Bishop Hill A declaration of orthodoxy
Apr 3, 2015 Climate: sensitivity When a mainstream climate scientist comes up with some findings that go against the narrative of impending catastrophe they usually feel obliged (or are obliged by others) to take steps to distance themselves from the implications - hiding them, issuing declarations of orthodoxy, or saying something rude about dissenters.
We saw something of this in Bjorn Stevens' recent paper on aerosol forcing, with the implications for climate sensitivity left to one side. Yesterday, however, Stevens went futher and issued a declaration of his absolute global warming faith.
Many scientists (myself included) believe that a warming of more than 2ºC from a doubling of the concentration of atmospheric carbon dioxide is consistent with both my new study and our best understanding. Some insight into our reasoning can be found in a number of excellent blogs reporting on a workshop on Earth’s Climate Sensitivities, which I co-organized just last week, e.g., http://www.realclimate.org/index.php/archives/2015/04/reflections-on-ringberg
So contrary to some reports that have appeared in the media, anthropogenic climate change is not called into question by my study. I continue to believe that warming of Earth’s surface temperatures from rising concentrations of greenhouse gases carries risks that society must take seriously, even if we are lucky and (as my work seems to suggest) the most catastrophic warming scenarios are a bit less likely.
The full statement is here.
Reader Comments (131)
What Steve Mc says. The Bjorn Stevens Credo and the RC post are virtually science-free. If they had any reasons why the arguments made here and elsewhere by Nic et al were not valid, they would have made them.
Anyone get the impression that Ken Rice's nose may be a wee bit bent out of shape due to Bish being asked to speak in public forums while no one asks him for his opinion?
Perhaps it hasn't occured to him that without a reputation for engaging in honest discourse, the desire of others to engage with him is not there.
A pro forma expression of orthodoxy does nothing to change the science Stevens reported. That science had significant implications for the sensitivity question. Those implications tend to reduce the likelihood of catastrophic consequences. By how much is an interesting question.
Simply by doing his science honestly Stevens undermined one of the many shakey pillars of CAGW theory. That he asserts that the theory remains true is somewhat beside the point. His science was not about the truth of the overarching theory; rather it brought a bit more precision to one small element of that theory. That more precision has the effect of making the overall theory less tenable is just the way science goes.
Stevens should be commended for his science. His profession of faith can safely be ignored.
"Aye... dip your fingers in the font of holy water, genuflect before you enter a pew. That Bjorn feels the need to affirm his beliefs rather than letting the data do the talking is indicative of the power of the orthodoxy..." --tomo
Amen, brethren and cistern. Say the shibboleth, utter the ecco la fica, bow down and show thy willingness to comply, lest ye be accused of heresy.
Apr 3, 2015 at 11:27 AM | ...and Then There's Physics
A stupid comment. Response, per host's request, at
http://bishophill.squarespace.com/discussion/post/2486307?currentPage=2
I agree with Jay Currie, and further wonder why Bjorn Stevens would think the RealClimate discussion was persuasive, as pointed to by Steve.
The big problem for the Masters of the Narrative is that with lowered sensitivity, it is increasingly more difficult to frighten the herd into stampeding into imprudent and premature actions. Note the urge to anchor 2 deg C. as a lower limit. Note the recent urge to frighten us with catastrophe at 1.5 deg C., possibly, I note cynically, in response to Richard Tol's optimistic work on future impacts. As a side note, I've even found the use of 3.6 deg F. instead of 2.0 deg C; one wag @ Judy's wanted to know how to say 3.6 deg F. in Chinese.
So the great unwieldy galleon wheels slowly around, against the waves, the current, the tide and the wind, to fire yet another broadside of double shotted fear and guilt. Certain, blessed, wounded.
