Bishop Hill Conveying truth
Jan 4, 2012 Climate: Surface I had an interesting exchange with Doug McNeall on Twitter yesterday. Doug is a statistician at the Met Office and an occasional commenter here at BH. We were discussing how scientists convey uncertainty and in particular I asked about a statement made by Julia Slingo in a briefing (warning 10Mb!) to central government in the wake of Climategate:
Globally, 17 of the warmest years on record have occurred in the last 20 years.
This statement was made without any caveats or qualifications.
If I recall correctly, I've posted on the briefing paper before, so for today I just want to concentrate on this one statement. I think Slingo's words represent very poor communication of science since they do not convey any uncertainties and imply to the reader that the statement actually means something. There is, of course, a possibility that it signifies nothing at all.
By this I mean that the occurrence of the 17 warmest years on record could have happened by chance. Doug and I agree that this is a possibility, although we differ on just how much of a possibility. Doug assesses the chances as being very slim based on comparison of the temperature record to climate models. I don't see a problem in this per se, but I think that by introducing models into the assessment, certain things have to be conveyed to the reader: the models' poor performance in out-of-sample verification, our lack of knowledge of clouds, aerosols and galactic cosmic rays, and the possibility of unknown unknowns being obvious ones. Doug reckons our knowledge of clouds and aerosols is adequate to determine that that the temperature history of recent decades is out of the ordinary. This is not obvious to me, however.
But more than that, is the very fact that we are having to introduce models into the equation needs to be conveyed to the reader. Were our knowledge of temperature history better, we would be able to show based on purely empirical measurements that the temperature was doing something different in recent decades. That we cannot do so needs to be conveyed to the reader, I would say.
My challenge to you, dear readers, is to convey in, say, four sentences, the state of the science in this area. (We will take it as given that it is reasonable for Slingo to convey the basic statement about recent temperatures that she has chosen to do. If you feel otherwise, feel free to make your case in the comments.)
Reader Comments (125)
My instant reaction — and with a bit more time later in the day I may have another think — is why she bothered making the statement in the first place.
What does it mean? Why is it important that the layman (or anyone else for that matter) knows that 17 of the warmest years on record happened during the last 20 except as an interesting factoid? To which aspect of our lives is the global temperature relevant? What is anyone supposed to do with the information? Is it reliable (setting aside your comments about the use of models) enough to form the basis for ...... anything?
And then ... how long is this "record" she is quoting from? Are the figures robust enough to be worth publishing? How good are the data?
According the UAH data, 2011 was the 4th coldest year this century!
From these two tiny fragments of bone our scientists have been able to recreate the entire Gigasaurus.
The statement "17 of the warmest years on record have occurred in the last 20 years" is a deliberately misleading statement of the same calibre as the "97% of scientists believe........" statements; it is a standard weapon in the climate alarmists' armoury.
It is used to con the target audience - regular people who do not have the time or the incentive to research or test AGW claims and may still have some trust in climate scientists - into believing that we are in the midst of a global warming crisis.
An honest statement would acknowledge that the"record" is the instrumental temperature measuring record starting around 1850 (although I have sometimes seen the "record" refer to the much shorter satellite data record).
An honest statement would also acknowledge that the recent (i.e. the last 150 to 200 years) warming is the natural consequence of the world's emergence from the Little Ice Age which was the coldest period in the Holocene (or the last 11,000 years).
Globally, 17 of the warmest years on record have occurred in the last 20 years. This confirms the climate's continued gradual rebound from the cold climate experienced during the Little Ice Age during the 18th century.
It says nothing about temperatures in the near future -- scientists are divided over whether we are on the verge of returning to a cooler natural climate phase or whether gradual warming will continue
Globally, 17 of the warmest years on record have occurred in the last 20 years. Which could be considered as perfectly normal attribution for the high point of combinations of multi-decadal natural cycles. Any underlying linear trend will become apparent from accurate data covering several cycles which will then allow models to hind cast past, pre-modern era climate, and forecast future trends with some level of accuracy. This eventuality is still some decades away from being realised even with modern computing power as it is the accurate data that is required to derive the trends.
