The missing heat

It seems that a number of people are talking about a recent Nature News Feature that discusses missing heat, or why surface temperatures have risen slowly for the last 16 years or so.

An explanation for the supposed “hiatus” that is discussed in this news feature is that the rate of surface warming depends on the phase of the Pacific Decadal Oscillation (PDO). The PDO is a cycle that lasts a few decades, during which the Pacific will go through a phase of being warmer than normal, followed by a phase when it’s cooler than normal – illustrated in the figure below (taken from the Nature News Feature).
Warming2
When the PDO phase is such that the Pacific is warmer than average, the surface temperatures rise quite quickly. When in the cool phase, the surface temperatures rise more slowly, or stall. This is shown below (taken from the Nature News Feature) and illustrates that the warm or cool phases could last for 20 – 30 years. The current slowdown/pause started about 16 years ago, and so some are suggesting that it could continue for another 10 – 15 years (maybe until 2030).
Warming
There is, however, an issue with the current slowdown persisting for as long as another 15 years. The figure below is from Hansen et al. 2011 and shows surface temperatures and planetary energy imbalances for three different models. If, as the figure above illustrates, there was a surface warming pause between 1945 and 1975, then the figure below indicates that the planetary energy imbalance increased – during that period – from around 0.1 Wm-2 to about 0.4 – 0.5 Wm-2. This is actually consistent with what one would expect based on the increase in atmospheric CO2 over that period.

(credit : Hansen et al. 2011)

(credit : Hansen et al. 2011)


So, is it possible that the current slowdown/pause could persist until 2030? Well, the energy imbalance in 1998 was probably around 0.6 Wm-2. If we follow a BAU emission scenario, atmospheric CO2 could increase to around 450ppm by 2030. Using ΔF = 5.35 ln (C/Co) would suggest that anthropogenic forcings would increase by about 1 Wm-2 if a surface temperature standstill also persisted until 2030. So, we’d have an energy imbalance of between 1.5 and 2 Wm-2 and the oceans would be absorbing significantly more energy than they are today. I guess it’s possible, but it seems somewhat unlikely. The oceans would need to absorb an ever increasing fraction of the excess energy.

So, the basic idea seems plausible, but even from the article itself it appears that it’s not accepted by all. However, it would seem unlikely that one could maintain the current conditions for much longer unless the planet is able to have a significantly higher energy imbalance than today without driving faster surface warming. I’ve written this quite quickly, so there’s probably much more that could be said and there may be some things I’ve missed, or mis-interpreted. The article itself, however, ends with

At present, strong tropical trade winds are pushing ever more warm water westward towards Indonesia, fuelling storms such as November’s Typhoon Haiyan, and nudging up sea levels in the western Pacific; they are now roughly 20 centimetres higher than those in the eastern Pacific. Sooner or later, the trend will inevitably reverse. “You can’t keep piling up warm water in the western Pacific,” Trenberth says. “At some point, the water will get so high that it just sloshes back.” And when that happens, if scientists are on the right track, the missing heat will reappear and temperatures will spike once again.

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128 Responses to The missing heat

  1. Rachel says:

    There’s something about that Nature article that bothers me a bit. The wording the journalist has used seems a bit dramatic in places and geared more towards creating controversy than simply explaining the science. This sentence in particular: “But the pause has persisted, sparking a minor crisis of confidence in the field.” Really? A minor crisis of confidence in climate science? This sounds more like something I’d read on a contrarian blog than in Nature. I also noticed there was no mention of the Cowtan and Way paper.

  2. Ian Forrester says:

    This graphic from Skeptical Science shows temperature trends for El Nino years, La Nina years and neutral years. The slopes are identical. It can also be seen that the latest anomaly for La Nina years is almost as great as the anomaly for the last El Nino year. So even if we stick with La Nina conditions the temperature increase will remain quite high.

    http://www.skepticalscience.com/graphics.php?g=67

  3. AnOilMan says:

    I’ve been gleaning bits and pieces here and there about this.

    I came across this… which mentions some aerosol data that can be added back into the climate models. (You can find it in PDF form elsewhere.)
    http://www.nature.com/nclimate/journal/v3/n9/full/nclimate1972.html

    Then there is the question of accuracy of your measurement system. What is covered by those thermometers, and what isn’t? The arctic appears to have the biggest variation yet the poorest coverage. i.e. has a lot of heat headed up there?

    Then there is the issue of short term weather events;
    http://www.skepticalscience.com/rahmstorf-foster-cazenave-2012.html

  4. Ian Forrester says:

    Rachel, I thought exactly the same thing. I checked on Tollefson and he is not a scientist but a journalist. he therefore either has little grasp for scientific nuances or he kew exactly what he was doing.

    The editorial policy at a number of journals are not what they should be Two examples are the furor in the independent scientific community on an editor’s decision to retract a paper not for the accepted reasons but because the results were “inconclusive”. If we went by that criterion the scientific literature would be reduced to a few papers per year.

    http://www.gmfreecymru.org.uk/news/Press_Notice13Jan2014.html

    The second is an embarrassing trick that Nature Biotechnology played on a Russian scientist.

    http://www.gmwatch.org/index.php/news/archive/2007/5923-journal-sets-up-scientist-for-brutal-attack

    It would appear that some journal editors are succumbing to corporate pressure.

  5. Rachel says:

    OilMan,

    “What is covered by those thermometers, and what isn’t?”

    This is exactly what the Cowtan and Way paper found which I should have linked to: Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends. The Arctic has been warming faster than most other places and yet there are few instruments there leading to underestimation of the temperature trend.

    Ian,
    As soon as I read that article I went looked up the author and discovered he was a journalist which didn’t surprise me. The language has journo written all over it.

  6. Rachel,
    Yes, maybe it was a slightly odd article. I was surprised that it said that temperatures hadn’t changed in 16 years which, even without Cowtan and Way, isn’t strictly correct.

    Ian,
    I’ve been following your exchange over at Scotty’s. It seems as though you may be on the way to being a banned. A positive outcome, IMO 🙂 I also notice that it’s not only climate scientists that can’t get funding if they don’t toe the party line. It seems that hisorians interested in Scottish history can’t get funding unless their work illustrates how badly the English treated the Scottish.

    AnOilMan,
    I should probably give you some credit for this post as it was partly your comment on my previous post that motivated this.

  7. Rachel says: “But the pause has persisted, sparking a minor crisis of confidence in the field.” Really? A minor crisis of confidence in climate science? ”

    Could not agree more. I’ve been having fun telling people about the pause since 2007. The biggest significance was not the actual trend, but the massive over reaction of certain people.

    This showed that their views were not scientifically but emotionally based.

    When people stop reacting emotionally, it will loose most of its importance.

  8. ScotScep,

    the massive over reaction of certain people.

    This showed that their views were not scientifically but emotionally based.

    When people stop reacting emotionally, it will loose most of its importance.

    I agree with what you’ve said, but I suspect I’d disagree with which people you thought over-reacted.

  9. John Mashey says:

    Anyone who expects science journalists to get everything as optimal as possible every time, in complex fields … is doomed to disappointment,

    Generally, I’ve found Tollefson to be pretty good and I’ve had productive email exchanges with him, at least a few years ago.

    What to do about poor science reporting offers some suggestions that might be productive and might help people who have not spent a lot of time talking to journalists and seeing what happens.

  10. John,

    Anyone who expects science journalists to get everything as optimal as possible every time, in complex fields … is doomed to disappointment,

    Yes, that’s probably true. Whenever I interact with journalists I’m always pleased if they don’t get it too badly wrong 🙂

  11. BBD says:

    What worries me is the emotional reaction of all the fake sceptics who have invested so much in the pause-which-is-not-a-pause-but-a-slowdown-in-the-rate-of-surface-warming when the rate of surface warming increases again, as it must.

  12. andthentheresphysics says: “I agree with what you’ve said, but I suspect I’d disagree with which people you thought over-reacted.

    The first time I used it … I thought I would get a sensible reply like “but 5 years is not statistically significant” or “but one expects to get periods without warming”. Instead the person just flatly denied it. I obviously showed them the LR of the figures showing it was true, but they continued to deny it.

    And that’s been the reaction for the last 7 years.

    Then finally I read Rachel’s post … and guess what … 7 Years later … I was hoping to have that conversation I’ve been waiting to have … about the meaning of the pause, not yet another conversation from yet another person denying a linear regression

  13. Sorrt — if the first time I used it was as I remember 5 years … that would make it 2006, not 2007 as I started using the 1.4-5.8C prediction of 2001 as the basis for my early work.

  14. ScotScep,

    I was hoping to have that conversation I’ve been waiting to have … about the meaning of the pause, not yet another conversation from yet another person denying a linear regression

    Clarify please. I don’t understand what you mean by this.

  15. Rachel says:

    Actually Scotty, you have made it look like you are quoting me in your previous comment when actually you’re quoting the Nature article. I did not say that. I was quoting something from the Nature article that I didn’t like very much.

  16. Joshua says:

    SS –

    “I’ve been having fun telling people about the pause since 2007. .”

    Is that the “pause in global warming,” that you’ve been talking about, or the relatively short-term decrease in the rate of increase for land surface temps, only?

    ‘Cause if you were talking about the “pause in global warming” then you, yourself were over-reacting (well, either that are you don’t accept the basic physics of the GHE).

    What I mostly see is “skeptics” (although not only “skeptics”) talking about the “pause in global warming.” So, the question that Anders asks above is indeed in need of an answer.

    My guess is that you were talking about the “pause in global warming.”

  17. andthentheresphysics,
    I was hoping to have that conversation I’ve been waiting to have … about the meaning of the pause, not yet another conversation from yet another person denying a linear regression

    Clarify please. I don’t understand what you mean by this.

    8 years is a long time to remember where I was hoping the conversation would go. I guess, the issues would be these:
    1. What is a statistically valid period for climate – I can now answer that and say there is no distinguishable period, but for simplicity I’d have accept “10 years” … but it’s easy to say that 8 years after I started the conversation about the 5 years of pause.

    2. How often do we expect e.g. 5 years of warming (10 years would be a more sensible question now). The answer to this is that I’m still looking for something about the statistics of this kind of noise.

