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.
eric @ 222
Yes. It’s called adaptive management in the policy trade.
===
undecided @ 230
I’ll just chip in my 2 cents on this part:
There are all kinds of alt med cranks peddling woo out there. Michael Savage even manages a twofer, pushing woo and denialism (lest you think woo is entirely a lefty enterprise). The “debate” isn’t legitimized by the mere fact that it exists.
If you poke around long enough, you will find that climate scientists have developed an impressive body of expert knowledge over the years and that they will gladly discuss, quantify where they can, its strengths and weaknesses. There is no perfect knowledge in medicine or any of the sciences… anywhere… anywhen. Life’s a bitch that way.
Completely fed up try reading the Jones interview first available in a link in the blog entry. Second of all I never stated he denied that he states that the data shows mostly man made means increasing warming since the 1950’s. I am not sure what you stand to gain from denying Jones’ own words.
Dhogoza I know you actually read the interview and I respect most of your posts, but he still does respond to the debate is over with some admission of large uncertanties, mainly paleoclimate in nature. I see a warming trend an the past decade is the hottest on instrumental record, but there is also a switch to cooler global temperatures the past couple of years, while certainly not a trend, it is something to investigate further. I am as always supportive of lowering GHG emissions, lowering pollution in general which is even a bigger concern than GHG themselves and planting more trees–lowering the rate of deforestation. AGW is not the main concern of pollution, but as the science improves further we will learn more about the potential dangers.
Question:
If there is no statistically significant trend since 1995 how come we keep getting told the planet is warming at a ever increasing rate? It is a win for the skeptics to get Jones to agree there has been no discernable trend for these shorter periods meaning no claims can be made about acceleration in warming. Further AGW predicts acceleration reinforced by positive feedback. No observed acceleration no evidence to support the theory.
[Response: Signal vs. noise. It’s not hard. – gavin]
To quote Comment by flxible — 16 February 2010 @ 11:05 PM
“My appeal to Gavin, who I believe is the most well spoken among the group of exceptionally intelligent bloggers here [commenters aside] would be: please carry on with the most excellent public face you’re putting on science and scientific integrity. Your choice to keep the public up to speed on the leading edge of the science is appreciated and valuable. Sorry your being so knowledgeable on this important topic results in being a crank magnet!”
I agree.. Keep up the great work guys.. There are many of us who greatly appreciate your work and keeping us up to speed!
BPL: What part of “It’s warmer now than at any time in the last 2,000 years, and possibly a couple of orders of magnitude longer than that” did you not understand?
So BPL if you are able to know for sure that current temperatures are “warmer now than at any time in the last 2000 years”, I assume you have a good estimate of the PREVIOUS record. When was the second warmest period in the last 2000 years, and with which anomaly with respect to the current one? (you’re allowed to give a confidence interval of course).
“K-Bob@208,
I was looking at records recently. The period from Tambora (1815) to Krakataua (1882) was remarkably free of large volcanic eruptions. Moreover, the end of the period looks to have a very large spike in the data, perhaps indicative of an El Nino. I think the trend is largely explainable in terms of these two factors.
The period 1910-1940 was also largely eruption free, and solar irradiation was increasing. Moreover, greenhouse gasses were increasing with some rapidity in this period. I think these are plausible explanations.”
I see no correlation between trends and volcanic eruptions. The positive trend of the beginning of XXth century stopped abruptly in 1940, just in the middle of a very calm period, although there has been no major eruption before Agung in 1963. Then it started again to rise in 1970 shortly after Agung. A figure like http://www.ipcc.ch/graphics/ar4-wg1/jpg/faq-8-1-fig-1.jpg is very deceiving : the agreement between data and models is largely superficial. First data have been compared to a set of models, not the best one (which is quite unusual). With a range of models and parameters, you can cover evrything !. Then although the average VALUES of anomalies are approximately reproduced, the details in TRENDS are not. As I said, the breaks occured in 1940 ans 1970, with no correlation with volcanic eruptions. Volcanic eruptions are visible as sharp steps, but nothing like this is seen in the instrumental curves. Volcanic eruptions “shifts” model curves to compensate trend differences , the instrumental trend before 1940 being fairly larger than what models give. All this look more like “tricks” to fit data, than a real physical description.
