Bishop Hill Cool exchange
Apr 12, 2012 Climate: Sceptics Climate: other A couple of weeks ago Tamsin Edwards discussed what I think might be a better way forward for those who are interested in understanding the climate debate.
I think a large part of the audience who visit this blog (thank you) contradict these findings. Your trust in the science increases the more I talk about uncertainty! And I think you place greater importance in “calculative” rather than “relational” trust. In other words, you use the past behaviour of the scientist as a measure of trust, not similarity in values. I’ve found that whenever I talk about limitations of modelling, or challenge statements about climate science and impacts that I believe are not robust, my “trust points” go up because it demonstrates transparency and honesty. (See previous post for squandering of some of those points…). Using a warm, polite tone helps a lot, which supports Hebba’s findings. But I would wager that the degree of similarity to my audience is much less important than my ability to demonstrate trustworthiness.
Reader Comments (166)
"Trust points": A few years ago, when I believed in AGW, I saw footage of Dr. John Christy saying that his unit at Alabama Uni had produced some duff global temperature data because "to our embarrassment" they hadn't compensated for the decay in the satellite's altitude.
At the time, hovering between the two opposing views on AGW, I figured that I'd sooner believe somebody with the integrity to admit mistakes and correct them. But that's the "argument from authority" which can easily be circular.
The best approach is to acquire sufficient grasp of the physics to make one's own mind up.
Don - don't leave. I always enjoy your unique Californian-Irish (iirc) perspective. I also think mydogs is on to something. I can only follow his argument so far - usually until he mentions Provost Exchange. But I just know from observation that atmospheric CO2 does not have any significant or measurable impact on local surface temperatures (or global). I accept that there is back radiation, but except in rare situations (temperature inversions) it does not contribute any warming or 'forcing'. Rather all it does is increase the time it takes for surface warmth to escape to space (but the warmth does escape none-the-less). I'd like to, but I don't have the time to actively get involved in these discussions. I do usually manage to read all the threads, and don't mind when MDGNN pops up - if it turns out that he is right even about one minor aspect of the radiative physics and we or the Bish have excluded him it will be a travesty for science, considering how many billions have been mis-spent on the CO2 end-is-nigh thesis.
I think sceptics have been courteous on Tamsin's new blog and hope that continues. I agree that snarky ad-homs and rudeness are indefensible and totally counterproductive. In fact often the trademark of certain vociferous CAGW supporters rather than sceptics. I think Tamsin's and RB's initiative is welcome.
There are certainly some whose ethical virtue is questionable. In all walks of life. But I suspect that most genuinely believe the 'consensus' view and have never seriously questioned it, and that is the principal problem. The great frustration for sceptics with the CAGW behemoth is groupthink. How often when one receives a reply from anyone caught up in the groupthink like an MP or BBC executive the standard genuflexion is to the IPCC consensus, however courteous and civil it might be.
Peter Lilley, the long-suffering lone sceptic sitting in that great groupthink echo chamber called the Houses of Westminster, is a typical sceptic in his scientific training and rational logic.
Tamsin could scarely do better than study his 2009 Wall Street Journal opinion piece on the climate groupthink phenomenon in order to gain an good appreciation of the prime concerns I suspect each of us here would probably concur with.
http://online.wsj.com/article/SB10001424052748704238104574601762696721506.html
Does anyone know if any of the climate model has shed light on 'any' aspect of climate, that has then been examined and been found to be true? Have the models predicted any phenomena that was previously unknown?
Very soon you will be discussing understanding the understanding and Dr. Edwards will be talking about post modern trust points, or something.
Yes, it's nice to hear Tamsin and Richard profess that their colleagues are as 'open' and trustworthy as they appear to be. Then something like this comes along:
http://wattsupwiththat.com/2012/04/12/envisats-satellite-failure-launches-mysteries/#more-61214
And I go back to thinking the whole shoddy business is likely a sham.
How did people think the CAGW obsession was going to end? Did people really think it was going to be a massive monolithic reversal, complete with Nuremburg trials for the culprits?
A cursory glance at the history of science shows this never happens. All reversals start with a small uneasy group of scientists who start doubting in private but still have to toe the line in public. At some crystallisation point, there is enough of them to represent an 'opposing view' which then garners credibility as an alternative theory and eventually, as they outlive/outretire the old guard, the view becomes accepted as mainstream. From 50 or 100 years away, it looks like we suddenly discarded the ideas of aether or phlogiston or catastrophism. In reality they were clung to and fought over for years.
