There’s been no pause in global warming!

I discovered this over at Climate Denial Crock of the Week, but thought I would also post it here. It’s very good video explaining why there has been no pause in global warming. I think it explains the basic science extremely well. What I particularly liked is that it starts with a suggestion that the recent media coverage of the supposed slowdown in global warming is based on a misunderstanding of the science. I completely agree with this and it is very good to see this case being made by credible scientists who are directly involved in climate science research. Whether you believe scientists should advocate for policies or not, this video is a great example of what scientists should be doing. Explaining the science as honestly and clearly as they can.

Advertisements
This entry was posted in Climate change, Climate sensitivity, ENSO, Global warming and tagged , , , , , , . Bookmark the permalink.

59 Responses to There’s been no pause in global warming!

  1. Rachel says:

    Great video. I’ve seen that interview with James Hansen before and I thought he responded really well. This is a good example of how to communicate science with the public.

  2. BBD says:

    If only the “sceptics” would watch/read/try to understand.

    Their #1 talking point (let’s not call it an actual argument) is no warming for [17/16/15/whatever] years so AGW is bunk (the thick ones) or S is much lower than we thought (the ones who know nothing about paleoclimate behaviour).

    And by God it is wearisome. As is the inevitable sequel. I or someone else points out that OHC 0 – 2000m is increasing, and we invoke the spirit of Rob Painting in more or less detail. The “sceptic” then retreats into data denial, often as not “referencing” Tisdale’s hogwash about OHC reconstructions at the Other Place.

    It is too weep.

  3. Skeptikal says:

    Haven’t you guys heard the LATEST explanation for the lack of warming?

    Forget about the oceans apparently sucking up all the missing heat… now it’s a cooling pacific causing the ‘hiatus’.

    http://www.theguardian.com/environment/2013/aug/28/cooling-pacific-dampened-global-warming

    You can stick your head in the sand and keep chanting “There’s been no pause in global warming!”, but there’s a lot of scientists out there looking for reasons for the pause which you won’t even acknowledge.

  4. Skeptical, read this. The idea you claim is some smoking gun against AGW, is actually entirely consistent with AGW.

  5. BBD says:

    Skeptical

    You can stick your head in the sand and keep chanting “There’s been no pause in global warming!”, but there’s a lot of scientists out there looking for reasons for the pause which you won’t even acknowledge.

    There has been no pause in global warming. OHC continues to increase. There has been a slowdown in the rate of tropospheric warming, but as I believe I have mentioned to you before, the troposphere is *not* the entire climate system. It is just a little bit of it.

    Do be sure to follow Wotts’ link back to his earlier post, and read at least the first comment in which Rob Painting provides a lucid summary of what scientists acknowledge.

    Forget about the oceans apparently sucking up all the missing heat… now it’s a cooling pacific causing the ‘hiatus’.

    You will find that, as Wotts says, your claim is confused and mistaken.

  6. Skeptikal says:

    Yes, everything is consistent with Global Warming. I’ve yet to hear of anything which is NOT consistent with Global Warming.

    How the addition of heat to the pacific ocean can result in its surface cooling is a bit of a mystery to me… but I’m sure that this phenomenon is also consistent with Global Warming. 😉

    BTW… you should have linked to the blog post where Judith was actually blown away… here.

    I’m not sure how good my eyeball estimates are, and you can pick other start/end dates. But no matter what, I am coming up with natural internal variability associated accounting for significantly MORE than half of the observed warming.

    Like I said, my mind is blown. I have long argued that the pause was associated with the climate shift in the Pacific Ocean circulation, characterized by the change to the cool phase of the PDO. I have further argued that if this is the case, then the warming since 1976 was heavily juiced by the warm phase of the PDO. I didn’t know how to quantify this, but I thought that it might account for at least half of the observed warming, and hence my questioning of the IPCC’s highly confident attribution of ‘most’ to AGW.