(The disagreement between effects of volcanoes and measurements is also visible on the figure relative to the pressure increase on the top of troposphere… http://www.ipcc.ch/graphics/ar4-wg1/jpg/fig-9-14.jpg )
I love these discussions. Real Climate tells it like it is, amplification and more information is presented by informed posters. Then the denialist assault begins: illogicalities, tired old rehashed furphies and the sheer will to believe are pitted against information and science and denialism shambles away licking its wounds.
54:Didactylos
Personally, 15,30 or even 100 years is no enough to even call anything a trend. 100 years is the equivalent of 22 msec of a 24 hour day in earth time. I have serious doubts of any claims that AGW is a proven fact. There is just not enough knowledge yet to make any claims from either side of the argument.
Comment by Syl — 15 February 2010 @ 9:02 PM
Helpful translation:
“Scientists claim the planet was inhabited by perhaps millions of dinosaurs, but because we have found only some thousands of fossils purported to be “dinosaurs,” I conclude those very few fossils that do exist cannot be proven to be dinosaurs.
Or, if they are dinosaurs, they obviously spontaneously generated or were sent here by aliens as an experiment, then died in very convenient places knowing only then would their existence ever be known to their posterity. (This is not evidence of intelligence; they “just knew” where to die.)
Further, since scientists are imperfect, and make errors, we must conclude that it is unlikely that dinosaurs existed at all since I cannot recreate a dinosaur in my garage. Even more enlightening, the scientists refuse to release the supposed DNA of any supposed dinosaurs to me, nor how to regenerate it, so they are obviously hiding something.”
Just wrote to the Press Complaints Commission: this clearly breaches –
i) The Press must take care not to publish inaccurate, misleading or distorted information, including pictures.
“The headline and article grossly misrepresent Professor Jones’ views. He was asked by the BBC whether the trend from 1995 was statistically significant – it isn’t, only just, and that’s the nature of drawing statistical conclusions from short timespans. The Daily Mail used the BBC interview to support a false headline.
I’ll quote the blog Realclimate, who say this better than I could, since they’re climate scientists:
“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.”
(From https://www.realclimate.org/index.php/archives/2010/02/daily-mangle/)
There is no possible way to unintentionally misinterpret what Jones meant, to the extent of claiming he has made a “u turn” and now believes there has been no global warming since 1995. Well – it could be that a science writer might not understand the most basic statistical knowledge required to know what ‘statistical significance’ means. Either way, the article, and the headline in particular, is a clear misrepresentation of Professor Jones’ view on the matter.
It is extremely dangerous if scientists start to believe they can’t openly talk about these most basic of points without distorting headlines like this being the consequence.”
“They also show the need for time varying and most likely spatially varying parameter estimates.”
Why?
Are you speaking klingon too?
“Even oblations to the Right Reverend Bayes do not buy you the degrees of freedom necessary to accomplish that task.”
No, we can watch the rolling pin roll down the slope. ALL errors are contained within the historical record. Any deviation from outside the sensitivity of temperature to CO2 must remain within the parameters it has occupied in the past (around 3C per doubling).
whatever you’re talking about cannot change that fact. The only thing that can is an event that is not natural and yet of sufficient magnitude to create a visible global change.
Are you saying that humans are big enough to do that?
“Therein lies a problem. It seems that there is legitimate debate as to the confidence in those proxies”
You would then be able to delineate these problems and ascertain what proxies would be useful and prove their utility.
Can you?
Oh, no, it appears not.
No proxies show even less evidence of southern warming in the MWP.
