Bishop Hill GCMs and public policy
Aug 24, 2014 Climate: Models Climate: Parliament In the thread beneath the posting about the Chen and Tung paper, Richard Betts left a comment that I thought was interesting and worthy of further thought.
Bish, as always I am slightly bemused over why you think GCMs are so central to climate policy.
Everyone* agrees that the greenhouse effect is real, and that CO2 is a greenhouse gas.
Everyone* agrees that CO2 rise is anthropogenic
Everyone** agrees that we can't predict the long-term response of the climate to ongoing CO2 rise with great accuracy. It could be large, it could be small. We don't know. The old-style energy balance models got us this far. We can't be certain of large changes in future, but can't rule them out either.
So climate mitigation policy is a political judgement based on what policymakers think carries the greater risk in the future - decarbonising or not decarbonising.A primary aim of developing GCMs these days is to improve forecasts of regional climate on nearer-term timescales (seasons, year and a couple of decades) in order to inform contingency planning and adaptation (and also simply to increase understanding of the climate system by seeing how well forecasts based on current understanding stack up against observations, and then futher refining the models). Clearly, contingency planning and adaptation need to be done in the face of large uncertainty.
*OK so not quite everyone, but everyone who has thought about it to any reasonable extent
**Apart from a few who think that observations of a decade or three of small forcing can be extrapolated to indicate the response to long-term larger forcing with confidence.
So, let me try to explain why I think GCMs are so important to the policy debate.
Let us start by considering climate sensitivity. As readers here know, the official IPCC position on climate sensitivity is largely based on the GCMs. This time round we have had some minor concessions to observational estimates, but a significant proportion of the probability density of the observational studies remains outwith the IPCC's likely range of 1.5-4.5°C. Proponents of GCMs might counter that the upper end of the GCMs are ignored too, but I would suggest that one should conclude that an ECS of 5-6°C in the light of temperature history.
Estimates of climate sensitivity - and therefore in practice GCM estimates of climate sensitivity - directly inform estimates of the social cost of carbon. So when people like Chris Hope are arguing for a carbon tax of $100/tCO2, this is a function of GCMs. I recall, I hope correctly, that Chris suggested a figure of $18/tCO2 if one used an ECS of 1.6, in line with observational estimates. This matters of course, because the policy response, if any, to an $18 problem is significantly different to that for a $100 problem.
Wherever we look in the interactions between scientists and politicians on climate questions, we see an emphasis on catastrophe. We see no confessions of ignorance, but only occasional reference to uncertainties. Here's some notes of Tim Palmer addressing the All-Party Climate Change Group:
With the amount of carbon dioxide already in the atmosphere, future emissions will need to be reduced by half to that of historical emissions to limit global average temperature rise to 2°C. However, if emissions are not curbed (under the business as usual scenario), the amount of carbon dioxide in the atmosphere will be three times the historical emissions and the temperatures might rise up to 4°C.
And on the other hand they might not. This idea does not, however, seem to have been put forward for consideration.
Readers might also wonder what explanations were given to our political masters on the credibility of the GCMs. Here's what Palmer said:
Climate models are only flawed only if the basic principles of physics are, but they can be improved. Many components of the climate system could be better quantified and therefore allow for greater parameterisation in the models to make the models more accurate. Additionally increasing the resolution of models to allow them to model processes at a finer scale, again increasing the accuracy of the results. However, advances in computing technologies would be needed to perform all the necessary calculations. However, although the accuracy of predictions could be improved, the underlying processes of the models are accurate.
Apart from the transport of heat to the deep ocean, if Friday's paper from Chen and Tung is to be believed.
You can see that policymakers are getting a thoroughly biased picture of what GCMs can do and whether they are reliable or not. They are also getting a thoroughly biased picture of the cost of climate change based on the output of those GCMs. They are simply not being asked to consider the possibility that warming might be negligible or non-existent or that the models could be complete and utter junk. They are not told about the aerosol fudging or the GCMs' ongoing failures.
And this is just scratching the surface.
[BTW: Could commenters who like to amuse themselves by baiting Richard please refrain from so doing!]
Reader Comments (306)
michael hart:
Something I've often thought but seldom articulated. Thanks for doing so. A subject much bigger than this thread. We should come back to it, whether or not Dr Betts ever turns up here!
"Climate models are only flawed only if the basic principles of physics are ..."
Apart from the clumsy wording, the above statement is garbage. One of the basic principles of physics ought to be: "You cannot model open systems." The earth is an open system and subject to variable inputs and outputs that are yet to be identified, let alone quantified -- unknown unknowns, if you like. Even an accurate model must be regarded as worthless because its accuracy must be presumed to be fortuitous. However, none of the models yet generated has proven to be accurate to any meaningful degree so the dilemma of choosing whether to reject a hitherto accurate model does not arise.