Let's welcome the small uneasy group. Best we open our arms to them and risk being fooled by them than turn them away and delay the end of the madness a single moment longer than neccesary.
Some people prefer the fight more than the peace. That's fine too. Churchill was a fine war-time leader, not so good in peace-time. Peacemaking is hard, it requires you to tolerate being in the company of those who you consider 'the enemy', making compromises, forgetting but not forgiving what has gone before. There are always some who cannot do it. For ever IRA at the Good Friday table, there is a Continuity IRA who isn't. Human nature.
mydogsgotnonose, Don Pablo de la Sierra
Keep up the good work chaps, besides bringing issues to the forefront I for one am appreciative of your contributions. Believe it or not the lack of contribution from some of the 'old school' is starting to be noticeable, are we now in post normal blogging or is it the fact that the science is now being discussed rather than being stated?
As far as Tamsin and Richards contributions are concerned, the amount of insight into the science and the process is more than welcome and I think that more and more contributers here are becoming open to discussion rather than making statements, whichever side of the fence they sit upon. This can only be a good thing and I hope that as this process continues then more of the issues that seem too hot for the scientists to handle will become acceptable matters for discussion without fear of recourse.The process works both ways, even if there is a feeling that there are some area's that need 'explaining to sceptics' whilst other area's are definitely no go.
Maybe there are areas that need explaining to sceptics, maybe I don't understand anything, but some bloke saying he does understand and proceeding to insult my intelligence with an 'extra' eight watts which does not exist at least in that form, does not make me confident that there is not an attempt at deception.
If they are right, why do they need to cheat?
Pharos, that WSJ article is talking complete rubbish by the 3rd paragraph, so why would I trust any of the other conclusions.
The absurd idea that the Y2K bug didn't exist and $600bn was wasted fixing it is truly ridiculous. The Y2K bug was turned in to a non-event precisely because $600bn was spent preventing it.
I can assure you, and anyone else who was not a software professional in the late 90's, that a very detailed examination of all critical software was undertaken over a two year period and an enormous number of fixes were applied.
This indeed lead in part to the stock-market collapse of the software industry, as much of the 90's bubble was due to massive software expenditure leading up to 2000, which of course almost completely stopped after the event, as now nearly all systems were running up-to-date code that wouldn't need replacing for some years.
Since none of this information isn't freely available to the public, anyone who writes for the WSJ should be aware of it, and if they are not, why trust anything else they say?
@rickbradford
There have always been three components to scholarship: (1) research, (2) convincing peers of your results, and (3) informing the wider public. Newton's mechanics is much easier to explain to a lay audience than Higgs bosons; and in Newton's time the audience was much smaller. That is why science communication has emerged as (a) a teachable skill and (b) an object of study.
Don Pablo de la Sierra 7.33
If you have understood what MDGNN is on about, well done. It is not obviously nonsense and seems to make some sort of sense, but nobody other than you seems to have figured out what he's really saying.
"They do NOT want to understand." I think that is quite untrue - I believe that most people here would like to understand his ideas.
My own take is that perhaps he has worked out some sort of quantum coupling formulation that means he can compute correct answers without needing to invoke exchange of radiation in two directions at once. Or perhaps it's hogwash. Could be either from what I've seen so far.
Before you bugger off for good, why don't you do a favour to MDGNN and all of us by writing up his ideas in a form that someone with an elementary knowledge of quantum theory (1st year degree level, say) can make sense of?
To Don Pablo,
Please do not abandon this site. There are many more people who read and appreciate your posts than those who actually respond to them.
stevata
Thanks for your strong views on the Y2K issue, although it was not central to Lilley's article. I accept that IT software experts did a good job on truly critical software, and probably received inadequate public recognition for it. I can only relate to my own experience- I was a consultant in a US major at the time, and saw huge and wasteful overkill caused by management panic. Probably about 20% of their Y2K expense was on justified active systems replacements and fixes and 80% complete a complete waste of effort diverting every employee and consultant for weeks sifting through dormant archive 123 spreadsheets and the like deleting date cells. My son was an IT supervisor in a major engineering firm during the lead up to 2000 saying at the time there was huge overkill and unnecessary panic, so Lilley probably did have a point in alluding to the groupthink meme, at least in the view of those outside that particular groupthink bubble.
To Tamsin and Richard,
I very much appreciate your participation on this blog site. I don't know of anywhere else where scientists from the warmist camp will engage with sceptics actually discussing the science. Skeptical Science and RealClimate are heavily censored and littered with ad homs.