“The obvious question is, if the MWP is clearly expressed in NA, North Atlantic and Eurpoe adn parts of Asia, why does the reconstruction of MBH98 and afterwords not have a MWP in the data? ”
Because if the MWP was a warming of 1C in the north and 0C in the south (Extreme values for clarity of example), and the current warming is about 1C globally, then when you take the global picture, the MWP is half the size. 0.5C.
Given the interannual error is +/- 0.5C, the MWP disappears into the noise.
“Firstly the neurologist has many years of actual data that can and has been proved over and over again.”
Really?
Ever seen a neuron fire?
How can that be proof?
(see how you can just shift those goalposts)
“Frankly, I’m fascinated by the differing subjective requirements for proof on all sides – because reasonable minds can differ. Even Bohr and Einstein – both unquestioned geniuses – differed.”
You’re no Einstein.
Subjective is what proof isn’t.
“229
grzejnik says:
16 February 2010 at 6:43 PM
Completely fed up, to your points:
1. Yes really, he said so, and did not/could not provide the data. ”
Which? Surely if he cannot provide the data, then it is certain he did not. This does not mean the data is gone.
“2. I say “lost” in quotes to imply he “lost” it on purpose, or like he said its unorganized”
Then I say you lie. I don’t put quotes around it because I know you’re lying.
You know he didn’t lose (no quotes), so implying it by putting quotes around it is cowardly so that you can’t have come-back on it (cf the Beckian gambit: I’m not saying anything…”).
And it’s not his data.
“3. If this data used in published papers were available online for any and everyone there would be no issue and no cost to the UK taxpayers.”
They weren’t.
Since this is past perfect, stating “if they were” doesn’t make the expense go away.
Since they cannot give away someone else’s data, they could not put it on a website for anyone.
So your point 3 is insanity itself:
1) “If” doesn’t make it true
2) Being not true, there IS an expense. Go get your own bloody data and stop scrounging off us UK taxpayers, you leech
3) You’ve already said they couldn’t give the data away, so why is giving it away on the enternet allowed? Does this mean P2P sharing is not copyright infringement because grz says it’s not?
Buffoon.
Bud,
Okay, let me make the question more explicit.
There is only enough sunlight to heat the world to a mean global annual surface temperature of 255 K, well below freezing. This is a point first made by Fourier in 1824. But the world’s M-GAST is actually 288 K. Why? Where is the extra heat coming from?
“Natural variation” doesn’t cut it. What’s the explanation?
TS: This is particularly laughable given the extent of manipulation of the journals and suppression of dissent shown in Climategate.
BPL: The manipulation of the journals was happening with the Baliunas article being rushed through peer review by a friend. The climatologists were trying to correct that bit of interference.
TS: I don’t have to prove you wrong for you to not take my hard earned taxes. You have to provide clear and convincing evidence that you are right.
BPL: The evidence is overwhelming, jack.
TS: IMO the climate models / predictions are not solid enough yet to declare imminent disaster and make large lifestyle changes over.
BPL: And you’re an expert on the subject, I take it?
The complexities of the climate system together with large uncertainties in our knowledge of cloud microphysics and radiation budgets means that any conclusion about the magnitude of human influence on climate has to be somewhat equivocal, given the current datasets. This is fully reflected in the details of the IPCC reports.
If AGW is as important as many models suggest then in the next ~10 years the equivocations will become weaker and the case stronger, until it is utterly irrefutable.
While AGW advocates would like to see faster policy changes everywhere in the western world there is a strong push for reducing carbon emissions. The message has been received by policy makers that something is potentially very wrong with the way we live. A lot has therefore already been achieved.
Personally I see a great danger when scientists feel that in order to make their case to policy makers that it has to be so simple as to not allow any ambiguity even when some ambiguity, or at least uncertainty, exists. The science can be wrong. Hypotheses change.
