A real time global warming index

This is a guest post by Karsten Haustein, a researcher in the School of Geography and the Environment at the University of Oxford. The post is about a new paper that discusses their real time global warming index.

Have you ever wondered what the current level of human-induced warming really is? Well, here is something that might help.

Published in one of the more recent Nature spin-offs (Haustein et al. 2017), we introduce a real-time Global Warming Index (GWI) which provides an estimate of the fraction of anthropogenically caused warming up to the current date (or even second for that matter).

The initial idea was put foward in a paper led by my colleague and co-author Fredi Otto (Otto et al. 2015), using annual data only. Since it didn’t come with an uncertainty analysis, we went back to the drawing board, updated all the forcing estimates and included a sophisticated uncertainty analysis based on the best available science to date. The result is made publicly available on the aptly named globalwarmingindex.org website. The index is updated monthly as soon as the lastest global temperature estimate is released. In the meantime, the counter on the top of the website extrapolates the current (10-year) warming trend up until the current second.

The basic idea in a nutshell: the temperature response to any given change in external radiative forcing (accounting for fast and slow responses, with e-folding response times of 4.1 and 219 years, respectively) is regressed against global mean surface temperature; with the resulting slope determining the magnitude of the forced signal. This is done separately for anthropogenic and natural forcing contributions. The former includes greenhouse gases (CO2, ozone, methane, a variety of trace gases), land use change and aerosol effects (direct and indirect for SO2, NH3, OC, BC, as well as BC on snow), whereas the latter includes explosive volcanic eruptions and changes in solar incoming radiation. Apart from the associated forcing uncertainty, we have also accounted for response model uncertainty, observational uncertainty and last but not least uncertainty due to internal variability.

Figure 1: Global Warming Index from Jan 1950 to May 2017 for HadCRUT4. The anthropogenic contribution in orange (with 5–95% confidence interval). The natural contribution (solar and volcanic) in blue. The red line shows the combined (total) externally-driven temperature change. The dark red line shows the evolution of the GWI when only past forcing and temperature data are used. The thin black line are the monthly (HadCRUT4) GMST data. For illustration, blue diamonds indicate when major climate summits took place in context of the monthly GMST at that time. (Figure 1 in Haustein et al. 2017)

Since anthropogenic forcing components tend to change slowly over time (for example, greenhouse gases are well-mixed in the atmosphere and therefore concentrations increase fairly linearly), short-term fluctuation from ENSO or volcanic eruptions are effectively filtered out. We have demonstrated the robustness of the index by going back in time to re-assess what the attributable warming would have been (see figure 1 which is an updated version of Fig 1 in the paper). Turns out, the inappropriately named “hiatus” left no more than a barely visible dent in the index estimate. That said, it is important to understand that – by construction – the GWI is controlled by the forcing rather than the temperature. Hence the fact that the trend appears to be increasing during the last 5 years (the current rate of warming based on 10 year trends is +0.16-0.17K/decade as shown in figure 2) or so is somewhat worrying, as it merely reflects an accelerated increase in radiative forcing, primarily due to an upward revision of methane forcing.

Figure 2: Figure showing 3, 5, 10 and 20 year trends, plotted against time, and the 5-95% uncertainty interval for the 20 year trend.

This is one of the strengths of our index: it shows straight away why we shouldn’t have been surprised by the rapid temperature uptick during the strong 2015/16 El Niño, as much as we shouldn’t expect the temperatures to ever go back down to pre-2014 levels (barring a strong volcanic eruption).

Given that the latest IPCC report (AR5) provided a quantitative assessment of the human-induced warming for the 1950-2011 period only, the public was left guessing what the fraction of anthropogenic warming since pre-industrial times really is. This has now also changed, and we certainly hope that our work fosters a more conclusive statement in the next IPCC report.

Figure 3: Same as Figure 1, except using the HadCRUT4-Cowtan/Way surface temperature dataset.