Rather than waste time and money on worthless models we should stick to science i.e. empiricism. This will necessarily entail some serious reshuffling at the tops of several branches of science and is unlikely to happen in the foreseeable future. Anyway, who wants a Chief Scientist who says, "I don't know!"?
“Science seeks the truth. And it does not discriminate. For better or worse it finds things out. Science is humble. It knows what it knows and it knows what it doesn’t know. It bases its conclusions and beliefs on hard evidence -- evidence that is constantly updated and upgraded. It doesn’t get offended when new facts come along. It embraces the body of knowledge. It doesn’t hold on to medieval practices because they are tradition.”
― Ricky Gervais
Mr Gervais is patently an intelligent man and it is depressing to note his failure to discriminate between what OUGHT to be and what IS. Climate science has massive problems, as do other branches of science where theorising and speculation are allowed to trump hard data and solid reasoning. Modern scientific orthodoxy has many things in common with religious dogma, not least of which is unquestioning faith in the revealed truths of acknowledged prophets (or is that 'profits'?). Retrofitting prophecies to developing reality is another good trick. In the final analysis science, like almost any other human activity, is about power. If you can muster the numbers, however dodgily, your views prevail -- effectively becoming the 'truth'.
Anthropogenic Climate Change (or warming, or whatever) will be defeated by the failure of any genuine climate catastrophe to materialise. Most people find that thinking about the science makes their heads hurt. SO much easier to rely on experts. With luck, the present generation of catastrophists will be safely retired or, better still, dead before they have to admit they got it wrong. They certainly won't be held to account for their incompetence.
I feel ripped off, again.
Cripes, if we're not careful it will become unreadabale, like Judith Curry's often is.
- People emoting all over the place
- People running the same old stories about their pet theory; and
- Endless and boring and repetitious disputes.
We have WUWT and Judy's for that. Please cut as and when, as Steve McIntyre does.
You are both a star and a gem.
The level of noise generated by supporters of GCMs appears to a layman to be designed to distract from some fairly basic facts resulting from observations.
Let me run these ones past you (figures are approximate since it's a nice day here and who knows how many more of those we'll have this year and I can't be bothered digging!).
The increase in CO2 which is supposed to be the main driver of global warming began around 150 years ago.
The temperature increase which is supposedly the result of that increase is slightly less than 1C.
One of the tenets of the GW hypothesis is that, absent other factors, a doubling of CO2 will increase temperatures by ~1.2C.
If we accept that the effect of CO2 increase is logarithmic and that we are around half-way there that tenet looks pretty good from where I stand.
Which implies that the "positive feedbacks" which are the basis for the scaremongering are not happening.
That is where we are at the moment. The GCMs are the only thing that can tell us where we will be in 50 years time and to date they have been wrong on virtually every count.
They can't hindcast; their forecast for temperature is way out; they failed to see the "pause".
Meanwhile the climate is apparently doing what it has always done during inter-glacials — varying between certain reasonably well-defined limits according to the behaviour of the sun and its effect on the oceans and quite probably with some assistance from the moon and the position of the planets as well.
There is not a lot of room left for CO2 to have the sort of dire effect on mankind's future that the catastrophists are predicting and if the GCMs are saying that there is than it is looking increasingly like a function of how they have been programmed than anything else.
I see no reason to panic. What am I missing?
http://www.tandfonline.com/toc/TCPO/12/sup01#/toc/tcpo20/12/sup01
Betts having been co-guest editor of a special number of Climate Policy journal, maybe somebody will be able to elucidate how he made sure GCMs weren't central to that "issue" at least
There is mounting evidence that the correlation between CO2 and atmospheric temperatures is very tenuous, indeed, if not actually non-existent. Why do some insist that we have to (as if we really can) control CO2 levels in the atmosphere?
ATTP, it is also possible that Earth may be hit by a meteor, or that the western Canaries could collapse, swamping the Caribbean and US East coast with a tsunami, or that the Yellowstone Park volcano could erupt. All these could severely affect property prices in the USA; is buying a home there a risk worth taking?
Get real – life is full of risks; live with it.
John Marshall (11:59 AM): where do you get that 2,500ppmv figure from?
Climate Models - could it be that they are an over ambitious attempt to foretell long term future weather, climate, and temperature, failing miserably on all counts.
Factoring in guesstimated figures for climate sensitivity due to anthropogenic carbon dioxide have failed to concur with actual observed temperatures.
The science of Meteorology was founded on weather observations which has enabled very accurate forecasts to be made of repeatable events.
Weather satellites have enabled the forecaster to see the weather patterns developing and moving our way, long gone are the days of the Atlantic weather ships.
The climatologists at the Hadley Centre have admitted in recent years they do not fully understand all the factors affecting our weather - such as the jet-stream and the polar vortex.
