prompted by a comment made by Schrodinger's Cat :
"
Schrodinger’s Cat says:
August 14, 2013 at 9:53 am
“…Worse than that, since the models are clearly not fit for purpose, does this mean that discussing climate sensitivity is a waste of breath?”
//////////////////////////////
YES. YES. YES.
Any discusssions of Climate Sensitivity are disengenuous unless they make it clear that presently we are not in a position to estimate this concept from observational evidence/data, and that any figure proposed is just a speculative guess.
Climate sensitivity and natural varuiation are instrinsically linked. Climate sensitivity can at best expalin any temperature change whiich temperature change is not itself the result of natural variation.
Accordingly, before one can begin to meaningfully discuss climate sensitivity one first has to eliminate any and all temperature changes brought about by natural variation. It is only then that one will be left with the signal (if any) of climate sensitivity.
Accordingly as a matter of logic, we first need to fully know and understand everything there is to know and understand abouut natural variation, before we can start to evaluate climate sensitivity. Accordingly we need to know and identify each consituate forcing which goes to make up natural variation, the direction of that forcing and the upper and lower bounds of each and every constituent forcing.
Since we do not yet know what natural variation encompasses, we cannot begin to meaningfully discuss climate sensitivity.
All we know are the most general of matters such as natural variation trumps climate sensitivity (ie., is a stronger force) as is apparent form the 1940s to 1970s cooling (natural variation was stronger than any CO2 forcing brought about by increasing CO2 emissions/levels during that period), and is at least equal to climate sensitivity encompassing the residual CO2 emissions of the last 50 to 70 years (depending upon claimed residency times) plus recent emissions (say post 1995) in view of the temperature stasis these past 16 to 22 years (depending upon data set used).
Given that there is no first order correlation between CO2 and temperature in the sat record; it being essentially flat between say 1979 and up to and around the 1998 super El Nino, and then essentially flat post that El Nino to date, with only a step change taking place in and around the Super El Nino then unless that El Nino was in some way caused by CO2 (and as far as I know no one alleges that it was caused by CO2 emissions), one would be led to conclude from 33 years worth of sat data that climate sensitivity is so low that it cannot presently be measured with present equipment and the limits of resolution of that equipment."
AND
For those interested in Climate Sensitivity and the carbon cycle there was a very good (and clear) debate on this issue in the recent article “Murry Salby responds to critics ” See:
http://wattsupwiththat.com/2013/08/11/murry-salby-responds-to-critics/#comments
This debate is well worth a read. The contributions by Bart, Richard Courtney, dbStealey, Allan MacRae, and (for the warmists) by Nick Stokes, Ferdinand Engelbeen and Nyq Only are in particular worthy of note. The debate was very clearly set out and the contributors are to be congratulated for the clarity of their response which makes it particularly easy for the reader to understand and follow the arguments being made. I highly recommend a read of this debate as it is is illuminating.
In this dabate Bart produced evidence that suggested that CO2 is driven by temperature, and the consensus view that CO2 drives temperature is not supported by the observational data. Now I do not wish to misinform what was conceded, but I gained the impression that it was accepted that temperature drives CO2 but only as far as recent response is concerned and it is a short term effect, not a long term response.
There was a debate whether there could be a different short and long term response, and whether the long term response is simply an accumulation of the short term response, but leaving that issue to one side, the effect of the concession to Bart’s evidence (see http://www.woodfortrees.org/plot/esrl-co2/derivative/mean:12/from:1979/plot/rss/from:1959/scale:0.2/offset:0.125) would seem to make it very difficult to measure climate sensitivity from short term observational data. So whilst Steven Mosher call for more data and extolls the virtue of the examination of recent data (something that I do not disagree with), it may well be the case that this data will give little insight into climate sensitivity because of the link (at least in the short term response) that changes in temperature drive changes in CO2 levels.
I have never claimed to be a scientist, but am just one of the majority scuffing their heels along the street of life, enjoying the views and hoping to find a few pennies in the gutter. I have no idea how the street was built or where it is going, but like to think that I can spot a flaw in its structure. Climate sensitivity is, to me, one of those flaws; a paving stone sticking up to trip people. Since its revelation to the public, I have felt that it is just another article of nonsense created to cover scientific embarrassment in climatological circles; however, not being a scientist, I kept quiet, unable to add weight to my argument to its fantasy; it is, I suspect, another suit to be hung in the rapidly-growing wardrobe of Hans Christian Anderson’s emperor. It is smugly satisfying to see others with greater credentials than mine moving along the same path.
For Rhoda, Richard Vermey, Martin A...
I'm not sure that you're appreciating the full elegance of the formulation of CS and the attempts to calculate it. CS is just a particular attempt to formalize the relationship of the secular increase in temp and CO2 concentration. I believe (please correct if I'm wrong) that you all think that any such relationship is either too complex to be captured by such a simplistic formula or is in practice swamped by "natural" factors.