We note two more things: (1) the exact definition of what “pre-industrial” means remains somewhat contentious. While the 1850-79 period chosen in our paper is defensible given the rather small amount of greenhouse gas induced radiative forcing before that time, there is still some debate about the optimal definition (see Hawkins et al. 2017 for more details). (2) Despite having accounted for observational uncertainty, the bias due to the missing coverage of the Arctic in HadCRUT4 is larger than their error model suggests. Hence the choice of the observational temperature dataset is adding to the overall index uncertainty as highlighted by the figure on the right (Figure 3), by comparing the GWI based on HadCRUT4 with the version using HadCRUT4-Cowtan/Way (Cowtan et al. 2015). The index goes up from 1.02°C to 1.08°C. Using Berkeley Earth instead (not shown), the index is as high as 1.12°C. Arguably, HadCRUT4 is biased low and so is the associated GWI estimate. Eventually, infilling will become the standard and the products should converge in the not-so-distant future.

Together with continuously updated estimates of the ocean heat content and Earth’s energy imbalance (see for example von Schuckmann et al. 2016), we believe that the GWI is a helpful tool to monitor of the state of the rapidly changing (near-surface) atmosphere in real-time. It neatly bridges the information gap caused by the periodic nature of our academic assessments.

For more information, we refer to the Supplementary information and the info page on our website. Also, we encourage everyone to download the accompanying spreadsheet and play around with it 🙂

Finally, all credit belongs to my co-authors Fredi Otto, Piers Forster, Dave Frame, Dann Mitchell and Damon Matthews in general, and Myles Allen, who had the original idea, in particular.

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56 Responses to A real time global warming index

  1. John Hartz says:

    Karsten Haustein: Kudos to you and your colleagues for creating this much-needed index.

  2. So the anthropogenic contribution since pre-industrial times looks close to 100%, yes?

  3. Dana,
    Yes, I think that is essentially what they’re arguing. I would guess that the one thing you can’t easily account for the is the pattern effect (i.e., the pattern of sea surface warming that may be influenced by natural variability and that may suppress, or enhance, the forced response). However, I think they are essentially arguing that most/all of the warming since the mid-1800s is anthropogenic. Karsten said he would try to check in over the next couple of days and respond to comments.

  4. Thanks. I’m also curious about this:

    we shouldn’t expect the temperatures to ever go back down to pre-2014 levels (barring a strong volcanic eruption).

    Does that mean we shouldn’t expect any future year to be cooler than 2014? I’d think a strong La Niña could probably still do it even without a strong volcanic eruption.

  5. Dana,
    I think that’s referring to the GWI estimates, which remove the impact of El Nino events. So, yes, I think we could still see surface temperatures lower than 2014 if there were a strong La Nina, but the GWI estimate is unlikely to drop below the estimate for 2014, unless there were a strong volcanic eruption.

  6. Everett F Sargent says:

    It would be kind of helpful if someone could explain the 5-95% (orange shading prior to say ~1960) …

    I’d expect error bars to be larger going back in time, not dropping to almost zero. Yes?

  7. The Very Reverend Jebediah Hypotenuse says:

    Let me join others in thanking you Karsten Haustein (and ATTP) for bringing this to our attention.

    Everett F Sargent says:

    I’d expect error bars to be larger going back in time, not dropping to almost zero. Yes?

    I wondered about that too.
    Perhaps the relative uncertainties are larger as one looks to earlier years – but the absolute uncertainties are smaller since the delta-T is much smaller then…?

    I am also wondering why a simple OLS regression was used on the entire 2013-point data-set (i.e 1850 onward) where the trend is obviously changing dramatically around 1970?

  8. Everett F Sargent says:

    The Rev,

    Yes I read that one sentence in the paper…
    “Ordinary least squares is appropriate because the output of the simple model is almost free of stochastic variability, hence the noise is very small.”

    The error bars almost appear to be proportional to the slope?

    A smooth response suggest a form of low pass filtering, resulting in a low frequency curve with extremely high auto-correlation, standard practice is to decimate below the effective half-point of the filtering procedure.

    Though, I must admit, that their fit looks a lot like the CMIP5 fits to the historical record.

  9. JCH says:

    Where I live pre 2014 is 2013 (.65 ℃) and back. 2011 was .58 ℃. 2008 was .52 ℃.

  10. Steven Mosher says:

    Great work.

  11. Christian says:

    “I’d expect error bars to be larger going back in time, not dropping to almost zero”

    Its the range of forcing realisation. In other words, if you had uncertainy of 5% and your number is increasing (and the forcing has near steadly risen), then your range by 5% uncertainy becomes relativ wider.