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omnologos
Your remark about me illustrates precisely why Stevens has to clarify his position carefully - if one does not do this, one get misrepresented, just as you've done to me here. I've always been clear that I am less certain of the 'catastrophic' aspects of AGW - I think human influences on climate pose risks and it makes sense to take steps to address these risks, but I don't talk up CAGW in order to get funding as you seem to imply. Please read my papers - like Stevens, I often present work which suggests things may not be quite as bad as previously thought, e.g.: here. This does not mean I think it's a non-issue - I just think it's more nuanced than is often presented in the media and on blogs.
It strikes me that some commentators like to paint the more careful thinkers as being at one end of the polarised debate or the other, in order to either claim them as an ally or discredit them as an enemy.
Catastrophes? Naw, perish the thought.
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The great thing about weather (and climate) is that it's always changing. This means it can serve as a never ending subject of study. Perfect academic fodder - catastrophe or not. The less likely it is ever to be understood the better; bit like 'social science' really.
Let's face it, physics is a stupid thing to study; it's all so predictable.
/sarc
Catastrophe? Naw, but maybe maybe or nearly near; keep fear and guilt alive!
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The Precautionary Principle: Maybe maybe or nearly near, let fear and guilt survive.
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Praise where praise is due. Stevens’ letter contains the sensible perspective: “As fond as I am of my own ideas, one should resist concluding too much, too soon, from a single study.” Had similar sentiments been expressed – by, say, authors of MBH98/99, or M08 – in a letter for “general release”, and had these or similar cautionary words been widely disseminated through the same channels that are now enthusiastically promoting Stevens’ letter of repentance, then climate sceptics (yes, ATTP, “sceptic”) would surely be fewer in number; perhaps even (unthinkably) The HSI would never have hit the bookshelves.
Off to google, not my favourite, but good for climate alarmism. I cannot find a single link that claims anthropogenic climate change is called into question by Stevens’ paper. Dellers at Breitbart kicks in with “A new scientific paper has driven yet another nail into the coffin of Catastrophic Anthropogenic Global Warming theory”, but CAGW is a quite different beast from low-sensitivity-AGW.
Mediamatters.org, true to form, hide the pea. In http://mediamatters.org/blog/2015/04/03/climate-scientist-no-my-study-is-not-a-death-bl/203166, they report reasonably that “According to right-wing media, the study represents a ‘death blow to global warming hysteria.’”. They proceed to ruin a rare piece of balanced journalism by declaring “Unsurprisingly, none of the right-wing outlets contacted Stevens before promoting his report as a "death blow" to climate science ...”, which no outlet – right wing or otherwise – to the best of my googling, has ever claimed.
The issue is fairly clear, one would have thought. Stevens’ paper implies a notably lower sensitivity. It does not call into question anthropogenic climate change, but no-one has said that it does. Stevens says in his letter: “... the most catastrophic warming scenarios are a bit less likely”. A "bit less", eh? At least Stevens has the courage to qualify his "less", unlike the NAS panel which said "Less confidence can be placed in large-scale temperature reconstructions for the period A.D. 900 to 1600". Sure, less, but how much less? A little less, a lot? We'll never know.
I digress. Stevens is on thin ice with his a "bit" less. As the Bish pointed out in his original post: “.. the IPCC's official upper bound is 4.5°C, but Stevens' results suggest that ECS can't be above 1.8°C <within the 17-83% range>”. The qualifier "a bit" is the weakest part of Stevens' letter, and reveals much about his discomfort within the "community". Our host's employment of the gently mocking “declaration of orthodoxy” metaphor is entirely justified.
@Richard Betts: I really do like to read your comments on this blog. Especially when you say such things as:
If I understand it, you are talking CAGW down. Now all we need to know is, by how much? Are you, in fact, an adherent - a believer - of the 2 Deg C tipping point - and that we are on target to reach it? You see, it is not what a man does NOT believe in that interests me: it is what he does believe in. Life is a risk; crossing the road is a risk; being a Christian in Nigeria is a risk; but anthropogenic climate change?You can hardly be affronted by people who think your livelihood depends on belief if you are not ready to 'come out' so to speak.
