Yesterday, the Daily Mail of the UK published a predictably inaccurate article entitled “Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995”.
The title itself is a distortion of what Jones actually said in an interview with the BBC. What Jones actually said is that, while the globe has nominally warmed since 1995, it is difficult to establish the statistical significance of that warming given the short nature of the time interval (1995-present) involved. The warming trend consequently doesn’t quite achieve statistical significance. But it is extremely difficult to establish a statistically significant trend over a time interval as short as 15 years–a point we have made countless times at RealClimate. It is also worth noting that the CRU record indicates slightly less warming than other global temperature estimates such as the GISS record.
The article also incorrectly equates instrumental surface temperature data that Jones and CRU have assembled to estimate the modern surface temperature trends with paleoclimate data used to estimate temperatures in past centuries, falsely asserting that the former “has been used to produce the ‘hockey stick graph’”.
Finally, the article intentionally distorts comments that Jones made about the so-called “Medieval Warm Period”. Jones stated in his BBC interview that “There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia” and that “For it to be global in extent, the MWP would need to be seen clearly in more records from the tropical regions and the Southern hemisphere. There are very few palaeoclimatic records for these latter two regions.”
These are statements with which we entirely agree, and they are moreover fully consistent with the conclusions of the most recent IPCC report, and the numerous peer-reviewed publications on this issue since. Those conclusions are that recent Northern Hemisphere warming is likely unprecedented in at least a millennium (at least 1300 years, in fact), and that evidence in the Southern Hemisphere is currently too sparse for confident conclusions. Mann et al in fact drew those same conclusions in their most recent work on this problem (PNAS, 2008).
Unfortunately, these kinds of distortions are all too common in the press nowadays and so we must all be prepared to respond to those journalists and editors who confuse the public with such inaccuracies.
Update 2/16/10. Phil Jones has confirmed to us that our interpretations of his comments in the BBC interview are indeed the correct ones, and that he agrees with the statements in our piece above. He and his CRU colleagues have also put up an response to some of the false allegations in a previous piece in the UK Guardian. We’ll report further such developments as they happen.
“But it is extremely difficult to establish a statistically significant trend over a time interval as short as 15 years….”
Only if you assume that 15 years means only 15 data points. However, the data showing no significant global temperature trend since 1995 is monthly data, and the P-value for trend with that data is nearly 0.5, which most definitely is NOT statistically significant.
Clear evidence that the MWP was a global event:
Here are a few papers from the ‘Southern hemisphere’:
(1) South Africa
The Little Ice Age and Medieval Warming in South Africa
P. D. Tyson1, W. Karlén2, K. Holmgren2 and G. A. Heiss3.
1Climatology Research Group, University of the Witwatersrand
2Department of Physical Geography, Stockholm University
3Geomar, Wischhofstr. 1-3, 24148 Kiel, Germany; present address: German Advisory Council on Global Change (WBGU), P.O. Box 120161, 27515 Bremerhaven, Germany, E-mail: g.heiss@gmx.de
Abstract
The Little Ice Age, from around 1300 to 1800, and medieval warming, from before 1000 to around 1300 in South Africa, are shown to be distinctive features of the regional climate of the last millennium. The proxy climate record has been constituted from oxygen and carbon isotope and colour density data obtained from a well-dated stalagmite derived from Cold Air Cave in the Makapansgat Valley.
The climate of the interior of South Africa was around 1oC cooler in the Little Ice Age and may have been over 3°C higher than at present during the extremes of the medieval warm period. It was variable throughout the millennium, but considerably more so during the warming of the eleventh to thirteenth centuries. Extreme events in the record show distinct teleconnections with similar events in other parts of the world, in both the northern and southern hemispheres. The lowest temperature events recorded during the Little Ice Age in South Africa are shown to be coeval with the Maunder and Sporer Minima in solar irradiance. The medieval warming is shown to have been coincided with the cosmogenic 10Be and 14C isotopic maxima recorded in tree rings elsewhere in the world during the Medieval Maximum in solar radiation.