  7. I must admit that I rather broke one of my promises when I responded to your initial comment. I’ll point you to a response I made to one of your comments a few months ago. Until we can establish whether or not you understand the concept of energy conservation, I don’t really see much point in discussing any other aspects of the science associated with climate change/global warming. Understanding energy conservation is a fairly crucial part of this whole issue.

  8. BBD says:

    How the addition of heat to the pacific ocean can result in its surface cooling is a bit of a mystery to me…

    Then read the links! Explore boldly! Resolve the mystery! Be the Indiana Jones of climate change “scepticism”!

    🙂

  9. BBD says:

    You quote Judith Curry:

    I’m not sure how good my eyeball estimates are, and you can pick other start/end dates. But no matter what, I am coming up with natural internal variability associated accounting for significantly MORE than half of the observed warming.

    She appears to have been really quite badly in error. More here!

    And remember, it’s your duty as a sceptic to read it and evaluate it objectively!

  10. Skeptikal says:

    Yes, I understand energy conservation.

    As I said previously…

    Except for the work done. If it all gets converted back to heat, then the work was done for free.

    Energy can’t be work done AND heat.

    http://en.wikipedia.org/wiki/Work_(thermodynamics)

    According to the first law of thermodynamics for a closed system, any net increase in the internal energy U must be fully accounted for, in terms of heat δQ entering the system and the work δW done by the system

    Maybe we should explore how much you understand about the concept of work.

  11. Skeptikal says:

    And remember, it’s your duty as a sceptic to read it and evaluate it objectively!

    Okay… I’ve read it and it appears that tamino’s computer model knows best… because tamino says so.

    I evaluate it as propaganda.

  12. No, Skeptical you don’t understand energy conservation. If some work is done so that an object gains kinetic energy, for example, then some initial form of energy has been converted into kinetic energy. However, if the object that gained the kinetic energy stops, then the kinetic energy is converted to heat. So, work was done and the end result is heat. You seem to think that if work is done, the energy has been used up and never returns as heat. This is wrong. I think you should read the wikipedia link you included a little more carefully.

  13. Skeptikal says:

    You seem to think that if work is done, the energy has been used up and never returns as heat.

    I didn’t say that. I said that it can’t be work AND heat. Work can ‘store’ energy, be it as potential, chemical or other… and that is no longer heat. You can’t keep that work and get the heat back.

  14. Sure, you can’t “keep the work” and have heat (although that doesn’t really make sense, but I think I know what you mean). Remember how this started though. You seemed to think that a TOA energy imbalance didn’t matter because the excess energy could simply be doing work and not heating the system. Your initial comment is here and does seem to imply that an energy imbalance is needed in order to provide the energy that does work. Your implication was that this wouldn’t heat the planet because we can’t have work and heat. This is true, but all work done must eventually return to heat or else everything would simply get faster and faster or higher and higher. A positive energy imbalance has to heat the planet even if the energy initially does some kind of work.

    This is a fundamental point and I really would like to know if you agree or not.

  15. BBD says:

    @ Skeptical

    I evaluate it as propaganda.

    Really? I’d say hit square amidships!

    The human mind is a perplexing thing.

    🙂

  16. Skeptikal says:

    Your implication was that this wouldn’t heat the planet because we can’t have work and heat. This is true, but all work done must eventually return to heat

    ‘Eventually’ is a fairly broad term… it could mean a hundred years or a hundred million years, so in that sense yes it will ‘eventually’ return to heat.

    On land the ‘eventually’ will be a lot sooner than in the oceans. In the oceans (which cover 70%) of our planet, work sinks to the ocean floor where it stays for a very long time.

    Articles like this one should give you an idea of how much energy is converted to work in the ocean and then lost/sequestered to the ocean floor.

    This is solar energy converted to work through photosynthesis. It’s energy coming in that will be stored in the oceans for millenia, not as heat but as work. I still think that we need a TOA energy imbalance to account for the work being done across the planet.

  17. Really excellent video. We need more of this sort of thing, explaining that surface temperatures are only one component of the climate system, and a really small component at that. We previously had to focus on surface temps because it was by far our most reliable record, but now that ocean heat content measurements are improving, we’re getting a much better picture of the climate as a whole.