Bart,
I think you may have missed the point of my comment. If there is one thing about which we can be virtually certain, it's that the rise in atmospheric CO2, since the mid-1800s, is anthropogenic. It's not really worth arguing with those who think otherwise. I was simply surprised that since this is a site where the commenters regard themselves as informed about this topic, and the host regularly speaks pubicly about this topic, that someone could suggest that it might be non-anthropogenic without being challenged. Okay, maybe I'm not that surprised.
aTTP so if 'we are all agreed' that man made CO2 has caused the warming, what caused the LIA and MWP? Or do you subscribe to Mann's maths, and knock them flat with a Hockey Stick?
It's not yet as bad as people who convert sunshine-joules in Hiroshima's though. I suspect that one backfires on them in Japan.
Golf,
Want to try reading my comment again?
Five precepts of the intelligentsia:
Don't think.
If you think, then don't speak.
If you think and speak, then don't write.
If you think, speak and write, then don't sign.
If you think, speak, write and sign, then don't be surprised.
Many thanks to Manniac for explaining the origin of the 30,000 signatures on the Oregon Institute climate petition
Apr 3, 2015 at 7:17 PM | Richard Betts wrote:
Nuanced?! And careful thinkers?! Perhaps you could share with us some of the "nuances" -and/or 'careful thinking' - one can find in what appears to be your primary and preferred mode of "communication", i.e. the twitterverse.
Not to mention that on those relatvely rare occasions when you do choose to grace the blogosphere with your presence, there are far too few instances for comfort in support of your claim that:
The rather conspicuous absence of which I (and others) have recently documented.
aTTP, I did read your comment.
So what did cause the LIA and MWP? Or are you confirming that any rise in CO2 since the 1800's is irrelevant/coincedence.
Golf,
I'm really just failing to see how asking me about the LIA and MWP has anything to do with whether or not the rise in atmospheric CO2 since the mid-1800s is anthropogenic or not (just to be clear, it is anthropogenic).
aTTP I was just curious about any link between CO2 levels (man made or natural) and temperature.
Your assertion that the rise in CO2 is man made, may or may not be true, but if CO2 is the cause of recent warming, which is not currently rising, then logically, some other factor must have caused the LIA and MWP.
I thought it was a simple question.
@Harry Passfield
I do think we are on track to reach the symbolic 2C global warming - even Nic Lewis's low transient climate response estimates suggest that there's a good chance this will happen this century, and in any case I think Nic's estimates are probably too low.
However, I don't subscribe to 2C being some sort of 'tipping point' as you put it. I don't think there's anything special about that level of warming in terms of being a boundary between 'safe' and 'dangerous' warming. In fact I doubt if there is any neat number which can be defined as 'dangerous', it depends on lots of other factors too.
I think the risks of climate change are deeply uncertain, but I also think that the further the climate moves away from what we are used to, the more likely it is we will find ourselves in conditions to which we are not adapted. Hence, in my view, it makes sense to look for suitable ways to reduce our influence on the climate, whilst also looking for ways to adapt to the climate change that is already in the pipeline (and also to the natural climate variability that happens anyway).
@Hilary Ostrov
Thanks for illustrating my point so neatly ;)
Richard Betts
Could you please help with a little clarification/quantification? In 2009 a possible +4c by 2060 was implicit your message of the day:-
"4 degrees of global warming: regional patterns and timing"
As you
could you now, 6 years on, revisit your opinion of the probability of +4c by 2060?Are you still of the same opinion? Or could it now be +2c by 2060? +6c by 2060? +3c by 2060? Or 4c by 2080? +6c by 2100?
What would be the combination of +c and year you would now be the most comfortable in putting you name to? 6 years is a long time in this juvenile science, knowledge/awareness surely must have been gained? I do hope the awareness gained does not preclude any future implicit declarations of +c by year?
GC,
I'm no fan of ATTP, but on this exchange I have to side with him. He specifically said "since the mid-1800's." That excludes the MWP and LIA. If you disagree with his statement on the certainty of all of the increase in CO2 concentration since then being anthropogenic, argue that point. If you are trying to show that CO2 concentrations do not matter, as shown by the MWP and LIA, then you are switching the subject.