(2) New Zealand
Evidence for a ‘Medieval Warm Period’ in a 1,100 year tree-ring reconstruction of past austral summer temperatures in New Zealand
Cook, E R | Palmer, J G | D’Arrigo, R
Geophysical Research Letters. Vol. 29, no. 14, pp. 12-1 to 12-4. 15 July 2002
The occurrence of the Medieval Warm Period (MWP) in the Southern Hemisphere is uncertain because of the paucity of well-dated, high-resolution paleo-temperature records covering the past 1000 years. We describe a new tree-ring reconstruction of Austral summer temperatures from the South Island of New Zealand, covering the past 1100 years. This record is the longest yet produced for New Zealand and shows clear evidence for persistent above-average temperatures within the interval commonly assigned to the MWP. Comparisons with selected temperature proxies from the Northern and Southern Hemispheres confirm that the MWP was highly variable in time and space. Regardless, the New Zealand temperature reconstruction supports the global occurrence of the MWP. (Author)
(3) South America (Patagonia)
Ricardo Villalba1, 2
(1) Department of Geography, University of Colorado, 80309-260 Boulder, CO, USA
(2) Present address: Laboratorio de Dendrocronologia, CRICYT – CONICET, Casilla de Correo 330, 5500 Mendoza, Argentina
Received: 22 September 1992 Revised: 27 October 1993
Abstract A tree-ring reconstruction of summer temperatures from northern Patagonia shows distinct episodes of higher and lower temperature during the last 1000 yr. The first cold interval was from A.D. 900 to 1070, which was followed by a warm period A.D. 1080 to 1250 (approximately coincident with theMedieval Warm Epoch). Afterwards a long, cold-moist interval followed from A.D. 1270 to 1660, peaking around 1340 and 1640 (contemporaneously with earlyLittle Ice Age events in the Northern Hemisphere). In central Chile, winter rainfall variations were reconstructed using tree rings back to the year A.D. 1220. From A.D. 1220 to 1280, and from A.D. 1450 to 1550, rainfall was above the long-term mean. Droughts apparently occurred between A.D. 1280 and 1450, from 1570 to 1650, and from 1770 to 1820. In northern Patagonia, radiocarbon dates and tree-ring dates record two major glacial advances in the A.D. 1270–1380 and 1520–1670 intervals. In southern Patagonia, the initiation of theLittle Ice Age appears to have been around A.D. 1300, and the culmination of glacial advances between the late 17th to the early 19th centuries.
Most of the reconstructed winter-dry periods in central Chile are synchronous with cold summers in northern Patagonia, resembling the present regional patterns associated with the El Niño-Southern Oscillation (ENSO). The years A.D. 1468–69 represent, in both temperature and precipitation reconstructions from treerings, the largest departures during the last 1000 yr. A very strong ENSO event was probably responsible for these extreme deviations. Tree-ring analysis also indicates that the association between a weaker southeastern Pacific subtropical anticyclone and the occurence of El Niño events has been stable over the last four centuries, although some anomalous cases are recognized.
[Response: Line up the peaks of these papers with the European ‘MWP’ peaks, and then explain how the same ‘event’ is hundreds of years different in different places. The problem is that people have had a tendency to claim that any warm period prior to the last cold period must be the ‘MWP’ without much in the way of proper comparison of actual timings. This is the same problem that was highlighted by Hughes and Diaz in 1994! – gavin]
Pete (351): Only if you assume that 15 years means only 15 data points. However, the data showing no significant global temperature trend since 1995 is monthly data, and the P-value for trend with that data is nearly 0.5, which most definitely is NOT statistically significant.
BPL: Since the proper scale for temperature trends is 30 years, using monthly figures artificially inflates your sample size. It’s like saying it’s risen 10 degrees C here from 6 AM to 9 AM. You can break that into 180 one-minute measurements and measure a highly significant trend. Extrapolating, the seas are going to boil in a few days!
Say what? The number of data points that are required depend on both the magnitude of noise and signal in the dataset.
“nearly” as in 95% confidence level.
Of course, Jones said it was just shy of the conventional 95% confidence level. The fact that it’s was close to that – 93%? 94%? – is suggestive. And itt’s not as if the 95% convention falls out of any fundamental theoretical theory of statistics, or anything else.
Don’t believe me? Read this.
Oops something got deleted …
If it were “nearly 0.5”, i.e. 95%. Not what you meant to say.
Eh, “<” and “>” were getting eaten.
On least try:
If it were “nearly 0.5”, i.e. < 0.5, the confidence level would be greater than 95%, not what you meant to say.
Mr. Ladbury:
Sorry for getting your name wrong (a Blackberry can sometimes make it difficult).
And thank you for your comments. Giving me something to think about.
Pete28, You do not in any way increase statistical significance in going from yearly to monthly data, because monthly data are strongly autocorrelated. Take that into account and you will find that you get about the same significance as for yearly data.
After all, if you are talking about long-term trend, it would be silly to presume that monthly averages contained information that yearly averages did not.
BobFJ,
The question of credibility can be a subtle one in science. However, in the case of MicroWatts, it’s pretty simple. The question is simply if a person repeatedly demonstrates themselves unable to separate good science from lunacy or to draw the correct interpretation from scientific papers, then how are they going to know who is doing good work and who is not?
In other cases, the question is more subtle. Would you trust the opinion of a scientist with a strong publication record but who had an agenda over one with solid but not brilliant publication record who was known by all as a solid broker?
