Bishop Hill Reacting to Rose
Mar 18, 2013 Climate: Models Climate: Surface Climate: sensitivity In the wake of David Rose's Mail on Sunday article yesterday, Piers Forster tweeted that he was unimpressed with the article. I asked him if he would be willing to set out why in a bit more detail and this is his response:
It's fine to say that current models overestimate the last decade of warming. They clearly do, and as I say in my quote I think we can rule out some high sensitivity values because of this. But to do a far comparison you need to remove the effects of variability. Note also that some model runs also get the temperature evolution pretty right - although the majority don't. Even with a suggested ECS of around 2.5 C or so we can end up with a very significant climate change by 2100 if we don't do something - therefore I think the tone of the article in terms of its implications for the IPCC, climate science and the climate itself are all wrong.
He also sent the full quote that he gave Rose for his article, which gives some context.
Basically, the climate sensitivity has always been very uncertain. > estimates have put it somewhere between 1 to 5 C for a doubling of CO2. The IPCC best estimate has been around 3C. The fact that global surface temps haven't risen in the last 15 years, combined with good knowledge of the forcing terms changing climate over the satellite era: greenhouse gases, volcanoes, solar changes and aerosol is beginning to make the high estimates unlikely. Given this, i would put the best estimate using this evidence around 2.5 C. There are still uncertainties though particularly in heat going into the ocean, but climate sensitivities above 3.5C or so don't seem to fit. Keep in mind that this is only one line of evidence for quantifying climate sensitivity. Other lines of evidence have been able to firm up the bottom end. We now have good observational evidence for a positive water vapour feedback and even clouds, which have always been the largest headache in climate change, are beginning to be understood and a positive cloud feedback is looking more likely. This line of evidence helps rule out climate sensitivities below 2C. So I see it very much as a positive story that careful science ( and time) is helping to reduce the most significant uncertainty in climate science.
This thread will be tightly moderated for tone and relevance.
Reader Comments (187)
"I have looked all the way through the bumper book of scientific terms"
You need the new climate science edition.
"pretty right" lies between "damned close" and "in the ballpark".
The problem with Forster's view which he fails to address is that so called climate sensitivity has no basis in the real world.
First because it depends the concept of a global temperature which, no matter how precise the methods of measurement, which is far from the case, has no meaning. There can be no such thing over the surface of the globe spinning in space with one half lit by sunlight and the other half radiating into the blackness of the cosmos. As most so called 'climate scientists' know perfectly well: but seem loth at admit.It is no more than a meaningless statistical artifact and it is not possible extract meaning from the fluctuations of a notional figure that has no meaning of itself.
Secondly because assumptions are made about the level of CO2 in the atmosphere which is increasing at the moment, supposedly due to the burning of fossil fuels. Whilst elaborate calculations are made about this they are worthless because they lack any reliable data on the rate at which the earth is still outgassing CO2, chiefly beneath the oceans, and the various means by which this excess CO2 is transported into the upper regions of the seas or the time lags involved in doing so: these are not even studied let alone quantified or understood. There is no reason to suppose that fossil fuel use has any perceptible effect on overall CO2 levels in the atmosphere; let alone some hypothetical doubling of it that is so widely touted.
The problem with the case advanced by proponents of AGW is that there is no empirical evidence to support their assertions which properly belong to the realm of metaphysics, (literally beyond physics, the science of measurement), which amongst other things tries to examine such elaborate chains of supposition to discover whether they might have some meaning in the real world.
By contrast we do know that we can observe if the globe is cooling or warming by whether the ice is advancing from the poles towards the equator or retreating towards the poles: as it has done many times before. Of course this a slow process but it is the only reliable method known: at the moment there is no other.
And therein lies the rub. No amount of dressing up flawed concepts with fashionable elaborate calculations and statistical analysis renders that concept either valid or useful: flawed it still is and and consequently worthless either in describing what is happening in the real world let alone providing any basis for forecasting what might or might not happen.