    3. The last question is how much noise is present in the climate. At the time I started this conversation … the level of “hidden cooling” would have to be about 0.17C. It’s now around 0.35 (about the same the Met Office failed prediction used).

    4. When would this level be significant.
    1910-1940 it warmed 0.48 … 1970-2000 we have 0.48C warming. At a typical warming prediction of 0.35/decade that would suggest a pause of more than 14 years (after 2001) would require 0.48 of “hidden cooling” to offset the “hidden warming”, suggesting that natural variation is as large as the warming after the global cooling scare (1970-2000) and the largely natural warming (before CO2 measured rising) between 1910-1940 warming.

  18. Joshua says: “I’ve been having fun telling people about the pause since 2007. .”

    Is that the “pause in global warming,” that you’ve been talking about, or the relatively short-term decrease in the rate of increase for land surface temps, only?

    It was the pause in HADCRUT3

    8 years waiting for a group of people claiming to be “scientists” to agree that the linear regression of the British dataset shows a pause … finally I get the next step in the discussion.

    It’s a bit like waiting for deep thought … and finally I get it “What do you get if you multiply six by nine?” … 42?????

  19. ScotScep,
    Let me make it clear that considering only surface temperatures misses an awful lot of the energy flow in our climate. More than 90% of the excess energy goes into the ocean.

    1. What is a statistically valid period for climate – I can now answer that and say there is no distinguishable period, but for simplicity I’d have accept “10 years” … but it’s easy to say that 8 years after I started the conversation about the 5 years of pause.

    When considering surface warming trends, most would argue for longer than a decade. There are two reasons for this. One is that variability (such as ENSO cycles) would need a number of decades to average out. The Nature News Feature may indicate that you may need as much as 50 years to ensure that you consider both phases of the PDO.

    Another point is that if one considers only surface warming, the uncertainty in the trend decreases with increasing time. If you consider your chosen period (2001-2013) the uncertainties in the trends (depending on the dataset) are between 0.16 and 0.2oC per decade. So you think it’s been flat? I think that even if the mean trend is flat, the uncertainties mean that there is a 95% chance that the actual trend is between 0.2 and -0.2cC per decade. So, if you want smaller uncertainties you need to consider a longer time period.

    How often do we expect e.g. 5 years of warming (10 years would be a more sensible question now). The answer to this is that I’m still looking for something about the statistics of this kind of noise.

    I don’t really understand what you mean.

    The last question is how much noise is present in the climate. At the time I started this conversation … the level of “hidden cooling” would have to be about 0.17C. It’s now around 0.35 (about the same the Met Office failed prediction used).

    Again, I don’t quite understand what you mean. If our current energy imbalance is around 1 Wm-2 then – in the absence of feedbacks – surface temperatures would need to rise by around 0.3oC to cancel this excess. If one considers Otto et al. (2013) it appears as though radiative feedbacks are comparable to the anthropogenic forcings. That would imply something closer to 0.6oC. So, the level of “hidden cooling” (in terms of reaching equilibrium at least) is around 0.6oC.

    When would this level be significant.
    1910-1940 it warmed 0.48 … 1970-2000 we have 0.48C warming. At a typical warming prediction of 0.35/decade that would suggest a pause of more than 14 years (after 2001) would require 0.48 of “hidden cooling” to offset the “hidden warming”, suggesting that natural variation is as large as the warming after the global cooling scare (1970-2000) and the largely natural warming (before CO2 measured rising) between 1910-1940 warming.

    Again, I’m not quite sure what you mean here. There are periods where the surface warming can exceed 0.2oC per decade and others where it is below 0.1oC per decade. This variation is likely internal variability. The long-term trend (1950-2013) is around 0.12oC per decade.

    So, sometimes more of the energy excess goes into the oceans than at others and this leads to variability in the surface warming trend.

  20. I already debunked that 1910-1940 talking point the last time Scotty accused me of being a charlatan “crying wolf” over a nonsense scam. I also shared open source code that would allow a real skeptic to learn about statistical significance of short trends vs. long trends, see how much noise is present in the climate, etc.

    A real skeptic could easily use this code (or the SkS calculator) to verify that there’s been no statistically significant change in the surface warming rate.

  21. andthentheresphysics says: “I don’t really understand what you mean.”

    … so finally you admit the pause, and does the earth shake and the world come to an end.

    No … it’s pretty boring questions about statistics. However, as you say, it’s proving difficult to understand my question.

    So, perhaps I could put it simpler:

    When Pooh & Piglet dropped the sticks over the bridge, they came out the other side apparently randomly placed with respect to each other. But to their disappointment, these sticks that just seemed to get further and further apart under the bridge, far from jumping out the river as they seemingly must, they both carried on down the same river.

    From this, Pooh and Piglet deduced that the sticks get further apart under the bridge where they cannot be seen but this does not happen where they can be seen. From this they theorised that the sticks must be shy, and that they continue in the river rather than jumping out (as they ought) because they do not want to be far apart from their friend.

    In a chaotic stream, why don’t the pooh sticks continue getting further apart?

  22. BBD says:

    So the term “missing heat” is incorrect when considering the climate system as a whole rather than just surface GAT, and there’s insufficient data to claim “pause” in the first place. It’s hard to see the actual basis for the supposed concerns about climate science. There appears to be nothing to be concerned about. And let’s not forget that nobody ever said natural variability would stop and warming would be monotonic.

  23. BBD says:

    Um, why are the sticks supposed to jump out of the river? I didn’t think sticks could do that. So you’ve rather lost me there, I’m afraid.

  24. BBD says: “Um, why are the sticks supposed to jump out of the river? I didn’t think sticks could do that. So you’ve rather lost me there, I’m afraid.

    Because sticks dropped in together get further apart (at least under the bridge). Therefore Pooh concluded that if he continued watched the sticks as they travelled down the river, they would soon get so far apart they would have to climb out the river to get further apart.

  25. This is why we can’t have nice things.

  26. BBD says:

    But the sticks are in the river, and the river is contained and channelled by its banks. So I still don’t see why the sticks should jump out of the river unless they were sentient, capable of jumping, and wanted to do it. All of which is a bit of a stretch, really.

  27. BBD says:

    Wasn’t Pooh a “bear of very little brain”, or am I confusing this imaginary being with another one?

  28. BBD says:

    Memory serves, for once:

    When you are a Bear of Very Little Brain, and you Think of Things, you find sometimes that a Thing which seemed very Thingish inside you is quite different when it gets out into the open and has other people looking at it.

  29. I think you’re confusing this with a conversation that has any redeeming value.

  30. Joshua says:

    “It was the pause in HADCRUT3”

    Seems that you might be avoiding my question.

    Let me try again. Would you agree that those talking about the “pause in global warming,” are reacting emotionally (or don’t accept the physics of the GHE)?

    If so, it’s good to see a “skeptic” willing to criticize the overly-emotional reaction of so many other “skeptics.” That is something that I’ve found most “skeptics” to be rather reluctant to do.

    I’ve also found them rather unwilling to talk about the difference between a “pause in global warming” and an apparent short-term pause (ok, if you must) in the trend of significant increase of surface temps, only.

  31. BBD: We are dealing with a bear with a very small brain.

    Was Pooh right to suggest they would “stay together”? (from which he concluded they must be attracted to each other as friends). How often do we expect such sticks to “come together” – and how often do we expect them to be in a position beyond the banks?

  32. Joshua says: “It was the pause in HADCRUT3″

    Seems that you might be avoiding my question.

    The pause is just a statistic. I’ve suggested a trend of between 0.07C and -0.07/decade. Above 0.07C, it would be closer to the lower bound of the IPCC 2001 prediction than it is to zero.

    And it is a bit rich to criticise me of “avoiding the question” when it has taken your side 8 years to answer mine and agree on basic matter of fact statements about the current trend being a pause.

    Yes, one of the the next questions is what does it actually mean in terms of actual temperature trend in the climate. … however, again, it was us sceptics who suggested that the HADCRUT3 temperature change over the 20th century might not be a true reflection of actual climatic change … and your side rejected any such idea … so it’s a bit rich to suggest that I’m saying it is what is the same as global temperature.

    it is just a statistic on a dataset which was never perfect.

  33. AnOilMan says:

    A seagull flew in…

    First… this isn’t new. Not at all. Look at the paper Trenberth was referencing in the so called ‘climate gate’ emails. The comment “Its a travesty we can’t account for all…” wasn’t exactly private, he was referring to a paper he wrote and was public knowledge;
    “An imperative for climate change planning: tracking Earth’s global energy”
    http://www.wired.com/images_blogs/threatlevel/2009/11/energydiagnostics09final.pdf

    “While a long-term trend is for global warming, short-term periods of cooling can occur and have physical causes associated with natural variability. However, such natural variability means that energy is rearranged or changed within the climate system, and should be traceable.”

    Second… if heat goes missing, sooner or later you will find it. My Hyundai Pony exploded when the radiator failed. That was how I found out the thermometer was broken, and in fact I was missing quite a bit of heat. 🙂

    Third… there is something interesting going on, and its too early to tell what it is. *gasp*… maybe we have a shift in the PDO (assuming it still exists anymore I might add). Eventually we’ll see where this energy has gone.

    Dumb Sci can probably attest to this….
    …a few years back when the oceans went down. The Denial community was abuzz that if oceans went down then all of global warming must be over. Instead it was just a year that rained so hard that the ocean level dropped. This is the very stuff of energy rearranging itself for the new level of energy we are at. I also recall that there wasn’t a measured answer to the issue at the time.

    http://www.vancouverobserver.com/blogs/climatesnapshot/2011/09/27/nasa-it-rained-so-hard-oceans-fell

    Curious… but how much energy would it take to move that much water. It doesn’t just store heat, it weighs a lot.

  34. BBD says:

    Scottish says:

    it is just a statistic on a dataset which was never perfect.

    Which no doubt is why we now have HadCRUT4. Not to mention Cowtan & Way, as Rachel mentioned earlier.

    There appears to be no basis for concern, as I mentioned earlier.