  18. Tom Curtis says:

    Skeptikal, when you put out nonsense like the last post, it is no wonder people consider you (at best) intellectually challenged. The article you linked to did not discuss the “sequestration” of work. Granted, the carbon sequestered in the ocean depths contains chemical energy, but it contains no more chemical energy than when it existed as a fossil fuel. Therefore, the chemical energy sequestered by carbon sinking to the depths is no more than 25% of total human waste heat, or 25% of 1% of the the radiative forcing of greenhouse gases. Even that assumes generously that the carbon sequestered on the ocean floor is not digested by abyssal life, nor decomposes – neither of which are safe assumptions.

  19. Marco says:

    Skeptical, you refer to Tamino’s takedown as “propaganda”. Do you consider John Nielsen-Gammon’s comment on Judith Curry’s inability to understand the paper (I quote: “Curry’s mind-blowing reading of the paper is incorrect”) also propaganda? Xie, the senior author on the paper also attempted to correct Judith Curry, but as usual these attempts fail because Judith Curry somehow knows better than anyone else, even those who did the actual research.

    You seriously need to reconsider your sources for information.

  20. It does seem as though this message is starting to get out. When I started writing about this 6 months ago it really seemed lacking, but there are more and examples of people (yourself included) who’ve presented the bigger picture really well. So there’s hope at least that the message is slowly getting through to some people.

  21. Skeptical, Tom Curtis has already covered some of this below, but the article is about sequestering CO2, not energy. It even says “after decomposition” and “microbial decay”. As Tom pointed out, if all that’s left is the CO2 that was, essentially, carbon in a fossil fuel then all it’s prevented is the release of some of the heat associated with our use of the fossil fuel. It hasn’t sequestered the energy that was absorbed by the animal that sank to the sea floor. That’s all been released as heat. It might be in the deep ocean, but it’s still heat (as an aside, I had thought that you were amongst those who couldn’t see any way of getting heat to the deep ocean, and here we have a way).

    As far as timescale is concerned, the energy can only be sequestered for a long period of time (centuries or longer) if it does not decompose and hence would need to be stored as peat, or coal, or oil, or gas. Based on how much fossil fuels we have on the planet and how long it’s taken for them to form, Tom Curtis showed in the earlier post that the rate of sequestration was about 10^-8 J/yr. Far smaller than our energy imbalance.

    You finish with

    I still think that we need a TOA energy imbalance to account for the work being done across the planet.

    No, we definitely do not need an energy imbalance to account for the work being done across the planet. Most of the work being done returns to heat on short timescales (much less than a century). The energy that is used to do work clearly comes from the Sun and, once the work has been done, is converted into heat. For the planet to not warm up (undergo long-term global warming) the amount of energy we receive from the Sun (and from geothermal) must match the amount of energy we’re losing back into space.

  22. To paraphrase Skeptical, “Yes, everything is consistent with thermodynamics. I’ve yet to hear of anything which is NOT consistent with thermodynamics.”

  23. Skeptikal says:

    Well, in that case my idea must be wrong. If only 25% of human waste heat is going back into chemical energy, then the other 75% of human waste heat must be trapped as heat somewhere in the climate as it’s not making any impact on the TOA imbalance.

    There’s too much missing heat… where is it all going?

  24. Tom Curtis says:

    That “too much missing heat” is, as already mentioned, just 1% of the radiative forcing of WMGHG. Alternatively, it is less than 5% of the TOA energy imbalance. So in answer to your question, it is part of the TOA energy imbalance, but is too small a contribution to be detectable given the current levels of accuracy in measuring that imbalance.

  25. Ooh, you sound just like Kevin Trenberth 🙂

    Why would our energy consumption be having an impact on the TOA imbalance? Firstly our total energy consumption per year is about 5 x 10^20 J (if my calc is right). So, maybe 5 – 10% of the TOA imbalance (10^22 J per year). Furthermore, in a steady state the system would tend back to an equilibrium in which the total energy absorbed (solar + geothermal) matched the energy radiated back into space. Our release of energy would, I think, result in a tiny reduction in the surface temperature (i.e., energy radiated from the surface plus energy released by us must match energy absorbed).