What Forster asserts has no basis in the real world; whatever his protestations to the contrary.
Kindest Regards
There is a fundamental point that David Rose's article missed. It's worse than we thought.(naturally) If we take Kevin Trenberth at his word the computer models are not even predictions.
Forester126: thanks for quoting from David Whitehouse - exactly what I was thinking. Rose may have gone beyond what the data allowed as far as the 95% confidence bands of all GCMs are concerned - but surely not by much for at least one! And Bellamy was unwise to mention solar theories, in such a small space, in my view. Even so, I can think of recent MSM articles that were far wilder in their treatment of what they were calling science which attracted nothing like this level of concern from climate scientists. And Whitehouse was the key man quoted by Rose in finishing up:
The spurious urgency to 'do something' - however stupid - needs to be disavowed by all climate scientists who want to win back public respect. On this Rose and Whitehouse were spot on. But the debate here is good - very good.
My lecture on plants and climate change went down well with a young (18-30) audience who, up until now, have only been exposed to the "Alarmist" view through the Media and the education system.
They were gobsmacked went I told them that;
1) Hurricanes are not increasing in frequency or intensity,
2) Droughts are not increasing in frequency or intensity.
3) Floods are not increasing in frequency or intensity,
4) There has been no record high Continental temperature set in the last 30 years.
5) The World is greening at a rate of 1%/year.
All these are "good" things- particularly (5)- increased Primary Productivity will help feed the World.
I went on to show how this increased plant growth is directly related to increased CO2.
All this was backed by the peer-reviewed scientific literature- (references were provided on each slide).
Many students came up to say what an interesting and eye-opening lecture it had been and why had they not been told this stuff before. There was not a single dissenting voice.
When people are presented with real evidence, rather than hype, they rapidly see through the Climate Change scam/scare.
Can anyone produce evidence to prove that the recent warming was due to man-made CO2 rather than natural climate variability?
I mean evidence, not speculation based on computer models programmed with the assumption that CO2 drives climate.
There are some nice graphs of RH and low/medium/high cloud trends at
http://www.climate4you.com
I don't know how accurate they are, but they affirm my prejudices and as such I recommend them. RH not rising with temp, low level cloud increasing with temp. I wonder what sort of feedback that implies.
JF
"Note that he quotes the coefficient multiplying the logarithm to three significant figures. I asked him where he got this stuff and he replied simply:
"I read the literature"
(Mar 11, 2013 at 3:13 PM)
I hope he will send the references he read to Professor Piers Forster. The Prof seems uncertain compared with Entropic Man's confidence in the precision of the formula above."
You are confusing two issues, but I dont blame you as the issues has been confused for a while.
1. Climate sensitivity: Climate sensitivity is defined as the system response to changes in forcing:
solar forcing, volcanic forcing, C02 forcing.. it is Delta C / Delta Watts. If we increase
or decrease forcing by one watt, what will the change in C be? So for example if a change in solar
forcing of 1 watt creates a change in temperature of 1C sensitivity is 1. If 1 watt of forcing
leads to .5C, the sensitivity is .5 .5C per watt.
2. The additional forcing due to changes in C02. The 5.35ln(C02ti/C02t) formula tells you how much
additional forcing you get from increasing C02 from Co2t to CO2ti, where doubling would be
5.35ln(560/280)
These are put together to give you a sensitivity to doubling, so #2 will give you 3.7 additional watts
and if sensitivity is 1, then your sensitivity to doubling is 3.7.
Folks need to keep these separated although people always talk aboutthe sensitivity to doubling.
Why separate them? Well for the simple fact that #1 is highly uncertain and #2 is well known and
verified.
The best source for #2 is I believe Myhre 98 ( as I recall). there is no leverage in debating #2. If you double C02 the forcing increasing. the issue is #1, what is the change in C per change in Watts,
REGARDLESS of whether those watts come from increase solar or increased GHGs. Skeptics who want to challenge #2 are welcome to collect their Nobel prize by over turning decades of measurement
and validation. Skeptics who want to challenge #1 will find plenty of ways to make a case. As always apply strength to weakness. just sayin.