  35. Joshua says:

    And it is a bit rich to criticise me of “avoiding the question” when it has taken your side 8 years to answer mine and agree on basic matter of fact statements about the current trend being a pause.

    So, in other words, “Mommy, mommy, they did it fiiiirrrrssstt?”

    Did you consider the tendency towards Mommymommyism when you wrote that post with that matrix of the characteristics of “skeptics” and climate scientists?

    And btw, SS, you’re still avoiding the question.

  36. Me: it is just a statistic on a dataset which was never perfect.

    BBD says: There appears to be no basis for concern, as I mentioned earlier.

    No this is disastrous news. The whole fun of the climate debate was laughing at the people who wouldn’t admit the pause. If your side suddenly starts being sensible, we may never find such a rich vein of blogging material again.

    Or to put it another way … once your side stop coming out with hair brain temperature predictions which ignore the pause and therefore are obviously too high … the day may be soon dawning when you turn around and ask us sceptics what we think the global warming trend really is … and then we are snookered, because that is a far harder question to answer than whether or no it is too high.

  37. Louise says:

    Does anyone else think the link between UKIP and ‘skepticism’ is more than coincidence? Roger Tallbloke, Sottish Sceptic, Monckton; Latimer Alder, etc. Can you name a British ‘Sceptic’ that comments on blogs not linked this way?

  38. Kevin Cowtan says he talked to Tollefson on the phone for an hour about this piece. Yet Cowtan & Way wasn’t even mentioned. An absolutely glaring omission. You can’t talk about the ‘pause’ without talking about the fact that it’s in large part an artifact of coverage bias, as their paper showed. It might have been a decent piece with a discussion of that issue, but without it, it’s just fundamentally flawed.

    I’ve talked to a journalist with Nature Climate Change who’s also working on a ‘pause’ piece. I suspect hers will be much better.

  39. AnOilMan says:

    But Scottish Sceptic… No one said there wouldn’t be a pause in global surface temperatures. Its people like you insisting that some how that is true. In fact they didn’t say it would be monotonically increasing either. They also stated very very clearly that they were not modeling weather like the PDO or ENSO and what not. They also stated very very clearly that there were a lot of uncertainties around how oceans would affect surface temperatures. Read the first IPCC report. All this is stated there. Now we have ARGO… confirming what they knew.

    How about we be clear about this. Global Warming as continued unabated (we know this because oceans are getting hotter and sea level is rising, etc). Surface temperatures appear to have paused, and by that I mean the rate of increase appears lower than it should be.

    I’d be in your camp if it weren’t for the fact that we are able to account for a considerable amount of what is happening, as well as the fact that the oceans are still rising and that takes a huge huge huge amount of heat.

    It takes some 4 Hiroshima Bombs second to make that ocean rise…
    http://4hiroshimas.com/

    Welcome to the sauna vortex baby!

  40. Anyone who’s laughing at “people who wouldn’t admit the pause” should first determine when this “pause” started, then calculate trends and their very important 95% confidence intervals for equal timespans before and after that point. Do their confidence intervals overlap? If not, it seems like there hasn’t been a statistically significant change in the surface warming rate.

    Anyone whose computer doesn’t let them click on links might still be enlightened by pondering these AR5 trends (and their very important 95% confidence intervals):

  41. AnOilMan says:

    Dana Nuccitelli: I’m waiting to see a decent reconstruction of what is going on like a lot of other people. I get that its hard to do, but to me we need a one stop shop that explains the current discrepancy. There is more to it than just Cowton and Way. Adding aerosols (missing in many models) to model data also increases modeled temperatures. IMO there is a lot more going on. On the other hand that is always the case.

    As long as there isn’t a clear answer, the denial community will step in and sew FUD. (Fear Uncertainty, and Doubt.)

  42. AnOilMan refers to research done by a team led by Dr. Carmen Boening about the 2011 La Nina, which was so strong the oceans fell. Water is heavy, but the latent heat of vaporization seems much larger than any transport energy. If the latent heat of vaporization was all used to lift the water vapor, it would be launched hundreds of kilometers into space.

  43. The open source code I shared estimates confidence intervals in the presence of auto-correlated noise. These statistics are so old I don’t even know when they were first published. Scientists have warned about noisy surface temperatures since at least the 1990 IPCC AR1 WG1 report which said in the Executive Summary that “The rise will not be steady because of the influence of other factors.”

    Gary and Keihm 1991 showed that natural variability in only 10 years of UAH data was so large that the UAH temperature trend was statistically indistinguishable from that predicted by climate models.

    I don’t know how old the more conservative WMO definition of “30 years” for climate is, but that longer minimum timespan just makes questions about some alleged surface “pause” seem even more like fishing expeditions deep in the noise. Can we please stop playing Groundhog Day?

  44. Correction: Do their confidence intervals overlap? If so…”

  45. When I got to read that article yesterday, I felt instantaneously disillusioned given that it boils down to selling the controversy. It contains nothing new whatsoever. Worse, cherrypick seems to have become the new normal. How can Nature not object to a sentence like this: “[…] average atmospheric temperatures have risen little since 1998 […]“. Perfectly okay if put in the right climatological context. Jeff however puts it in a climate model context instead: “[…] in seeming defiance of projections of climate models and the ever-increasing emissions of greenhouse gases.” He keeps banging on that myth later in his essay by comparing model and observed trends for the cherrypicked interval 1998-2012 (the same selection criteria for the interval prior to that would lead to the opposite conclusion). The climate ostriches couldn’t have asked for more.

    The rest of the article is okay, though still afflicted with lots of handwaving. Why is it that journalists can’t get their head around the fact that more than one explanation is part of the story? While Jeff initially explains all the contributing factors, he seemingly dismisses the volcanic share in the forcing puzzle when he cites Mark Cane. It’s still there and John Fyfe himself had a GRL paper out last year which managed to quantify the effect. Suddenly it’s all down to PDO. As if we hadn’t known this from Foster and Rahmstorf 2010 already. Why are people so surprised. I’m sorry when it sounds arrogant, but I don’t get it! If you don’t believe in the informative value of multiple regression, just check the global distribution of the temperature trend before and after 1998. A(n almost) perfect ENSO match. Sure, we don’t know the exact contribution of each player, but it should be clear that they do play a role (especially when it comes to the comparion with models).

    The next problem is just around the corner. PDO might do the trick right now, but not over longer periods of time. PDO as well as MEI are indices which are standardized with respect to a specified SST or SAT climate reference period. If this reference period falls within a period of strong forcing changes, the low frequency variability can’t be properly attributed. Therefore, the Southern Oscillation Index (SOI) seems to be the better metric as it is based on instantaneous pressure differences only. Comparing the three indices, we see that SOI shows much less cyclic behaviour over the past 80-90 years. It suggests that the mid-century cooling (1950-80) is indeed primarily forcing driven rather than ENSO driven. I mention it, because it is evidence against true oscillatory behaviour. Therefore PDV rather then PDO. Also not new, but it doesn’t get mentioned in the article.

    Which brings me to the last point. Neither the winter WACCy-problem (Warm Arctic Cold Continent) is mentioned, nor the latest Cowtan and Way finding. While the latter might have been simply too late for this article (which it obviously wasn’t according to Dana’s comment above), WACCy is the most interesting problem by far given that the NH-winter trend is the most conspicuous element in the slow-down. It seems to be a negative feedback of sorts, may it be temporary in nature or not. If only temporary, the subsequent rise in temperature could be quite drastic. We haven’t even begun to understand what’s going on. We only know that there is something going on. And speaking of WACCy, we just returned to this very pattern these days. Unfortunately, the reader of this Nature editorial won’t learn more about WACCy. I wonder whether the casual reader will have learned anything after all. But then, I’m certainly way too harsh. On the other hand, I’m obviously not the only one who didn’t like the article 😉

  46. Tom Curtis says:

    ScSc wrote:

    “At a typical warming prediction of 0.35/decade that would suggest a pause of more than 14 years (after 2001) would require 0.48 of “hidden cooling” to offset the “hidden warming”…”

    (My emphasis)

    This quote shows there is not point in debating with the Scottish … [Mod : minor edit].

    The fact of the matter is that the typical warming prediction over the period from 2000-2030 is 0.2 C per decade (AR4) to 0.23 C/ decade (AR5). That the Scottish … [Mod : minor edit] inflates that figure by 50-75% shows there is no point discussing the issue with him. He is clearly happy to make up “facts” to suite his case rather than to report honestly on the actual projections of climate models.

    No doubt this comment will be severely edited by the moderator, but I again make the point that if it is offensive to be called a liar, logically it must be even more offensive to lie. The Scottish … [Mod : minor edit] shows his deceit to be no accident, no error in typing, by using it in his calculation.

    The only way he can plead ignorance rather than deceit is by admitting he cannot distinguish between a linear and a non-linear trend – ie, that he genuinely believes that a warming of 3.5 C over a century is only possible with a linear trend of 3.5 C per decade. If he thus admits that scientifically he hasn’t even caught up with Newton, and apologizes for wasting our time with his foolishness, I will admit that I have taken stupidity for deceit, and apologize for that.

    [Mod : some minor edits for consistency with the comment/moderation policy.]

  47. AnOilMan says:

    Tom Curtis: It’s called motivated reasoning… Or was that Kruger Dunning?

    PS. You forgot the error bars. What kind of sawed off physics course did you take any ways! :-). You can do better than that!!

  48. John Mashey says:

    Dana: sorry to hear that about Jeff … odd.

  49. ScotScep,
    I note you’ve barely considered my response to your initial question. Also, you should consider the possibility that the reason I didn’t understand what you were asking is not that what you were asking was complicated and difficult to understand, but because it didn’t really make any sense in the first place.

    Given that you seem to have ignored my response to your comment, that I’ve had to moderate mildly another comment in response to what you’ve said here (and, to be clear, I’ve only moderated that because it just violates my moderation policy and not because I disagree with what was said) I plan to simply delete any future comments you make unless they happen to be constructive and thoughtful. If you object, feel free to not comment.

  50. Karsten,
    Yes, I’m somewhat new to this but I too thought that the article was presenting ideas as being new when in fact they’ve been around for a few years. I didn’t find it a terrible article, but it could certainly have presented a more balanced view.