Even presuming one was unfamiliar with Watts’ penchant for publishing absolute crap on his blog, there remains the question of why a journalist would turn to a scientifically illiterate former TV weatherman rather than a dissident scientist for sources. I mean a quick perusal of the Wall Street Urinal editorial pages would have quickly produced the names of Lindzen, Christy or Spencer, all of whom at least have a publication record relevant to the subject. As it was, BBC wasted an opportunity to ask real “tough questions” rather than dwelling on irrelevancies.
BobFJ says: 19 February 2010 at 6:35 PM
“What do you think?”
I think that physics and mathematics are oblivious to the BBC. Whatever inconsistencies and errors may lurk in our understanding of climate will inevitably be revealed by researchers plugging away in the field. The more empirical observations swerve from theory, the more curious researchers will become about this topic and the more effort they’ll devote to satisfying their curiosity.
I also think that for whatever reason you appear to be thoroughly intrigued and even perhaps delighted by what you perceive as a change in the public relations climate between journalists and the subjects of their reporting. I don’t know why you’re relentlessly trying to involve me in your fascination, it should be fairly obvious by now that I’m simply not interested.
Jerry, Ray works just fine as a handle for me. Shorter to type, too. Always keep thinking.
Gavin —
Re 352 Ken Lambert: “Line up the peaks of these papers with the European ‘MWP’ peaks, and then explain how the same ‘event’ is hundreds of years different in different places. The problem is that people have had a tendency to claim that any warm period prior to the last cold period must be the ‘MWP’ without much in the way of proper comparison of actual timings. This is the same problem that was highlighted by Hughes and Diaz in 1994! – gavin]”
Perhaps you can clarify how the examples cited by Ken Lambert support your comment.
MWP roughly 950 – 1250; i.e., 10th – 13th centuries
The examples cited:
Patagonia: warm 1080 – 1250
New Zealand: “clear evidence for persistent above-average temp within the interval commonly assigned to the MWP”
South Africa “may have been over 3 degrees C higher than at present during the extremes of the medieval warm period,” specifically 11th – 13th centuries.
It seems to me that they overlap, and there are not hundreds of years difference.
Are you disagreeing with their conclusions, their data, or their interpretation of the data?
[Response: If you define the MWP so widely as to include all the various peaks, you’ll find that the average signal smears out since the peaks in the different records are not two hundred years long in general. For instance, one of the most common ‘MWP’ records brought up – the GRIP borehole record – peaks between 800-1000 AD. The Osborn and Briffa paper has more examples. Thus putting it together you end up with a broad period that is warmer than the later centuries of the Little Ice Age, but that doesn’t stand out as much as you see in any individual record. And for any particular 50 year or 100 year period, you get a lot of structure in the reconstructed temperatures (Mann et al, 2009). Specifically, you can’t find a particular 50 or 100 year period where all records are ‘degrees’ above their baseline. – gavin]
Sou; You wrote in part in your 340/p7:
Well as you should know by now, Jones was not trapped in a verbal face-to-face, but responded over an extended written exchange via the UEA Press Office, and thus he had plenty of time to think and to consult colleagues. Have you actually read all of the Harrabin questions rather than the brief paraphrased extracts in the lead article?
Here for example is question A
A – 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?
Is that a silly question, and if so, why? What about the other 17 questions? Which of them are silly, and why?
Q & A: http://news.bbc.co.uk/2/hi/science/nature/8511670.stm
Dhogaza; You wrote in part in your 349/p7
Could you run that by me again please? Are you suggesting that he should NOT give an honest reply, in fear of misinterpretation, despite that he had time to consult with colleagues etc. for a written response. But, anyway, see next item:
You also wrote:
What you (and Gavin et al) fail to mention is that the Daily Mail gave three headline bullet points, including your exampleThere has been no global warming since 1995 that were then explained in the full text thus:
He further admitted that in the last 15 years there had been no ‘statistically significant’ warming, although he argued this was a blip rather than the long-term trend.
Thus, as you and Gavin et al should know; headlines do not and cannot fully define a story, or otherwise there is no need to insert any text beneath the headlines.
In response to my 3) in 348/p7:
3) Harrabin, (and the BBC) have in recent years been extremely supportive of catastrophic AGW allegations. However, following on from Climategate and IPCC “errors” etc he has done a U-turn and has asked Jones some questions that appear to have been obtained from sceptical scientists. Does this signal a change in policy on AGW at the BBC?
You wrote:
I find that to be a surprising response, particularly because Gavin et al are complaining about such tendency in the lead article, and the BBC does tend to influence the print media in the UK and abroad, and has a “World Service” in radio. Are you suggesting that you can speak for “The Planet” of how many billions of people?
Nice article. To Private Eye readers in the UK, the paper is known as ‘The Daily Wail’
Gavin,
My Comment #352 and your reply:
The South African paper quotes the MWP at before 1000AD to 1300AD, the NZ paper says ‘the interval commonly assigned to the MWP’ and the South American paper quotes 1080AD to 1250AD.