There is still a lot to learn, as witness the attempts in recent years to explain the temperature hiatus. Research into oceanic water temperatures may give a greater knowledge of the atmospheres historical internal variability it pays no regard to any variability in solar forcing.
Some years ago James Delingpole produced a graph of CET records from 1659 to 2009 with a temperature trend of 0.26 degrees per Century. From 1820 CO2 emissions are overlaid, and logically with increasing amounts one would have expected a large increase in the temperature trend. Such is not the case, indicating that anthropogenic carbon dioxide had little or no effect on temperature in Central England - Britain's workshop.
Let me tell you a story. Way back in the late 80s, early 90s I was involved in the nuclear industry in ICAAP (International Code Analysis and Assessment Program). Part of the programme was to test the codesd against experimental data from International Stamndard Problems (ISPs), These were tset facilities at various scales of nuclear power stations on which accidents could be simulated. Blind ests would be carried out and the initial and boundary conditions would be given to participants, who would attempt to predict the outcome of the tests using their code (model). There were codes developed by Government Labs, by vendors and Universities. The codes would be of varios complexity, ranging from one attempting to calulate everything from first principles to others which had various correlations (parameterisation). All codes would be based on the "basic principles of physics", such as conservation of mass, momentum and energy. The results of the calculations would be submitted, the test results would be released and the participants would then try to see why they were wrong (or right). A meeting would be arrabnged where the results and findings could be disussed. I can assure our readers that despite all the models using basic physics principles, the results of the calculations were all over the place. Even people using the same model would get wildly different answers. The code calculting everything from first principles was as bad as the worst and was soon amended.
The overall message from this long-running exercise was that no matter how much model development was performed, no matter how many experiments there were to provide basic correlations and no how matter how much validation was performed, various of the relevant parameters could never be calculated with much confidence. In my case the exercise was used to develop code validation and user guidelines so that reactor accidents could be predicted with the required amount of conservatism, hence a safe design could be achieved (far too much over-design in my opinion). Compared to the climate computer models, with their parameterisation based on guesses and assumptions (not experimentla data), their lack of validation and an open climate system with no known initial conditions, at least we could eventually calculate something resembling reality. I have absolutely no faith in predictions of any of the hundred plus climate models in use.
Climate models based on "basic principles of physics" are fundamentally flawed, one of the flaws being their users.
Johanna, I have to agree with Shub, here. Mr Physics seems to be attributing to BH the idea that GCM influence climate sensitivity, neatly sidestepping the point that the Bishop is merely stating that it is the IPCC who have that belief. Then, he points out that BH is saying GCMs are unreliable, thus undermining the falsely-attributed “original” argument. It is a clumsy attempt to pour ridicule upon the debater by falsely attributing contradictory arguments when such contradiction does not exist. Then he alludes to the GCMs actually providing evidence! Such a claim has to damage his credibility.
The position of most sceptics (a label that any scientist should be pleased to hold) have is that not a lot is happening, so why do we need to do anything? – and, anyway, we have very little understanding of the whole process, so have no real idea of quite what needs to be done should things turn nasty, or that we could have any effect even if we did it. What is wrong with that?
Radical,
No, I'm suggesting that the IPCC do not have that belief (okay, I'm using your words). It is my understanding that the range for climate sensitivity is based on more than just GCMs. I'm also suggesting - as Richard Betts pointed out - that the range for climate sensitivity would not be very different even if we didn't have GCMs. I'm certainly not claiming that this is BH's idea - that would seem remarkably odd. I'm suggesting that his claim about the belief of the IPCC is wrong.
Just to be clear (and this isn't a terribly complicated concept) what I have expressed is my impression of the argument that is being made. My impression may be wrong, but it's still mine. My impression of the argument cannot misrepresent it, because it's my impression. If you think it's wrong, convince me that I am, rather than simply stating that I am.
I rather fail to see how this is inconsistent with what I've been saying. We have a great deal of understanding of the process. Just because you don't understand it, doesn't mean everyone doesn't understand it. Given your suspicion about the use of the term "forcing" (a view you expressed on the Discussion Board) I have to conclude that you really don't understand this. The term "forcing" is simply a word used to describe the radiative influence of some external effect. It's nothing to be suspicious about.
Michael Hart, of course no sentient being who knows anything about computer models denies their usefelness, especially in areas like engineering.
Please see my comment upthread about that.
My point is about asking the right questions in the first place. As a project manager whose job was usually to fix up others' problems/impending catastrophes, I can assure readers that in every case, it hadn't happened. The "questions" were poorly formulated, or, worse, decided in advance.
I'll give you an example. Governments, banks and other large organisations have spent spent billions on (frequently failed or cost overrun) IT projects about "integration". The assumption is that punters are hanging out for it.
Actually, that's the opposite of what they want. They don't want to deal with call centres instead of real people. But, that what they get. It came home to me a few years ago when I rang my bank branch, to discover that there is no such thing as a bank branch manager anymore.