  51. Louise,
    I’ve noticed the same myself and commented on that here in the past. My initial thought was that it is related to the link between one’s ideology and one’s view on climate change. I have heard a possible plausible alternative which is that UKIP is the only party that is openly skeptical of man-made climate change and hence is attracting such people. Either way, it does appear as though there is a statistically significant link between being openly and vocally skeptical of climate change and being a member/supporter of UKIP.

  52. verytallguy says:

    Andy Dessler congress testimony (h/t Eli Rabett)

    the problem in very short temperature trends (like a decade) is that climate variability such as El Niño cycles completely confounds ones ability to see the underlying trend. However, this short-term variability can be removed, and, if one does that, then the hiatus essentially disappears [Foster and Rahmstorf, 2011; Kosaka and Xie, 2013]. Because of this, I judge that there is virtually no merit to suggestions that the “hiatus” poses a serious challenge to the standard model.

  53. verytallguy says:

    Whilst I’m no Andy Dessler, I had a go at very simply modelling noisy data to see what the signficance of the pause is. If you assume white noise of magnitude 0.2 degrees with a linear trend of 2 degrees/century then you can expect a 10 year negative trend nearly 20% of the time.

    And that’s taking a regressed trendline, not the simple start and endpoints.

    We should expect hiatuses, they are normal.

    See also the escalator.

  54. VTG,
    Yes, I saw Eli’s post and thought Andrew Dessler’s testimony was very good. He made a strong case, didn’t try to beat around the bush, and seemed to focus on those things that we think that we understand well – which I think is important.

  55. Barry Woods says:

    I’m aware of scientists looking at the ‘pause’ or being aware of it since at least 2008…
    BUT, this is not how it has appeared in the media, when talk of the pause has resulted in attacks on those talking about it (fairly famously, with Mark Lynas and Dr David Whitehouse)

    The media have not, talked about the ‘slowdown’ or ‘counted it with ‘it’s the warmest decade (bot facts, that do not contradict each other) (the slowdown/pause which has been acknowledged in literature), and organisations and chief scientist types have not publically corrected (maybe they have tried) the media. thus, now it look like goalpost shifting.

    on top of that we have had statement by scientist saying it would 15 year, 17 years before they got worried about the pause.. and now we are at that, or beyond, and scientist like Trenberth are now saying it may be much longer, And I linked to Met Office’s Julia Slingo (RSclimate meeting) , now suggesting a 30 year pause possible. In that same audio, Prof Mike Hulme raises a very good question, about how will it be perceived if the air temp indicator (so dominate for decades) suddenly no longer matters.

    Questions will surely be asked about previous predictions and policy based on those predictions (the Met Office 2007, 0.3C by 2014 prediction, which was why the current Met Office decadal forecast ( a new one due in a week) gained so much attention, when it indicated temps would now be flat until 2017, resulting in a minor media frenzy (made the Today program, and Newsnight), in part kicked off by Roger Harrabin saying this would indicate a 20 year pause which he said would raise questions.

    Now, the ‘it’s still warming, it’s going into the oceans, you silly sceptic’ response by a few. I don’t think will play that well, not least because the political target was 2C air temp, will the politicians need another 20 years to agree a ocean temp anomaly, how to explain that to them?

    As the Surface Air temp has been the measure of global warming for decades. people will perhaps ‘perceive’ that this is goalpost moving, and a lack of understanding.

    I made this point at Making Science Public Blog:
    http://blogs.nottingham.ac.uk/makingsciencepublic/2013/09/27/just-one-number-has-the-ipcc-changed-its-supply-of-evidence/#comment-231591

    And Prof Mike Hulme had this to say (prior to RSclimate):
    http://blogs.nottingham.ac.uk/makingsciencepublic/2013/09/27/just-one-number-has-the-ipcc-changed-its-supply-of-evidence/#comment-232361

    “…..Until the last few years, global surface air T was *the* iconic index to reveal human influence on the system – and of course the global policy goal is terms of global T. As temperature flattened, attention moved first to Arctic sea-ice and now, also, it seems to ocean heat content. In today’s Independent for example of 4 graphs included the one of global T was missing. Unthinkable that this would have happened 6 or 12 yrs ago.

    The other point is about the spread betting on the climate sensitivity. If there is now no agreement amongst scientists across lines of evidence it is a great illustration of the futility of relying on consensus claims to coerce the population (cf. Cook et al and the 97% claim). In 2007 there *was* agreement on this crucial index of human influence; in 2013 this is *no* agreement. Was the 2007 agreement premature? Not necessarily – but science often works this way – it doesn’t progress in a straight line towards the truth, but meanders around not quite knowing where it is going to end up. This seems the case of the climate sensitivity – and also the high end of the SL rise scenarios.

    I’m glad to see these remarks of dissensus in AR5. I’ll be looking out for more of them on Monday. Dissensus in science, as much as consensus, is of great public value.

    Mike”

  56. Barry Woods says:

    Previously, hiatus were described as possible, but no longer than say 8-10-12 years, the longer they now occur make it more of an issue..

    this is not helped by organisations making very strong predictions for the previous and this decade.. An early one being James Hansens prediction for this decade, being between 1.1C -2.2C hotter) – I’ll dig up the link later.

    or the Met Office making very strong statement (very few caveats, like they would make now) including the phrase predictions..

    For example – Met Office Vicky Pope predicting 0.3C by 2014
    (note not projections, no caveats about longer pauses possible,and other strong statements)

    video (september 2007) here

    2 quote Vicky –
    “we are predicting 0.3C by 2014 compared to 2004.
    “very strong statement about what will happen over the NEXT 10 years)”

    Based on the Met Office first decadal forecast / press release here
    http://web.archive.org/web/20080708230357/http://www.metoffice.gov.uk/corporate/pressoffice/2007/pr20070810.html

    News release
    10 August 2007
    The forecast for 2014…
    Climate scientists at the Met Office Hadley Centre will unveil the first decadal climate prediction model in a paper published on 10 August 2007 in the journal Science. The paper includes the Met Office’s prediction for annual global temperature to 2014.

    Over the 10-year period as a whole, climate continues to warm and 2014 is likely to be 0.3 °C warmer than 2004. At least half of the years after 2009 are predicted to exceed the warmest year currently on record

    These predictions are very relevant to businesses and policy-makers who will be able to respond to short-term climate change when making decisions today. The next decade is within many people’s understanding and brings home the reality of a changing climate.

    The new model incorporates the effects of sea surface temperatures as well as other factors such as man-made emissions of greenhouse gases, projected changes in the sun’s output and the effects of previous volcanic eruptions — the first time internal and external variability have both been predicted.

    Team leader, Dr Doug Smith said: “Occurrences of El Nino, for example, have a significant effect on shorter-term predictions. By including such internal variability, we have shown a substantial improvement in predictions of surface temperature.” Dr Smith continues: “Observed relative cooling in the Southern Ocean and tropical Pacific over the last couple of years was correctly predicted by the new system, giving us greater confidence in the model’s performance”.

    Notes

    Total global warming, on a decadal average, is 0.8 °C since 1900 (IPCC 2007)
    1998 is the current warmest year on record with a global mean temperature of 14.54 °C

    -end press release————

    So this decade has had strong predictions made for it.

    but now(2014), the Met Office forecast is flat until 2017 (who knows the next one due in days might be lower) and Slingo is suggesting the pause could be 30 years, how much policy based on those previous ‘predictions’ for the coming decade?

  57. Barry,
    Rather than quoting various things that may or may not be relevant to the public discussion of global warming/climate change, could you possibly express a well-defined view of your own. At the end of the day, there is just science/physics. That something unexpected happened and that it has taken a while to understand is not that unusual.

    For example, my interpretation of the whole “missing heat” issue (Trenberth) was that basic physics was saying that we should be warming. The slowdown/pause in surface warming was therefore surprising. Hence, there was “missing heat”. This was either because it was going somewhere else, or there was a problem with the physics. As good scientists do, you investigate and try to understand what’s happening. It now appears that we’ve been in an ocean cycle phase that has lead to more of the excess energy going into the oceans than was the case in previous decades. Hence surface warming has slowed.

    To me, this is a great example of how science works. You have models and calculations that don’t quite match what happens. You then try to work out why. Nothing unusual. The problem though is those who try to frame this as scientists moving the goalposts, when – in my view at least – it’s simply how science works. Those who frame it this way are either ignorant of how science works, or are actively trying to undermine scientific results that are inconvenient. In any other area, it would have been framed as a great improvement in our understanding of a complex system. In climate science it gets framed as some kind of failure.

    I agree that how science is discussed with the public is important and it can easily go wrong if it is presented poorly. However, that doesn’t change the scientific reality. Furthermore, much of the problem with the public discourse is because of those who frame (intentionaly or not) it in a way that undermines the scientific message.

    So, rather than focussing on issues related to public engagement, maybe you could either explain the relevance of this issue, or express a view as to our current understanding of climate science. As far as I’m concerned the world is warming. The energy imbalance is roughly what physics would predict, but a cool PDO phase (and possibly a cooler Sun and anthropogenic aerosols) have lead to slower surface warming than maybe we expected (although, as Dana points out, maybe not as slow as we think). When a warm PDO phase returns (and when aerosol concentrations drop) we will likely move into a phase of more rapid surface warming (the energy imbalance has to eventually be cancelled) and there is every chance that the we could see more than 2 degrees of surface warming over the rest of this century.

    So, rather than pointing out potential issues with the public discoures (which may be valid but are probably irrelevant from a scientific perspective) can you possibly answer my earlier question about why you are a lukewarmer. What evidence is convincing you that we’re likely to see (over the next century) warming well below the IPCC mean?

  58. Barry,

    Slingo is suggesting the pause could be 30 years, how much policy based on those previous ‘predictions’ for the coming decade?

    As I point out in the post, 30 years seems unlikely given the excess energy that would need to be sequestered in the oceans. As far as policy for the coming decade is concerned, I really don’t care.

  59. Barry Woods says:

    Hi Anders.. there is nothing wrong with scientist being wrong, learning something new, explaining it, this is how science progresses. My point is there appear to be a little rewriting of the past going on. hence my links. showing strong statement were made..