What dates do you ‘commonly assign’ to the MWP?
Also please explain why the Hughes and Diaz 1994 paper could serve as a rebuttal of the New Zealand paper published in 2002?
[Response: Where did I claim such a thing? H&D pointed out more than a decade ago that the records claiming an ‘MWP’ didn’t line up in time. New records aren’t going to change that conclusion – and in fact they’ve made it stronger. You can cherry pick one or two records that seem to fit, but if you take the totality of the records (which are sparse in the SH), they don’t all line up at the same time. Even if you take the ‘skeptics‘ picture of the MWP (discarding the records that don’t have good enough age control to be useful – most of the ocean sediment cores for instance), you find that they just don’t line up. Some records are warm in the 9th Century, some in the 10th, some in the 13th! Some records that are warm in th 12th C are cool in the 9th C and vice versa (even assuming these are even temperature related records – which is not always the case). Each of these mismatches reduces the signal at the global scale. – gavin]
“351
Pete28 says:
20 February 2010 at 1:41 AM
“But it is extremely difficult to establish a statistically significant trend over a time interval as short as 15 years….”
Only if you assume that 15 years means only 15 data points.”
No, only if you assume that 15 years takes 15 whole years to pass.
Peter seems to be another one who thinks Achilles cannot catch the tortoise.
Ken and Don Schor, Let’s take an example. Let’s say you have several tables playing at dice. We look at a time series of the rolls at one table, and we find that the mean over a certain series of throws is anomalously high. We suspect the dice might not be honest. So we look at the other tables for similar anomalies and find them. The thing is that when we line up all the time series, the anomalies don’t line up. And when we average them, the anomalies go away entirely. We’re left with no evidence of a “global dice cheat”. That doesn’t mean that there were no cheats at any of the tables, but it does mean that there was nothing global at all the tables.
“I guess given the tenor here, that by “wing-nut” you mean Anthony Watts. However, be reminded that Watts was not asked for any of his personal advice,”
And if someone wants to lead you astray when asking about proof of the evolution of man, would you give Professor Dawkins name or give the name of that dude who started that evolution history museum where T Rex is vegetarian with Adam and Eve?
BobFJ:
No, I’m not suggesting he should’ve been dishonest, I’m suggesting he should’ve said something honest, but simple and short. Like “15 years isn’t a long enough time to determine the trend”. Period.
That would be much harder to quotemine.
The headline is false. The denialsphere has been widely quoting it, and that’s the take-home message people are being fed.
Don’t defend dishonesty. It won’t earn you much respect around here.
Thanks to Ray and Gavin for the explanations about the MWP. I see that Mann et al 2009 addresses this in much more detail, at least from what I can see of the abstract (I don’t have a subscription to Science, so I’ll have to see if the full text has been posted out somewhere else on the web).
So if I’m understanding this correctly:
— there was a MWP in Europe, North America, etc.
— data from the southern hemisphere is more sparse
— there were warm periods around the globe that overlap with the MWP, but data suggests they were regional and not consistent through the time period.
I assume that, even with all that, the global temperatures during the period known as the MWP were higher than during the LIA. I assume that you are saying global temperatures were lower than the 20th century. This may be a stupid question, but were the global temperatures within a range that would be “expected” by gcm’s? That is, with CO2 out of the equation, is that range of variability natural within the current models? To put it in layman’s terms, could another MWP occur in northern Europe even without CO2, and still be within the range of projected outcomes?
dhogaza 329/p7:
Completely Fed Up 368:
These are rather silly analogies because Harrabin’s Email to Watts was highly specific and restrictive, this being an extract:
I am trying to talk to UK scientists in current academic posts who are sceptical about AGW.
Thus, keeping this short, Harrabin would almost certainly detect any inappropriate ID’s of people that he may have contacted. Furthermore, it seems from his comments that Watts himself was unable to assist. Furthermore, Harrabin realized that those holding current posts may have good reason for not stepping forward. Of course he may have emailed others as well because it would be wrong to assume Watts and his readers as an exclusive source.
BTW, what is the topic of this thread again? Repeatedly lambasting Watts is becoming boring and childish and is irrelevant.
Harrabin e-mailed a guy with a high school education and a background reading news on TV who is convinced that photography disproves science, looking for a list skeptical scientists.
How is my suggestion having the BBC ask some creationist with a high school education for a list of skeptical scientists “silly” anything but identical, other than in particular field of science in question?
Don Shor (370) — My amateur take on the situation is that minor ups and downs for the last 2000 years are consistent with previous times, to the extent we have proxies. On decadal to centennial scales the various temperature and proxy records all show approximately
http://en.wikipedia.org/wiki/Pink_noise
with the exception of the last century, for known reasons.
I should point out that the last, say, 6000 years may be rather exceptional; please read W.F. Ruddiman’s popular “Plows, Plagues and Petroluem”.