If I may criticise, I do feel that your posts tend to be heavy on diplomacy but light on content and reactive rather than proactive. As you are responsible for a major climate model I would like to see more comparisons of past projections with current outcomes, your views on temperature data adjustments, how you amend your models in the light of research findings regarding feedbacks, etc.
And you need to respond to difficult questions. As an example, a few topics back, Richard defended your past projections by claiming that periods of temperature stasis such as the last decade were permitted by the model and were within the model's error bars. This sounded lame at the time. Richard was challenged to produce a memo from the time of the relevant model run predicting the current temperature record as a likely outcome.
To MyDog,
I, too, would like to read a full exposition of your ideas. No doubt there will need to be much technical detail to satisfy the PhDs who will read it. So can there also be an English language version for non-scientists. There are a number of aspects of the "warming by back radiation" case which, to my mind, don't pass the "smell test" whereas, so far, your ideas seem to ring true.
Asserting, as you do, that the greenhouse effect does not exist, I can understand that you will find many of the discussions on this site futile and irrelevant because they are predicated on the greenhouse gas hypothesis. But perhaps you need to hide your exasperation and stay on topic. After all, we are all here and able to express our views thanks to the indulgence of the website host, Bishop Hill.
David, did mydog say greenhouse effect doesn't exist? Or rather that it isn't significant, the models make wrong assumptions and there is no back radiation. He is not saying that CO2 doesn't pick up IR and reradiate it. And thus he is not denying the effect.
I'm still waiting to see Richard's justification of his claim to have a prediction of the flat bit. Except if it amounts to the possiblity of drawing a line within the error bounds which is flat or declining, that doesn't seem like much of a trick, and would get easier the more error-prone the model. Anyway, let's take that run, or the nearest run to that, and throw away the rest?
I'm still waiting to see Richard's justification of his claim to have a prediction of the flat bit.
As I said earlier, RB has never specifically said that the models predict the flat bit. That's why I said he has used his political acumen to lead you by the nose. What he said was something along the lines of ' our models project periods of little or no trend followed by a strong recommencement of the upward trend later. His model predicted that most of the 10 years after 2009 would be records globally. That's why they have frantically revised HadCRU 3 to 4. They were then able to make 2010 the HOTTEST year ever, ever. Read very very carefully, several times if you have to.
You need to read very carefully, and with a political bent, to all that these people write. They are not the nice people they would have you believe. I am sure you could enjoy a nice meal and bottle of wine together but once back on the sunject of GW, listen carefully.
Their models predict nothing. They cannot predict La and El niña(o) a year in advance, accurately, they cannot predict solar actions, they cannot predict volcanos, they cannot predict the climate. They can only hindcast (predict backwards) when they have completed many runs with appropriate parametric adjustments at the beginning of each run until they get the answer they want and even then it is only reasonable close to the past. Once they have that, they claim that the model is right in the past and must therefore be right in the future.
@stephen richards
IIRC, RB's claim is that the recent decade+ of essentially static temperature falls within the error bounds publicly quoted for the model.
In that respect, I genuinely can't see what the complaint is in this specific case; if the temperature falls within the claimed bounds, it is trivially true that the model's prediction was correct.
What seems to be at issue is an understanding of what the prediction actually was in the first place - not your understanding of course, but the understanding of the general public, policymakers and the people who write the cheque to continue funding.
What it is difficult to get a handle on is how impressed anyone should be with the stated bounds in the first place, given the effort and expense involved.
Apr 12, 2012 at 7:33 PM | Don Pablo de la Sierra
Please can you tell me specifically which of my papers you have a problem with, and why?
Have you actually read a single one of my papers? I reckon not. In fact I doubt that you actually know anything at all about my own research. However, I'd be very pleased to see evidence to the contrary.
mrsean2k, I think we'd just like to see that result, to gauge what is trivially true and also what happens next in this truest of examples. Or, to put it another way, just how broad the bands are. Then we can come to some conclusion about this particular model and the value of post-predictions (predictions which were not declared at the time but have been found to have been made subsequently).
Perhaps I don't move in the right circles, but I haven't seen any short term predictions (projections?) telling me what will happen next after the flat bit. Will all the pent up heat rush out? Or will a slow increase resume?
mrsean2k why even mention "continued funding". Surely it's trivial?
I'd always assumed that "deniers" were unhappy at the apparently huge level of (ignorant?) public and political support for "warmism" rather than the cost.