We are steadily increasing our ability to measure the climate system and at the same time the AGW signal should also be increasing. Time is on the side of the AGW advocates, if they are right of course. Policy is already moving in the right direction. I think there is a little too much hysterical reaction to the media reports here, as if anyone who doesn’t follow the AGW orthodoxy is an existential threat. There is no need for this, and while there is even a small room for doubt, doubters will exist. Let them. As long as the evidence continues to grow in favour of AGW such voices will be steadily sidelined from the debate.
grz 229: I say “lost” in quotes to imply he “lost” it on purpose
BPL: In other words, you’re accusing a man you never met of lying on the basis of how some political blogs interpreted an email he sent.
You might want to watch that. Accusing someone of lying when they’re not is itself lying.
The amount of money at stake here is massive. Sloppiness denotes poor stewardship and poor science. A changing of the guard is in order. I see no substantive evidence of crisis when statistical machinations are so sensitive to carelessness. I don’t have to question your motives to question your conclusions. I only need to watch for your short and long term predictions to be proven accurate in statistically significant measures. If the work is sloppy and the data not statistically significant, then I can’t support the conclusions.
Color me Confused@848:
Think of Energy & Environment as being like The Onion without the humor.
grzejnik #229
“This is a barking mad blog, everyone is so righteious and indignant about skeptics yet there are gaping holes in this science. Open your eyes, its time to wake up.”
I have my eyes open and am wide awake. You inhabit a strange world if you think misrepresenting Phil Jones (that is the topic here) in a UK newspaper is perfectly OK and us getting indignant about it makes us “barking mad”. On the evidence I have seen to date your earlier accusation that Jones is a “sloppy scientist” is baseless. Either you present your evidence for this or you go away.
As to the “statistical significance” issue, I have three questions.
1) How is “statistical significance” defined in this context?
2) How much warming would there have to be in a 15 year period to call it ss?
3) At 0.12C per decade warming, how many years would it take to be ss?
Thanks in advance.
Thank you realclimate staff for being able to drag yourselves out of bed in the morning and face the maelstrom of distortions and put-downs. It must feel pointless at times but you must never stop because you are a part of the only group who can stand up to it. If I didn’t have places like realclimate to visit, that I knew to be written by scientists (and not journalists and lobbyists and ‘useful idiot’ cranks) in the end I would have to start believing all of their distortions.
You are at the centre of one of the most historically significant events of our time. Future generations will look back at places like realclimate when they try to make sense of our inaction. So don’t ever give up.
Re: #246
Stop feeding this troll. He really doesnt want the right answers,
You have raised a problem, but I am not sure that “starve the troll” is the right solution. The biggest trolls are the Telegraphs,Mail and half (or more) of the climate books in one of the biggest local bookshops. They seem to thrive on any kind of diet.
Lack of statistical power
It seems to me that the discussion we see here between believers and skeptics revolves around statistical power. There are insufficient temperature reconstructions and therefore there is a lack of statistical power to conclude that there was a Medieval Warm Period in the southern hemisphere.
The believers use this lack of statistical power to conclude that there was most likely no global medieval warm period. The skeptics use this lack of statistical power to conclude that the Medieval warm period was indeed real and most likely global.
The global temperature increase we have seen since the 1970’s appears to have levelled off during the last decade. But the time period is too short to statistically demonstrate that warming has stopped. The believers use this lack of statistical power as an argument that warming most likely continues. The skeptics use this lack of statistical power as an argument that warming most likely has levelled of.
What strikes me here as that the believers use lack of data demonstrating warming to dismiss warming during the MWP while they use lack of data demonstrating warming to support warming in recent times.
In any case, can believers and skeptics agree that warming has not accelerated during the last decade? To me, that is a comforting thought, because this may give us some extra time to adapt to the catastrophies that await us in a warm future.
Neil@244,
Throwing around a bunch of technical jargon on a blog intended to educate the public is just a transparent and pathetic attempt to make yourself feel smart. Those of us who actually do modelling are not underwhelmed.
If you have a technical comment on the paleoclimate models, the appropriate place is the peer-reviewed journals climate , where I notice your name is conspicuously absent.