We all remember the bleak early years of automated answering services. And, even worse,early voice recognition services. And, their associated endless loops.
But, in the last couple of weeks, I have had discussions with ladies from the gas conpany and the bank - and both of them have been Australian and polite and helpful. After being directed by auto things. So, all is not lost!
@Aug 24, 2014 at 1:28 PM | Unregistered CommenterStephen Richards
You assert that GCMs can only be wrong if they get the basic physics wrong.
Models fail for things all the time. Not because they get the basic physics wrong, but because they apply the physics incorrectly.
Since the GCMs have demonstrated no predictive power, it is a good conclusion that the GCMs are misapplying the physics.
The question that is interesting is how climate science got its free pass to fail, fail and fail again and still be held credible.
I do not regard RB's position as consisent with what it has been in the past. Is it just me?
Aug 24, 2014 at 11:53 AM | rhoda
No Rhoda. It isn't just you. They squirm and riggle as the weather and climate move away from their long held positions. I just so detest these people.
@Aug 24, 2014 at 1:28 PM | Unregistered CommenterStephen Richards
You assert that GCMs can only be wrong if they get the basic physics wrong.
Not quite what I said, Hunter. My point there, I think, was that the 'basic' physics may well be correct but the incompetence lies in the interactions between each part of the basic physics. Ie. If they included clouds how does the model interface the physics of clouds with the complex interfaces at the ocean - atmosphere interface. That's just one problem. You see, both sets of 'basic' physics could be correct, although not accurate, but you will still get the wrong answers if they are incorrectly interfaced in the software modules.
Everyone ****** agrees that the RATE of warming was higher from 1900 to 1945 than it was from 1945 to 2014.
Therefore ... man-made CO2 could well be a negative feedback.
****** those who pay attention to real data
Back in the 70s we had scientists telling us that human activity was pushing the earth into a new ice age Because Physics. See, man was putting all these particulates into the atmosphere and particulates block sunlight and less sunlight means it's gonna get colder. Come on, you can't deny that, it's basic physics! Are you some kind of crank who doesn't believe in physics? We have physics on our side, so you better do what we say!
They were completely wrong then, but the Masters of Physics have got this climate thing totally sorted out this time. Honest, they do. You can trust them Because Physics.
@ ATTP
"You may not like the IPCC projections or the other estimates of climate sensitivity, but they do exist and they do suggest that the warming could be large. They also suggest it might not be."
Oh dear, I think that this better be the last in our exchange.
Could be, but might not be. Admittedly you're got it all covered there, but with the best will in the world I fail to see how anyone could possibly interpret that - unless they really, really wanted to - as "large warming is probable".
Wouldn't you say that a much more honest position would be:
"These are the posibilities, but in terms of what is probable we really have no f**king clue"
JerryM,
Indeed, I have no idea how you seem to have concluded that I was suggesting that a large warming was "probable", as I very clearly did not say that.
Not sure about "we".
Yes, that would probably be best.
ATTP how does it feel to be able to comment freely here without being moderated/censored like on your own blog?
ATTP,
You appear to be suggesting that uncertainty demands immediate reduction in fossil fuel use. I disagree. Considering the costs associated with rapid reductions in FF use, I think the only prudent course is to work on narrowing the uncertainty. This ultimately means gathering better data for direct and indirect aerosol effects, and better quantifying ocean heat uptake, especially below 2 Km depth, where data is today almost non-existant. Uncertainty in these two areas is what separates us from much tighter observational constraints on climate sensitivity. Any narrowing of uncertainty in forcing and heat uptake, even with no change in the mean estimated value for current forcing, will hardly change the lower plausible limit for sensitivity, but will dramatically reduce the plausibility of very high sensitivity (eg, >5C per doubling).
The cost for better measurements is tiny compared to the cost for rapid reductions in FF use.
Told you. We fundamentally think differently to warmists. They say ‘we have a problem’. We ask ‘how big?’ They reply ‘isn’t it enough to know there is a problem?’ It’s our fussy need for accuracy that’s the root of the problem.
I wonder if Lord Deben would agree with ‘we can't predict the long-term response of the climate to ongoing CO2 rise with great accuracy. It could be large, it could be small. We don't know. The old-style energy balance models got us this far. We can't be certain of large changes in future, but can't rule them out either.’
I think not.
Thought exercise – your doctor tells you that you’re going to die. Do you cash everything in and work on your bucket list or plan for a comfortable old age? Now tell me that the details don’t matter.
Richard something:
"CO2 is a GHG "
that has about as much information in it as saying that
"a lit match heats the atmosphere."
Both are true , sort of. But to be useful in energy policy discussions it would be needed to QUALIFY them.