Being critical of the cost of researching something when it's pretty carefully controlled, unlike, for example the cost of cancer research - which also has pretty widespread support from the public.
My personal take is that the science of climate change is pretty sound. It's bound to be, how to do all science is well understood and well taught in the better universities. Even the science of cancer research, for all of it's lack of real progress in finding cures, is also sound. Establishing what causes cancer - epidemiology - has been done successfully and usefully for decades, and can even be done when the actual mechanism is unknown. Though of course that was pretty useless research at first when trying to convince the wider public. As all it takes is one smart arse to say "but you've no idea how smoking causes cancer" and millions die for no good reason.
Apr 13, 2012 at 5:43 PM | stephen richards
Sorry, have we met? I am trying to think of the time when we met in person so you could judge whether I am a nice person or not.
Or are you simply someone who makes up their mind about individuals in advance, just because they are part of a group of people that you have simply decided you don't like?
There are very few people who I would call a "denier", but I'm afraid that your sheer unwillingness to see past your own pre-conceived ideas and have a constructive dialogue makes you a candidate for that category as far as I'm concerned.
stephen sniped - "they cannot predict solar actions, they cannot predict volcanos"
Can they at least predict exchange rates, car crashes, spread of disease, election outcomes, murders, rapes and lost keys? Or can't they do these things either? Blimey, what a waste of public money! (on your education - or did your parent pay? Oh, how sad that would be)
Rhoda, I accept what you say. My usage of the term "greenhouse effect" was meant to convey more than just that GHGs absorb and re-emit radiation, but also that this radiation warms the surface of the earth. As I understand it, it is this last bit which MyDog disagrees with. I think he is claiming that the radiation from the surface and within the atmosphere has 2 components : (i) radiation which is flying around in all directions at all points in the troposphere and at the surface and which all cancels out thereby not affecting the surface temperature, and (ii) a net flow upwards which is the same as would be the case if there were no GHGs. Scientists only believe that downward radiation from GHGs warms the surface because they point their instruments upwards so that the detectors are shielded from the complementary upward radiation. There is no empirical evidence that back radiation actually causes warming.
MyDog, have I got that right ?
My stance is that I would like to read more of the science behind this idea, favourable and critical, particularly regarding what happens at the molecular level at the surface of the earth. But even if MyDog were wrong, the current CO2 paradigm fails on its own terms. The model predictions are hopeless, probably because the water vapour feedbacks, cosmic rays and ocean oscillations are modelled incorrectly or not at all.
This is why communication with Tamsin and Richard is so important as they run one of the major climate models. They can provide us with insights, justifications and falsifiable predictions. We will give their ideas a lively examination and provide feedback.
Hi Rhoda
Thanks for your question, sorry to take so long to answer (I'm on holiday, and only dipped in here briefly because I saw Tamsin tweet about this post about her!)
mrseak2k is correct that my point is that the observed temperatures are within the noise of variability so are therefore within the projections from the models. See this paper for more details.
Our forecasts for the next decade are here. Again, please note the wide error bars, but also note that the lower limit still implies a resumption of warming relative to the last few years (but with one caveat being this this assumes no major volcanic eruptions like Mt Pinatubo in 1992, which cooled the planet for a couple of years).
Cheers
Richard
@ Apr 12, 2012 at 10:42 PM | KnockJohn
part of your comment, especially i agree with
re-
"I, for one, am grateful that Tamsin and Richard are making strides towards greater communication and greater understanding of the sceptical understanding of the science of climate change. I HOPE that this may lead to better science."
as a layman I visit all the usual Climate & related blogs for info & food for thought, so i appreciate input/ideas from both sides on one site, but realise most blogs are one sided (the nature of the game).
i think what Bish is doing (my thoughts only) is trying to encourage/enable input/ideas from both sides.
that can only be for the good, and am puzzled by comments from long time valued (by me) commentators who would abandon the blog because of this.
ps. no matter the CO2 scare we need to understand the planet/weather/geo etc anyway, so don't throw the baby...
I do feel genuine sympathy for Tamsin. Her current blog thread on communication has kick started again but is getting comprehensively carpet bombed by a Wiki edit climateer before she even has a fighting chance to engage with her reasoned and civil reflections. Rather unhelpful but predictable.
Any new venue immediately becomes a battleground for who will finally hold the fort. For this phenomenon to break out, the host should be reasonably well-known and nominally neutral. We've seen the same in Keith Kloor's blog, Bart Verheggen's blog, Judith Curry's blog, and now Tamsin's blog. It is the same story over.