    Perhaps it is naive,
    but a look at that Nature graphic, would show a longer term 0.07 deg C per decade per century rate of temp rise, (presumably natural, as it is there, before any significant co2 relases in the 50’s – consistent with IPCC) On top of that there are at least one process at work, PDO, which cause shoter periods of warming, stalling, on that background rising trend

    So a starting point would be to suppose that natural process would continue this century, and to look for any AGW signal on top of that.

    It seems entirely reasonably to me to suppose that a 1940’s-1980 pause pattern (see global graphic Hadcrut4) may repeat itself for another 20 years, and as the Nature and Trenberth suggest this is/was due to PDO.

    We shall see: if temps rise over the next 20 years, this could be proof of an AGW signal!, ie the scientist now expect a natural pause, (PDO related) depending on the rate of rise, we should be able to get a value for sensitivity, constraining or vindicating model projections, or it may stay flat, or even fall slightly, which may indicate sensitivity is lower..

    so for science the next 10-20 years of data, will I think go a long way to our understanding of climate.

  60. Barry,

    It seems entirely reasonably to me to suppose that a 1940′s-1980 pause pattern (see global graphic Hadcrut4) may repeat itself for another 20 years, and as the Nature and Trenberth suggest this is/was due to PDO.

    Direct science question. Why do you think this is possible? As I point out in the post, the 1940-1980 pause was accompanied by an energy excess that increased from around 0.1 to 0.4 Wm-2. Today we have an energy excess of around 0.6 – 0.9 Wm-2. If we follow a BAU scenario, this could increase by 1 Wm-2 in the next 15 – 20 years. So, the oceans would need to be absorbing an ever increasing fraction of the excess energy (and probably absorb energy at a rate higher than at any time in human history). So, why do you think it could continue for 20 years? Because it’s happened before? Because you’ve actually done some kind of back-of-then-envelope calculation that suggests that it’s plausible? Wishful thinking?

    Also, you still haven’t answered my question as to what evidence has convinced you that the climate sensitivity is likely at the low end of the range.

  61. Barry Woods says:

    when I said a look at the Nature graph, I was referring to this one
    https://andthentheresphysics.files.wordpress.com/2014/01/warming.jpg?w=640&h=293

    which picked out the 1940’s to 80’s stalling period: quote

    “After sharp warming in the early 20th century, global warming stalled”

    so it seems very reasonable to suppose that this pattern may be (should be about to) repeat itself (2000- 2030, 2040)

    Which is very useful useful, as should a ‘stalling’ NOT repeat, and temps rise, this could be proof of AGW overwhelming the natural pause.

    or if it stalls or falls, AGW is perhaps small, or anything in between. So the next 10 20 years of data, will be really useful.

  62. Barry,

    My point is there appear to be a little rewriting of the past going on. hence my links. showing strong statement were made..

    Really? This is important because? Do you feel good that you’ve pointed this out? People will look back on this era and say “although the world was clearly warming and the scientists were essentially correct, it’s really good that some people were willing to delve through all the various things that were said over the decades and point out the little things that scientists said that turned out to be wrong, or were inconsistent with what they said later. It was important to know this. It really helped move the debate forward and had a positive influence on the discussion.” Do you really think that’s how history will look at this era?

  63. Barry Woods says:

    The fact that temps are currently at the low end of model projections, suggest to me that sensitivity is at the lower end of the IPCC range, the longer the slowdown continues, the more confident I will be, obviously IF temps take off, I will reconsider. so ‘convince’ is too strong, ‘seems most likely’ is better based on available observations..

    But for earlier projections, under all scenarios (by 2040) we need to be warming at a rate of 0.3C per decade, now and the longer it pauses, the higher the rate needed to reach those 2040 projections.

    I had most of that/this chat with Prof Richard Betts at the Met Office, and after 6 hours shooting the video, we were in some agreement (neither of us is Brad Pitt, sadly )

    I

  64. Barry,
    I know you were looking at that one. My question was why you thought it might continue for another 20 years. I’ve shown you a calculation that suggests that our energy excess today is much greater than it was between 1940 and 1980 and hence that we’re in a different regime today than we were then. Hence, I would suggest that another 20 years is unlikely. Do I take it that your suggestion that it could be another 20 years is based purely on the fact that a 30 – 40 years pause has happened before? It’s possible I guess, but would seem quite remarkable. Of course, maybe the physics is wrong, which would be interesting and maybe we should hope that it is. So far, however, no real evidence that the basic physics is wrong. Maybe the oceans really can continue to accrue most of the energy excess for the next 20 years. I guess we really don’t know, but expecting the oceans to accrue an ever increasing fraction of the energy excess would seem somewhat unlikely.

  65. verytallguy says:

    Barry,

    There seem to be many interpreations of “Pause”. Perhaps you could define what you mean by a pause, as well as how long you believe any such pause would need to be to matter.

    I’ll go first to show you what I think that could look like.

    We could use, in rising order of rigour,
    (1) simple straight line from temperature at start of “pause” to current temperature is less than expected long term trend.
    (2) simple straight line from temperature at start of “pause” to current temperature is less than zero
    (3) a least squares linear trendline over the length of “pause” with gradient below the long term expected
    (4) a least squares linear trendline over the length of “pause” with gradient below the long term expected at a statistically significant level (95% confidence)
    (5) a least squares linear trendline over the length of “pause” with gradient numerically below zero and below the long term expected at a statistically significant level (95% confidence)

    My definition of a pause is (5). That’s because a pause semantically implies no warming, hence zero gradient. 30 years because we know there is very significant interal variability on a timescale of <30 years. Finally, I think it's important a statistical test is included as to whether it is within expected variability or not.

    My definition of a slowdown would be (4)

    What would your definiton be? Can you pick one of my 1-5 and explain why, or propose your own?

  66. Rachel says:

    Barry,

    We shall see: if temps rise over the next 20 years, this could be proof of an AGW signal!

    This is a strange thing to say. There is already proof of an AGW signal. Do you acknowledge this? I thought you did. Did you read VTG’s comment quoting Andy Dessler above?

    Too much emphasis is being made of a temperature trend that does not follow a straight line. This is perfectly reasonable to me and not indicative of a failure of climate science or models. It also not something we can draw comfort from. Climate change will continue unabated and placing bets on a short-term variation is incredibly risky and very misguided in my opinion.

    If surface temperatures rise slowly over the coming decade, great, but what of rising sea levels, melting ice, increasing ocean acidification and changing rainfall patterns?

  67. Barry Woods says:

    GW is obvious, just look at HADCRUT4

    sorry, Badly phrased, proof of the amount of AGW !

  68. Barry,
    You seem to be using the slowdown as evidence for the lower end of the range. You also mention 2040. Precisely what are you arguing? Are you suggesting that the temperature in 2040 may be lower than model predictions? This is possible, given the current slowdown. However, bear in mind that there have been periods in the past (recent decades) when the trend exceeded 0.2oC per decade. Hence, given that the energy excess will likely be higher in the coming decades than it was in past decades, 0.3oC per decade is not impossible.

    Or, are you referring to climate sensitivity? We will likely double CO2 by 2050 – 2060 if we follow a BAU emission pathway. If the Cowtan & Way analysis is correct, even in the slowdown, the surface temperatures are rising at around 0.1oC per decade. If this remains, we reach a TCR of 1.3oC and (multiplying by 1.7) an ECS 2.2oC. Are you willing to bet on the trend remaining at 0.1oC per decade for the next 3 decades. We’re in the cool phase of the PDO. We’ve had more La Niñas than El Niños. So, climate sensitivity on the low-end of the range seems highly unlikely.

    So, what are you actually arguing for? Lower temperatures in the coming decades (possible) or lower climate sensitivity?

  69. Barry Woods says:

    verytallguy. the met Office talks of the pause. the Chief Press Office prefers the phrase ‘hiatus’ others use ‘slowdown’, if climate scientists are happy to talk about a ‘slowdown’ in GAT as real and of interest (which they do), so am I

  70. verytallguy says:

    Barry,

    I am not in any way objecting to you talking about a pause. I am merely trying to understand what you mean by it.

    It is impossible to have a meaningful dialogue on its significance without a definition; I’ve offered you a range, which are worlds apart in terms of how much they matter.

    I think it would help if you defined what you mean by a pause.

  71. Barry,
    You notice that in the video, Richard Betts says that depending on the length of the slowdown the time at which we reach 2 degrees could change by a few years. Seems quite plausible and makes sense. Doesn’t really seem to be an argument for climate sensitivity being on the low-end of the range.

  72. Barry Woods says:

    I’m saying the possible projected PDO current slowdown is useful..

    as you said IF it rises at 0.1C per decade, and we have a natural stall projected, we will get better values, if it doesn’t, we will get different better values.

    ie- if science now expect a slowdown to continue, naturally due to PDO and it doesn’t!
    it will/should help us pin down a value for AGW sensitivity.
    ie if it warms more than a projected stall, we may be able to quantify and attribute the AGW signal
    or if it warms more slower, or is flat, or cools.

    so what ever happens in observed temps, over the next decade or 2, it will help us get better values (be it higher or lower value for sensitivity). which is good for climate science.

  73. OPatrick says:

    My point is there appear to be a little rewriting of the past going on. hence my links. showing strong statement were made.

    I may have missed something but as far as I can see you have only linked to one such statement, the Met Office’s decadal forecast. I am sceptical of your claim that rewriting of history is taking place, or rather I suspect it is more that people such as yourself, and ‘Scottish”Sceptic’ above, are more guilty of rewriting history.

  74. verytallguy says:

    Barry,

    so what ever happens in observed temps, over the next decade or 2, it will help us get better values (be it higher or lower value for sensitivity). which is good for climate science.

    Yes, but probably not by all that much. Because of the inherent noise and uncertaintly in other forcings, the observed temps do not, as I understand it, provide a very strong constraint on ECS. One more decade won’t change that very much either way I expect, unless something really sensational happens (very unlikely). Even two decades, not so much.

    Remember that you need a model to relate current obs to ECS.