If I've got that right (and your views turn out to be correct) then you should be very pleased that climate scientists have nailed their colours to such a fragile mast. Because, whether believers or critics, they'll keep calculating using increasingly "ingenious" methods and their answers will diverge and contradict (BTW, Martin A, I'm not sure why you think that it can't be calculated in a reasonable time. It's been calculated numerous times in numerous different ways. A few years ago John Daly had a summary of half-a-dozen different rough estimates all of which were around zero).
So it's not correct to say it isn't scientific. It will be tested and, if found wanting, dropped. And that's where the elegance comes in for the climate scientists aren't just being given enough rope; they're actually growing their own hemp. (Although that's really what science involves, at least if it's done properly: sticking your neck out).
Simon Anthony --
(BTW, Martin A, I'm not sure why you think that it can't be calculated in a reasonable time. It's been calculated numerous times in numerous different ways. (...) ).
I don't think I explained myself well. I am sure CS estimates can be calculated very quickly.
My understanding of CS is that it is the eventual total change in global temperature resulting from a doubling of atmospheric CO2 and the time for this change is thought by climate scientists to be 100+ years. So to verify the calculation by comparison with reality, quite apart from the list of other reasons it cannot be done, would take longer than you or I will still be around. That's what I was on about.
So it's not correct to say it isn't scientific. It will be tested and, if found wanting, dropped.
You haven't given any suggestion how it can be tested as I requested.
How "will it be tested"? So far as I can see, it's inherently incapable of being tested in any normal sense of the word. It can't be falsified and it can't be confirmed.
For Martin A
What you say re CS is true in a literal sense but the CS definition implies and is implied by a certain rate of increase of temp with CO2. In that sense it's continually possible to estimate its value. Of course the errors (or uncertainties as people prefer to call them) in the estimates should decrease with increased measurement time (at least if the "theory" is correct) but even if you waited for the implicit doubling time there'd still be an uncertainty.
Entropic Man (Aug 15, 2013 at 1:12 AM) opines" Why are you so keen to concentrate entirely on the fast feedback parts of the climate system and ignore the slow feedback parts?"
There are 2 obvious reasons that come to mind.
First, CAGW was built on fast feedback and in particular the late 1970s to late 1980s warming (I am not inferring that the warming, if any, stopped in the late 1980s but rather that it was the 10 year period up to the late 1980s that spwaned CAGW and the Hansen testimony).
Second, the deep ocean (the slow feedback response to which you refer) is of no concern. CAGW is dead if the 'additional' energy is being sequested to the deep ocean since the energy is being diluted by dispersion throughout a huge volume of water.
From what we know (and of course, we might not know everything) the deep ocean turn over is measured in thousands of years (not centuries, still less decades) such that the additional heat (energy) which has allegedly beeen recently sequestered there will not come back to haunt us this century, nor next, in fact not for a thousand or more years.
If by chance the deep ocean circulation could happen quicker, and the content of the deep ocean rapidly re-surface then there would be global cooling, not further warming!
In this scenario it does not matter whether the deep ocean temperature has risen a few thousands of degree due to the alleged effect of the additional energy resulting from increased CO2, because what would be coming up from the depths is ocean water at a temperature of only a few degrees (or a few degrees plus a few thousands of a degree of recent warming) and this would cool the surface (or near surface) water temps down from about 15 degrees. Depending upon the volume and the rate of the upwelling of deep ocean, it could cool it by a degree, or even by several degrees. The result is global cooling, in a severe case, the onset of an ice age.
It is because the deep ocean is so cold notwithstanding some 4.5 billion years of solar and DWLWIR that has taken place ever since planet Earth acquired an atmosphere (consider the periods when CO2 was more than 2000ppm) that we have ice ages. If the deep ocean was warm, even with orbital changes the ocean would act as an effective buffer keeping these at bay.
Simon Anthony
If there was a relationship between atmospheric CO2 and global temperature, it would not be static, it would be continually changing. The more CO2 that was added to the atmosphere, then the lower the sensitivity would be.
If there is a level of atmospheric CO2 at which there is no further effect then what is the point of CS?
For Dung
You seem to have made my point but without seeing that you've done so. Science works by people putting forward a testable hypothesis, in this case that there is a constant and particular relationship (at least within some range) between the increase in temp and CO2 concentration. Then measurements and calculations are done to test that hypothesis. If, as you suggest, the relationship changes, the measurements will show that to be the case and the hypothesis will be shown to be wrong. The hypothesis testing is currently going ahead, and the quantified relationship is being quietly modified. Eventually perhaps it will show the behaviour you think likely and lead to people deciding that CS is irrelevant (as I suggested earlier but you seem not to have noticed).
What puzzles me is that, in this particular instance, climate science is behaving like a "proper" science and yet contributors to this blog seem to object. I'd give the scientists credit for making a testable prediction and encourage them in their efforts.
I'd give the scientists credit for making a testable prediction and encourage them in their efforts.
Aug 15, 2013 at 7:12 PM | Unregistered CommenterSimon Anthony
SA - You keep waffling on about how CS predictions are testable but without even outlining how this might be done, despite having being asked to do so a couple of times.
It's nonsense to say CS predictions are testable and your inability to say how it could be done just confirms the point.