It is also interesting to note how elaborately systematized the purported objections to the Hockey Stick Illusion book are.
The heavy burden of consensus baggage.
Richard,
Your paper link is not correct ' page not found' error.
@michael
I'm having trouble seeing the relevance of most of your reply to my post.
My reference to "trivial" isn't that the derivation of the prediction is a trivial exercise or that the prediction itself is obvious - I make no comment on that at the moment. It's merely that the prediction is by definition correct if the measured values then fall within the stated bounds.
As @Rhoda alludes, whether or not we should count that as something worth the effort is more difficult to resolve.
£60m may be counted as loose change in these circles. It seems like a decent wedge of money to me, and it's certainly garnering a good deal of hyperbole and publicity. My cynicism in this instance derives from the timing of the announcement and my interpretation of the stated purpose of the funding - to mine for a link between human activity and disaster.
The press release is around 50% notes of caution, qualification, ambiguity and getting-your-excuses-in-first, but manages to leave a somewhat different impression.
On a more general note, I'd still like a handy guide that explains the difference between a prediction and a projection. It appears to me that a projection is thrown around with authority as if it was a firm prediction, right up to the point where it is put under pressure, where it becomes a more fluid and forgiving concept.
Apr 13, 2012 at 7:12 PM Michael
You are joking, right?
Michael, what's your background? Not physics or any other hard science, I would hazard a guess.... "Better universities" such as UEA, perhaps?
Michael, what's your background? Not medicine I would hazard a guess... Progress in finding cures has been truly collossal.
Richard,
Your paper link is not correct ' page not found' error.
Apr 14, 2012 at 8:19 AM Lord Beaverbrook
This may be it:
http://www.agu.org/journals/jd/jd1122/2011JD016263/
Martin, I chose deliberate to come here NOT to show how clever I am. In issues like this it has no real value despite assertions by some that they might be convinced if personally schooled by some all knowing genius. Hence my background is irrelevant. This might seem silly, but given how easy it is to find stuff out on the internet, anyone asking that question of me can't be the sharpest tool and I don't wish to appear a (complete) bully.
I strongly believe that much science can be understood and usefully employed by those of average or lower intelligence - that's true, I really do.
Back to searching the internet. Ever tried googling "cancer cure"? Or asking your doctor for one?
Of course cancer is MUCH better understood today and that understanding advances rapidly. Understanding of climate denialism will no doubt advance too - I'm fairly sure it's heritable.
mrsean2k - this might be related to some of the above. Why ask me for "a handy guide that explains the difference between a prediction and a projection" Or was that not directed at me but thrown out more widely? As someone will no doubt figure out "what" I am, it probably won't hurt to say, for my personal purposes - computers make projections, people make predictions. Depending on your own circumstances something more formal might be required if you want to reference it rather than quote some hearsay from a comment on a blog. In which case http://www.ipcc-data.org/ddc_definitions.html should do the job nicely.
You see I can be helpful, but NEVER trust me to be so. I'm much happier showing how stupid others are than boasting how clever I am. But there are oh, so, many stupid people in the world, and so little time.
As for funding. Should research in all controversial matters be denied funding? Stem cells, GM, fracking, space travel, HIV.... OF BLOODY COURSE NOT!
Apr 13, 2012 at 9:57 PM | Registered Commenter Richard Betts
Richard, two out of three of the forecasts you linked to (commencing 1985 and 2005) wandered "way high" towards the latter part of their course (although the 2005 prediction still has some way to run). The middle forecast was more consistent with observed temperatures but only, I would suggest, because of the still-unexplained (as far as I know) step rise leading to the ongoing temperature plateau since the fierce 1997/8 El Nino (remember it well).
So my question is: How can the very steep rise in the new prediction possibly be justified, when the graph suggests that a rise of that magnitude, in 8 short years from now, would be unprecedented relative to observed temperatures since 1950? The forecasts were previously inaccurate two out of three times. Why should we place any reliance on the new one?
@Michael
Thanks for the link. The casual ad-hom not so much. Hey ho. Again I find a good chunk of your post is composed of your own strawmen - these need no response. We can have fun enumerating them later if you fancy it. I know exactly what you are in some detail, but rest assured I don't care and won't let that colour my responses.
The question was gently aimed at Richard but he generally has enough on his plate with slightly more aggressive challenges, so I prefer not to prod directly.
Although I "defend" his reponse in this case, it would be a lot easier and more accurate for him to assert when challenged that the model didn't predict it - as it is not in the business of making predictions. Of course he may then find himself explaining why he believes the prediction / projection distinction doesn't matter in this particular case.