    For Example;

    0.1W/m^2 by 5% = 0.095 to 0.105
    1W/m^´2 by 5% = 0.95 to 1.05

    so mean, as higher as your forcing get, the higher gets your relative uncertainy

  12. Yes, I think what Christian has described is the main reason for the smaller error bars at early times.

  13. Christian says:

    and this is a simplification, in a more way to the work, they also split aersol forcing to the domain of emission not just as global integrated forcing, as a result of this, the response in temperature could differ from global integreated or say so, 5-95% range gets wider

  14. Christian says:

    ATTP,

    “Dana,
    I think that’s referring …()”

    I think you got this wrong (perhaps me too, only Karsten knows^^), but as much as i Karsten know and on this point, we often agree, La-Nina is no more able to cool down the planet to temperature before 2014.

    If you more interest why, look here: http://www.realclimate.org/index.php/archives/2017/11/el-nino-and-the-record-years-1998-and-2016/#comment-685792 and thats the same, why global temperature has risen so strong, its so clearly detectable… but dont get me wrong, i talking about my opinion, have not the be Karstens.

  15. Everett F Sargent says:

    ATTP, Christian,

    I’ve checked their spreadsheet and further checked using OriginPro 2017.

    dependent variable = temperature time series
    independent variable = integral of anthro forcing time series with 4 and 209 year exponential damping coefficients

    dependent variable = temperature time series
    independent variable = integral natural forcing (almost entirely volcanic) time series with 4 and 209 year exponential damping coefficients

    So, I think I’ll buy into your scaling argument.

  16. BBD says:

    Great stuff – thanks Karsten for posting. Very interested to see that ~1C from ~1850 is confirmed as (a possibly conservative) response to increased anthropogenic forcing.

  17. Chubbs says:

    Thanks for the post and spreadsheet. Note that the fit in the spreadsheet could be used to adjust the index to a 1750 baseline or to project forward for any assumed future forcing outlook. If I’ve down the calculation properly, a 1.5C index value will be reached in 2042 under the assumption that forcing increases at the same rate as the past 20 years.

  18. The Very Reverend Jebediah Hypotenuse says:


    So, I think I’ll buy into your scaling argument.

    FWIW, I now concur as well.

    Very interesting.

  19. The use of the descriptor “real-time” to describe this software is funny to us that actually know what real-time software entails.

    Part of the interest I have in the geophysics of climate science is in being able to simplify the models that the consensus has been applying. For example, clearly the GC models for ENSO are overkill at this point. The climate scientists that have pointed to toy-models for the actual mechanisms, such as Zebiak-Cane and delay differentials (Ghil) have been on the right track all along. All one has to do is apply lunisolar gravitational forcing to a simple delay differential and the ENSO time-series pops out, and all the El Nino/La Nina peaks and valleys align. The software formulations and solution techniques are simple enough that it will make it a companion to the real-time software that is used for tidal analysis and prediction — such as this:

    https://journals.lib.unb.ca/index.php/ihr/article/view/23216

    “Towards a Real-Time Tidal Analysis and Prediction” Tianhang Hou, Petr Vanicek
    Abstract: In the practice of tidal analysis and prediction, the number and kind of astronomical tidal components that are to be included in a tidal model depend on the length of available tidal record and the desired accuracy of prediction.

  20. paulski0 says:

    Hi Karsten,

    Congratulations! Very nice work.

    I was a bit surprised that the natural contribution wasn’t stronger, particularly at mid-20th Century, based on previous work I’ve seen from you. Looking at the figures at your website, it seems that your base model does produce more natural warming – about 0.1K at 1960 relative to 1850-1879, with skewed uncertainty towards greater amounts – but the D&A regression couldn’t see that large an effect in the data. Is that about right?

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  22. Thanks all. Sorry I couldn’t reply earlier due to travelling (in the midst of India).

    @Dana: I guess my point was that the accelerated forcing increase made it extremely unlikely that we’ll see something like 2011 again. Not only because a record La Nina is needed, but also a severely cold Eurasian winter. It’s virtually impossible that the GWI itself drops below 2014 again.

    @Everett: The GWI is zero at the mid-point of the reference period, which is 1850-79 (i.e. 1864). Hence the uncertainty in 1864 is zero by construction too, and only increase slowly the further we go into the future. Essentially, all uncertainties are zero-ed with the same reference period.