  75. Barry Woods says:

    he also says he agres/expects it needs to warm at 0.3C per decade at some point..

    as this conversation was in relation to a UK Forecast report projection that under all emission scenarios by 2040, it wold be warmer than now by at least 0.9C.. (a 1.3C anomaly) and that is the low end of the 2040 projections under all scenarios. And as I pointed out that 0.3C need to start very soon, or the rate of warming will have to be even higher, to hit that 2040 projection. which is only 26 years away.

    and that these models projections will be constrained if higher rates of warming are not observed.

  76. OPatrick says:

    I wonder, Barry, how much you would endorse this quote from David Whitehouse:

    “The fact is that the global temperature of 2007 is statistically the same as 2006 as well as every year since 2001. Global warming has, temporarily or permanently, ceased. Temperatures across the world are not increasing as they should according to the fundamental theory behind global warming – the greenhouse effect. Something else is happening and it is vital that we find out what or else we may spend hundreds of billions of pounds needlessly.”

    Do you think it deserves to be criticised?

  77. Barry Woods says:

    in the video we were referring to this:

    Foresight Report: – International Dimensions of Climate change
    http://www.bis.gov.uk/assets/foresight/docs/international-dimensions/11-1042-international-dimensions-of-climate-change.pdf

    ref temperature – pg70 – 2.2 Summary of Climate effects:

    “Temperature: Up to about 2040, mean global temperature are projected to increase by 1.3C – 1.7C across the world (relative to the 1981-1999 global average) under the three scenarios used in this report.”

    2.4.1:
    Temperature
    Mean Global Temperatures are projected to increase across the world for at least the next three decades in all scenarios used in this Report (High and medium emissions and aggressive mitigation, Section 2.3.1)

    ——————————-

    2040 is only 26 years away, a decade or 2 decades of pause, or a lower rate of warming, will significantly impact these projections.
    Even with aggressive mitigation scenario(unlikley?) these are projections of at least 0.9C (1.3C anomaly in 26 years time)

    a decade or 2 of pause or a much lower rate of warming, will (and Richard agreed) constrain these projections)

  78. verytallguy says:

    Barry,

    there’s a difference in constraining a specific timepoint prediction and the overall value of ECS.

    What’s your definition of a pause and why? I’ve given you mine.

  79. Barry Woods says:

    ref whitehouse.
    1st sentence: is either factually correct or not
    2nd sentence is arguably correct, depending on first being correct
    3rd sentence is i think too strong, ie could have still been variability (at the time) ie scientist were saying 8-10yrs possible

    but 3rd sentence is stronger now.
    the rest is opinion. should it be discussed/criticised even, of course.

  80. Barry Woods says:

    why do yo want my definition of a ‘pause’ in GAT I’m happy to go with the climate scientist one.. or do you think they are wrong to acknowledge / investigate it?

  81. OPatrick says:

    Why are you unwilling to say what your understanding of the term ‘pause’ is?

  82. Barry,
    Okay, so you’re arguing that we need a couple of decades of rapid warming in order to match a 2040 prediction and that leads you to conclude that the low-end is more likely than the mean. Is that a fair assessment?

    The problem I have is that you’re focusing partly on a specific time, rather than on something like TCR/ECS/ESS. So the slowdown will likely effect global temperatures in 2040 and, as Richard Betts says, may change – by a few years – when we reach a certain temperature (depending on the emissions pathway). The slowdown, however, doesn’t really provide evidence for a fundamental change to the TCR/ECS/ESS. So, are you a 2040 lukewarmer, or do you really have some evidence for a lower than expected TCR/ECS?

    Personally, I think what David Whitehouse says is mostly garbage. If one is considering trends then saying the temperature today is statistically the same as 10 years ago doesn’t really make sense. Overall global warming has not stopped or ceased (oceans). Temperatures are not increasing as expected because of ocean cycles/aerosols/Sun and global warming is about energy, not only about surface temperatures. Something has happened to change the rate of surface warming (and we probably roughly understand why) but the fundamentals of global warming remain sound and the planet is warming as predicted by the fundamental theory.

  83. OPatrick says:

    The first sentence of Whitehouse’s quote may or may not be factually correct (I assume it is as it would, I think, be exceptionally unlikely for such a short period to show statistically significant warming) but by far the most important thinga bout the sentence is that it is basically meaningless. The second sentence does not follow from the first – do you really want to argue that it does? If you think the third sentence too strong what was the point you were making when you said ‘fairly famously, with Mark Lynas and Dr David Whitehouse’? Presumably you were referring to these two pieces in the New Statesman – Whitehouse, Lynas.

    And I think the quote I gave was about the most moderate of Whitehouse’s article. It starts with the following, for example:

    Global warming stopped? Surely not. What heresy is this? Haven’t we been told that the science of global warming is settled beyond doubt and that all that’s left to the so-called sceptics is the odd errant glacier that refuses to melt?

    Aren’t we told that if we don’t act now rising temperatures will render most of the surface of the Earth uninhabitable within our lifetimes? But as we digest these apocalyptic comments, read the recent IPCC’s Synthesis report that says climate change could become irreversible. Witness the drama at Bali as news emerges that something is not quite right in the global warming camp.

    Do you endorse Whitehouse’s article more that Lynas’s response?

  84. Barry Woods says:

    pause, at it’s simplest, an acknowledgement that 10 year hiatus, or paused are seen in models, and beyond that it is of great interest to them, this clearly is of interest to climate science, whatever statistical analysis you put on it. IE, they were predicting higher temps, falling back on whether is is statistically a ‘pause’ or not or not, is the correct thing to consider, but not to, not try and work oout what is happening in the climate system.
    Do you not agree that models and ECS sensitivities will be constrained somewhat, if observed temps come in below the models projected temps.. (why not ask Met Office yourself, I’ve had long chats with them about this, off camera)

    ie if instead of 0.1C warming you put forward, we see a 0.05C warming per decade, and of course it temps were to fall, the Met Office decadal forecast, had this possibility)

    why not discuss your definitions with Dr Doug McNeall statistician at the Met Office, and I will happily concur with Doug’s statistical definition of the ‘pause’. his blog is betterfigures
    http://betterfigures.org/about/
    and i would really be interested to see that discussion.

  85. Barry Woods says:

    I would prefer it if Lynas and Whitehouse hadn’t phrased things as they had. fighting a battle both on a side.. Mark has certainly mellowed (a lot) since then..

  86. Barry,

    Do you not agree that models and ECS sensitivities will be constrained somewhat, if observed temps come in below the models projected temps.. (why not ask Met Office yourself, I’ve had long chats with them about this, off camera)

    The point is that this doesn’t logically follow. The surface temperature will (and is expected to) show variability. The model ensembles will tend to smooth out this variability and will, consequently, largely show the long-term trend. Hence, there will be periods when the model trends exceed that observed and periods when the observed trends exceed that of the model ensembles. Therefore, using a period of slower surface warming to suggest that the ECS should be reduced is not a logical conclusion to make.

    Of course, if it turns out that the long-term observed trend is below that of the models, then it would make sense to conclude that the ECS is likely lower than the model forecasts. My point is simply that using a single period of slower surface warming to conclude this does not make sense.

  87. OPatrick says:

    Barry, could you be specific what you object ot in Lynas’s article? I’ve quoted the start of Whitehouse’s article which, in my opinion, deserves nothing but contempt. Bearing in mind that Lynas was responding to this article I would be interested to see what you can find that you think makes them even equivalent (yet alone supports your implication that Lynas was at fault for attacking Whitehouse – remember that this was your example to support your claim that “BUT, this is not how it has appeared in the media, when talk of the pause has resulted in attacks on those talking about it “).

  88. Rachel says:

    Barry,
    I wonder whether you accept the idea behind this post which is that the climate system continues to accrue energy, despite surface temperatures rising more slowly over the last decade than in the one prior? Do you accept that? Because if you do, then variations in the pace of change should not really matter. Sometimes surface temperatures will rise faster than at other times and sometimes slower. What matters is where we’re heading and the longer we delay doing something about it, the more costly and more difficult it will be to fix.

    Apparently the WGIII report has been leaked and according to news sources – NYTimes – the delay is going to end up costing us more in the long run. This is significant and seems to confirm what the science says. Notably, this from a recent paper by James Hansen and others: had we started reducing emissions in 2005 then a reduction of 3.5% per year would have taken us back to 350ppm by 2100. If we start now, we need to reduce emissions by 6% per year. If we wait until 2020, we must reduce emissions by 15% per year. An impossible task I would say.

    The only pause I can see here is the pause in tackling the problem. It is unforgivable that we are not only dumping the problem on our children and grandchildren to solve but we are also making it worse at the same time.

  89. verytallguy says:

    Barry,

    why do yo want my definition of a ‘pause’ in GAT

    Because it’s very hard to have a meaningful discussion without a definition

    I’m happy to go with the climate scientist one..

    I don’t think there is one. Everyone means different things when they say pause, hiatus, slowdown or whatever – which is why it’s hard to make headway in any discussion and why it would be really helpful for you to give a definition.

    or do you think they are wrong to acknowledge / investigate it?

    I have already said there’s nothing wrong at all in investigating it. Whether it’s significant (Curry) or not (Dessler) is another matter entirely.

  90. verytallguy says:

    ATTP

    Of course, if it turns out that the long-term observed trend is below that of the models, then it would make sense to conclude that the ECS is likely lower than the model forecasts.

    Is that actually the case? Or would it depend on the cause?

    For instance, if the cause was that models underestimated ocean mixing, then the dynamics (rate ie TCR) of warming would be affected but not the final value. If the cause was for example that lapse rate feedback was underestimated then both would be lower.

    Is that right?

  91. VTG,

    Is that actually the case? Or would it depend on the cause?

    For instance, if the cause was that models underestimated ocean mixing, then the dynamics (rate ie TCR) of warming would be affected but not the final value. If the cause was for example that lapse rate feedback was underestimated then both would be lower.

    Yes, that’s a good point. I think you’re right. If we have the ocean mixing wrong, then the TCR would be lower without necessarily affecting the ECS. If the lapse rate feedback was lower, then both would be lower. My main point stands though. You can’t use a decade of slower than expected surface warming to conclude that climate sensitivity is likely low.