Don't forget this BBC story
http://www.bbc.co.uk/news/uk-16366078
"2011 is UK's second warmest year on record - Met Office"
Globally, 17 of the warmest years on record have occurred in the last 20 years. However 'global temperature' is itself a meaningless construct, given the paucity and unreliability of data, particularly in regards to the southern hemisphere, so we should take neither caution nor comfort, in fact nothing at all, from this statement.
"Global average temperature" may be sensitive to the warming from extra CO2. Breaking it down a little, the warming is generally more noticeable in cold and dry locations like Siberia. But even in those individual locations, it has been warmer in the past (e.g. Greenland has been much warmer in the past thousands of years). Also the increase in an abstract average temperature has no direct impact on weather and the decrease in extremes (from warming of colder locations) should lead to less violent weather.
It is the verbal equivalent of 'Hide the Decline' to disguise the 21st century's plateauing of global average temperature. It is clear that rather than objectively analysing and interpeting data with open minds, the climate community devotes most of their effort in searching for persuasive soundbite phraseology and suitably dramatic visual props to preach the message to the masses. It is a consequence of the political hijacking of science to promote an agenda.
'We can see no justification for an IPCC procedure which strikes us as opening the way for climate science and economics to be determined, at least in part, by political requirements rather than by the evidence. Sound science cannot emerge from an unsound process' (House of Lords 2nd Report of Session 2005-06 The Economics of Climate Change)
Put it this way....
Last August was one of the coldest on record.....
If it had been one of the warmest, we woulhd have heard a lot more about it....
-warmest or coldest, proves nothing anyway, either way...
Alan Reed
"From these two tiny fragments of bone our scientists have been able to recreate the entire Gigasaurus."
Spot on for me!
2011 was the second warmest year in the CET record. That is a fact but none of the months were particularly warm or cold. The summer was below average in temperature with April and November much warmer than usual. These had the effect of making the year so warm. The CET annual average is in fact very sensitive to winter temperatures, with winter months showing the largest range in temps. Summer months show much smaller ranges. Over the 350 years there has been a trend in winters getting warmer and some warming in spring and autumn. However summer ave temps have shown virtually no change in 350 years and Junes have actually shown a cooling trend. The entire change in the record could be accounted for by increasing cloudiness which could be accounted for by an increasing frequency of westerly winds. I keep an extensive database of CET figures.
As a Chartered Engineer I do have a little issue with computer models! Was it not computer modelling that allowed us to be transported to a galaxy far, far away, a long time ago, on numerous occasions? Was it not computer models that transported tyranical creatures from 65 million years ago to modern days? Was it not computer modelling that produced all these wonderful effects to feed our imagination & fool our minds, even if only for a few hours? On a more serious note, in reference to modern day computer power, as an engineer I can safely say that if you get the design philosophy wrong, no amount of computing power will get you out of the Sh1t, you just get there that much faster! Also computer models are infinitely tunable & you can get any answer you want out of them. @ George Lloyd, was not the Younger Dryas the coldest event rather than the Little Ice Age?
most of the earths heat energy lives in the oceans. water has large thermal inertia. the 1998 super el Nino explains the warming over the last 20 years or so. surface temperatures follow the oceans. QED
of course this does not explain heating of oceans but my mum says it's the big orange ball of fire in the sky.
Interesting discussion, and my first comment here. I will think about the 4 sentences later, but I think the CET points are particularly relevant.
For CET we do have a long enough record to better estimate the natural variability empirically from observations alone, without using climate models. This may not be the case for global temperatures as Bishop Hill describes. But, when we compare the fluctuations in observed CET with the natural variability for the same region from a climate model we get an encouraging answer:
http://www.met.reading.ac.uk/~ed/blog/2011/trends-in-cet/
The comparison is not perfect, and this alone tells us nothing about global temperatures, but at least the magnitude of natural variability in CET appears broadly right in at least one climate model....
Prof Slingo, like others at the Met Office, assumes she knows that human emissions are causing the current warming, so proof for her that humans are causing warming is that it's warming.