In that respect, it would be just a matter of courtesy by the warmish and you alike, in this BH discussion, to quickly point to a link where Harry Dale Huffman's comparison Venus <-> Earth is refuted.
And if this does not get done, then BOTH the lit match and the "CO2 is a GHG" memes get struck off the list,
in this BH discussion.
It shouldn't be THAT easy to understand as a method, even for a cnut with 2 Phd's and a CV full of so called "achievements"
Thank you.
Bloke in Illinois, you are a man after my own heart.
While the rest of the crowd are arguing about "the physics" (as if their foodfights were going to change anything - ha!) - how about we go and have a couple (note the missing "of") Martinis.
Let's discuss uncertainty and sensitivity. Unlike the background noise, we might even reach a conclusion ...
You can see that policymakers are getting a thoroughly biased picture of what GCMs can do and whether they are reliable or not. They are also getting a thoroughly biased picture of the cost of climate change based on the output of those GCMs.
Nobody is preventing you, anybody else or your esteemed policy hacks from reading and understanding the scientific literature. This stuff is freely available at your local university research library at under 10 cents per page copy charge. Methinks that not only do we need better anti-science nutjob science deniers, we also need better scientific skeptics and better policy wonks.
Because really, whatever it is you think you are doing here, you are not doing a very good job of it considering the laughs you are getting from the peanut gallery.
Thomas Lee Elifritz, tell me again how fast man made CO2 is dropping? It's not the sceptic's job to unearth the gems out of the climate science dross, it's the job of climate scientists to make the truth, clear. It's time for them to stop working on the fine detail and get the big picture right or at least admit they can't
"Climate models are only flawed only if the basic principles of physics are."
WRONG
A Climate Models will be flawed unless all of the variables are factored into it"
Some heat is 'missing'; so obviously GCM's haven't incorporated all the correct factors.
I began work with global eneryg, climate, and economic models in the days when the equations were represented by analog circuits, the results displayed by strings of colored diodes, and the inputs were selected by literally tweaking knobs on potentiometers. The "basics" of the design were established by the Club of Rome.
It's my understanding that the General Circulation Climate Models have several input "knobs". CO2, albedo, population, insolatioin, etc. The historical conditions at start of a model run are input, a knob or two is tweaked, and the output is compared to the actual record. This is, as I infer, "hindcasting". It seems that of all the knobs tweaked, twiddled or frobbed, the CO2 knob has the most dramatic effects on the model outputs. From this, the modelers recommend policy.
Without saying the circuits are in anyway unrepresentative of the physical globe, it is not possible there are basic physical processes going on that are not built into the model, are not hooked up to a knob, or are linking one physical knob to another in ways that are not reflected in the model-knobs. Clouds, for instance, resulting from water vapor, and affecting albedo. We don't need to say the circuits or knobs are incorrect or mis-set to postulate that clouds -- an arena of known unknowns-- may affect whether we see red or green diodes flashing.
In any case, the Club of Rome's physics and the US-ERDA (later, US DoE) models showed conclusively in the mid 1970's that the world population would have crashed to below one billion by now, and the air quality would be intolerably toxic. Oh, also, the waste products of nuclear reactors would be noticably (detectably) affecting the bio-sphere. The analog models were completely based on basic physics. The runs were honestly conducted and documented. The results, after 40 years -- not so helpful...
ATTP: yeah, we think we understand so much – which is why CO2 is still being scapegoated as the principle cause of global warming – or, to be more accurate, human-produced CO2 (and how is that different from other CO2?) is the culprit – yet CO2 continues to rise, and temperatures do not. Ah! It is no longer “global warming” it is now “climate change”…. How very convenient; it is no longer a measurable metric that is rising (because it no longer is), but a rather more amorphous concept – indeed, given the rather fickle nature of British climate, how can anyone be so sure that it is changing? Are the climat-o-meters in more stable climates measuring significant changes?
As for my suspicions about the term “forcings”, I’ll repeat what I said, as I feel that it is referring to elements of the system are somehow not part of the system, but affect the other parts, hence I am suspicious. Similarly, the claim that CO2 is THE driving factor in “climate change” (though never seems to be referred to as a “forcing”) – except when it isn’t. It would appear that the “forcings” come into play, for whatever reason can be made up at the time. So which is it? Is CO2 the sole driving factor, and control of CO2 will control the temperature, or is it not? If it is the only driving factor, how can other “forcings” downplay its effects? (And it is interesting to note that these other “forcings” invariably downplay its effect, they never seem to boost it.) I doubt that there is one single controlling factor in the climate; I would not be surprised if we never fully understand the dynamics of the system. It is a chaotic system; would it ever be possible for humans to understand or predict in such a system? You might have heard of Brownian Motion; I moot that, when someone develops a model that can predict (note: predict, not emulate; i.e. forecast the position of a selected particle after a selected time) the motion within a Brownian chamber, then, and only then, could I accept that models for the considerably larger and more complex system of the Earth’s atmosphere might be feasible in giving realistic results.
