Bishop Hill More on GCMs and public policy
Aug 27, 2014 Climate: Surface Climate: WG3 Climate: sensitivity Richard Betts Richard Betts posted some further thoughts on GCMs and public policy in the previous post on this subject. Since the thread is now heading for 300 comments I thought I'd post his ideas up here and respond in turn.
Richard first set out his understanding of my position.
I'd initially thought that you were claiming that the very need for any kind of climate policy was based on GCMs. Clearly it isn't, for the reasons I stated, but it seems this isn't your point here anyway. You seem to be moving a step further and talking about the importance of GCMs to the details of climate policy (eg. a carbon tax). Here I do partially agree with you - GCMs do of course play a role in the details, as they help with understanding the climate system, but they are by no means the only source of information. Moreover, I don't think the examples you give would be substantially affected if we didn't have GCMs.
In fact his earlier understanding was more correct. The case that AGW is a big problem is a function of GCMs: the bigness of the problem is determined by the estimates of the social cost of carbon and these are a direct function of GCM estimates of climate sensitivity. Richard's point about carbon taxes seems to misunderstand the SCC. Once you know the SCC you can decide which of the possible measures you can take in response are cost-effective. Carbon taxes are one possible response. Drowning us in windfarms is another (allegedly).
To the best of my knowledge there is no evidence of statistically significant changes in observational records of the climate. The Met Office concurs, at least as far as surface temperatures are concerned. When I have advanced this argument in the past, they have told me that their understanding of AGW is based on physical models, not observations of the climate. It seems to me that the official Met Office position can be paraphrased as "global warming is a problem because our GCMs say it is". Richard's position of "climate policy is not dictated by GCMs" therefore seems to contradict the official position.
Richard goes on to dispute my take on where the IPCC position on climate sensitivity comes from.
You state:
Let us start by considering climate sensitivity. As readers here know, the official IPCC position on climate sensitivity is largely based on the GCMs.
No. The concept of Equilibrium Climate Sensitivity was basically developed as a simple metric of how climate models responded to increased GHGs, so the models could be compared. It is not something that we will ever be able to measure directly in the real world, as we won't ever see a neat doubling of CO2 with no other changes happening. But instrumental and palaeoclimate records have been used to try to constrain ECS, and the AR5 'likely range' of 1.5 to 4.5C is based on these constraints, not models - see AR5 WG1 Chapter 10 section 10.8.2.
Ignoring the first couple of sentences, which don't seem relevant to me, the nub of Richard's argument seems to be that alongside the instrumental records, the paleoclimate records are also modifying the official position on ECS. This seems unlikely. The IPCC itself notes that the paleoclimate records barely constrain estimates - they contain very little information. This is all explained in Nic Lewis's GWPF report on the subject. Readers may recall the graphs I posted last year which made this point.
;)
The observational estimates, in green (apart from Otto, in black) do not point to 2-4.5°C. The paleoestimates in blue are all over the place and are a function of their priors rather than their data. 2-4.5°C is a function of the GCMs.
This time round we have had some minor concessions to observational estimates
I wouldn't say it was 'minor' - there's quite an extensive discussion - and in any case it's not 'this time round' either, as there's also quite an extensive discussion in AR4 WG1 Chapter 9". I'm surprised you've forgotten about that, since Nic Lewis commented on it some years ago, and it was discussed at Climate Audit and I'm sure we discussed it here too a while ago.
"Minor" of course referred to the impact the observational estimates have had on the overall assessment of ECS. An extensive discussion is irrelevant. Words are cheap.
The handling of ECS in the Fourth Assessment has indeed been discussed here. Readers may recall that the first of the observational estimates - Forster and Gregory 2006 - was available for consideration in AR4. Thus there was evidence at that time of the divergence between observations and GCMs. But the IPCC did not allow this to affect their overall best estimate of climate sensitivity. Instead they restated the Forster and Gregory results using an inappropriate prior and thus making it seem hotter than otherwise. It was not until AR5 that observational estimates had any effect on the ECS assessment.