    @Paul: Yepp, the OLR scaled the natural forcing response considerably down, due to the subdued correlation coefficient. The choice of fast response time provides some leverage, but the natural response hasn’t got any bearing on the result of the anthropogenic response (only the total).

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  25. russellseitz says:

    To better immanenetize the present eschaton , the Real Time Index website might be equipped with a rolling number widget continuously counting up the climate change in microdegrees.

  26. John Hartz says:

    Important breaking news (perhap deserving of a new blog post)…

    Missing Arctic temperature data, not Mother Nature, created the seeming slowdown of global warming from 1998 to 2012, according to a new study in the journal Nature Climate Change.

    A University of Alaska Fairbanks professor and his colleagues in China constructed the first data set of surface temperatures from across the world that significantly improves representation of the Arctic during the “global warming hiatus.”

    Xiangdong Zhang, an atmospheric scientist with UAF’s International Arctic Research Center, said he collaborated with colleagues at Tsinghua University in Beijing and Chinese agencies studying Arctic warming to analyze temperature data collected from buoys drifting in the Arctic Ocean.

    “We recalculated the average global temperatures from 1998-2012 and found that the rate of global warming had continued to rise at 0.112C per decade instead of slowing down to 0.05C per decade as previously thought,” said Zhang.

    The new data also improved estimates of the global warming and the Arctic warming rate.

    Added Arctic data shows global warming didn’t pause, Phys.org, Nov 20, 2017

  27. Christian says:

    John Hartz,

    “Important breaking news ”

    I disagree, its not really new stuff, that coverage can altering/bias the trend and for that, the arctic which is amplifier the warming results in lower trend when its not covered in Temperature-Dataset. See also Cowtan and Way 2014 “Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends”

    The only thing whats interesting, they found stronger arctic warming

  28. angech says:

    “Added Arctic data shows global warming didn’t pause,’
    John, whether this is true or not, the fact is that if the added data were not added then there was a pause.
    On the original data.
    All the hand waving afterwards and altering of the data sets afterwards do not change the premise, at the time, on the data that was available and used, that there was a pause.
    In fact your article corroborates said pause.
    The problem becomes worse, in that a lot of people here dispute that there was a pause at all without your added data.
    What you should be saying is in fact, “”look guys, there was an acceleration in warming from 1998-2012 “, or “Added Arctic data shows global warming accelerated”.
    Lt’s hope nobody else comes up with other data also proving that the pause was not real, otherwise I would be tempted believe global warming fell off a cliff in that time period.

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  30. BBD says:

    otherwise I would be tempted believe global warming fell off a cliff in that time period.

    It didn’t, the ‘sceptics’ were wrong (again) and that’s really the end of that. There was no pause. End of story.

  31. JCH says:

    John, whether this is true or not, the fact is that if the added data were not added then there was a pause.
    On the original data.

    That is just extraordinary. The original data was wrong (incomplete means it was wrong,) so there was no paws. You will fall for anything. The paws fooled a lot of very smart people. Be one who wises up.

  32. angech says:

    “The problem becomes worse, in that a lot of people here dispute that there was a pause at all without your added data.”
    It is inconceivable, perhaps I do not know the meaning of this word, that the very point I am making is used as a rebuttal to the point I made.

  33. Mal Adapted says:

    angech:

    All the hand waving afterwards and altering of the data sets afterwards do not change the premise, at the time, on the data that was available and used, that there was a pause.

    Except there was no pause, if by ‘pause’ you mean a short-term interval when the slope of the long-term statistical trend in GMST fell to zero. There was an interval between 1998 and 2012 when observed GMST appeared to the eye to rise more slowly than projections for that interval produced by an ensemble of coupled GCMs, although still within modeled lower confidence bounds. Change point analysis, more rigorous than eyeball methods, found no statistically significant change in the trend of the previous three decades. From the latter article, by Rahmstorf, Foster and Cahill earlier this year in ERL:

    [T]he data are fully consistent with a steady global warming trend since the 1970s, superimposed with random, stationary, short-term variability. All recent variations in short-term trends are well within what was to be expected, based on the observed warming trend and the observed variability from the 1970s up to the year 2000. We discuss some pitfalls of statistical analysis of global temperatures which have led to incorrect claims of an unexpected or significant warming slowdown.