BobFJ,
OK, let’s make this less personal. The individual that Harrabin contacted:
a)has no relevant degree, training or experience
b)has no publication record in a relevant field
c)has repeatedly demonstrated an almost perverse glee in getting the science wrong
d)allows working scientists to be slandered on his blog
e)has no understanding of how science works, as evidenced by his Surface Stations debacle
I would contend that using such a person as a “source” even on background is sufficient grounds for questioning the understanding or competence of a journalist.
This feeling is further aggravated by the questions that Harrabin wound up asking, which were over trivial points that shed no real light on where ther real uncertainties lie wrt climate science and anthropogenic climate change. To me, it looks like a journalist’s attempt to “be tough” at the expense of being enlightening or informative. In other words, it had BBC Science reporting written all over it.
Don Schor, Temperatures in the North Atlantic are particularly susceptible to influence by the strength of the Gulf Stream. Remember, Rome is at the same latitude as Indianapolis! Add to that, responses to large volcanic eruptions, changes in insolation, ENSO, NAO, PDO, etc., and not surprisingly you find quite a bit of variability.
However, as Ray Pierrehumbert says, these changes go up and down, up and down. They do not explain a sustained rise like we’ve seen over the past 35 years.
The Daily Mail is not debating what Dr. Jones actually said; instead, the reporter Jonathan Petre is making a shameful straw man argument that is being recycled in Pravda by way of FOX News. http://english.pravda.ru/news/science/earth/16-02-2010/112242-phil_jones_global_warming_fuss-0
Dr. Phil Jones was asked a loaded question: “Do you agree that from 1995 to the present there has been no statistically-significant global warming?”
Let me make an analogy that the readers of this women’s tabloid may be able to grasp: If you weigh yourself every hour for a twenty-four hour period, it will be difficult to know if you are gaining or losing weight. Various factors such as how much water you have been drinking, when you ate your last meal, or when you last visited the toilet will obscure the trend in your weight. But if you weigh yourself every day for a year, any upward or downward trend will be evident.
So it is with global warming: Scientists often acknowledge that factors other than greenhouse gasses can affect the earth’s temperature in the short term.
Ray Ladbury 359:
You wrote in part concerning Harrabin’s search for a list of: UK scientists in current academic posts who are sceptical about AGW: (and willing to ‘out-themselves”…. that’s a tough ask!)
So you assume that Harrabin only sought advice from Watts? Is it typical of you that you jump to baseless conclusions like that?…. See also my 371.
There have been some fifteen comments so-far to me that allege and rant about the incompetence of Watts, and an implication that Harrabin must therefore also be incompetent. In his Email to Watts, (and maybe to others?), as background to his enquiry he linked to his recent article:
Harrabin’s Notes: Raising the error bar (1/Feb/2010)
In his regular column, BBC environment analyst Roger Harrabin says that one certainty in the climate debate is the existence of uncertainty – and that it must be addressed.
http://news.bbc.co.uk/2/hi/science/nature/8491154.stm
Try reading it, it’s not hard. It seems to me that Harrabin is very perceptive and lucid in his comments, and can hardly be given the “low-life” status that has been implied by you and others.
Doug Bostrom 360:
In response to my item 4) in 348/p7; Harrabin has since stated: “…government ministers may have to reconsider their description of sceptics as “deniers” and “flat earthers”…” I guess that also means that he will avoid making such slurs too. What do you think?
Well it does not matter how dumb you think the BBC (staff) is, but what IS relevant, and IS the concern of this thread is; increased media reporting that is alleged to be inaccurate and biased against catastrophic AGW.
If you are simply not interested, then perhaps you should go somewhere else?
Personally, I wouldn’t engage with BobFJ.
(cue theme by Grieg)
BobFJ says: 21 February 2010 at 7:56 PM
To be more specific, I’m not interested in what you think, BobFJ.
Let me clarify further. I’m not arguing with you. You mentioned Watts and thus provided me an opportunity to mention his fallibility, something I like to do for the benefit of the general audience here when given the chance. The rest of your hypothesis is deadly dull. Carry on with your preoccupation concerning the BBC, just don’t bother trying to elicit an opinion about it from me.