We all know it’s possible to come up with a model that is too complicated to be workable. Congrats, you’ve done that.
Jerry,
Ah, would that my name were Ray Bradbury (it’s close, Ladbury). I am sure you will agree that as scientists we have to go with the evidence that exists, right? It is a shame that we don’t have as many proxies for the Southern Hemisphere as we do for the North, but that is life.
The thing is that what data we do have do not indicate a warm period contemporaneous with that around the N. Atlantic. They aren’t even close. The fact that the attempts by the Idsos, who believe in a MWP, to gather all the data together fail to make their point I think speaks volumes. The fact is that nobody has managed to come up with a global termperature reconstruction with MWP temperatures anywhere close to those we are experiencing today.
It might be an interesting exercise to try to reconstruct what temperatures would have been needed in the SH to bring the global average up to today’s levels. I suspect the result would be pretty unlikely.
Reisz, Really understanding the scientific method is rare even among scientists. I’ve known some scientists who were very good at doing science without ever really understanding how it all fit together. The thing is that doing science is somewhat intuitive for humans. However, fitting together all the evidence into a comprehensive theory is not. People get pieces–e.g. empirical study, hypothesis generation, testing and falsification (ala Popper), etc. But comprehending the role of consensus–or even what scientific consensus is, eludes even most scientists.
@Global Sceptic (#25):
Let me get this straight: A BBC reporter asks Prof. Jones a question (one of “several gathered from climate sceptics”), which he could answer in two ways, truthfully (like he did) and in any other way. The Daily Mail then reported by “simplifying” the answer to a simple talking point (had he given the alternative answer it would have been “Climategate II: Prof. Jones caught lying again”.)
Then someone tells you to look at the actual answer and you start to repeat one of Monckton’s distortions of truth that has absolutely nothing to do with the issue at hand?
As if we actually needed more proof this was a set-up, and the deniers HQ has its staff astro-turfing in the various comment sections to this new Blahblah-Gate.
Re : #254.
Acceleration is very hard to observe for the reason that Gavin gave. But in addition I don’t agree with Elliot over this:
” Further AGW predicts acceleration reinforced by positive feedback”
Unfortunately projections of accelerated global warming might turn out to be correct
if (a) new forms of positive feedback kick in or
if (b) greenhouse gas emissions increase at a super-exponential rate
but if neither of these happens, and there is no acceleration, we shall still be stuck with the existing positive feedbacks and trend which will corroborate AGW and may not be very nice at all.
#224 Fred Magyar:
I use a medical analogy similar to yours titled A Conversation at a P oker Game to illustrate why information needs to come from expert consensus.
The spam filter doesn’t like the “p” word. It is a game of skill, you know. :)
Re: my last comment
Condition (b) needs to be rephrased (weakened) to allow for the predicted decreasing relative importance of aerosols
Dear Fed. Please read Mann 2008 and the supplemental material–I think you will find the ridge regression used has a fairly explicit error structure that has absolutely nothing to do with fact. It is the analyst’s choice of specification and the results can vary rather substantially by changing that–which was exactly the point of Anand and Hargreaves (and Hoerl and Kennard mentioned earlier). Error specification matters. You might try actually reading the Anand and Hargreaves paper you cited. Or you could take the data and code from Mann and change the specifications. Octave (http://www.gnu.org/software/octave/) is free if you haven’t saved enough money sleeping on you parent’s couch to buy Matlab.
Gavin and RC teams I am out of here. Thanks for all the great data and examples that lend themselves well to multiple interpretations. Thoroughly enjoyable, but there is the text book that sits unfinished. Cheers.
#242 The MCE (or MWP) isn’t shown on the hockey stick. Why not?
Thgis one drives me crazy! LOOK at the g-d graph! There are three clear, distinct, pronounced periods of warming shown in the late 12th, late 13th and late 14th C. The LIA is also clearly depicted.