Depends on which data T sets you set store by.
The T rebound from the LIA has been bountiful but it won't last, exaggerations about it being the warmest, decade, year, period - are just that, it is not possible to make that assertion, however since the El Nino year of 1998, temperatures have flatlined and are marginally but perceptibly declining. We can say, in the geological past, with reference to; stratigraphy, lithology and the fossil record: it probably has been MUCH warmer than the present day world average T's.
Alan the Brit wrote:
"@ George Lloyd, was not the Younger Dryas the coldest event rather than the Little Ice Age?"
I believe the Younger Dryas was immediately before the Holocene (between 12,800 and 11,500 years before present whereas the Holocene commenced about 11,000 years BP).
Nevertheless, the Younger Dryas, otherwise known as the Big Freeze, was bloody cold at the start although it warmed up quite a bit in the transition to the Holocene - following quote from Chapter 2 of the Arctic Climate Impact Assessment Report, 2004 (http://www.acia.uaf.edu/pages/scientific.html):
"the return to the cold conditions of the Younger Dryas from the incipient inter-glacial warming 13 ky BP took place in less than 100 years. The warming phase at the end of the Younger Dryas, which took place about 11 ky BP and lasted about 1300 years, was very abrupt and central Greenland temperatures increased by 7 oC or more in a few decades."
In isolation, this statement would be frightening and persuasive to the uninformed and that is the intention.
Unfortunately, the majority of the people that I know would accept it at face value.
Those of us who follow the debate recognise a sound bite when we here one.
I do not think that we know what it implies, and it may well be of mo real significance whatsoever..
What would be interesting is if we were to do a similar assessment say in 1900 or in 1870 or in 1837 how many of the warmest years would have occured within the prior 20 years. In other words, is what we are see now rather unique or has it previously occurred.
If in such an assesment one see 15 or 16 or 17 of the warmest years having occurred in the prior 20 years (ie., 1881-1900, or 1851-1870, or 1818-1837 etc), I think that we can conclude that there is little significance in the observation, or at any rate no cause for alarm.
We a gradual rebound from the LIA, I expect something similar has been observed in the past.
Assumming the statement is correct then Slingo should have said:
"Globally seventeen of the the warmest years on record occurred in the last twenty years however the record is only 150 years old and hence this is of no statistical value as there are no temperature records going back three hundred thousand years."
I forgot to mention that everyone should read Chapter 2, "Arctic Climate - Past and Present," of the Arctic Climate Impact Assessment report (http://www.acia.uaf.edu/PDFs/ACIA_Science_Chapters_Final/ACIA_Ch02_Final.pdf) particularly section 2.7. "Arctic climate variability prior to 100 years BP," commencing on page 46, which puts the whole mess into a historical perspective and has been a major factor in the formation of my sceptical views (forget the rest of the report - it is largely alarmist BS).
The other day I was thinking it was time for a "Where are they now?" section. I was wondering about Slingo amongst others.
I thought that Julia Slingo had eventually ealised what an ass she was (or had it impressed upon her) and that she was no longer allowed out alone. Nice to see that is still the case.
But why does she still have a job?
If you measure the height at the top of a hill, take a few steps away and measure the height again you will get another pretty high measure. Take a few more steps away and similarly. Maybe auto-correlation and the inherent lack of independence is lost on some?
If I believed that "17 of the warmest years on record have occurred in the last 20 years", then I would rejoice in the wonderful conditions we are living through - warmth and lots of CO2 to make my garden grow. As I don't believe the statement, then I treat is a what it is, namely just Met Office alarmist propaganda.
I have been lazy and picked my four sentences from a paper I have started to study this morning as part of my ongoing struggle to try to make sense of the physics of the CO2 scare. My poor old brain has been unhelpful about this for a while since I had promised it more time on gardening etc, and is not making huge progress other than to note that whatever it is that is agitating the CO2 alarmists so greatly, it has not been enough to agitate the climate in ways we can convincingly detect.