Also you are wrong in your claims that climate scientists keep policymakers in the dark about uncertainties. The IPCC SPMs are full of clear statements differentiating the more certain and less certain aspects of the science - that's why all those confidence statements are there. For example the IPCC AR5 WG2 SPM says:
Responding to climate-related risks involves decision making in a changing world, with continuing uncertainty about the severity and timing of climate-change impacts
and
Uncertainties about future vulnerability, exposure, and responses of interlinked human and natural systems are large
Your narrative of "climate scientists only use models: climate scientists hide uncertainties from policymakers" is false. We use observations too, and are open about uncertainties. That's why policymakers have to make a judgement call in the face of these uncertainties, having been made aware of the full range of possible outcomes for their different policy choices.
I ask again: do policymakers know that GCMs are fudged?
But when it all comes down to it, I think we need to understand what Richard's understanding of the case for climate policy is, whether mitigation or adaptation. My simple understanding is this:
- Carbon dioxide is a greenhouse gas
- Greenhouse gases will, other things being equal, warm the planet
- GCMs suggest that other things are not equal and that the warming will be larger than what you would get from the greenhouse effect alone
- GCMs suggest that there will be painful impacts too.
- Economic models suggest that a warming of this magnitude and its associated impacts will carry net costs
- Economic models suggest that there are things we can do to mitigate and/or adapt to these changes that are net beneficial in terms of cost.
- Therefore we should do these things.
What is Richard's take?
(As an aside, Bob Tisdale has a post at WUWT looking at Richard's earlier comments.)
Reader Comments (91)
This is a simple assertion and assumes that we have a full understanding of natural variability. That we do not have that understanding is borne out by the ever more desperate attempts by the consensus scientists to explain away the lack of warming for 17+ years. It is already clear that natural variability plays a much bigger role than we, the public, were led to believe by amongst others the UKMO. So, Richard, as far as I am concerned there is nothing to suggest that the climate is already responding to GHG emissions. Case not made.
The recent clarification from RB is very helpful. I now understand his views on this matter.
It would be impossible for him to produce a simple list and also do justice to the uncertainties implicit in such a list.
However, the overall conclusions depend critically on one's interpretations and assumptions linked to each bullet point. It is clear that he and I end up with different conclusions from our assessments of these bullet points.
It would be very interesting to discuss each bullet point in turn to find the most controversial and the most critical. However that is something our host may have views on.
Richard,
Could you provide a source for this evidence in respect of CO2 causing huge changes Agreed Agreed Agreed Pushing, the climate system, in as far as a fly pushes an elephant Could you provide a source for this evidence But we don't understand the system so don't have all the evidence invalidating a risk assesment on terms of huge uncertainty Invalid argument Invalid argumentI agree with the host and with Schrodinger's Cat that we should think over Richard's answer. I'm grateful for his response and to this blog for making such an important discussion possible.
I wonder about Richard Betts motivation.
Does he truly believe in what he espouses or is he the disingenuous canary for the MO?
"Go on Richard, float this one out there and see what happens, we're right behind you. The response will help us spin and defend our position, we'll have the usual de-briefing session when you've finished the campaign".
Being a cynic I lean toward the latter.
RB's list above is the long version of what all arguments with warmists ultimately devolve into:
"Mankind is emitting CO2 in quantities which can be expressed in Big Scary Numbers. We must be having an effect on the environment! We just must!"
The subtext is an unwillingness to believe that we do not, in fact, have control over our environment, which is a hard thing for many scientists to admit.
As for point 6, that's been reduced to the "unusual weather" meme which is the latest in a long list of supposed effects which have been shown to be fictional or unrelated to CO2.
Bishop,
I beg to differ from your assessment:
1) CO2 is a grrenhouse gas. OK
2) Greenhouse gases will, other things being equal, warm the planet.
So far the jury is out as to whether greenhouse gases have had any effect whatsoever. Climate sensitivity is based on GCM's and observation of temperture rise, but assuming that CO2 is the cause.
3) GCM's assume warming will be larger than from CO2 alone.
Again the GCM's say that, but reality is telling a different story. All the GCM's have been shown to over-estimate warming.
4) GCM's predict that there will be painful impacts too.