  92. verytallguy says:

    ATTP

    You can’t use a decade of slower than expected surface warming to conclude that climate sensitivity is likely low.

    That’s also my understanding, or to put another way, that the surface record does not strongly constrain estimates of ECS.

    i wonder if anyone could give a view as to when we would expect the surface record to provide a sufficiently tight constraint on ECS to be conclusive vs other methodologies?

    I don’t expect 10 years from now but maybe 50 years from now? 100?

  93. BBD says:

    Perhaps some time after we reach 2xCO2 (if that happens) and TCR estimates can be compared with observations. So perhaps between ~2060 and ~2100. This is merely me thinking out loud.

  94. Barry Woods says:

    my point is not one decade, but if three (as Slingo suggested) what impact would that have on the estimates.

    On a separate issue, what effect would that have on policymakers, if projections of high temps,(as I linked to) within 2-3 decades, by 2040, become increasingly less like observed reality, will they carry on with policy, agree a new ocean anomaly political target, etc.

    one further point, for all the talk amongst the scientist about a ‘pause’, hiatus’, or slowdown.
    (the RSclimate debates being a very good example, of where it was discussed in detail)
    I have actually not seen a consistent agreed definition of it amongst the climate scientist so perhaps VTG definition, or a similar would be a good place to start. Maybe he could chat with Doug Mcneall about it.

  95. Barry Woods says:

    so, I’m agreeing with VTG, there should be an agreed definition of what the ‘pause’ would look like.. besides the rate of warming has dropped off, for x,y & z many years, with different people saying x,y or z matters. Unless they all agree on this, they will talk cross-purposes, and there will be no testability (if there is such a word ?!)

    time for school run now, and after school stuff. so bye for today. (or late evening, but wine maybe more tempting than blog commenting, a v busy week))

  96. Barry,

    my point is not one decade, but if three (as Slingo suggested) what impact would that have on the estimates.

    Sure, but the point that I’m trying to make is that basic physics would suggest that extending the slowdown to 2030 would be quite remarkable. From a scientific perspective fascinating. From a societal perspective, good news. However, basic physics would probably suggest that it is unlikely.

    On a separate issue, what effect would that have on policymakers

    I’m sure it will have an effect, but since I’ve been trying to focus on science and not policy, I don’t really care.

    I have actually not seen a consistent agreed definition of it amongst the climate scientist

    My view is that scientists don’t see the point in coming up with a definition. Why? It’s still a short timescale. We can describe it in various ways anyway. We can talk about the surface warming trend – with uncertainties. We can discuss the rate of ocean heat uptake. We can discuss the Arctic sea ice. Why would need a definition? What would we be defining and how would such a definition help?

  97. Barry Woods says:

    but as they are talking about, and investigating a ‘pause’ or ‘slowdown’, surely they should agree amongst themselves( at least) the definition of it?

  98. OPatrick says:

    From a societal perspective, good news.

    Really? It would have the potential to be good news. It should be good news. But in reality I suspect it would the worse thing that could possibly happen, given that magic leprechauns aren’t going to take the energy imbalance away. If this is used as a further excuse for inaction, and it would be, then we are simply going to store up more pain for the future.

  99. but as they are talking about, and investigating a ‘pause’ or ‘slowdown’, surely they should agree amongst themselves( at least) the definition of it?

    I don’t really see why. They’re investigating something that has happened and that was somewhat unexpected. I don’t see why they need to define it. If they discover that it’s because of some specific as yet undefined phenomenon, then I guess they could define that phenomenon, but if it turns out to just be a combination of internal variability, aerosols, slightly weaker Sun, then I don’t see why one should define it in some special way.

  100. OPatrick,

    Really? It would have the potential to be good news. It should be good news. But in reality I suspect it would the worse thing that could possibly happen, given that magic leprechauns aren’t going to take the energy imbalance away.

    Yes, you’re right. I had meant that if it was because our physics was wrong and we weren’t going to warm as much as we think we are. If it is just an extended period of internal variability that will then be followed by a period of rapid warming (to catch up), it would be extremely bad news.

  101. verytallguy says:

    Cmon Barry, be serious.

    You seem to be arguing that the pause is significant. In order to consider if you’re right or not, we need to know what you mean by it.

    Neither you nor I (nor probably anyone) are in a position to define this formally for the scientific community, as you seem to suggest.

    So please, get off the fence and define the pause. For yourself, not for anyone else.

    Otherwise I’ll take my definition for you:

    (5) a least squares linear trendline over the length of “pause” with gradient numerically below zero and below the long term expected at a statistically significant level (95% confidence)

    With a 20 year timescale to be interesting and a 30 year timescale to falsify the standard model of climate.

    In which case there is no climatically relevant pause as such.

    Scientific investigation of the short term temperature wiggles is, naturally still interesting, and potentially relevant to understanding the longer term climate response.

  102. Joshua says:

    my point is not one decade, but if three (as Slingo suggested) what impact would that have on the estimates.

    Seems that would have to depend. If the “hiatus” in the trend of significant increase in global surface temps should last three decades, the implications to estimates would depend on what other developments are made in understanding. If along with that “hiatus” scientists have reason to estimate that global surface temps will catch up to the previous trend in a relative short period of time, the estimates (of global surface trend) would remain essentially unchanged.

    The problem I see here is that “skeptics” have some legitimate points to make, but many “skeptics” throw those legitimate issues overboard in their zeal to vindicate their sense of victimhood and to score points in the partisan climate wars.

    So some “skeptics” move on from perhaps legitimate criticism of an ill-suited focus on the part of some climate scientists on trends in global surface air temps to themselves place disproportionate focus on global surface air temps – as we can see in Judith’s recent Congressional testimony, where she didn’t even mention OHC as she discussed the policy implications (as an advocate, of course) of climate change. The uncertainty monster just got up and flat out walked away from the Senate hearing as soon as Judith began speaking.

  103. AnOilMan says:

    I just read through all this since my last post, and one thing really comes to mind. Barry is not looking at or discussing any of the work being done in the area of the ‘pause’. (I’d almost guess Barry is one of those cuddly people I don’t like.) He’s naming it… arguing facts while remaining technically insignificant.

    It appears to be an issue, I agree. But ;
    1) our thermometer may very well be broken
    2) there are other gasses (cooling aerosols) not included in the models
    3) have weather, ENSO, PDO

    All these things clearly affect perception of temperature as defined by Global Warming.

    However the point is moot since all that heat has clearly been found. One day it will come home to roost.

    In engineering, when something fails, we don’t walk away. We determine the cause.

    So Barry, what do you think about broken thermometers, Aerosols, and Weather? What do you think about all that heat found in the oceans.

  104. Barry Woods says:

    This paper (from a few years back, 2009) quantifies what was the expectation, and goes someway to define a discrepancy when/if observed temps fall out of projections, and as i said earlier, a slowdown in rates was of interest and being discussed a number of years ago.

    Do global temperature trends over the last decade falsify climate predictions?—J. Knightht, J. J.Kennedy.C. Folllland, G. Harris, G. S. Joneses, M. Palmelmelmer, D. Parkeker, A. Scaifefe, and P. Stotttt
    http://www.metoffice.gov.uk/media/pdf/j/j/global_temperatures_09.pdf

    O”bservations indicate that global temperature rise has slowed in the last decade (Fig. 2.8a). The least squares trend for January 1999 to December 2008 calculated from the HadCRUT3 dataset (Brohan et al. 2006) is +0.07±0.07°C decade–1—much less than the 0.18°C decade–1 recorded between 1979 and 2005 and the 0.2°C decade–1 expected in the next decade
    (IPCC; Solomon et al. 2007).This is despite a steady increase in radiative forcing as a result
    of human activities and has led some to question climate predictions of substantial twenty-first
    century warming (Lawson 2008;Carter 2008).”

    it discusses zero or even negative trends are not uncommon in simulations, for a decade or less and discusses natural internal variability the likely cause, for the ten years observed (nothing for me to disagree with at the time)

    and It also states that:

    “simulations rule out (at the 95% level) zero trends for intervals of 15 years or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present day rate of warming”

    it concludes:

    “These results show that climatemodels possess internal mechanisms of variability capable of
    reproducing the current slowdown in global temperature rise. Other factors, such as data biases and the effect of the solar cycle (Haigh 2003), may also have contributed, although these results show that it is not essential to invoke these explanations. The simulations also
    produce an average increase of 2.0°C in twenty-first century global temperature, demonstrating that recent observational trends are not sufficient to discount predictions of substantial climate change and its significant and widespread impacts.

    Given the likelihood that internal variability contributed to the slowing of global temperature rise in the last decade, we expect that warming will resume in the next few years, consistent with predictions from near-term climate forecasts (Smith et al. 2007; Haines et al. 2009). Improvements in such forecasts will give greater forewarning of future instances of temporary slowing and acceleration of global temperature rise, as predicted to occur in IPCC AR4 projections..” –

    Now as we are now in 2014, those next few years have passed,and the ‘expected’ rate of warming has not (yet ) resumed and the ‘slowdown’ is still ongoing, with some suggesting extending to 30 years. Not least because, this paper was linked to from this Met Office press 2009 press release:
    http://www.metoffice.gov.uk/news/releases/archive/2009/global-warming

    which states:

    “One such internal fluctuation over the last decade could have been enough to mask the expected global temperature rise. However, the Met Office’s decadal forecast predicts renewed warming after 2010 with about half of the years to 2015 likely to be warmer globally than the current warmest year on record.”

    yet since 2009 and that press release, warming has not yet renewed, and later decadal forecast by the Met Office (Dec 2012) suggest the slowdown’ to continue to 2017.. as BBC’s Roger Harrabin observed taking the pause to 20 years….outside of the earlier 15 years that were ruled out by simulations.

    nothing is conclusive yet, but I suggest that another few years or more of a ‘slowdown’ will be.

  105. Barry Woods says:

    sorry, formatting has gone a bit wrong.