So here are 'my' 4 sentences, marked [S1], [S2}, etc:
'[S1] Recently, Gerlich and Tscheuschner listed a wide variety of attempts to explain the so-called atmospheric greenhouse effect. [S2] They disproved these explanations at the hand of fundamental physical principles like the second law of thermodynamics. [S3] By showing that 1) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, 2) there are no calculations to determine an average surface temperature of a planet, 3) the frequently mentioned difference of 33 K is a meaningless number calculated wrongly, 4) the formulas of cavity radiation are used inappropriately, 5) the assumption of a radiative balance is unphysical, 6) thermal conductivity and friction must not be set to zero, they concluded that the atmospheric greenhouse conjecture is falsified.
...
[S4] Based on our findings, we argue that 1) the so-called atmospheric
greenhouse effect cannot be proved by the statistical description of fortuitous weather
events that took place in a climate period, 2) the description by AMS and W•MO has to be discarded because of physical reasons, 3) energy flux budgets for the Earth-atmosphere system do not provide tangible evidence that the atmospheric greenhouse effect does exist.'
Source: Kramm and Dlugi ‘Scrutinizing the atmospheric greenhouse effect and its climatic impact’ (http://www.scirp.org/journal/PaperInformation.aspx?paperID=9233)
(hat tip: Greenie Watch, http://antigreen.blogspot.com/2012/01/carefully-reasoned-new-paper-finds-no.html#links)
Surely this assertion:
implies that we know enough to adequately predict the temperature trends of the last decade.
But we didn't - or at least the IPCC modelling didn't, something that is plain to see from Lucia's ongoing analysis.
So the chance of observing depends on the covariance structure. Did you ask Doug if he had estimated said structure? Please ask him if he has any jobs would you, but I'm not about to compromise my scientific integrity?
Well spotted Bish. It's exactly the point that I mentioned in anger to Richard Betts. They are not behaving like scientists so why should we treat them like scientist?
Love your site.
I would say: "Globally, 17 of the warmest years on record have occurred in the last 20 years. This may be just chance (but that is not likely), it may be because natural climate cycles have peaked together, it may be because of the increased CO2 in the atmosphere, or it may be because of some combination of all these factors and maybe others we have not thought of at all. We shall wait and see"
Of course if you don't actually include what Slingo said then the task is trivial - you can say whatever you like. And most of your commenters did.
The sea is out and you begin to record the tide mark every 5 mins. After several hours you notice that the last 17 measures have all been the biggest. What is the probability?
The record period has already been mentioned - but which record are we talking about? There are records which have been adjusted so much that CRU have lost the original data, records where pre 1970 gets progressively colder and post 1970 gets progressively warmer. What are the assumptions underlying the evaluation?
I could go on but this is an unsubstatiated soundbite for the Biassed BBC not a scientific statement.
How about this (OK, I cheated by making some of the sentences long-ish):
"Globally, 17 of the warmest years on record have occurred in the last 20 years. This recent period is thereby slightly warmer (by 1 degree C or less) than other periods in the 150 years in which records are available. Computer simulations that model temperatures based on the physics of the atmosphere suggest that some of the current warmth is man-made, caused by emissions of greenhouse gases. However, many parameters in the computer simulations are not well known, and it is also possible that a large part of the current warmth simply reflects natural variability."
Globally, 17 of the warmest years on record have occurred in the last 20 years, which you would expect as we come out of the little Ice Age. The global warming scare is based on computer models that cannot calculate the present from past data. Blaming an increase in CO2 as the cause of present warming is as redundant as blaming an increase in the number of cathedrals for the Medieval Warming.
Make that 'for present warming'.
The statement in the document is in fact
The statement just needs to be translated. As Pharos says, it is an admission that global warming has stopped. Without this translation, it is an attempt to mislead readers. A similar attempt to hide the decline in warming is figure 3 of the same document, where the 'scientists' have put recorded temperatures into ten-year bins and plotted them as a bar chart. These two tricks (the n warmest years have all occurred in the last m years, and plotting temperatures as decadal bar charts) have only been introduced in the last few years to hide the slowing down of the warming - you won't find them in documents written 10 years ago such as the IPCC TAR.
