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  1. Shouldn’t it be “It never rains but it pauses”?

    [Response: No. But if I need to explain a pun, then it is probably not going to work for you. – gavin]

    Comment by Peter Adamsi — 4 Mar 2014 @ 10:42 AM

  2. Perhaps the ($) placeholders should be deleted.


    Comment by Steve Fish — 4 Mar 2014 @ 10:55 AM

  3. Re: 1, I thought I might be missing something. That’s what happens when you multi-task.

    Comment by Peter Adamsi — 4 Mar 2014 @ 11:07 AM

  4. OK, groaner time.

    Comment by Peter Adamsi — 4 Mar 2014 @ 11:09 AM

  5. Appreciate informative summary. FYI, hyperlink to Nature Geoscience editorial does not work – at least not for me.

    Comment by Randall W. Parkinson — 4 Mar 2014 @ 11:23 AM

  6. It’s more than a little concerning that the last decade has had all these extreme events that well carry on, despite the hiatus.
    One question out of curiosity, not scepticism: there was no talk of a hiatus even 2-3 years ago. Why has it taken 15 years for us to figure we are experiencing a hiatus?
    in solidarity,
    Nagraj Adve
    New Delhi

    Comment by Nagraj Adve — 4 Mar 2014 @ 11:50 AM

  7. It appears as if the hiatus is the sum of the response of Earth dynamic climate system – negative feedbacks driven by internal variability. And there are slow negative feedbacks (Ocean currents) and fast negative feedbacks (Volcanoes), but response depends on the forcing and could switch mode from negative to positive feedback (i.e. La Nina -> El Nino).

    Comment by prokaryotes — 4 Mar 2014 @ 12:10 PM

  8. Nagraj Adve, see for example An imperative for climate change planning: tracking Earth’s
    global energy
    (Trenberth 2009)

    Comment by prokaryotes — 4 Mar 2014 @ 12:28 PM

  9. It’s gratifying to see reviews characterizing the supposed hiatus as a combination of the varied explanations, and not as a contest between competing explanations. It’s still the real world out there, and there are always many more things than one going on at once.

    Comment by Lance Olsen — 4 Mar 2014 @ 12:34 PM

  10. The mismatch in forcing datasets identified in the Nature Geoscience papers seems like a real problem for the scenarios. Wouldn’t it make sense to include either (a) a steady non-zero background volcanic aerosol forcing, or (b) a stochastic volcano timeseries whose integral matched the 20th century volcanic emissions applied randomly to each ensemble member, in future scenarios for the next CMIP? Obviously we can’t know what the future volcanic emissions are like, but zero volcanoes would seem to be a pretty extreme assumption, and this would avoid the discontinuity between a historical record that includes volcanoes versus a future that has no volcanoes. At a minimum couldn’t there be some sort of RCP4.5V that includes such a volcanic forcing to compare to the standard RCP4.5?

    Comment by charlie — 4 Mar 2014 @ 1:02 PM

  11. Nagraj Adve @6

    ‘Slowdowns’ and ‘accelerations’ due to natural variability have always existed, both in global temperature records and in individual model runs, and scientists have always been very well aware of them. However, they didn’t show up in published projections, which were of course based on the average of model run ensembles and so smoothed them out. The media—and of course ‘sceptics’—picked up on the so called ‘hiatus’ when it appeared that the global temperature record was diverging downwards away from the projections. And at that point the scientists had to explain what to them was very obvious. To put this in context, it should be noted that leading up to 1998 another noticeable divergence away from the projections had occurred: this time in the other direction as temps rose ahead of the models. Not unsurprisingly, sceptics didn’t make a big deal of this.

    So if there was an error it was that scientists hadn’t explained the facts in sufficient simplicity to take the public along with them. Well that’s what I as a lay person put it down to. I’m sure Gavin or someone with more knowledge will put me right if I’m wrong.

    Comment by John Russell — 4 Mar 2014 @ 1:10 PM

  12. charlie:

    Jonathan Gregory discussed similar thoughts back in 2010:


    Comment by Ed Hawkins — 4 Mar 2014 @ 1:51 PM

  13. The pause conundrum came about because of the public’s need for an intuitive and familiar measure of warming. This measure turned out to be that of surface temperature. If instead, we had used an aggregate energy measure such as retained free energy, we wouldn’t have this argument. The free energy would include temperature+heat capacity, kinetic energy, latent energy, and potential energy, that would have evened out the fluctuations that we are seeing.