Richard Betts:
"and in any case I think Nic's estimates are probably too low."
Why and with what probability?
timg56 ok, thanks!
not banned yet
Those few simple words illustrate what is wrong with, modern day, post normal, "science".
Inference without substance.
Professor Phil Jones (CRU) sells the jerseys.
Please note that even if the the increase were statistically significant, 0.12C per decade is not enough to trigger any political CO2 reduction.
The BBC's environment analyst Roger Harrabin put questions to Professor Jones, including several gathered from climate sceptics. The questions were put to Professor Jones with the co-operation of UEA's press office.
Do you agree that from 1995 to the present there has been no statistically-significant global warming
Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.
C - Do you agree that from January 2002 to the present there has been statistically significant global cooling?
No. This period is even shorter than 1995-2009. The trend this time is negative (-0.12C per decade), but this trend is not statistically significant.
Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?
An initial point to make is that in the responses to these questions I've assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.
Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).
I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.
So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.
http://news.bbc.co.uk/1/hi/sci/tech/8511670.stm
Richard Betts -we've been through this before.
A. There's no need for you to constantly see accusations of malice. Every trade unionist sincerely believes no job should be lost wrt their trade. Likewise every researcher will argue that their field needs more funding and it's fundamental to society.
B. Therefore it's expected that human nature will find the path of least resistance to such an argument
C. In the case of climate science there are countless historical examples where the argument has always been that the previous mild climate would no longer continue and portentous changes be in the pipeline, therefore climate research needs more funding
D. You and Schmidt and many others have been making a huge mistake in the pursuit of the same argument. You believe that the ethically challenged alarmists are on your side and keep dreaming of them as supporters. This is absolutely wrong. They'll be ready to drag your name through mud as you refuse to acknowledge it's happened to Pielk Jr and it's been happening to Richard Tol.
E. You've experienced the same with the extremely naive attempt to bring sanity to the website of that guy with some physics background. No amount of ganging up and no outpouring of collective bile has convinced you as yet that those people will stab your efforts in the back if you will ever remotely suggest that there might not be a case of anything to do wrt climate change apart from adapting to the current climate
I can lead the climate researcher to the fundamental truth that alarmism is fundamentally intolerant but I cannot make you think 8)
Bish and all - it's sad to get so many OT comments. I wish I could block people, especially those who keep blathering about this or that aspect of climate physics in every thread, even the ones where the subject is why scientists feel obliged to reaffirm orthodoxy.
This is independent from my opinion on the physics. It's just that the obsessed are insufferable bores, even when they're right.
Brent H. says
What you are looking at is the equilibration between the three fast reservoirs, the upper ocean, the atmosphere and the biosphere. Think of three tubs of about the same size connected by pipes and you pour water into one of them. The water will flow into the other two until the higher level in the one you poured water into goes down and the level in all three is equal.
Now let there be a very small leak out of one of them (the upper ocean) into the lower ocean . . .
It's a bit more complex, but that is the gist. Here is a nice explanation of the slow and fast carbon cycle
http://earthobservatory.nasa.gov/Features/CarbonCycle/
Omnologos,
I can see why someone pointing out aspects of the science that almost everyone (well everyone sensible) regards as virtually certain must be irritating and inconvenient. It must be hard to maintain your narrative when people do so. Personally, my preference is that people are informed, rather than mis-informed, so I'll happily keep doing so despite your rather unbecoming pearly clutching (well, until the Bishop decides to listen to your kind of whining and ban me, I guess).
Just to clarify, my request for on-topic comments wasn't addressed to the ethically challenged, as I am aware they'll be doing bad and worse in the Pursuit of The Cause.
"If there is one thing about which we can be virtually certain, it's that the rise in atmospheric CO2, since the mid-1800s, is anthropogenic..."