My 4 sentences would be
1. The average global temperature rose by about .7C during the 20th century.
2. There is no evidence that this temperature rise or the rate of rise is in any way unusual.
3. Warming has slowed over the last decade or so.
4. 'Climate scientists' have employed a variety of misleading tricks to try to hide this slow-down.
The difficulties of defining what is meant by global temperature aside, I think Jeremy's shot is the best one so far for any prize the Bish has in mind.
I wonder if there is any equivalent of Prof Sligo from the Mevieval Period, when she might well have made a similar claim. I'd guess she'd have been an abbot running a studious monastery, tracking the seasons. If this abbot had associations with some doomsday cult (of which there were several in Eruope alone), then so much the better.
See Cohn's book (The end of the millennium has always held the world in fear of earthquakes, plague, and the catastrophic destruction of the world. At the dawn of the 21st millennium the world is still experiencing these anxieties, as seen by the onslaught of fantasies of renewal, doomsday predictions, and New Age prophecies. This fascinating book explores the millenarianism that flourished in western Europe between the eleventh and sixteenth centuries. Covering the full range of revolutionary and anarchic sects and movements in medieval Europe, Cohn demonstrates how prophecies of a final struggle between the hosts of Christ and Antichrist melded with the rootless poor's desire to improve their own material conditions, resulting in a flourishing of millenarian fantasies. The only overall study of medieval millenarian movements, The Pursuit of the Millennium offers an excellent interpretation of how, again and again, in situations of anxiety and unrest, traditional beliefs come to serve as vehicles for social aspirations and animosities.) for examples (http://www.amazon.com/Pursuit-Millennium-Revolutionary-Millenarians-Anarchists/dp/0195004566)
John Shade
Yes, I like Jeremy's take as well.
My four sentences:
1 The concept of a global temperature is meaningless.
2 Various instrumental temperature records are available (when not lost) from various sparse locations around the globe for about 200 years.
3 Data clerks (masquerading as "top climate scientists") have used that data and, by a process of cherry-picking, adjustment, interpolation, extrapolation and use of home-made statistical techniques, derived a meaningless global temperature graph which bears no relationship to the energy stored in the oceans and atmosphere.
4 The statement derived from the graph that "17 of the warmest years on record have occurred in the last 20 years" has no validity and is the sort of meaningless statement used by global warming advocates to frighten the public and politicians into "doing something very expensive" to "tackle dangerous climate change", whilst handsomely rewarding, at the taxpayers' expense, those making such a statement.
Fickle is my name. I'm now rooting for Paul's 4 sentences.
Great question Bish. I fully agree with Stephen Richards:
Not that I had the same conversation with the great Richard Betts (when all other tribalism has been forgotten, we Richards must stick together) but the anger I recognise. Slingo is not behaving like a scientist but a lawyer - and a lawyer representing a particular party in a dispute, not giving dispassionate advice to government. This is so far away from what a scientist should do in communicating with policy makers that Slingo should lose her job as an adviser to government merely for this statement.
What she should have said? As others have pointed out it should have included:
1. The record only goes back 150 years, in a period we are coming out of the Little Ice Age, so nothing can be deduced from 17 'warmest years' being recent ones. Nothing at all.
2. The difference between coldest to warmest is small (~.8 degC) compared to the projected increases in the next hundred years (~2-3 degC) that are said to spell danger - and that danger is far from proven. There is no evidence of an acceleration only a tailing off since 1995.
3. Claims that man emissions are the main cause of the rise since 1860 or 1945 are incredibly shaky. It may be true but it's currently established not by empirical evidence but by a show of hands of those involved in the IPCC. This isn't science.
4. Even if man's emissions are the main cause of the warming since 1945 there's no cause for concern. Deaths from extreme climate events have been coming down since the 1920s. There's no crisis.
OK, four paragraphs rather than sentences, without mentioning sensitivity (if the IPCC plays so fast and loose with Forster & Gregory they don't believe in it either). Science is being traduced and the consequences of that are going to be many, all of them bad. Like Stephen, I'm angry.