    Alas, it will take a long time to slow down the inertia of using temperature.

    Comment by WebHubTelescope — 4 Mar 2014 @ 3:37 PM

  14. Hiatus discussions may become very pointless in the next 2 years if we get a moderate to strong El Nino. Although someone could have said the same thing in 09/10.

    Comment by bigbass — 4 Mar 2014 @ 4:41 PM

  15. Thanks to SkS for this link:

    “How scientists, media and the public see the surface warming ‘pause’”

    “A prestigious journal has released a special issue on what’s become something of a preoccupation in the crossover between science and mainstream media recently – an apparent slowdown in surface warming over the last decade or so.

    Nature Climate Change dedicates a whole issue to the so called ‘pause’ – looking at how scientists, the public and the media have been talking about it.

    The issue talks a lot about lessons for scientists in engaging with the media, but is it worth so much soul-searching when evidence suggests the ‘pause’ has barely made a ripple in the public consciousness?”

    Comment by wili — 4 Mar 2014 @ 7:49 PM

  16. note: both ”time” magazine and ”nytimes” are poised to deliver big ”cli fi” novels and movies news stories this month of ”march” 2014. cl fi is new genre for climate fiction novels and movies, from sci fi to cli fi, google it. I don’t know the NYT reporter’s timeline, or which section the story might
    appear in, and I believe he visited the cli fi lit class of a professor in
    california and spoke with quite a few other people. His topic is
    ”climate change education”. I assumed he might have talked with some of you here too!

    Comment by dan bloom — 4 Mar 2014 @ 9:00 PM

  17. Gavin, is there anyone in your department considering adjusting models to contain feedbacks,(pos or neg) that were previously ommitted?
    If the models fail to follow observed trends, its not the science that has failed, just the models.
    Could be time to re think the feedbacks.

    [Response: Feedbacks are emergent properties from the models and so are diagnostic, not input. We are rethinking processes all the time in order to better represent the real world, but as yet, they have not much changed the main feedbacks. In any case, it would not be possible to ‘fix’ feedbacks to change responses just for one decade without changing responses in all other metrics. – gavin ]

    Comment by Alan Bryant — 4 Mar 2014 @ 9:07 PM

  18. Excellent summary at Nature Geosc. Gavin, even if I still can’t see any “pause“, however I look at it. You correctly separate “pause” and CMIP5 miss-fit. I wonder how many others manage to.

    Steve @#2: That was a snark after Peter @#1, right?

    Comment by GlenFergus — 5 Mar 2014 @ 3:18 AM

  19. For an updates on the Meehl Surface Records Study that I started see Dr. Jeff Master’s blog posted on 3/4/14 at:

    Indeed, for the uniformed public the “hiatus” in warming across the central and eastern U.S. has been very stark this winter. Global warming is the furthest thing on a cabby’s mind in cities like Chicago or New York.

    For the uneducated climate change denialist…the hiatus in warming can only fuel arguments to further delay mitigation efforts leading
    to even more dire consequences in the future.

    P.S. It’s almost certain that the CO2 measurements coming from Mauna Loa will be above 400 ppm when the February report is made in a few days.

    Comment by Guy Walton — 5 Mar 2014 @ 3:37 AM

  20. Indeed, for the uniformed public the “hiatus” in warming across the central and eastern U.S. has been very stark this winter. Global warming is the furthest thing on a cabby’s mind in cities like Chicago or New York.

    For the uneducated climate change denialist…the hiatus in warming can only fuel arguments to further delay mitigation efforts leading
    to even more dire consequences in the future.

    P.S. It’s almost certain that the CO2 measurements coming from Mauna Loa will be above 400 ppm when the February report is made in a few days.

    Comment by Guy Walton — 5 Mar 2014 @ 3:39 AM

  21. Gavin,

    On the climate driver updates plot most of the negative difference in volcanic forcing appears to occur prior to 2000, whereas most papers discussing the impact of small volcanic eruptions have focussed on the period since 2000. Is this pre-2000 discrepancy part of the Pinatubo reassessment?