However, so far, all the GCM's have been shown to over-estimate warming. Let's remember that the overall warming since 1850 is less than a degree whereas the best estimate of the change in temperature between a glacial and an interglacil period is 8 - 10 deg C. We are claiming we can see an anthropogenic effect in a total temperature change (natural variation plus greenhouse) of less than 10 % of best estimate of total natural variability over the last 1 million years.
5) Economic models show that a warming of this magnitude will carry costs.
Economic models also show that the cost of mitigation is greater than any likely damage.
6) Economic models also show that there are things we can do to mitigate and / or adapt to these changes.
However many of the assumptions presently made are being shown to be invalid. For example, the efficiency of renewables and their energy density do not support the economics of switching to these energy forms. Recent studies show that the cost of implementing these changes have been badly under-estimated.
7) Therefore we should do these things.
Actually, under present knowledge, the exact opposite deduction should be made. If present models over-estimate global temperatures, then we should not believe CAGW as persently theorised. If the costs of the cure are greater than the costs of the illness, no we should not do the proposed mitigation..
Finally, Richard Betts says that the climate system is an angry beast and we are poking it with a stick. This is utter rubbish. We have no idea whether we are really poking it with a stick or not. This is just a dramatic statement of the precautionary principle. The standstill in global temperature over the last 6 - 18 years says we are not poking anything with a stick at all.
[Snip - venting]
What we observe is:
--> The Met Office drops its 6 month seasonal weather forecasts because they routinely engender ridicule.
--> The Met Office continues to peddle global doom and gloom based on its GCM's - which attempt to model climate, which is may loosely be defined as a 30-year average of the weather ...
... which they can't forecast for the next 6 months for one country.
This is not the country I fought and died for.
Richard
Richard Betts
8." A responsible risk assessment usually involves some combination of minimising the risk and finding ways to live with the part of the risk that we can't (or choose not to) avoid"
Enter the precautionary principle which is abused so much by politicians to convert waverers to conform to the meme.
What they don't tell the waverers is that they are proposing to take out insurance, the annual premium of which is greater than the item being insured.
This strategy is ludicruous.
Bish,
This seems to fit here
http://noconsensus.wordpress.com/2014/08/27/time-for-a-little-healthy-skepticism/
It is truly disappointing to see an educated and intelligent fellow like Dr Betts demonstrate so conclusively that, after all these years in the field, he still does not understand the basic principles of risk assessment.
The Precautionary Principle is the opposite of risk assessment. It makes no attempt to evaluate risks, costs and benefits at all. It just says - something bad MIGHT happen sometime, somewhere, so we will close down all options except banning something, or not doing something, or similar prohibitive measures.
As for the angry beast thing, what is it with the "angry" meme? The BoM told us that last summer was "angry", Greenies tell us that Gaia is "angry", and now a chap with a PhD in meteorology and an undergraduate degree in physics is citing Earth's climate as an "angry beast". Of course, inanimate objects and artificial constructs such as seasons and climate are incapable of emotion. It says a lot about the degradation of science that this sort of terminology is not mocked and scorned by people who should know better. Sad, and depressing.
Can you imagine Niels Bohr taking seriously anyone who talked about angry atoms? Or Howard Florey promoting the concept of angry infected wounds? Because we are poking sticks at them? They would have thought that this was just bonkers.
Post modern science has a lot to answer for.
It is telling that some many opinions here are in harmony.
Thinking people arrived at much the same conclusions, based more on observation and logic than model output.
The first couple of Richard's guesses are the start of a train of illogic.
That CO2 is a GHG does not axiomatically mean that its increase will heat the atmosphere.
There is no observation that shows that overall heating is caused by CO2.
One needs more than input to energy balance - as in CO2 is a GHG.. One needs the output part also - that there is no accumulating heat increase, so heat must be getting lost. It is the rate and destination of the loss that is lacking inclusion in analyses.
All we have so far are 30 or so more guesses about where the heat goes.
This is not an adequate basis for major policy change.
Leave it alone, Richard. You are out of your depth. All of us are, to some degree.
Stop making apocalyptic statements if you wish history to be kind to your memory.