    Where’s the missing heat going? Well, the evidence suggests that it is currently going into the oceans. The paper that you referred in your first comment is suggesting that we are in a phase in which the sea surface temperature of the tropical pacific is low and so the land and atmosphere are not undergoing much heating at the moment. The basic idea (which is from Rob Painting’s comment on the post I linked to) is that the wind driven ocean circularization is bringing cool water to the surface and taking the warmer water (which is warmed via AGW) to deeper levels. This will likely reverse (or stop) and we will see significant increases in land and atmosphere temperatures sometime in the not too distant future (well, physics would argue that you can’t continue to move energy into the deep oceans indefinitely).

  26. Tom Curtis says:

    Wotts, total industrial energy usage less renewable energy represents additional energy production in a given year. Or, more correctly it represents the release of stored chemical or nuclear energy (although a small fraction of the nuclear energy would have been released anyway, and should not be counted). As such it will slightly increase temperatures.

  27. Rachel says:

    There is something (which Skeptical has hinted at) that I have also wondered, although I suspect Skeptical is dismissive of it whereas I am just curious. How is it that surface temperatures of the ocean can remain static while the deeper ocean gets warmer? I am not doubting that this is happening because this is what the measurements are telling us. It just seems counter-intuitive. Is it because there is evaporation at the surface which keeps the surface cool? Or is it more to do with ocean currents? If there is heat going into the ocean though, doesn’t it need to go through the surface? It may be a dumb question, but one that I have wondered nevertheless.

  28. Skeptikal says:

    I have (genuinely) asked the same question. I cannot see how the heat can bypass the ocean’s surface on its way to the ocean’s depths.

  29. Jamea Westwood says:

    If you had a bucket of cold water. Then boiled a kettle and very carefully poured the boiling water onto the surface of the existing water you would end up with a hot layer of water on top of a cold layer.
    Then if you mix the bucket the surface will become cooler and the bottom of the bucket (deep ocean) will warm.
    The heat is not going through the surface. The heat is in the surface already and is being transported to the deep ocean via convection. It’s then replaces with colder upwelling water which has the effect of cooling the surface. There are still questions about why this fluctuates but you shouldn’t be surprised that the deep ocean can warm while the surface (well it hasn’t cooled but warmed only slightly).

  30. Yes, I suspected I was getting that the wrong way around. It’s an extra input of energy so has to slightly increase surface temperatures. Obvious when you think about it a little 🙂

  31. I an no expert at this so can’t answer the question authoritatively. My understanding is that it is through ocean currents driven by wind-ocean circularization. It doesn’t violate any of the laws of thermodynamics because it’s a flow of water, rather than a transfer of energy (i.e., it’s not conduction or convection, it is advection). We’re in a phase where the currents are bringing cool water to the surface and transferring warm water to deeper levels. When this stops (or reverses) the sea surface will retain the warm water and we will be in an El Nino phase and will see faster warming of the land and atmosphere. I suspect someone like Rob Painting, Tom Curtis or Dana Nuccitelli could explain this better than I have.

    There is another issue though. The ocean heat content data is showing that the o – 2000 m heat content is rising at about 10^22 J per year. Even if we don’t quite know how the energy is getting there, it appears to be doing so. Furthermore, I believe the measured rise in sea level is consistent with this. Therefore, for it not to be happening one then has to show that there is something wrong with all of this data.

  32. Interesting. I had assumed (and based on some of my reading) that a lot of this was actually due to currents which transported the water itself, rather than the energy (i.e., rather than being convection, it was advection). This is what I said in my response to Skeptical. I could, however, be wrong. I think there has to be an element of advection (rather than convection) because it’s driven by winds (I think) and it’s not clear how this would drive convection.

    Okay, having done a little reading to remind myself of what convection actually is, one can regard convection as a combination of advective and diffusive transfer. I suspect that in the oceans it is mainly advection, rather than diffusion, but I could be wrong.