    [Response: yes. – gavin]

    Comment by Paul S — 5 Mar 2014 @ 7:52 AM

  22. Hi:-). I’m just a lay person who like to look at historical temperature graphs. If that 30 year warming-cooling pattern is real, we could expect a pause until 2030 or so, not? And further, the temperature increase from one 60-year peak to the next 60-year peak:

    1880-1940 is ca 0,7 F
    1940-2000 is ca 0,8 F

    so following the pattern
    2000-2060 may see an increase of ca 0,9-1,0 F

    then the temp increase from 1880 to 2060 might be around 2,4 F or 1,4 C

    What indicates and worries that it may be higher, is that the cooling period at the moment, isn’t really getting colder. Anyway, we will probably not know much about the real upwards trend, independent of internal variablity, until it starts warming again after 2030. Just my thinking :-)

    Comment by Mari — 5 Mar 2014 @ 7:56 AM

  23. Guy Walton – I take it you haven’t been following the weekly updates? February’s measurements barely show any increase over January:

    It’s being a tease.

    Comment by Paul S — 5 Mar 2014 @ 8:00 AM

  24. Re- Comment by GlenFergus — 5 Mar 2014 @ 3:18 AM, ~#18

    Glen, no it is not snark but an attempt to provide a minor copy edit suggestion for the original post. I should have been more explicit. Note under the “Climate drivers” heading the first Santer reference has “($)” after it. There are several of these. My assumption was that Gavin was putting this symbol in as a placeholder for a reference number that would be filled in after the piece was finished. I used to do this. Gavin may have decided to not use numbers at all and forgot to remove the placeholders. Or maybe not.


    Comment by Steve Fish — 5 Mar 2014 @ 11:15 AM

  25. Gavin, in your response to Alan Bryant you wrote “Feedbacks are emergent properties from the models and so are diagnostic, not input. We are rethinking processes all the time”

    I think the word “feedback” gets confusing because the engineers, and the ecologists, use the word to mean something different than you do in climate modeling.

    Amateur questions follow, if/when you or any other climate scientists have time to comment:

    When and how do climate modelers incorporate changes in what we know about biology? How much difference does it make that we’re on a living planet? Do you call those processes, or feedbacks? Does a ‘whole new model’ need to be produced for these, or are they somehow incorporated from time to time?

    I’m thinking about what’s known from paleo records — the expansion of plankton from coastal forms to deep-sea forms, for example, changed the climate, but I don’t know if the models deal with that.

    For example (I can only see the abstract):

    The changing carbon cycle of the coastal ocean
    Nature 504, 61–70 (05 December 2013)

    Recent evidence suggests that the coastal ocean may have become a net sink for atmospheric carbon dioxide during post-industrial times. Continued human pressures in coastal zones will probably have an important impact on the future evolution of the coastal ocean’s carbon budget.

    and this suggests an immediate concern on our short time scale:

    Cenozoic Planktonic Marine Diatom Diversity and Correlation to Climate Change
    David Lazarus, John Barron, Johan Renaudie, Patrick Diver, Andreas Türke
    Published: January 22, 2014
    DOI: 10.1371/journal.pone.0084857

    Our results suggest that many living marine planktonic diatom species may be at risk of extinction in future warm oceans, with an unknown but potentially substantial negative impact on the ocean biologic pump and oceanic carbon sequestration.

    Comment by Hank Roberts — 5 Mar 2014 @ 11:45 AM

  26. I notice that even 15 years ago, Chinese air pollution was reducing photosynthesis to a worrisome degree:

    Case study of the effects of atmospheric aerosols and regional haze on agriculture: An opportunity to enhance crop yields in China through emission controls?
    November 23, 1999, vol. 96 no. 24

    … the so-called “direct effect” of regional haze results in an ≈5–30% reduction in the solar irradiance reaching some of China’s most productive agricultural regions. Crop-response model simulations suggest an ≈1:1 relationship between a percentage increase (decrease) in total surface solar irradiance and a percentage increase (decrease) in the yields of rice and wheat. Collectively, these calculations suggest that regional haze in China is currently depressing optimal yields of ≈70% of the crops grown in China by at least 5–30%. Reducing the severity of regional haze in China through air pollution control could potentially result in a significant increase in crop yields and help the nation meet its growing food demands in the coming decades.