Richard Betts summation seems more an appeal to fear-based emotion than a reasoned defense of whatever it is climate policy is based on, since it is not based on GCM's apparently. The climate system is remarkably placid, not angry: despite the increase in CO2 ppm, storms, droughts, slr, temps, floods, etc. are all flat to milder over the historical record. Despite human caused land use changes, rerouting of rivers, creation of lakes, draining of swamps, etc. the Earth supports huge varieties of life including record numbers of humans who are living longer and healthier lives.
We are not poking the climate with a stick. The sun is in control of the climate: A small % decrease in solar out put would freeze our Earth. A tiny increase in the same would cook us. Our impacts even now are trivial by comparison.
Just as no one seriously believes Hansen's old eyewash about Earth turning into Venus, it is time for people to let go of the rest of the climate apocalypse claptrap. Richard Betts already agrees with some of the main points of the skeptics: GCMs don't work and are not good for policy making. The range of possible change is not well defined. He only has to cross that barrier climate obsession has raised to find a truly rational approach to climate and energy. Be brave, Richard.
johanna: I was wondering where I last saw the 'angry beast' quoted. Here's where:
The irascible Chief Hydrologist aka Robert Ellison on Judy Curry's in December. And the same day:
And the next day:
Hardly a consensus flunky. Isn't this just a colourful way to talk about spatio-temporal chaos? None of what Betts writes makes any kind of 'mitigation' urgent, in my book. Did noone else detect a white handkerchief of surrender? (Last sentence to ensure everyone has something to disagree with in this! But also because I believe it will prove true.)
A Modeller was arguing with an Observer about the existence of CAGW and failing to get his point across. They had been arguing for two hours and finally the Modeller in frustration sat down.
"Listen," said the Modeller, "You are like a man in a dark room, with no lights and windows, wearing a blindfold looking for a black cat that isn't there. What do you say to that?"
The Observer thought for a moment.
"Yes, you are probably right," he said, "but you are also like a man in a dark room, with no lights and windows, wearing a blindfold looking for a black cat that isn't there. The only difference is, you have found the cat."
With all due respect to Dave Allen circa 1970
Green Sand
+1
It would be very interesting to discuss each bullet point in turn to find the most controversial and the most critical. However that is something our host may have views on.
Aug 27, 2014 at 7:38 PM | Unregistered CommenterSchrodinger's Cat
He does !!
"Yes, you are probably right," he said, "but you are also like a man in a dark room, with no lights and windows, wearing a blindfold looking for a black cat that isn't there. The only difference is, you have found the cat."
The only difference is, you have found the cat." claim to have the cat but don't know if it is a cat.
The point made is a good one. Have a +1 from me as well!
As for the angry beast thing, what is it with the "angry" meme? The BoM told us that last summer was "angry", Greenies tell us that Gaia is "angry", and now a chap with a PhD in meteorology and an undergraduate degree in physics[ and a senior manager in the Met Office - Martin A] is citing Earth's climate as an "angry beast". Of course, inanimate objects and artificial constructs such as seasons and climate are incapable of emotion. It says a lot about the degradation of science that this sort of terminology is not mocked and scorned by people who should know better. Sad, and depressing.
(...)
Post modern science has a lot to answer for.
Aug 28, 2014 at 12:47 AM johanna
It's a religion, with its congregation of True Believers.
And its High Priests who dress themselves in the robes of science.
But despite the fancy dress, the 1,000,000 line Fortran pectoral crosses and croziers, it's religion they are peddling, not science.
I guess my view is summed up by the classic quote:
"The climate system is an angry beast and we are poking it with sticks."
I'm so disappointed with Richard Betts for this statement.
Whats going to happen next Richard ?
Burning of skeptics at the stake ?
That sort of view is no better than the Witch Burners of the middle century. Which coincidently they were being blamed for the bad weather.....
http://en.wikipedia.org/wiki/Witch-hunt
In England, the Witchcraft Act of 1542 regulated the penalties for witchcraft. In the North Berwick witch trials in Scotland, over 70 people were accused of witchcraft on account of bad weather when James VI of Scotland, who shared the Danish king's interest in witch trials, sailed to Denmark in 1590 to meet his betrothed Anne of Denmark. The Pendle witch trials of 1612 are among the most famous witch trials in English history.[28]
There isn't ANY empirical data at all that shows the "Cliamte is Angry"
Give me ONE statistic.