Pre-industrial CO2 levels were about 265ppm and the current level is about 390ppm. Not a doubling but not far off.
Mar 18, 2013 at 1:24 PM | lapogus
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Uh? It's way off a doubling. It's an increase of 50%. A doubling would be 530ppm.
Martin A
The first paper to quote 5.35 for the constant alpha in the radiative forcing formula was probably this.
http://folk.uio.no/gunnarmy/paper/myhre_grl98.pdf
Myhre et al. 1998 included an updated figure in Table 3, a value reduced from the 6.3 quoted in the 1990 IPCC report. It has become generally accepted since.
Well done Don Keiller - truth will eventually overcome all the lies.
Satellite and Climate Model Evidence by Roy W. Spencer
a jones, above ... thank you.
Now a question, which I am yet to receive an answer to. All the panic about CAGW suggests that there is an optimum mean global temperature (pace a jones above), yet nobody can tell me what it is. If we don't know WHJAT it is, how then can we know when it might be dangerous?
Occam rules...
Don (Keiller),
1. Well done. Fighting the good fight with all your might.
2. Is there a video of your lecture available?
These claims as to accounting for "variability" are bogus.
All these "models" or manufactured constructions claim to account for elements other than CO2.
If they are wrong, it is because they do not understand climate.
Full stop. End of Story.
These "scientists" and any associated functionaries processing information do not know what they are talking about.
They have never known what they were talking about.
Not to have freely acknowledged this well prior to this time also makes them dishonest.
Flier here ... on clouds and sensitivity, is it my imagination that I read recently that they might have positive or negative sensitivity in differing scenarios?
How is this different from guessing? And I thought 'average' model runs were meant to be gospel, though I never quite understood how it is that a single run of the Earth behaves like an average run of a model (unless the only thing left in the average is the fudge factors ...).
But the observations are still within the 95% range of the CMIP3 models
Mar 18, 2013 at 3:07 PM | Registered CommenterRichard Betts
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But the model's wide ranges to date cover everything from a slight decline to a sharp rise. The only thing which wouldn't have been covered at all was an immediate vertiginous plunge!
The actual temperatures (even if we trust their accuracy) have almost dipped out of the low estimate a couple of times and will almost certainly do so very soon, probably permanently, as projections continue to rise.
In those circumstances the fact that temperatures "are still within the 95% range of the CMIP3 models" is deeply unimpressive.
Flier here ... on clouds and sensitivity, is it my imagination that I read recently that they might have positive or negative sensitivity in differing scenarios?
Mar 18, 2013 at 4:55 PM | jeremyp99
As a rough rule of thumb, low clouds (stratus) have a net cooling effect, high clouds (cirrus) have a net warming effect amd dynamic convective cloud (cumulus and cumulo-nimbus) are neutral.
Increased stratus would reduce sensitivity and increased cirrus would increase sensitivity. Overall cloud cover of both types are increasing,
Well, we are finally making some progress, grudging and slow to be sure. But we have finally landed somewhere BELOW IPCC's central estimate for the climate sensitivity. Of course, values of 2.5 deg are still much too high; the real value is almsot certainly going to be close to 1 deg C. But nevertheless the game is in play.
Piers Forster states:-
"There are still uncertainties though particularly in heat going into the ocean, but climate sensitivities above 3.5C or so don't seem to fit."
What are the "uncertainties though particularly in heat going into the ocean"? At present the sea surface temperatures are cooling, the 30 year HadSST3 trend has lost 20% of its magnitude since Dec 2003, the 10 yr trend has been negative since Jan 2011. Enso 3.4 area 30 year (WMO Standard) trend shows cooling at the rate of -0.16C/decade or -1.6c/century? You don't want to know what the 10 year trend is! Data from NOAA Reynolds SSTs:-
http://nomad1.ncep.noaa.gov/cgi-bin/pdisp_sst.sh
That is a significant cooling trend, where has the energy gone/still going? It has to go somewhere. Up or down?