  33. chris says:

    Rachel/Skeptikal, this doesn’t seem so problematic to me. It’s important to recognise that we should be thinking of these processes (heat transfers) as fluxes. It’s also worth reminding ourselves that qualitative explanations are often poor substitutes for analytical/modeling analyses which are more suitable for tackling problems such as heat transfer between layers that themselves are undergoing diffusion.

    Here’s how I think of this.

    1. Situation A where the response to a TOA forcing results in a certain amount of heat accumulation in the upper ocean layers (e.g. top 700 metres):

    let’s say that the ocean surface is absorbing 0.3 W.m^2 due to radiative imbalance. Thermohaline and wind driven currents results in mixing of this heat (by bulk transfer and diffusion) within the upper ocean layer (top 700 metres) and also to the deeper ocean layers (e.g. down to 2000 metres say). We could invent some numbers for illustrative purposes. Let’s say that thermal corresponding to 0.2 W.m^2 stays in the upper ocean layer, and 0.1 W.m^2 is transferred to the deeper oceans (we could calculate the distribution in thermal energy in Joules and in oC if we wished). Since the upper ocean layers are accumulating energy they will warm. Some of this energy will be transferred back to the atmosphere which will also warm somewhat.

    2. Situation B where the same TOA forcing results in the same accumulation of heat initially in the upper ocean layers. However now have a situation where wind and thermohaline drive currents transfer thermal energy more efficiently to the deeper oceans. We have the same 0.3 W.m^2 of energy absorbed in the upper layers, but now thermal energy corresponding to 0.25 W.m^2 is taken through the upper ocean layers to the deeper oceans (which is what we observe in the real world, ‘though my numbers are only illustrative), leaving heat equivalent to a minimal 0.05 W.m^2 in the upper ocean layers and v. little heating . So, even ‘though the “heat” is absorbed in the upper oceans, the heat transfer to the deep results in minimal warming of the surface.

  34. Jamea Westwood says:

    Convection would also transport the water. However, you are right it is actually advection. I think have overcomplicating it by making this distinction or I have over simplified 🙂

  35. Yes, I may have done the same 🙂 I was making a distinction between bulk flow and diffusive flow, but it’s all – in a sense – a form of convection.

  36. Jamea Westwood says:

    I mean people are more familiar with convection than advection and I don’t think the distinction between the 2 is that important to the point you are making.

  37. I just add a nice graphic provided from Stefan Rahmstorf which sums things up in the simplest possible fashion: Tilted thermocline
    (corresponding Blog post in German just in case ;): Klimalounge

    The net effect of the wind driven tilted thermocline (in the equatorial Pacific in this case) is a surface cooling and a deep(er) ocean warming.

  38. Yes, a very nice simple graphic. Will have to pass on the Blog post as my German is a little rusty (by which I mean non-existent :-)).

  39. May I suggest reading around “Ekman Transport” and “cool skin layer”?

  40. Yes, I suspect that would be worthwhile reading.

  41. Rachel says:

    Thanks, I will look them up. I actually emailed Scripps Institution of Oceanography some time ago asking the same question and I realise that people are very busy and don’t have time to answer lots of questions from random members of the public so I only asked for a link that would help me find the answer for myself. I never got a response.

    I appreciate all the other comments here about this too, thank you.

  42. BBD says:

    Rachel

    Simply put, the wind causes huge, rotating spiral eddies (“gyres”) to form in the major ocean basins. Wind-driven surface waters are screwed down into the depths at the centre of the gyre by a process known as Ekman pumping. The area at the centre of the gyre where this happens is called the Taylor column. This is how warm surface waters can be transported vertically to depth (via a spiralling downward path) by wind-driven circulation. It also provides one of the mechanisms by which variability in atmospheric circulation modulates the rate of ocean heat uptake.

  43. BBD says:

    Sorry Rachel – missed the link.