Is this the new physics? I don't believe I've ever heard anyone say that the warming since the mid-1800s is anthropogenic, where did you get that gem from. The last I heard from the IPCC was that they were certain that over 50% of the warming since 1950 was anthropogenic I've never heard, or read anyone suggesting that the pre-1950 rises in temperature were caused by human emissions (with the exception of a lame amateurish attempt by Dana Nutter of SkS to show that the increase in CO2 between 1910 and 1940 caused a 0.45C increase) so if you have a real scientific source for being "virtually certain" that the rise in temperature since the mid-1880s is anthropogenic I'd appreciate it if you could cite it.
@Richard Betts:
I'm pleased to hear that you don't subscribe to 2C being some sort of 'tipping point' "as [I] put it". But I think you'll find the term 'tipping point' is not a sceptic phrase but one often put out by alarmists.
So can I take it that in your present position you are communicating that thought to those in the media (the BBC springs to mind) who would put a different spin on your work?You go on to say:
Finally, you say [my bold]:
First, what you say implies that you and your colleagues seem to 'know' what the ideal climate is for this world of ours: that would be an interesting discussion to have; and secondly, you seem to be agreeing that - notwithstanding we may not be adapted to future climate yet - we should be planning to adapt - again, the implication being that we don't need carbon taxes, stranded assets etc, which are supposed to 'prevent' doom, but more a plan to 'adapt' to our new-found climate (if, of course, it ever turns up). But who knows, that 'new' climate may well be the ideal one for us.ATTP: "If there is one thing about which we can be virtually certain, it's that the rise in atmospheric CO2, since the mid-1800s, is anthropogenic..."
Geronimo: "Is this the new physics? I don't believe I've ever heard anyone say that the warming since the mid-1800s is anthropogenic, where did you get that gem from."
I think ATTP is right on this - note he's not referring to warming, he's referring to atmospheric CO2 rises.
Harry Passfield
2 degrees = 21 units = 5 portions = BMI of 30.
Every one of them figures plucked out of the air to satisfy our political lords and masters who need a nice clear narrative to use as a cattle prod on the electorate who are too stupid to think for themselves.
Correction: are too stupid to think the way We Who Know Best believe they ought to be thinking.
As Rhoda has pointed out more than once 2 degrees gives Oxford the climate of Bordeaux (where last weekend it was barely 12C and pissing down so you can keep it) and "the science" tells us that the temperature increase will be greater the further towards the poles you get so 2 degrees is likely to be fairly meaningless.
Kudos to Richard Betts for agreeing with that. For his insistence that "moving away from the present climate" (which I see no evidence we are doing) means we need to "do something", not so much.
TC. I stand corrected, I mis-read it as temperature rise. So apologise to aTTP.
TC and Geronimo,
This doesn't seem to happen very often, so thank you.
'....consistent with both my new study and our best understanding...'
"What d'you reckon, Bert..? Two degrees..? That sounds about right..."
Geckko wrote (Apr 3, 2015 at 2:20 PM)
"Presumably, Stevens isn't at the leading edge of research on the science of total climate sensitivity, like say, Nic Lewis."
That is incorrect. Bjorn Stevens is one of the leading researchers on the behaviour of clouds, which is probably the key uncertainty in determining climate sensitivity. Cloud behaviour is probably also the most important factor determining total aerosol forcing, the level and uncertainty of which is key to estimation of climate sensitivity from warming over the industrial period.
Jay Currie wrote (Apr 3, 2015 at 5:53 PM)
"A pro forma expression of orthodoxy does nothing to change the science Stevens reported. That science had significant implications for the sensitivity question. Those implications tend to reduce the likelihood of catastrophic consequences. … Stevens should be commended for his science. His profession of faith can safely be ignored."
I agree. IMO, Bjorn Stevens is a very good scientist.
Stevens wrote in his letter published on the MPI website:
"So contrary to some reports that have appeared in the media, anthropogenic climate change is not called into question by my study."
I don't know which reports Bjorn Stevens is referring to – I made no such claim in my
article about the implications for climate sensitivity of his new aerosol forcing estimate, which simply showed what effect, based on the Lewis and Curry (2014) study, adopting it in place of the AR5 estimate would have.