It is a sure sign of brainwashing when someone sees a graph or reads a statement and concludes the polar opposite of what is shown or stated.
calyptorhynchus @ 258
Then there are the Pythonesque Black Knights among them, hopping about on bloody stumps proclaiming “‘Tis but a scratch; I’ve had worse” or “It’s just a flesh wound” and “I’m invincible!”
On another topic, because this is a moderated list, trolls that get through the net are fair game IMHO.
It seems to me that there is no room for variations in the intrpretation of “no statistical significance” statement. To us, scientists it sounds like “no effect” -> “no warming”. How does it sound to you, climatologists?
[Response: Signal vs. noise on short time periods combined with a cherry pick of the metric. Hardly a difficult concept for a physicist to deal with. 2000-2009 warmest decade? Statistically significant, decrease in Arctic summer sea ice over last 10 years? Statistically significant. 20, 30, 40 years trends in temperature? Statistically significant. Combination of data, theory and simulation implying that the globe is still warming? Statistically significant. People getting confused by noisy timeseries? Insignificant. – gavin]
Question on the MWP. it seems to me that this warming occured where the population density was higher. Could it have been the land use/urbanization of these areas caused this upward trend? And if so, would not the earths’ system then try to reach equilibrium? And if the southern areas were still at a lesser warmth, then as the system approached equilibrium in the north, may it not overshoot that target and cool past equilibrium in the north? You know the LIA?
It just seems to me that with the higher land mass of the northern hemisphere climate events are going to be more pronounced.
“252
Jacob Mack says:
16 February 2010 at 11:38 PM
I am not sure what you stand to gain from denying Jones’ own words.”
I’m not sure (though I’m certain I’m not alone) why you think the words are being denied?
The misstatements?
Yes.
The implied spin?
Yes.
The words?
No, don’t see it.
“276
Geoff Wexler says:
17 February 2010 at 5:24 AM
You have raised a problem, but I am not sure that “starve the troll” is the right solution.”
Indeed not.
“Important” trolls complain that they are being silenced.
Others repeat their questions again, possibly using ALL CAPITALS to make sure that people who are hard of hearing catch it.
Neither help the signal-to-noise ratio.
So ridicule them.
They are ridiculous.
“289
Leo G says:
17 February 2010 at 11:10 AM
Question on the MWP. it seems to me that this warming occured where the population density was higher. Could it have been the land use/urbanization of these areas caused this upward trend?”
Alternatively, could it be that we have people noticing a MWP where they live and, in an age where international travel didn’t exist, not knowing about its lack where they didn’t live.
The mechanics for a regional MWP and even regional LIA are available for assessment.
“274
jonesy says:
17 February 2010 at 5:13 AM
As to the “statistical significance” issue, I have three questions.
1) How is “statistical significance” defined in this context?”
In the same way as any noisy record is treated in statistics.
“2) How much warming would there have to be in a 15 year period to call it ss?”
It depends on the noise level. Signal has to be distinct from the noise.
“3) At 0.12C per decade warming, how many years would it take to be ss?”
An irrelevant question, because it’s still thinking the wrong way.
There seems a lot accusations back and forth, but as an outsider when I read Dr. Jones’s statements they seem to raise a great many simple questions that I and many others would like to have answered in a direct and understandable manner.
Dr Jones states,“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.” How then were studies done showing earth temps to what seems an incredibly high degree of accuracy when records for over half of the earth are so sparse for that time period? There appears to be a direct contradiction that could use an explanation.
If the AGW crowd is to move their cause forward they need to present their case openly and freely admit what is fact from what is theory or speculation. When Real Climate mounts an all out defense of Dr. Jones when, to a layperson, it looks like he is claiming that the dog ate my homework, it looks like RC is more concerned about saving face than science.