So what is going on, why are SSTs cooling? Has to be more energy output than input? Simplistic I know, but how else can it be?
This is not about an El Nino or La Nina index,. it is what is happening to the 30yr trend of actual SSTs, not fully up to speed with the mechanics but have problems envisaging how a 30 year cooling trend is likely to promote El Ninos? Or how it can be classed as a "natural variation" reason for the 15 year standstill? Lots of questions, no answers!
Mosh:
Helpful framing and reference to Myhre 98 thanks.
Pre-industrial CO2 levels were about 265ppm and the current level is about 390ppm. Not a doubling but not far off.
Mar 18, 2013 at 1:24 PM | lapogus
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Uh? It's way off a doubling. It's an increase of 50%. A doubling would be 530ppm.
Mar 18, 2013 at 4:37 PM | jeremyp99
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But one of the issues is: what was the pre-industrial level of CO2? There were many experiments conducted in the 19th century which suggest far higher levels of CO2 than the IPCC uses..
Those experiments should be reproduced today (ie, using the same equipment, conducted at the same location and the time of year, using the same sampling method etc) and see what results are now achieved. In that manner, a like for like comparison could then be made to see to what extent CO2 levels have varied over and above those ascertained by experiment a century or so ago. I consider that would be not simply interesting, but in practice quite useful. I am surprised that it has not been done.
Of course, a thinking scientist might just consider that the real GHE << 33 K with the rest from moist lapse rate warming, near constant because water vapour level is near constant. I leave the rest to the reader's imagination!
The only CS figure that is consistent with measurements over the last 15 years is ~0.
No, I'm not claiming that's what it is, but perhaps Dr. Forster could persuade his colleagues to include in AR5 a much fuller discussion of:
(1) CS ranges and reasons
(2) The dearth of recent warming
(3) An extension of 'natural variables' beyond the usual (volcanoes, ENSO, etc) - eg: stratospheric water vapour (Solomon), cloud cover and height
(4) An explanation for the warming of the 1910s-40s vs. the warming of the 1980s-90s
(5) The 'hot running' of the models
then it is going to be a waste of money, time and trees.
No handwaving. Good explanations why *this* paper is right and *that* paper is wrong. Time for alarmists (and AR5 will no doubt continue the alarrmist tradition) to justify their alarm with proper numbers. If nuclear reactors had 'control knobs' as reliable as CO2 is in climate, I'd be worried.
Can anyone produce evidence to prove that the recent warming was due to man-made CO2 rather than natural climate variability?
I mean evidence, not speculation based on computer models programmed with the assumption that CO2 drives climate.
Mar 18, 2013 at 4:33 PM | Schrodinger's Cat
Try here.
http://www.abc.net.au/science/articles/2012/03/14/3452867.htm
My comment to Piers Forster, would be that the temperature increase at the end of the last century was attributed mainly or entirely to CO2. On that basis, a linear extrapolation inevitably predicted problems. However, since the climate can behave as it has since 1998, surely that shows there was no basis for the original assumption that the rise in temperature was due to CO2 (which has continued to rise) - and therefore climate sensitivities based on that data are obviously wrong.
This may be a naive point, but I am extremely dubious about the whole idea of positive climate feedback at all. This would tend to produce extreme climate instability after every knock to the system - such as major volcanic eruptions.
EM, do you expect us to read your links and notice that the article you link to answers a question different to the one Schrodinger's cat asked? And if co2 is being added at 2ppm/y and O2 is decreasing at 4ppm/y how many parts per million of air are in the air? Less than a million? Worse than we thought.
Entropic Man
The Cat meant "evidence", I think. As in scientific evidence not the output of the one broadcasting authority in the world that is arguably even more blinkered on the subject of global warming than the BBC.