Zinaida Zalyotchik Reur 376:
Here follows Harrabin’s question B, and Jones’ answer in full, my bold added:
Here follows what Pravda On-Line correctly reported:
Here follows what the Daily Mail correctly reported, below the headlines:
And again further down in the same text:
Here is some advice:
You should always read beyond the headlines which cannot, by definition, give the full story, and are intended purely to grab attention, from where it is essential to read the full text. Furthermore, if you believe that there has not been a recognisable cooling plateau, somewhat like that of around 1940*, then check-out the following Email exchange. Note that Wigley was director of CRU before retiring in 2004, and that Trenberth has been very powerful in the IPCC. Also note the highly significant circulation:
From: Tom Wigley
To: Kevin Trenberth
Subject: Re: BBC U-turn on climate
Date: Wed, 14 Oct 2009 16:09:35 -0600
Cc: Michael Mann , Stephen H Schneider , Myles Allen , peter stott , “Philip D. Jones” , Benjamin Santer , Thomas R Karl , Gavin Schmidt , James Hansen , Michael Oppenheimer
Kevin,
I didn’t mean to offend you. But what you said was “we can’t account for the lack of warming at the moment”. Now you say “we are no where close to knowing where energy is going“. In my eyes these are two different things — the second relates to our level of understanding, and I agree that this is still lacking.
Tom.
++++++++++++++++++
Kevin Trenberth wrote:
> Hi Tom
> How come you do not agree with a statement that says we are no where close to knowing where energy is going or whether clouds are changing to make the planet brighter. We are not close to balancing the energy budget. The fact that we can not account for what is happening in the climate system makes any consideration of geoengineering quite hopeless as we will never be able to tell if it is successful or not! It is a travesty!
> Kevin
Also, Trenberth’s more recent on-line elaboration discusses possible mechanisms for the current “bad news” cooling plateau, and laments inability to define it. Here is an extract which is not contradicted elsewhere:
“…Perhaps all of these things are going on? But surely we have an adequate system to track whether this is the case or not, do we not? Well, it seems that the answer is no, we do not…”
Note* see graph: http://www.cru.uea.ac.uk/cru/data/temperature/_nhshgl.gif Compare the current HADCRUT temperature plateau with that of around 1940. (and maybe 1877) Also, from this, see the relevance to question A.
Don Shor #362 and Gavin #365
Here is another paper from China re the MWP.
Quote:
The Medieval Warm Period in the Daihai Area
Jin, Z | Shen, J | Wang, S | Zhang, E
Journal of Lake Sciences [J. Lake Sci.]. Vol. 14, no. 3, pp. 209-216. Sep 2002.
Based on the rubidium to strontium (Rb/Sr) ratio, carbonate (CaCO sub(3)) content and organic carbon concentration (C sub(org)) record in lake sediments from the Daihai Lake, Inner Mongolia, dated by AMS- super(14)C and super(210)Pb, the climatic and environmental change process was reconstructed since the last 2,200 years, including two important climate events, i. e. the Medieval Warm Period and Little Ice Age. An increase Rb/Sr ratio but a decrease both CaCO sub(3) and C sub(org) correspond to a cold period, and vice versa. In this paper, we first suggest that there existed the Medieval Warm Period in the northern China during 900-1200a B. P. by a high-resolution lake record characterized according to lower Rb/Sr ratios and higher CaCO sub(3) and C sub(org) concentrations in the sediments from a single watershed, which a warm and humid environment was demonstrated by significant increase of chemical weathering and by a progressive increase of biologic productivity, and by a high lake level. The Medieval Warm Period has not only an inner climatic fluctuant, but also the strongest chemical weathering during the last 2,200 years, which are indicated by a higher-resolution natural record in northern China. Furthermore, the Medieval Warm Period in northern China is contemporaneous with the worldwide event identified in the lakes, oceans, land mollusk sequences, polar ice cores, pollens and historical documents. endquote
Lining up of ‘peaks’ supposes a close match of the timelines – something which would seem very unlikely from proxy reconstructions 1000 years ago and might not account for ‘noise’ in the system anyway.
As the only feasible external forcing is Solar for this pre-industrial period, heat added to the oceans from an imbalance would be expected to behave similarly to that of the current warming – get involved in complex circulations and hide in places (below 700m?) and possibly pop up to warm different regions at different times. Difficult to explain the physical process – but is that not what Dr Trenberth is suggesting is happening right now Gavin?
Ken, if that is the supposition, then where is the layer where all this heat is stored?
Has there been enough over-supply of insolation to give us this level?
And why is it getting warmer in just the right way to make it look like CO2 which has also been climbing and has a model that recreates the current and past climate changes.
“These are rather silly analogies because Harrabin’s Email to Watts was highly specific and restrictive, this being an extract:
I am trying to talk to UK scientists in current academic posts who are sceptical about AGW.”
Why ask Watts then?
There’s Nature. They keep a publication list.
If we are to accept conclusions on the basis of statistically insignificant evidence, does that go for the rest of science too?
If 95% confidence is the test in medical trials, why is climate science somehow different?
David Bailey – Medical researchers don’t throw out half their data before doing a statistical test – and they certainly don’t do a test with all their data, get a significant result, then throw out half the data, get a (marginally) non-significant result, and conclude that there is no evidence of an effect!