[Response: What is the logic here? Jones says that to demonstrate a global MWP you’d need a lot more data from the tropics and southern hemisphere that supported it (for the same time period as seen in the NH records). This is perfectly correct. However, that data doesn’t exist, and what data there is does not support the global MWP. That too is correct. Why is pointing out the logic of his statement ‘saving face’? Really, I’m puzzled at what you are thinking here. – gavin]
….the believers use lack of data demonstrating warming to dismiss warming during the MWP while they use lack of data demonstrating warming to support warming in recent times
But there is no such lack of data in recent times. Furthermore this is comparing apples with oranges.
State it more carefully:
Proposition A. “maximum mean global temperature in say the interval 1100 years before present to 700 years BP years was greater than global mean temperature in 2010”. The problem for the skeptics is lack of values for the global mean temperature.
Proposition B: Be careful ! No argument here about global temperatures so nothing comparable with proposition A. What is being discussed is something utterly different i.e extracting something useful from the temperature data i.e a stable estimate of the trend and ignoring something which is less useful at present which just goes up and down which is often called noise. Noise has always existed even before large emissions of greenhouse gases.
The problem for ‘believers’ is that short intervals give you unstable estimates which vary from year to year. That is the implication of Phil Jones answers to B and C. But that does not mean he or anyone else is stuck with no idea of what is happening. Just one method is to draw a straight line through the last 30 years data and look at its slope. The resulting trend line will be sloping upwards throughout the last 15 years. There are also a variety of smoothing methods for achieving roughly the same objective.
Your comment refers to “global warming in recent years”. There is more data on that from the troposphere and the heat energy in the upper layer of the ocean. See e.g.
http://www.skepticalscience.com/global-warming-stopped-in-1998.htm
(Apologies for plagiarism and lack of references but there would be so many now)
My point is that the statistical significance applies to analyzing a noisy trend.
It is definitely warmer now than 1995, assuming the thermometers have a low error range. Looking at annual CRU numbers, we see 1998 is the warmest to date. Sure the last decade was the warmest, but 2007 being warmer than 1997 doesn’t mean very much, when you are claiming no warming since 1998. If on the other hand you are claiming the previous global warming trend stopped in 1998, then that is a different matter, and the statistical significance is important. However, just a straight comparison of 1998 to now, or 1995 to now, you only have to klook at the thermometers for those time periods, and their error ranges.
CFU: No spin here, I just do not like people (not the majority of scientists of course) who make catastrophic predictions. As solar power become cheaper and those high altitiude turbines become more efficient we will be able to supply more near zero energy, but for now all we can do is put a few more windmills up, do some carbon capture, plant more trees, sell more solar panels to the wealthy in Germany and New Jersey, and drive some hybrids/new generation electric cars. Of course hybrids or vehicles are not the main GHG emitters; it is those factories. With the long atmospheric life of CO2 we are not experience an enormous warming,and with past warming not so well understood there is reason for Jones’ admission of there not being a statistically significant warming period from 1995 to 2010. Again, however, with such a warm decade there is certainly cause for concern and further research, and you cannot spin that statement. I think or atleast I hope your heart is the right place, but perhaps you should spend mpre time with the science and the math. Global warming and climate systems are complex, and even with a 30 year or 50 year trend those are just a drop in the bucket for trends for thousands of years or a planetary scale climate system for millions of years. As always I applaud RC as an en excellent source of information, but none of the climatoligists here are making dooms day claims either.
“near zero emission.”
To Completely Fed Up. Re #293. No thanks for the useless and wrong answers. I’ll wait for someone who knows what they are talking about to answer.
KM:
No, the so-called believers do so because those reconstructions that *do* exist don’t support the hypothesis that there was a synchronous, global MWP. In Jones’ view, there is insufficient evidence to settle the question. But insufficient evidence doesn’t mean *no* evidence.
Those who hypothesize that there was a synchronous, global MWP ignore the fact that the available evidence pointing the other way.
You paint the situation as being ying and yang, of being symmetrical. It’s not. One view is consistent with the available evidence, the other flies in the face of it (screaming “science fraud! science fraud!” when the fact is pointed out to them).