And apparently just as ignorant.
attn jeremyp99
In answer to your question above in recent geological time the earth has undergone relatively long cold periods, the ice ages occasionally relieved by warm ones, the interglacials, one of which is the Holocene, in which we live.
But it is important to appreciate that the change between warm and cold has little effect over most of the globe, the poles remain extremely cold and the equatorial regions very warm, The only affected regions by heating or cooling occur in the temperate regions of which most of the land mass lies in the northern hemisphere.
As to whether warming or cooling of the globe might be dangerous the question is to whom or possibly what. Not to humans really, we have survived all this before and learned to adapt with ever better technology.Do you imagine that humans who can not only successfully survive but also build complex civilisations around the globe from the equator to the polar ice, a huge difference of some 40 degrees K give or take are going to be much incommoded by a change of a few degrees?
Hardly. Whilst humans undoubtedly can affect local climates, for by example by building cities, and even regional ones by changing land and water use the idea that these tiny changes can perceptibly affect either the great forces that drive the weather systems of the planet or the global composition of the atmosphere is absurd.
Climate change exists but it is a natural phenomenon the causes of which are only imperfectly understood: if that. As for CAGW or some ideal global mean temperature these are pure fantasy, based on a mixture of arrogance, ignorance and superstition. The world will do as it wills and for the moment humans have no power to either affect it or predict how it may change. They will simply adapt as they always have.
You see before you can get useful answers you have to learn the right questions to ask. And bandying about meaningless but emotive words such dangerous is of no use at all.
Kindest Regards .
Can anyone imagine Cassandra riding around on a Vespa?
EM = Scooter and I claim my A$5
Read this from the top no1 swedish climate scientist.
http://klimazwiebel.blogspot.se/2013/03/lennart-bengtsson-global-climate-change.html
I think it is line with original article.
I think the underlying difficulty is that the Daily Mail has a well earned dreadful reputation for biased reporting. As a health care professional I could weep at some of the nonsense they headline on health issues, and although my knowledge of Climate change is from a hobbyist perspective rather than professional, I tend to treat any information headlined by the Daily Mail with a pinch of salt due to their poor performance in areas in which I have expertise.
David Bailey:
"This may be a naive point, but I am extremely dubious about the whole idea of positive climate feedback at all. This would tend to produce extreme climate instability after every knock to the system - such as major volcanic eruptions."
This is such a key point. The Earth's climate system has never crashed in 600 million years during periods when co2 levels were twenty times what they are today - and probably a denser atmosphere as well.
Feedbacks *measured* by ERBE and CERES (NOT MODELLED NB Piers Forster) are negative. End of argument.
In a sense these result are simply reporting the blindingly obvious. If feedbacks were positive we wouldn't be here to measure them anyway!
It's a classic case of the Emperor's new clothes. Expensive models (£30 million for the one at the Met Office) are a total waste of taxpayers' money.
Sorry, I simply don't buy it.
I asked on SoD and was referred to the Myre paper. That explained the the logarithm came from fitting formulas to the results from numerical radiation models.
... decades of measurement and validation. Oh yeah?Steve McIntyre tried to track down the origin of the log formula. But he got ... not very far.
http://climateaudit.org/2008/01/04/ipcc-on-radiative-forcing-1-ar11990/
http://climateaudit.org/2008/01/07/more-on-the-logarithmic-formula/
He stated:
"These paragraphs may very well be revealed truth, but they don’t meet the standards that I expect in an engineering report (I preface this by saying that I’m not an engineer.) The logarithmic relationship reported here is not a law of nature; the relationship is not derived or explained in this report."
My own conclusion is that it is simply climate science folklore. Everyone "knows" it but no-one can explain where it comes from (beyond perhaps stating that Arrhenius discovered it).
If Professor Forster reads this, maybe he can enlighten me on the origin of the log formula and how it has been "measured and validated for decades" (according to Mosher).