Just to be clear (and this isn't a terribly complicated concept), what I have expressed is my impression of the argument that is being made. My impression may be wrong, but it's still mine.
Well !! Can only say that I am totally bemused as to why Richard made a statement such as this -
"Bish, as always I am slightly bemused over why you think GCMs are so central to climate policy"
Haven't our policy makers been subjected via the IPCC and others to coninuous hype about the supposed dangers of CO2 emissions -
"A leading climate scientist has presented new research findings on the increasing potential for a 4 degrees Celsius rise in global temperatures if the current high emissions of greenhouse gases continue.
The conference at Oxford University is the first to consider the global consequences of climate change beyond 2 degrees Celsius, and is jointly sponsored by University’s Environmental Change Institute, the Tyndall Centre for Climate Change Research and the Met Office Hadley Centre.
Speaking at the international conference called ‘4 degrees and beyond’ at Oxford University, Dr Richard Betts, Head of Climate Impacts at the Met Office Hadley Centre, described the possibility of a 4 degree warming happening ‘before the end of the century’. He added that a scenario of very intensive fossil fuel burning could bring this forward by 20 years...
In today’s presentation Dr Betts warned that 4 degrees of warming could have extreme regional implications along with major changes in rainfall. He said: ‘If greenhouse emissions are not cut soon, then we could see major climate changes within our own lifetimes.’"
http://www.ox.ac.uk/media/news_stories/2009/090928_1html.html
And the conclusions of the presentation in question -
• Current CO2 emissions are near (but not above) upper end of IPCC
scenarios
• 4°C global warming (relative to pre-industrial) is possible by the
2090s, especially under high emissions scenario
• Many areas could warm by 10°C or more
• The Arctic could warm by 15°C or more
• Annual precipitation could decrease by 20% or more in many areas
• Carbon cycle feedbacks expected to accelerate warming
• With high emissions, best guess is 4°C in 2070s
• Plausible worst case: 4°C by 2060
http://www.eci.ox.ac.uk/4degrees/ppt/1-2betts.pdf
And the Met Office made quite sure the general public were aware of the dire effects of Climate Change in their booklet
"Warming, Climate Change - The Facts"
http://www.worcester.gov.uk/documents/10499/27253/DECC-MET-office-warming-brochure.pdf/c50df208-f61a-47ab-bff3-d672a8b31ad3
published at around the same time.
"Although some people claim that the Sun and cosmic rays are responsible for climate change, measured solar activity shows no significant change in the last few decades, while global temperatures have increased significantly. Since the Industrial Revolution, strengthening greenhouse gases have had about ten times the effect on climate as changes in the Sun’s output."
"Are the computer models reliable?
Computer models are an essential tool in understanding how the climate will respond to changes in greenhouse gas concentrations, and other external effects, such as solar output and volcanoes.
Computer models are the only reliable way to predict changes in climate. Their reliability is tested by seeing if they are able to reproduce the past climate which gives scientists confidence that they can also predict the future."
Hoi Polloi,
Given that Bishop deleted a comment of mine a couple of days ago, this would appear to not be strictly true. Having said that, even if he did decide to moderate or ban me, I wouldn't whine about it, because that's just childish and pathetic.
Maybe you could point out where I said that. I don't believe that I did. You wouldn't be putting words in my mouth, would you? My point about uncertainty is that it means that things could be better than we think they might be, or things could be worse than we think they might be. Ignoring the latter would seem to be a poor way of doing risk analysis.
Radical,
You can have it. To be honest, I don't quite understand what you're saying, so I can't really comment much further.
So ATTP is reduced to weasel words. Not surprising. And it looks like we have a new, more efficient troll warming up to come on stage. Exciting times indeed.
Can anyone tell me one unambiguous piece of evidence to support the CAGW assertions.
Perhaps it would help as a start if one has a method of disentangling natural variations from those due to CO2 emissions.
The precautionary principle can lead us to chase an ever receding horizon of doom.
"...I wouldn't whine about it, because that's just childish and pathetic."
But being able to say that feels good doesn't it?
Shub,
Oops, was that a bit too obvious ;-)
I would suggest that there is one word missing from the critical paragraph in Mr Betts comment, it reads
"So climate mitigation policy is a political judgement based on what policymakers think carries the greater risk in the future - decarbonising or not decarbonising."
I think it should read
"So climate mitigation policy is a political judgement based on what policymakers think carries the greater POLITICAL risk in the future - decarbonising or not decarbonising."
I fully support Bishs position and believe that the faith placed in GCM's, by those woefully ill-equipped to do so,the acolytes, the MSM and, most critically, the politicians is misplaced and to say the least dangerous.