Stevens also wrote:
"Many scientists (myself included) believe that a warming of more than 2 ºC from a doubling of the concentration of atmospheric carbon dioxide is consistent with both my new study and our best understanding."
I believe that this is probably on the basis that equilibrium climate sensitivity (ECS) may exceed the level that (effective climate sensitivity) corresponding to the strength of climate feedbacks experienced over the industrial period. This possibility was discussed both in AR5 and in Lewis and Curry (2014).
A number of the current generation (CMIP5) climate models, when forced by an increase in CO2 concentration, show a tendency for net climate feedback to decrease (and hence sensitivity to increase) over time. That could in principle reconcile an effective climate sensitivity estimate of, say, 1.6 C based on warming over the industrial period (such as that in Lewis and Curry 2014) with an ECS of above 2 C once the ocean had fully equilibrated. However, not all CMIP5 models exhibit this behaviour, and the behaviour of the models that do so may well be unrealistic. FWIW, the only next generation (CMIP6) model for which I have any information relating to this point appears to exhibit no decrease in net climate feedback strength over time.
Nic,
Here's a question I've asked you before (and is one I would be keen to see answered by yourself, Bishop, Matt Ridley,.....). Yes, there is some recent evidence that climate sensitivity might be lower than previously thought. A possibility that TCR might be below 1.5K and ECS might be below 2K. Fine, that would be wonderful if it were the case. However, few of these recent estimates rule out (with high confidence) that TCR might be close to 2K and that ECS might be close to 3K. Similarly, many of these methods have assumptions (such as feedbacks being linear) that mean that you can't use them to claim that other estimate - which suggest that such assumptions are wrong - are in error. It appears to me that yourself (and others) are using these newer estimates to argue that we have much more time in which to find possible solutions and that climate change is likely to be less severe than some people may suggest. Here's the question: given that climate change is likely to be irreversible on human timescales, what if such suggestions are wrong?
To be clear, this is a serious question. I'm not trying to catch you out or get you to say something that I can then pounce on. I am genuinely interested in what those who seem to be suggesting that we should base policy on climate sensitivity being low, think about the possibility of it not being low, and why they appear to largely dismiss the risk of it being high enough to produce severe impacts this century.
As was said elsewhere:
Orthodoxy is just your own doxie, while heterodoxy is someone else's doxie.
ATTP, I hope you aren't botherd when I try to answer your qestion with my opinion. For a climateer involved in the solution of the enigma of Climate Sensivity it's not the most important point to solve some if/thens. In AR5 I saw no progress to define CS better/ tighter than 20 years ago. This is (in my eyes) a travesty. So let the researchers do their jobs without some asking to poltical decisions, that's not the job of Nic and not yours. The mankind is faced with some risks: The danger of wars, the contrast between poor and rich: this must lead to maybe uncontrolabale tensions. The water shortage is a real problem and so on. Of course also climate change is a risk and it's necessary to balance the capital spending to avoid the possible outcomes from this risks. So it's very important to arrange in order the risks and to know much more exactly what the possible hazard for the mankind is. I think you are very strictly foccused on climate change, anyway: there are much more challanges. The possible impact of a TCR (which is imo the more important value vs. ECS for decision makers) of 1.3 is much more less than 2.0... so a climateer should be concentrated on research and not on if/thens.
Don't feed the thing.
Again, Ken, ponder that the higher the sensitivity the colder we'd now be without man's effect.
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By the way, Ken, I appreciate the tone and understand the seriousness of the question in your 12:49. Where is the real Ken Rice, and what have you done with him?
Seriously, the answer to your question is that we are not afraid of the future.
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We can't put enough CO2 into the atmosphere(we can't temporarily re-arrange the inexorable sequestration of carbon) to hurt the biome, and we can't put enough CO2 into the atmosphere to warm us enough to prevent glaciation. Perhaps we can ameliorate the onset of glaciation.
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Kim said
Strangely enough there are those that differ and they tend to know a lot about the question