    Also apologies if none of this is news to you, but hope this helps.

    http://oceanmotion.org/html/background/ocean-in-motion.htm

  44. Skeptikal says:

    Ekman transport explains how mixing occurs within the well mixed layer. It doesn’t explain how heat can be transported down into the deeper ocean (which is where the heat is supposed to be going). From the page which BBD links to…

    The stable pycnocline inhibits the transfer of kinetic energy to deeper waters, helping to contain wind-driven currents to the mixed layer; that is, the pycnocline acts as a permeable boundary for Ekman transport and surface currents.

  45. BBD says:

    @ Skeptical

    I think you are confusing Ekman pumping at the centre of subtropical gyres with Ekman transport.

  46. Rachel says:

    I’ve found a great post about this at Science of Doom called “The cool skin of the ocean”. http://scienceofdoom.com/2011/01/18/the-cool-skin-of-the-ocean/

    Here’s my summary:
    The ocean surface – the skin layer which is less than 1mm thick – is actually cooler than the water just below the surface and a little bit warmer than the atmosphere above (all new to me!). Solar radiation can penetrate the top few metres of the ocean and heat it up. Turbulence mixes this water and because hotter fluids rise, the warmer water rises towards the surface but not to that last millimeter skin layer. The reason for this I don’t fully understand, but it has something to do with viscosity of the surface which causes heat transfer to occur via conduction rather than by turbulence. Perhaps this is because of the surface tension of fluids?? So at the surface, heat is transferred by conduction but conduction requires a temperature differential for the heat to move. If there’s not enough of a temperature differential, then the heat below will continue to increase and increase until this differential is created and becomes high enough to push this heat out to the surface.

  47. Rachel says:

    One correction: solar radiation can actually penetrate tens of metres of ocean depth.

  48. “I cannot see how the heat can bypass the ocean’s surface on its way to the ocean’s depths.”

    There’s no reason to think it has. See my bathtub analogy:
    http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/aug/14/global-warming-solar-minimum-barely-dent

  49. Thanks, I hope so. Journalists do usually talk about ocean warming when they talk about the “pause”, but there’s still too much focus on short-term surface temp changes. But references to ocean heating are at least a big improvement.

  50. Also Skeptical says:

    There would be more acceptance of these explanations if just ONE of the many models that have been predicting climate disaster, or just ONE of the doomsayer scientists had predicted this as a possibility BEFOREHAND. The models and their designers didn’t. Which exposes the lack of knowledge underpinning them. Which is why the majority of the world is not willing to bike everywhere.

  51. So you’re skeptical because GCMs run in the 1990s failed to predict the “slowdown” in surface warming that started around 1998. It’s perfectly fine to be sceptical and it’s perfectly fine to take this into account when considering the evidence. The issue I have though is that since then we have direct satellite measurements of a top-of-the-atmosphere energy imbalance (about 0.5 Wm-2). We have measurements indicating that the ocean heat content has risen at about 10^22 J/year. So, in a fundamental sense the models have correctly predicted the continued rise in total energy. What they haven’t done well is predict how this energy will be distributed through the climate system.

    Let me throw something back at you though. I don’t know where you get the whole “predicting climate disaster” from. This may well exist in the media, but it’s not particularly prevalent in the scientific literature. So your rhetoric seems unduly extreme in my opinion. You also seem to put an enormous amount of significance on the failure to predict the slowdown. There’s nothing that can be done about this now. We can’t go back in time and get it right. There’s also been a lot of work to try and understand this slowdown. The evidence now suggests that it’s because of a period where the sea surface in the Pacific has been in a cool phase which has resulted in enhanced heating of the deep ocean and reduced heating of the surface. Furthermore it’s likely that the inherently chaotic nature of the systems means that it may not actually be possible to predict these slowdowns. So, expecting the models to do so may be completely unrealistic.

    So, it seems quite likely that you’re basing your views on something that may not be particularly significant (overall warming continues as expected) and that may have been impossible to avoid (it may not be possible to develop models that could actually predict such slowdowns). In my view, this seems rather rigid and rather unscientific (i.e., it seems as though you’ve made up your mind and there is little – apart from an actual catastrophe – that will change your mind).