Interesting to see a paper on reanalysis in Forster's list of references supporting positive feedbak from water vapour.
Paltridge's work on reanalysis suggests that the feedback is negative:
Theor Appl Climatol (2009) 98:351–359 DOI 10.1007/s00704-009-0117-x
Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data
Garth Paltridge & Albert Arking & Michael Pook
We call it flogging a dead horse LOL
@ Mar 18, 2013 at 4:35 PM | Julian Flood
It's better to look at specific humidity, if RH remains constant when increasing temperature that actually means a large increase in water vapour content in the atmosphere.
RH measures the percentage to saturation, but saturation water vapour pressure increases exponentialy with temperature.
Paul Dennis writes
Does anyone have a reference for/link to the Shaviv et al paper?
The assumption, following Aarhenius, that the Earth's surface emits a real black body energy flux is [Self Snipped!].........
[Readers may create their own ending based on real physics not Houghton's.......]
I see AE Dessler's Science classic was cited by Forster! This is the paper in Science with a correlation coefficient of ~0.0 - a classic in our time. (http://geotest.tamu.edu/userfiles/216/dessler10b.pdf).
(See Figure 2)
@ Richie Rich http://www.sciencedirect.com/science/article/pii/S0273117711007411
Ziskin and Shaviv look at both land and sea surface temps and allow for pretty much all known variables including aersols, solar variability, PDO. They use a genetic algorithm to optimize the model and find most likely sensitivity around 1 deg C for 2 x CO2, while total GHGs taken together (incl CH4, NO2..) were the largest contribution to 20th century warming. Solar variability next.
This fits with Lindzen or Spencer's analysis of outgoing radiation changes in response to terrestrial temperature fluctations as well as the series of volcanic eruptions in the 19th/20th century.
None of these by themselves is altogether convincing but the body of evidence points to around 1 deg for doubling.
Richie Rich -
I see that Noblesse Oblige has beaten me to the punch regarding Ziskin&Shaviv 2012, whose abstract includes the statement "the best fit is obtained with a negligible net feedback." [Implying that climate sensitivity to doubled CO2 is about 1.2 K, if I remember correctly.]
An older (2005) paper is here, which estimates sensitivity as 0.35 ± 0.09 K/(Wm-2), which (using doubled CO2 as providing a forcing of 3.7 Wm-2) implies a sensitivity to doubled CO2 as 1.3 ± 0.3 K.
@Entropic Man
It is hard to take you seriously when you proudly present your "proof" that the recent warming was due to man-made CO2 rather than natural climate variability. As told by ABC News
http://www.abc.net.au/science/articles/2012/03/14/3452867.htm
You really must try harder:-)
@jeremyp99 re my lecture.
No video, I'm afraid, just slides. Also I talk "off the cuff", so only the notes on the slides
If you want I will send it to Andrew- he can then decide whether to circulate it.
Green Sand wrote:
'What are the "uncertainties though particularly in heat going into the ocean"?'
Piers Forster means the increase in ocean heat content, which is reflected in the average rate of increase in ocean temperatures at all depths, 0-700 m being where most of the change occurs. That is by no means the same as, nor proportional to, the change in sea surface temperatures.
Unfortunately, there are several different ocean heat content datasets and they disagree by up to a factor of almost two on how much heat went into the ocean during the last decade for the well observed 0-700 m ocean layer. That is despite the build up of the Argo automated buoy network over 2001-2005.
Noblesse, Harold - Thanks for such a prompt response.
NicL - re the OHC datasets and the factor of two variation. Please do you have quick references for that? Thanks.
Nic Lewis wrote:-
Thanks Nic, I was sure that was the case what I am trying to get at is why has the disconnect - surface to 0-700m only appeared in the last 15 years? Why is the surface cooling if the body of water underneath is warming? Why is the surface cooling more prominent in the Enso area? I don't expect answers just ongoing observations.
Edit:- Hence the need to illustrate the surface cooling.