Ken Lambert (381) — Read W#.F. Ruddiman’s “Plows, Plagues and Petroleum” for the argument from land use change. But also note that there is enough reddish
http://en.wikipedia.org/wiki/Pink_noise
on those time scales to account for multicentennial ups and downs of regional temperatures.
David Bailey (384) — The notion of accepting conclusions based on statistical significane is really a question of risk management. It just depnds on how certain you need to be before taking some action. Do note the conservative care with which the IPCC AR4 WG1 report is written.
David 384: “If 95% confidence is the test in medical trials, why is climate science somehow different?”
Because have decided that medicine must “first do no harm”, so we’d rather lose 10 to heart disease than 1 to side effects. We have 6 billion individuals, so we can afford to play the numbers and lose some.
However, we have only ONE planet. So what you’re suggesting is that mere 90% certainty that we’re screwing up the planet isn’t enough to change.
So let’s boil it down to a more parallel scenario: You have only one life. If a doctor tells you he’s 90% sure that behavior X will kill you, do you stop? Or attack his science, and hold out for 95% certainty?
dhogaza 369:
Ah, but what you and Jones don’t admit is that there is more to it than a nominally supposed statistical trend, and that other notable climate scientists have treated the “recent lack of warming”, as a significant issue, and have broadcast it not only to Phil Jones but also to others. For example:
[Email] From: Tom Wigley To: Kevin Trenberth
Subject: Re: BBC U-turn on climate
Date: Wed, 14 Oct 2009 16:09:35 -0600
Cc: Michael Mann , Stephen H Schneider , Myles Allen , peter stott , “Philip D. Jones” , Benjamin Santer , Thomas R Karl , Gavin Schmidt , James Hansen , Michael Oppenheimer
Kevin,
I didn’t mean to offend you. But what you said was “we can’t account for the lack of warming at the moment”. Now you say “we are no where close to knowing where energy is going“. In my eyes these are two different things — the second relates to our level of understanding, and I agree that this is still lacking.
Tom.
++++++++++++++++++
Kevin Trenberth wrote:
> Hi Tom
> How come you do not agree with a statement that says we are no where close to knowing where energy is going or whether clouds are changing to make the planet brighter. We are not close to balancing the energy budget. The fact that we can not account for what is happening in the climate system makes any consideration of geoengineering quite hopeless as we will never be able to tell if it is successful or not! It is a travesty!
> Kevin
Also, Trenberth’s more recent on-line elaboration discusses possible mechanisms for the current “bad news” cooling plateau, and laments inability to define it. Here is an extract which is not contradicted elsewhere:
“…Perhaps all of these things are going on? But surely we have an adequate system to track whether this is the case or not, do we not? Well, it seems that the answer is no, we do not…”
Note; see graph: http://www.cru.uea.ac.uk/cru/data/temperature/_nhshgl.gif Compare the current HADCRUT temperature plateau with that of around 1940. (and maybe 1877) Also, from this, see the relevance to question A.
Yes, the headline is false. Jones did not say that and the headline has spread around. This sort of thing has been a problem for years in the media…. For instance; silly headlines about alleged unprecedented droughts in Australia, and fruitbats dropping dead from the trees due to AGW etc. I don‘t know why you think I‘m being dishonest, but it‘s good to see you orienting more towards media problems here, as per the thread topic. See also my 380 below.
Completely Fed Up #382
A recent paper by Von Schukmann et al suggests that 0.77 W/sq.m of ocean area equivalent forcing of heat over recent times is stored down to 2000m using Argo data. There is no clear description of mechanism or how it passes through the top 700m without showing up in other Argo analyses.
BobFJ,
Actually, Trenbreth’s statement is regarding our inability to fully comprehend the short-term to mid-term variability. It has nothing to do with long-term trends in climate.
jimt, nor do climate scientists, or do you have specific allegation? Naah, you seem more the vague inuendo and quiet slander type of guy.
BobFJ – how come you declare what you quote (“we can’t account for the lack of warming [at the moment]”) as the “[recent] lack of warming”?
the “lack of warming” needs a ‘when’ and ‘where’ attached, and I think you’re attaching the wrong ‘when’ – also note they appear to be discussing the certainties needed for geo-engineering, not about certainties sufficient to prescribe CO2 reductions [along the lines of “social engineering”], which would have a much different risk avoidance assessment
Ray Ladbury 390:
Yes, that is true, and it is fundamentally what I said in 388, quote:
“Ah, but what you [dhogaza] and Jones don’t admit is that there is more to it than a nominally supposed statistical trend, and that other notable climate scientists have treated the “recent lack of warming”, as a significant issue, and have broadcast it not only to Phil Jones but also to others.”
Furthermore, where dhogaza suggested [369] that Jones should not have given so much information, restricting it to only: “15 years isn’t a long enough time to determine the trend”, then that is avoiding the truth, whereas a better more complete answer might have been:
15 years isn’t a long enough time to determine the long-term trend, although there has clearly been a distinct plateau in warming that is similar to that seen around 1940. We do not know the reason for these plateaus, and it is interesting to note that after the 1940 one, there was a pronounced cooling period, especially in the NH.