I apologize for "having a go" at Mr Betts in an earlier comment, it's just that his comments frequently remind me of bureaucrats that I had to deal with in government agencies. They actively worked to avoid any accountability whilst accruing "power" and moved in which ever direction they thought the political wind was blowing or was about to blow.
I will need to do penance after this but advisors, as Mr Betts seems to couch his position, should not, in good faith, stand back and say that decisions based on their input were out of their hands, effectively they are emulating Pontious Pilot, and we all know how that turned out. They should be held as accountable, if not more so, for the political and policy decisions that they either ill informed or did not try to dissuade when they believed or, even worse, knew them to be erroneous. At the very least they should stand up and be counted in the public forum.
aTTP:
Sorry about that. I have tried to keep it simple; perhaps it is too simple. Should others be similarly perplexed, let me know, and I shall try and make it less complex, and use words with fewer syllables. Alternatively, perhaps the biter does not like to be bit.Radical,
Yes, keep the sentences short and try not to use words with more than two syllables. I might get it eventually :-)
"Climate models are only flawed only if the basic principles of physics are."
Absurd. Climate models are mere voodoo masks whose sole function is to lend an air of superhuman authority to the ignorant primitives hiding behind them.
"[Betts'] forays into the world of the sceptics is not so blatantly obnoctious as gavin eta" --Stephen Richards
Damning with faint praise, aren't we? I, for one, greatly enjoy Bett's "forays" here and welcome his views, imperfect though some of them may be.
Richard Betts kicks off with the usual disingenuous statement that we all agree CO2 is a GHG etc. This is to mis-inform straight off the bat. CO2 on its own does not have a serious effect. Its all about positive or negative feedbacks.
Secondly, the calculations on climate sensitivity make an assumption that warming is ascribed to forcings. The issue that the standstill in warming raises is that all the models got it wrong. We have had 38 reasons why the standstill is occurring and therefore why models do not agree with measured global temperatures.
This in turn implies natural variation is much more important than previously assumed. If natural variation can cancel out assumed CO2-induced warming as shown by the standstill, then it likely was a very large contributor to the warming which occurred from 1975 - 1998. With this, climate sensitivity is still more reduced than IPCC numbers.
Finally, he admits that we are not good at predicting the long-term effect of CO2, but on that basis he claims that it is sensible to spend vast sums on a policy of climate mitigation. Another equally sensible response would be to say this is not in any way proven, why would I spend anything on it at all.
In essence, his last point here is to take the precautionary principle to an absurd length (I don't know the climate system works and I don't know how to predict it, but I'm going to waste huge sums of money on it anyway).
ATTP the wannabe scientist and arch censor has found his way to ur blog Bish.
I assume I've somehow offended Richard and his friends as I seem to have become a persona non grata with them of late, but I must say it's a bit rich to finally come out with the consistent sceptic position as if it was new.
"Everyone agrees that the greenhouse effect is real, and that CO2 is a greenhouse gas.
Everyone agrees that CO2 rise is anthropogenic
Everyone agrees that we can't predict the long-term response of the climate to ongoing CO2 rise with great accuracy. It could be large, it could be small. We don't know. The old-style energy balance models got us this far. We can't be certain of large changes in future, but can't rule them out either."
Surely everyone here agrees that we've been pushing Richard's third point since day one, and the cliscis have been saying that they can predict (project) that there will be large changes in the future. Or have I been reading the wrong IPCC documents?
Stephan Richards,
Thanks for making your point clear enough even for me.
Well said, sir.
> Let us start by considering climate sensitivity.
Which, incidentally, matters way more to those who bet under the mainstream estimates.
Usually, one stacks up the deck against the opponent's hand, not one's own.
This approach definitely falls into the category of "watch the pea". It's a shell game.
I remember when Steve McIntyre was taking MBH98/99 apart, while many (incompetently) attempted to defend Mann's work, those who realised it was undefendable quickly switched tactic - often saying something along the lines of yes, but, proxies were never the core part of the policy, observations and models are.
When someone takes apart the models, we get the response yes, but the models aren't the most important part of the evidence.
The observations are probably the least easily, but of course observations alone cannot tell us what will happen in the future.
It is a little tedious when a debate gets to the point that something is undefendable, a wave of the hand is used to insist that other evidence is more important, when actually all of the pieces of evidence are incredibly weak.
EBMs are far too tuneable and easily modified to fit any position. Just add your own personal preferred "forcing". Add CO2 as a forcing. Then add aerosols. And the solar guys can add insolation. And the indirect solar guys can add cloud seeding from cosmic rays. And any other bunch of theories.
Then add the forcing efficacy, because of course each can have its own sensitivity and you end up with more terms in the model than you can shake a stick at.
DeltaT = k1*co2 forcing + k2*aerosol forcing + k3*solar + k4*cosmic rays + k5 * ...