  52. Tom Curtis says:

    I wish that people would not so blatantly lie in their chosen names. In this case “also skeptical” claims without any skepticism that not one model, and not one scientist predicted the slowdown before it happened. In fact all models predict periods of more rapid, and slower warming as a result of stochastic processes. Some particular model runs, including some from the IPCC AR4 “predict” negative trends of nearly twenty years in length, and one from an earlier IPCC report “predicted” such a slow down starting around 1997/98. Such “predictions” do not show up in ensemble means because they occur at different times and cancel each other out. That “also skeptical” had not bothered to read the science sufficiently carefully to distinguish between the prediction of the mean trend over extended periods (ensemble mean) and the particular realization of such a warming trend, complete with short term variations shows not skepticism but ignorance.

    As to what the scientists predicted, they all predicted an acceleration of the rapid warming trend from 1975 onwards. If anybody bothers to look at that warming trend to 1988, or to 1998, or 2007 will quickly see that it consists of a long term warming trend composed of a series of short term negative, flat, or sharply accelerated trends. The scientists, therefore, predicted a continuation of just that pattern. If “also skeptical” disagrees with this, he can disprove my point by simply showing the scientific paper where global temperatures are predicted to increase monotonically. Absent that paper, however, and he is shown to be misrepresenting the scientists predictions.

    “Also Skeptical” should have been about more skeptical, I think, about his powers of persuasion as well. With a well informed audience, you cannot pass of ignorance as skepticism – and he should not have tried to do so.

  53. Skeptikal says:

    If anyone bothers to look at the page you link to, they’ll find Cook’s Escalator. His escalator is manufactured around the observed temperature record, not around a climate model. The scientists all predicted continued warming… which is why they’re all running around now looking for a credible reason for the lack of warming.

    Maybe you’d like to provide a link to an actual climate model output which shows flat or negative periods of a decade or more.

  54. Tom Curtis says:

    Skeptikal asks, “Maybe you’d like to provide a link to an actual climate model output which shows flat or negative periods of a decade or more.”

    I will provide a link to a Real Climate article which discusses exactly this issue, and shows a histogram of model trends from 1995 to 2014. Over that period, one model showed a trend between -0.05 C/decade and 0 C/decade. A further two models showed trends between 0 and 0.1 C/decade. The current from 1995 is 0.092 C/decade, while that from 1998 is 0.038 C/decade (HadCRUT4). If these observed trends count as “flat”, then so also do the three modeled trends above, ie 5.5% of all models. A further 13 models show a trend between 0.1 and 0.15 C/decade (the modal trend). That is 23.6% of all 55 models.

    Real Climate also show a plot of all models from 1950-2020. It is not possible from the trend from 1995-2014 in that representation to predict whether the model will have a high or a low end point. It is even less possible to do so when the model projections are shown out to 2100. The low trends are due to small scale variability in the modeled climate system rather than differences in the long term trends.

    Real Climate links to a page from which all model runs can be downloaded.

  55. Marco says:

    Skeptical, you can learn something here:
    http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/
    See in particular the second figure, which shows the distribution of individual trends for periods of up to 20 years, where the latter still includes a negative trends as a possibility (again, that is a 20 year period in a model forced by increasing GHGs over that 20 year period).

  56. Marco says:

    Argh, Tom just beat me to it!

  57. Skeptikal says:

    Smoke and mirrors….

    I asked for a link to

    an actual climate model output which shows flat or negative periods of a decade or more.

    and what you give me is a link to someone who’s broken down one scenario of one climate model into its realisations… and found one realisation with a negative trend over 20 years.

    Are you seriously calling a single realisation “a climate model”?

  58. Marco says:

    Yes, Skeptical, a single realisation is an output of a climate model. In this case 2% of all realisations showed a trend over 20-years that was negative. That is, that climate model predicts a 2% chance of a negative trend in a 20-year period.

    What you seem to demand is a mathematical model that has an uncertainty interval that is zero. Good luck finding that anywhere in science.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s