Any Statistic.
Rainfall is average
Droughts are within historic boundaries.
Artic Ice is within historic norms.
Antarctic Ice is at record highs.
ACE is at an historic low....
Tornadoes are at lows.....
Its so disappointing to have that statement come from a Met Office Scientist.
Richard Drake, it makes no difference whatsoever what views an alleged scientist who inappropriately anthropomorphises scientific concepts is pushing.
It is what Monckton aptly describes as "baby talk."
Yes, that's where it came from, and agreed - Much missed, is Dave!
I think the 'angry climate' remark was more for consumption back at headquarters than here.
The only difference is, you have found it.
I'm not sure we can get through #7 (risk assessment) without GCMs... In fact, what else, other than modeling, has been used to indicate the 'could', 'maybe', 'probably', and 'will' of future climate change risks and countdown time-frames?
Well, humans have managed to survive, and increasingly prosper, for many thousands of years without CGMs. What we did was improve plant and animal strains, food storage and transportation, health care, infrastructure, etc.
It didn't require computer models of any kind, let alone ones that demonstrably don't work, to achieve most of those things.
Risk assessment is a feature of civilisation. It does not rely on CGMs.
Johanna,
I kind of disagree with what you're saying...
There are various things that we've done to improve our world that you've stated that do indeed rely on modeling, and even require them to be used prior to enactment. In particular, most infrastructure installations require all sorts of model-influenced and model-derived studies (new bridges, highways, grid-improvements, etc.) ... Even perhaps some improvements in medicine and agriculture have required or have been influenced by modeling to proceed down the path to regulatory approval.
As a result, any such modeling is a huge thumb on the scale as to what one can expect for risk magnitude and countdown time-frame. I can't think of a single talking-point sheet in support of any Greenpeace-endorsed climate-change policy that doesn't include what models project to be the 'maybe', 'could', 'probably', and 'will' effects "If we don't do [x] quickly". How would you make an acceptable 'risk assessment' case without them?
I do agree with you though that models that are used need to work. And (ironically), as Paul Krugman always says, if your model isn't verifying, you either change your model, rethink your ingredients, or both.
Salamano
People were building roads, bridges and aqueducts, some of which still stand today, more than two thousand years ago.
It is true that computer modelling is now commonly used in engineering, but that is relatively recent. The same goes for the other fields you mentioned (notice that in my original comment I used the word "most").
Apart from the fact that the kind of models used by engineers are completely different from CGMs - as engineers have so often reminded us in discussions about climate models - the fact is, even in the modern era, skyscrapers, aeroplanes, large bridges, the entire Dutch sea management infrastructure etc were successfully built without a computer in sight.
Computers can't successfully do anything that can't be done manually. They are just faster. And, just as we can't predict the climate (or the economy) very far in advance manually, computers can't do it either.
Johanna,
Surely there was modeling before computers. Could it be that your use of the term is more narrowly constrained than mine?
I would think design calculations could be construed to be modeling.
jferguson - but that is precisely what I said at 1.23pm!
"Computers can't successfully do anything that can't be done manually. They are just faster. And, just as we can't predict the climate (or the economy) very far in advance manually, computers can't do it either."
We should admire Richard Betts for his civil, thoughtful, and direct contributions in the comments he makes on this blog. So many from his 'side' prefer to deploy sarcasm, superciliousness, ill-natured jibes, or affect an ex cathedra tone if and when they respond to criticisms of their methods and perspectives. Most of course would not come here to take part in a month of Sundays.
I do not find his case outlined above to be a persuasive one, but I appreciate the way he takes part here, and the fact that he takes part at all. I remain astonished and dismayed by the dramatic political success that has been achieved on the back of so little by those who spotted the opportunity that the Keeling plot from Mauna Loa and the associated speculations of a handful, back then, of scientists in an obscure and lightly peopled corner of science presented. This brings no blame to the scientists back then for whom such speculation was merely part and parcel of doing their work. Some of them, though, went further and launched political crusades. Hansen and Schneider and Houghton are but three examples, and the Climategate Revelations point to several more. I like to think Betts is better than all of them.