John Shade,
"I wonder if there is any equivalent of Prof Sligo from the Mevieval Period, when she might well have made a similar claim."
I see a script for Blackadder in the making!
I wince when I see this statement.
The whole "we're all doomed" narrative was based on the RATE of change of the temperature record, i.e. it's getting worse and we're causing it. Now, when this has patently failed to materialise, clowns like Slingo resort to this shameful statistical semantics whose only purpose can be to con a gullible public.
As many have said above, the statement "17 of the warmest years on record have occurred in the last 20 years", is totally consistent with a gentle warming from the LIA with no accelerated effect from CO2. It fails to say anything about the crucial RATE of warming and could even be true when this is negative (march to the top of a hill and start going down again)
Anyone who uses this phrase goes in the same bin as those who see nothing wrong with the Climategate files or "Hide the Decline": Their judgement is compromised and their opinion devalued.
Slingo should be called to account. Mr Stringer please confront her on this issue!
http://www.upi.com/Top_News/World-News/2009/12/10/Met-Office-denies-petition-pressure-claim/UPI-90021260465428/
http://www.metoffice.gov.uk/news/releases/archive/2009/science-community-statement
If structural engineers relied upon computer models that managed to give reasonable predictions of the average stresses in a proposed structure, but were poor at pinpointing where minimum and maximum stresses would occur, then few sensible people (or at least those who hadn't been flattened by falling buildings) would consider those models to be of much practical value. Why should we have any confidence in climate models that are poor at prediciting both the vertical atmospheric temeperature profile and temperature distribution across the planet's surface? The climate modellers have rather less understanding than they claim.
.... after we adjusted and manipulated the uncalibrated data, cherry-picked the sampling sites, and smoothed out the topography of the planet.
I used to run statistical quality systems in the Automotive sector. If i'd tried to initiate action involving monetary loss on a 0.6 deg C shift when 70% of my instruments had an Instrument error of up to 5 deg C (http://berkeleyearth.org/pdf/berkeley-earth-station-quality.pdf) I'd have been laughed at and told to f**k off. In all honesty the instrument ratings on the best weatherstations and satellite are about the same size as the 0.6 C we're interested, in so my summary would be :- " The earth temperature record lacks the measurement capabilities necessary for it to be used in monitoring climate change or for informing environmental policy making."
Four sentences: Since the earth has warmed for 200 or 300 years, one would expect the 17 warmest years to be recent, rather than in the distant past. The question is how much of that warming is due to natural causes and how much assisted by mankind's activities. The answer to that question is now more uncertain to climate scientists than it has been for awhile, as global temperatures have stabilized for a decade or more, despite carbon dioxide levels growing every year. A published article has demonstrated that increased uncertainty by summarizing opinions of various climate scientists, who attempt to explain why the earth has failed to warm as much as their models predicted.
http://pielkeclimatesci.wordpress.com/2011/10/27/candid-comments-from-global-warming-climate-scientists/
I can't believe anything Slingo says. When at Reading University she part-chaired the World Modelling Summit for Climate Prediction, May 6-9, 2008, and stated:
"We’ve reached the end of the road of being able to improve models significantly so we can provide the sort of information that policymakers and business require."
The press releases from her University and the Walker Institute stated
"Professor Julia Slingo, Founding Director of the Walker Institute, argues that the accurate climate change predictions required by society, from governments to insurance companies, cannot be supplied by the current generation of climate models or by the computing power currently available"
Two months later she moved to the Met Office where, within a year, she declared:
"...the Met Office has provided the world’s most comprehensive regional climate projections with a unique assessment of the possible changes to our climate through the rest of this century. For the first time businesses and authorities have the tools to help them make risk-based decisions to adapt to the challenges of our changing climate."
So in 2008 it was absolutely impossible, but by 2009 it was not only possible, but fully achievable a century out. Slingo had changed employers: in 2008, she was angling for lots more cash (we can't do it, so give us the money!); in 2009 she was trying to sell services (we can do it, so give us your money!). But surely no self-respecting scientist can prostitute themselves to tell completely opposite and mutually exclusive messages like that and still be expected to be called a scientist, can they?