It would be in everybody's interest if the taxpayer, politicians and decisions makers at all levels understood that climate models generally do not make predictions. Except perhaps when it comes to additional funding.
When it comes to awards for the most stupid comment on a blog then this has to be on top of the nominations!
Lord B
For a laugh, you have to try hard to better:
"I strongly believe that much science can be understood and usefully employed by those of average or lower intelligence - that's true, I really do."
But in fairness, the thread has descended a bit into a Richard / Tamsin kicking and he's only doing his best to draw a bit of fire.
Understanding of climate denialism will no doubt advance too - I'm fairly sure it's heritable.
Are Political Orientations Genetically Transmitted?
Clearly more research is required. Anyone here got a twin?
mydogsgotnonose (Apr 12, 10:32 PM): Tell me how I get to the discussion post....
Martin A (Apr 12, 11:21 PM): http://www.bishop-hill.net/discussion/post/1784066
But no appearance. Is our canine still having trouble finding the way?
@Michael
You are Richard Bett's evil twin and I claim my £5.
"he's only doing his best to draw a bit of fire" You think?
What else might I be doing? Come, on, take a guess. Is it really that hard?
"You are Richard Bett's evil twin and I claim my £5." Close, but sadly no cigar.
"It would be in everybody's interest if the taxpayer, politicians and decisions makers at all levels understood that climate models generally do not make predictions. Except perhaps when it comes to additional funding." They (implicitly) do.
In several years doing what I do, where I do it, I've never heard of a request being made by a member of any of these groups for a model to explain a prediction. The request is always for a person to explain. Shame really, when we're so very close to intelligent machines outnumbering intelligent people.
@michael
"What else might I be doing?"
I don't know, overdosing on self-importance.
As I say, I know exactly who you are and what you do. Are you looking for the readers to gasp at the reveal and change their positions? Rest assured I don't feel bullied or intimidated by self-praise.
"Are you looking for the readers to gasp at the reveal and change their positions? Rest assured I don't feel bullied or intimidated by self-praise."
Of course not. I don't believe reasonable, and probably not possible, to change such traits.
Anyway, some of my best friends are deniers. We seem to get along because I don't take myself too seriously, I don't try and turn them, and they don't drag me to denier bars.
Hey, where are those denier bars? Now that's what I've been missing. Josh, you must know - but you never told me about the denier bars. This is serious :)
Stop jabbing your rapprochement in my face, it makes it difficult to remain soundly irked. You go in the book alongside Betts.
Anyway, somewhat on-topic again, do you have a written example that you'd say is an exemplar for communicating this sort of (un)certainty to purse-string-holding audience?
This isn't a jibe, I'm genuinely interested. In every situation I've been involved in where funding is at stake, it's been a balance between equivocating enough to remain honest and asserting strongly enough to make the case.
To Richard Betts:
For context please see my comments and questions above, Apr 14, 2012 at 11:21 AM
I have since come across these comments of yours on the Questions for the UKMO thread:
Hi Green Sand
The red plumes for 1985-1994 and 1995-2004 are hindcasts - ie: done recently (in 2005) but starting from 1985 (or 1995) initial conditions as if they were forecasts, in order to test the model. As you say, they did OK except for the 1992 eruption of Mt Pinatubo (which would not have been known about in 1985 so was excluded from the hindcast) and the 1998 El Nino. The only actual true forecast in the ref plumes is the 2005 one.
You are right that others have been done starting at other years since 2005 (you found the 2009 one) but by definition they have had even less time to be compared to observations (since they are more recent) so the 2005 forecast remains the best one for testing "out of sample", ie: the one that was actually done as a forecast, not a hindcast, with the longest overlap with observations.
Cheers
Richard (Mar 3, 2012 at 12:07 AM | Richard Betts)
This is the wording that accompanies the forecast graph:
Figure 1: Observed (black, from Hadley Centre, GISS and NCDC) and predicted global average annual surface temperature difference relative to 1971-2000. Previous predictions starting from June 1985, 1995 and 2005 are shown as white curves, with red shading representing their probable range, such that the observations are expected to lie within the shading 90% of the time.
Previous predictions, Richard? The model couldn't even emulate the temperature curve/meanderings with the benefit of hindsight, although sportingly Mt Pinatubo "which would not have been known about" was excluded from the parameters. The wording to the graph is just a tad misleading, don't you think? Time for an amended description, perhaps?