    It’s gotten much worse:
    Industrial SO2 pollution and agricultural losses in China: evidence from heavy air polluters

    Is the effect of aerosols on climate harder to detect than the effect on photosynthesis?

    How much difference has that been making downwind, in photosynthesis and generation of cloud-forming nuclei by biological activity in marine surface layers, over the same time span?

    Comment by Hank Roberts — 5 Mar 2014 @ 1:16 PM

  27. The “$” is to indicate that the article is behind a paywall. “OA” means open access.

    Comment by Steven Sullivan — 5 Mar 2014 @ 7:35 PM

  28. Re- Comment by Steven Sullivan — 5 Mar 2014 @ 7:35 PM

    Thanks. I should have been able to figure that out, but I didn’t.


    Comment by Steve Fish — 5 Mar 2014 @ 9:41 PM

  29. I think the pun requires a non-rhotic accent. To speakers of standard American English it’s rather opaque.

    Comment by Joseph — 6 Mar 2014 @ 8:54 AM

  30. It only requires that accent if you are trying to force it – it’s a pun! I think it’s actually more funny as it invokes the non-rhotic “bostonian” sound – I’d add this was a visual pun – i’m scanning realclimate and chuckled when I saw the heading before I had time to really analyze whether the pun was properly constructed.

    JB’s 1st rule of humor: If it makes you laugh it’s funny

    Comment by JB — 6 Mar 2014 @ 2:07 PM

  31. If you needed the pun explained, it probably isn’t funny any more. Good one though.

    Comment by Dan H. — 6 Mar 2014 @ 6:16 PM

  32. To an Englishman the pun works perfectly. :-)

    [Response: Of course. :-) – gavin]

    Comment by Richard W — 7 Mar 2014 @ 7:13 AM

  33. link for 1st reference above

    Comment by Pete Dunkelberg — 7 Mar 2014 @ 4:32 PM

  34. Whatsa matta youse guys? I appreciated the pun right away.

    Comment by Pete Dunkelberg — 7 Mar 2014 @ 6:01 PM

  35. The pun also works well for anyone living in the American South–however rhotic (or a-rhotic!) they may personally be.

    Comment by Kevin McKinney — 7 Mar 2014 @ 11:16 PM

  36. This set of data only points to the fact that climate is changing and changing fast. It’s no more a myth. There’s substantial evidence on hand regarding it. This collection of analysis can be really helpful in designing the right policy in an environment of confusion among various researchers. There’s a talk going on regarding Geoengineering. These trends may clear the air a bit regarding that.

    Comment by Shantanu Chauhan — 10 Mar 2014 @ 5:39 PM

  37. I have produced a blog that draws a link between the NASA forecast of an El Nino and the flooding of the low lying Marshall Islands.

    Comment by Bob Bingham — 10 Mar 2014 @ 10:13 PM

  38. Bob – El Nino causes sea level to fall dramatically in the western Pacific. See this rebuttal on Tuvalu sea level I wrote for Skeptical Science. Majuro, the capital, is shown in Figure 4. The strengthening trade winds since the early 1990’s have contributed to this greater-than-average sea level rise in the tropical western Pacific, however this trend will decline when the Interdecadal Pacific Oscillation switches to its positive (El Nino-dominant) phase in the near-future.

    As for El Nino, yes still looks very likely. The formation of tropical lows in the Western Pacific seem to be strengthening the westerly winds bursts so that big blob of subsurface heat in the equatorial ocean could begin to surface and shutdown the upwelling of deep cold water in the eastern Pacific. Time will tell.

    Comment by Rob Painting — 11 Mar 2014 @ 4:12 AM

  39. So what are the current best estimates of the range of temperature that aerosols are ‘hiding’ from the current warming? IIRC, it used to be something like .5 to 2 degrees C. Is it now below 1 degree?

    Comment by wili — 16 Mar 2014 @ 10:54 AM

  40. Given the situation in CA, this old musical version of the saying seems particularly apt:

    Comment by wili — 16 Mar 2014 @ 2:50 PM

  41. In new paper explores SLR rates and the pause, The Rate of Sea-Level Rise

    Comment by prokaryotes — 24 Mar 2014 @ 9:11 AM

  42. a rain’s slow journey

    oceans swell in hiatus

    divergent misleads

    Comment by Eliot Walter — 27 Mar 2014 @ 6:01 PM

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