John Shade:
My bold. Part of what I was getting at earlier in taking issue with johanna's critique of Richard's quote of Wally Broeker. Broeker's landmark Are We on the Brink of a Pronounced Global Warming? was published in 1975. With the benefit of hindsight we can take two views of the history. The suspicious one, looking for example to Margaret Mead's 1975 conference, 'Endangered Atmosphere', with Stephen Schneider, John Holdren, George Woodwell and James Lovelock, as a deliberate poisoning of the well. Or the more accidental one. Either way, we can't know if Broeker's famous metaphor of poking an angry beast was really meant to aid "the dramatic political success that has been achieved on the back of so little". (And it is so little.) I doubt it - and I second your comments about Richard himself.
These arguments are preposterous. With what degree of accuracy do we know the natural variation of global climate? I do not seem to have seen any comparisons, but what else could climatologists use as a reference for statements that observations show that there has been a significant departure from the norm?
GCM models have signally failed to predict the last 18 years, but "we know" that our models predict global warming with increasing CO2, therefore, that is enough to show that significant warming will occur. So models are key, but currently they have not been proved or verified to have any relevance to reality.
The basis for predictions of doom is pure conjecture.
As if by chance, Wally Broeker has just hit the radar on WUWT:
In 1975, as John said, "such speculation was merely part and parcel of doing their work." Today, after the experience we've had with CCS, and with all the evidence against alarm in the record of extreme events, and in corrections to climate sensitivity calculations based on observations, that's crazy.
RB Quotes: "The climate system is an angry beast and we are poking it with sticks."
Dr. Wallace Broecker
The last 2.5 million years have been characterised by long glacial periods interspersed with shorter warm periods.
Civlisation has developed in one of those short, warm periods.
Is it worth considering the possibility that high CO2 levels may prevent a transition from the current warm state to a catastrophic glacial state?
Have any of the climate models looked at the level of CO2 required to prevent the onset of a new ice age?
Richard, many thanks for those two links (Aug 28, 3:23PM). I had not seen either before (to my shame). As an aside I also attended the UN Population Conference in 1974, after which Mead says she was motivated to hold her conference. By contrast, I think the conference helped me to see the awfulness of the left, be they from within the iron curtain as it was then, or from the free world. I was one of the UK 'Youth Delegates', where 'youth' was defined as being under 27 years old as I recall. I remember challenging a Russian delegate when I chaired a discussion session which he wanted to take part in as a 'youth'. He looked ancient to me - at least 45. I refused to let him speak, and much consternation followed. There seemed to be no end of delegations from the USSR, all of whom prefaced their rote remarks with even duller recitations of the fraternal greetings they brought with them from all and sundry back home. One wag from the States interrupted a plenary session in which similar guff was being recited, and suggested that we just regard the Communist Manifesto and the American Declaration of Independence as read, and entered into the minutes, and then stop having all the slogans and suchlike from fraternal this and thats taking up so much of our time. While some of us rolled with laughter at this, another consternation storm brewed up, with comrades pressing to get to the microphone to denounce the frivolity of the suggestion. Happy days.
I told you before, Richard, that the scare is exaggerated and to just stop it. But do you listen?
==================
John Shade: Wow, you were there in 1974. Awesome. Sorry only just seen this. Happy days indeed.
1. There is VERY good evidence that Earth's climate has undergone very large and extensively damaging changes in the past, due to impacts with other celestial bodies
2. We are beginning to understand what these bodies are, and how they move.
3. More and more people are being born,
4. and we are building big cities over more and more of the planet.
5. Hence we are more and more vulnerable to even a medium sized impact
6. We have recently seen evidence of near-Earth misses
7. But we are still doing absolutely nothing about defending ourselves against this threat, though we have the technology to do so.
8. A responsible risk assessment usually involves some combination of minimising the risk and finding ways to live with the part of the risk that we can't (or choose not to) avoid
9. Hence we need to decide whether we should keep throwing money down the drain on climate science, or put some of it into a defence against a real threat which may well materialise...