See: http://www.cru.uea.ac.uk/cru/data/temperature/_nhshgl.gif
See also Harrabin’s question A
Ray Ladbury@391 – You missed my point completely – my “allegation” (fairly well proven I think you’ll agree) was that climate deniers cherry pick the data to get non-significant results – and then claim there is no evidence warming. I was responding directly to David Bailey @385.
David Bailey (384): If we are to accept conclusions on the basis of statistically insignificant evidence, does that go for the rest of science too?
If 95% confidence is the test in medical trials, why is climate science somehow different?
BPL: It isn’t. The point is that the sample size of 15 years is too small to show a significant effect. But we have 160 years of direct measurements and proxies going back orders of magnitude further. That data DOES show a significant trend. Please read:
http://BartonPaulLevenson.com/30Years.html
flxible 392:
I’m not sure what you mean, but I think that 1995 as a start-point is a bit of a stretch, even in the original Harrabin question. I would prefer to use 1998 as the start point, but then others argue that this is unfair because 1998 is the so-called super El Nino year. I counter that by arguing that 1999 and 2000 were sharp down “corrections”, such that hypothetically, it seems fair to average 1998 through 2000. Furthermore, if you look around the earlier up-spikes, although there is obviously a lot of noise, there does seem to be a tendency for a down correction after such spikes. Additionally, it seems logical that when there is a big release of heat from an ocean turn-over, then this could sensibly be followed by an opposite effect. However, if you are not happy with this hypothesis, then I’m content to consider the recent lack of warming to have started in 2001. Whatever, there is no disputing that such a period certainly exists from 2001, (and arguably earlier), per the HADCRUT record. As to when Trenberth and others consider it to have started; I don’t know.
I don’t agree with the rest of your comments, but perhaps my 393 may help?
Interesting article in the Globe and Mail.
Cherrypick:
“The key objection to the work of bloggers such as Mr. McIntyre is that they are engaged in an epic game of nitpicking: zeroing in on minor technical issues while ignoring the massive and converging lines of evidence that are coming in from many disciplines. To read their online work is to enter a dank, claustrophobic universe where obsessive personalities talk endlessly about small building blocks – Yamal Peninsula trees, bristlecones, weather stations – the removal of which will somehow topple the entire edifice of climate science. Lost in the blogging world is any sense of proportion, or the idea that science is built on cumulative work in many fields, the scientists say.”
More:
http://www.theglobeandmail.com/news/national/climategates-guerrilla-warriors-pesky-foes-or-careful-watchdogs/article1474924/
BobFJ (396): However, if you are not happy with this hypothesis, then I’m content to consider the recent lack of warming to have started in 2001. Whatever, there is no disputing that such a period certainly exists from 2001, (and arguably earlier), per the HADCRUT record.
BPL: It exists, but it has no meaningful implications because it’s too short to accurately determine the trend. Please read:
http://BartonPaulLevenson.com/30Years.html
Barton Paul Levenson 398
It is blindingly obvious that a 15-year trend (or less) on such noisy, and arguably naturally cyclic data as in HADCRUT, cannot be used for longer term prediction. Furthermore, let’s also consider the widely favoured 30 year nominal, by looking at the HADCRUT graph:
http://www.cru.uea.ac.uk/cru/data/temperature/_nhshgl.gif.
1) The 30-year 21 point smoothed trend from 1910 to 1940 is remarkably similar to the rapid warming from ~1970 to ~2000*
2) The 30-year 21 point smoothed trend from 1940 to 1970 shows moderate cooling
3) The 30-year 21 point smoothed trend from 1925 to 1955 is flat.
Thus, in that time-series from 1910 to 1970, no individual 30-year period has any meaningful implications as shown in the record outside any such period.
As described in my 380, two acclaimed scientists; Tom Wigley and Kevin Trenberth have agreed, with wide compliant circulation, that the current warming plateau is of unknown cause. Thus, since it is unknown, it is conjecture to assume that it is totally different to that of around 1940. (and maybe 1877, suggestive of a ~60-year cycle, although the T records may be a bit sus‘ in the 1800‘s?). Whatever, these are unknowns, and so temperatures may shortly start to ascend again, OR they may fall similarly to what happened after 1940. We simply do not know.
*note, for correctly applied 21-point (CMA simplified Gaussian) smoothing, the black line should end at mid 1998, not 2009!
I hope you have noticed this interview with Monckton where he tells that he is behind the question about “15 years” addressed to Phil Jones.
(Perfectly aware about the confusion of the meaning of “significant” that it caused, is my qualified guess)
http://www.youtube.com/watch?v=LUxxEDvkuLM