  106. Barry Woods says:

    The above paper, also shows that David Whitehouse was arguable wrong at the time (or premature), to say in 2008 warming had stopped.. (not enough evidence)

    (ie science was saying simulations allowed it, and internal variability).
    Though I would not say he was wrong to discuss a ‘pause’ at all.

  107. verytallguy says:

    Barry,

    So 15 years zero trend is your definition of a significant pause?

    If so, then think about it. If 15 years zero trend is ruled out at 95% it means that if you take 20 years at random, you can *expect* to see one of them with a 15 year zero trend for the years preceeding.

    So if you define AGW as being significant since (say) 1950, then you can expect to see a zero 15 year trend about three times in that period.

    Yes?

  108. Barry Woods says:

    Yes. Seems reasonable enough
    Which is perhsp why the previous strong predictions of temperature for this decade were perhaps unwise. Yes?

    And if we get 20 – 25 or 30? As Slingo and others are now suggesting as a possibility?

  109. BBD says:

    Barry

    I think it would be helpful if you read and inwardly digested what ATTP has repeatedly said about the physical likelihood (or rather unlikelihood) of this actually happening. What you are doing is harping on endlessly about something which seems extremely improbable while tuning out everything else. Which is a little wearing, to be honest.

  110. AnOilMan says:

    Barry Woods:
    “nothing is conclusive yet, but I suggest that another few years or more of a ‘slowdown’ will be.”

    Conclusive of what precisely? Conclusive that the Hadcrut data set only covers 84% of the earth’s surface? Conclusive that the climate models are missing cooling aerosols? Conclusive that ENSO and PDO are masking heat accumulation.

    Really… conclusive of what?

  111. BBD says:

    I feel the need to add that the sort of super-low sensitivity you clearly desperately wish for is incompatible with known paleoclimate behaviour, which doesn’t really admit to anything lower than ~2C/2xCO2 at equilibrium and is very strongly suggestive of a value of ~3C. Which brings us right back to the beginning again. Wishful thinking will not alter the laws of physics.

  112. BBD says:

    Seizing hold of a tiny little bit of data and blotting out all else is not a good way to proceed Barry. The bigger picture is more informative.

  113. OPatrick says:

    Barry, can I ask that you clarify whether you still support this statement:

    “BUT, this is not how it has appeared in the media, when talk of the pause has resulted in attacks on those talking about it “

    The example you gave for this was Whitehouse / Lynas, but as you have acknowledged Whitehouse was at least arguably in the wrong (and any sane person would look at the tone of his piece and accept that he was in the wrong in terms of the language he was using, by comparison to which Lynas’s writing is measured and constructive). Perhaps you have other examples in mind, but as I said earlier I am sceptical that your recall of how things appeared in the media at the time is accurate.

  114. BBD says:

    ATTP, upthread:

    Direct science question. Why do you think this is possible? As I point out in the post, the 1940-1980 pause was accompanied by an energy excess that increased from around 0.1 to 0.4 Wm^2. Today we have an energy excess of around 0.6 – 0.9 Wm^2. If we follow a BAU scenario, this could increase by 1 Wm^2 in the next 15 – 20 years. So, the oceans would need to be absorbing an ever increasing fraction of the excess energy (and probably absorb energy at a rate higher than at any time in human history). So, why do you think it could continue for 20 years? Because it’s happened before? Because you’ve actually done some kind of back-of-then-envelope calculation that suggests that it’s plausible? Wishful thinking?

    IIRC you never really addressed this Barry.

  115. It’s hysterical to see scientists accused of “rewriting the past” and “goalpost shifting” right after I linked to the 1990 IPCC report warning that the surface temperature rise won’t be steady, and linked to a 1991 paper making an eerily familiar point about the statistical significance of noisy trends. Anyone who’s willing to reconsider their position might want to ponder these 95% confidence intervals:

    HadCRUT4 1987-2000 trend: 0.177 ±0.196 °C/decade
    HadCRUT4 2000-2013 trend: 0.042 ±0.161 °C/decade

    I’ve tried different data sets and different changepoints. So far, all their confidence intervals overlap, showing that there hasn’t been a statistically significant change in the surface warming rate. Those confidence intervals are also very large, showing that the chosen timespan is so short that the climate signal is overwhelmed by short-term weather noise. That’s why real skeptics consider longer timespans, which clearly reveal the long-term statistically significant surface warming trend:

    HadCRUT4 1987-2013 trend: 0.149 ±0.065 °C/decade

  116. Last year, Eric Worrall and Jane Q. Public regurgitated a WUWT misrepresentation of a NOAA report. WUWT implied that NOAA referred to the raw trend by “accidentally” ignoring the previous sentence where NOAA explicitly referred to ENSO-adjusted temperatures in Fig. 2.8b, which was a graph of ENSO-adjusted temperatures. Of course, ENSO-adjusted temperature trends are positive and statistically significant even over timespans shorter than 15 years [Foster and Rahmstorf 2011].

    Hopefully we’re not playing Groundhog Day again?

    To find out, open that Met Office report. I’ve bolded the previous sentence that Barry accidentally forgot to include:

    ENSO-adjusted warming in the three surface temperature datasets over the last 2–25 yr continually lies within the 90% range of all similar-length ENSO-adjusted temperature changes in these simulations (Fig. 2.8b). Near-zero and even negative trends are common for intervals of a decade or less in the simulations, due to the model’s internal climate variability. The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more…”

    Again, can we please stop playing Groundhog Day?

  117. Tom Curtis says:

    Barry Woods quotes Knight et al as saying:

    ““simulations rule out (at the 95% level) zero trends for intervals of 15 years or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present day rate of warming””

    (My emphasis)

    He claims that that supports his opinion, but he is yet to show a 15 year interval in HadCRUT4 with a zero trend, ie, an interval with a trend equal to or less than 0 +/- X. Showing a 15 year trend of Y +/- X, where X =>= Y (ie, what he can show from the record), does not satisfy the condition specified by Knight et al. Given that, he is premature talking about more extended zero or negative trends.

    I note that in talking about supposed inconsistency of climate scientists on this point, he does not specify the conditions being discussed by the scientists discussing various intervals, a necessary precondition to showing that they are in fact inconsistent. It is irrelevant to his point that Julia Slingo indicated a thirty year interval is required if it is required to determine that the mean 15 year trend estimate is as reliable as current 30 year trend estimates; or that others have indicated 22 years as the maximum interval with a lower confidence range =<= 0 as these are not apples to apples comparisons.

    The ambiguities Woods allows in his discussion means that, IMO, he has yet to state anything substantive, let alone demonstrate it.

  118. Tom Curtis says:

    Dumb Scientist, ENSO adjustment in context does not help our case. Specifically, in the Knight et al article, they examine the 1999-2008 trend, ie, a La Nina to La Nina trend, with a string of (on their data) successively stronger El Ninos in between. The result is that the ENSO adjusted trend over that period is weaker than the observed trend, and is in fact 0 +/- 0.5 C per decade.

    I would argue that using a temperature based index of the SOI is a mistake, as it necessarily incorporates any effect of global warming in the central Pacific into the ENSO signal. It is much better to use the SOI, which shows a string of successively weaker ENSO states, with the 2012 La Nina showing the highest monthly SOI value on record (ie, the strongest monthly La Nina signal). Therefore, their ENSO adjusted signal of 0 degrees for 1999-2008 is misleading.

    That, however, is beside the point. The fact is that Barry Woods cannot show a 0 trend (as opposed to a trend Y +/- X, such that X>Y) for 15 years on any data set, and can only show 0 trends for 10 years in data sets that do not have global coverage (NOAA, HadCRUT3, HadCRUT4), or which exaggerate ENSO effects (UAH, RSS, HadCRUT3 and HadCRUT4).

  119. As I’ve discussed, removing ENSO noise leads to a shorter minimum timespan for identifying statistically significant warming. Which is what NOAA and the Met Office did, and that’s one reason why Eric Worrall and Jane Q. Public and Barry Woods are wrong to imply that their statements apply to noisier raw temperature trends.

    We can agree that no 15 year confidence interval excludes global surface warming. These larger confidence intervals just show that such short timespans of raw global surface temperatures are dominated by weather noise (including ENSO), not climate signal.

  120. AnOilMan says:

    I remember that about a year ago skeptical science was running a graph with ENSO subtracted. I get that it was a kinda mathematical voodoo, but why, and why did they stop using it as an illustrative point?

  121. Global surface temperatures are affected by many factors, including our CO2 emissions and natural variability like ENSO. In principle, removing ENSO (using a pressure difference based, not temperature based, SOI) should increase the signal to noise ratio, allowing shorter timespans to have statistically significant surface warming trends. Skeptical Science stopped using their graph with ENSO subtracted because they thought that particular method of removing ENSO added more uncertainty than it removed. I disagreed.

  122. Tom Curtis says:

    AnOilMan, Skeptical Science still shows the original trend calculator using the Foster and Rahmstorf adjustments. You can find it without the link by using the button on the sidebar at SkS to go the the trend calculator, pressing the link in the box at the bottom of the page, and then choosing the Foster and Rahmstorf adjusted trend calculator. Unfortunately the F&R adjusted trend calculator does not include HadCRUT4, let alone the Cowtan and Wray adjusted HadCRUT4.

  123. Just to clarify my last comment, it was actually the method of subtracting long-term volcanic effects that might have added more uncertainty than it removed, not ENSO subtraction.

  124. dana1981 says:

    AnOilMan – certainly Cowtan & Way (2013) isn’t the whole picture on the mythical ‘pause’, but it’s a critical component. Some of the ‘pause’ is due to coverage bias (i.e. it’s not as large as previously believed. I still see people claiming 0.05°C per decade, including Curry in her congressional testimony I believe, when it’s actually ~0.12°C per decade). Some is due to increased aerosols and decreased solar activity (though the latter is a very small contribution). And some is due to more efficient ocean heat uptake due to ocean cycles. If you want to see it all put together, I did so in this post:
    http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/dec/31/2013-climate-change-science-policy-review

    The graphic you refer to (there’s one for Foster & Rahmstorf, and another that breaks out the surface temp record into La Niña, Neutral, and El Niño years) is located here:
    http://www.skepticalscience.com/graphics.php?c=3

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