And with all of this, you just make it match up with around 2-3 degrees of freedom over a 120 (ish) year data set. It's a joke, right? It is no surprise that everyone and his dog can fit a different model to the observational data. The problem is hopelessly unconstrained. This lack of constraints is why we are up to 38 "explanations" for the pause. Anyone can find correlations, tweak the parameters, match any climate history you can think of. It isn't science.
GCMs should solve this. Much less scope for tuning, right? Wrong. Dan Hughes comment is spot on here. The real dynamics of the system - the complex, non-linear attractor of climate - is the interesting thing that we would want to understand. But this is completely destroyed by the many parameterisations and sub-grid processes which are trivially used to force the GCMs to converge towards an equilibrium state, drowning out the real variability of climate. The result is GCMs produce attractors that look absolutely nothing like the real climate, either globally or locally, and end up achieving little more than EBMs do (in fact sometimes worse).
GCMs have the potential to be very powerful tools - in understanding the complexities and limits to our knowledge (NOT for predicting - or projecting - the future, they are nowhere near that, neither are EBMs). But the way they are used at the moment is a really bad joke.
geronimo
The changes are observed, recorded, and are there for those not yet brainwashed. Sadly the illogical indoctrination has been extremely effective. Not by malevolence or design, but by a politically designed ignorance.
ATTP:
You know what I'm talking about. On your own blog one of your fanboys an ad hom referring to a contrarian commenter as being part of the KKK (Climate Clown Club). I commented about this, the result being my message never showed up and you redacted the ad hom comment. Well done Anders aka Wotts, you're as much hypocrite as most of the other alarmist bloggers.
Even Stevie Wonder can see you're here to troll around, nót to participate in a reasonable discussion.
Okay, aTTP, let us get back to basics: as your chosen name infers that you consider yourself a physicist, I shall assume that you do know what Brownian motion is. Has any computer model yet been created that can predict the movement and location of a single particle in a Brownian chamber over a specified length of time? The answer, I suspect, is, “No,” but please enlighten me should I be wrong.
Such a chamber can have a limited number of parameters, is small enough for study of its entirety, and for conclusions to be made from observations over a relatively short period of time, yet no prediction can be made of the chaotic system. Now, why do you think that the considerably larger “Brownian chamber” that is the Earth’s atmosphere, which contains considerably more variables, both known and unknown, than the lab chamber, and can only be observed in extremely small, isolated locations can be modelled with any degree of confidence at all?
Jorgekafkazar has it right: GCMs are voodoo masks that the stupid hide behind.
Hoi Polloi,
Ahhh, I didn't know what you were talking about. Yes, someone made that comment at 5.01pm. You made a snarky response at 5.12pm. I moderated the comment that you mentioned and didn't bother posting yours since I would have ended deleting it anyway given that it was referring to a comment I'd moderated. Not quite sure why that's hypocritical but I'm guessing that there's little I can do to convince you otherwise. Of course, it's possible that you don't understand what the word hypocritical means.
You may have a point, as I'm yet to be convinced that a reasonable discussion is actually possible - the earlier part of your comment being a perfect illustration of why.
Radical,
Argument from incredulity?
Rodent, as a non-scientist (but someone who has worked with models of chaotic systems, i.e. economic models) your comments make perfect sense to me. So do hoi polloi's, and any others that I have neglected to name, along the same lines. Perhaps ATTP and his pals are on a different wavelength, or something?
The principles that my colleagues and I used when working with economic models were pretty simple. Firstly, the more variables you use, the less reliable the outputs. Second, the longer into the future you try to project, the less reliable the outputs. That was pretty much it.
Generally, they were more useful for analysis than for projection anyway. For example, we used modelling and synthetic data to work out the value of non-cash benefits (like free health care) to people's incomes, and how that affected "inequality" as measured by cash income only. It was good stuff, very useful for working out the effects of government policies and expenditures, and how to get the best bang for the taxpayers' buck.
In my experience, economic forecasting using models was voodoo. A decent economic analyst who kept up with the news and knew a bit of economic history could do better.
ATTP,
You wrote: " However, it is also possible that warming could be substantial and could take is beyond the range that any economic model has been able to study (i.e., more than 3 degrees by 2100). Is this a risk you think we should taking?"
Def: "A rhetorical question is a figure of speech in the form of a question that is asked in order to make a point. The question, a rhetorical device, is posed not to elicit a specific answer, but rather to encourage the listener to consider a message or viewpoint." Wikipedia
Your rhetorical question is what made me think you were suggesting uncertainty in climate sensitivity presents an unacceptable risk, and so demands we substantially reduce FF use. You could clarify your position on FF use by just answering your own question; that would ensure that everyone understands your position on FF use accurately. Please accept my apology for 'putting words in your mouth' if you were not in fact using that rhetorical question as a means to suggest a need to reduce FF use.