    Although the alleged ‘pause’ was not statistically significant and was conclusively terminated in 2014, it attracted attention from climate scientists seeking to resolve ‘internal’, short-term variability to forcings. Rather than casting doubt on the AGW consensus, the short-term slowdown in observed warming led to refinement of models as well as datasets. Climate science advanced pretty much as one expects, and the consensus case for AGW grew still stronger. AGW-deniers hoping to weaken it, OTOH, found their ‘pause’ rhetoric had backfired ;^D!

  34. angech says:

    “The problem becomes worse, in that a lot of people here dispute that there was a pause at all”
    Mal Adapted says: re
    “All the hand waving afterwards and altering of the data sets afterwards do not change the premise, at the time, on the data that was available and used, that there was a pause.”

    “Except there was no pause, if by ‘pause’ you mean a short-term interval when the slope of the long-term statistical trend in GMST fell to zero”

    Note I did say premise, not fact.
    And thank you for one definition of what a pause might be.
    It is difficult to discuss what one believes does not exist.
    Particularly when giving proof that it did not exist because you [*Xiangdong Zhang] have found extra missing data that proves it did not exist.

  35. angech says:

    Mal Adapted
    “Except there was no pause, if by ‘pause’ you mean a short-term interval when the slope of the long-term statistical trend in GMST fell to zero”

    I would be happy with a definition of a pause, in general, to be a zero slope trend for any graph with a time base over any reasonable fraction of the presented graph.
    This is not a standard definition but since we are discussing unicorns this is the sort of definition I would prefer.
    At Lucia’s 2 years ago she and others argued that a steady slope with no acceleration could be taken in some circles to mean a pause. I get the idea of a non changing rate being paused but in the real world I would insist on a zero slope, that is there was a rate which has now altered to a zero slope.
    As for short term there is no short term in my definition if showing a single pause as the requirement is for it to be visible on the graph shown.

    Commenting specifically on “[T]he data are fully consistent with a steady global warming trend since the 1970s, superimposed with random, stationary, short-term variability”
    We have a graph of 47 years, the authors dispute the existence of a pause while admitting several occurred by my definition [random, stationary, short-term variability]. Karsten himself acknowledges a pause was seen and named by some people ” the inappropriately named “hiatus”. John Hart references “average global temperatures from 1998-2012 ” which would be a significant 14 years out of 47, hardly short term in the context of a 47 YO graph.

    Since a lot of people here dispute that there was a pause at all.
    Not to mention all authors referenced above
    With good arguments.
    Too short a time frame.
    The graph actually went up 0.05C in the misquoted study.
    Cherry picking a time after El Nino.
    Definition of a pause is completely wrong.
    etc.
    There is no need to throw in studies showing there was a pause but….

  36. BBD says:

    angech

    There’s was no pause. OHC carried on increasing throughout. Stop muddling between the troposphere and the climate system as a whole, which is mostly ocean. Pause rhetoric is tedious. Move on. Find something else to quibble about.

  37. Roger Jones says:

    Mal Adapted,
    the change point analysis conducted by Rahmstorf et al. is flawed, as are all the papers they cite in the introduction. Why? They are all based on the premise that step-like change is surface/atmospheric warming cannot occur under gradual forcing, so none of them analyse for it. Having assumed nothing can happen, then conducting an analysis that proves nothing, is easy. It’s a good thing for them that global warming is real, otherwise they could never get away with such poor reasoning.

    Step-like changes can occur in surface warming, they can be detected, they are the result of forcing. The hypothesis that gradual anthropocentric warming can be independent of nonlinear natural greenhouse driven variability, where roughly 155 W/m2 global average forcing is driven to the top of the atmosphere and the poles to keep Earth in temperature balance is unsustainable. Anthropogenically-forced photons carrying this heat energy are unable to behave differently to naturally-forced photons. Separating them into different statistical entities, signal and noise, violates basic physics.

    The signal to noise model might be the simplest method of analysis (cue Occam’s Razor) but it requires an extra step in theory, where anthropogenic warming does not become part of the same processes that drive ongoing climate variability but acts separately. Adding anthropogenically-derived energy into the standard, nonlinear dissipative system that transports naturally-generated heat to the top of the atmsophere and the poles is the simplest theoretical position, because there is no special pleading – all energy is treated as equal. The fact that it may be statistically a little more complex (steps over trends) is tough cookies. Science is about theory number 1, method number 2. (Values mess with both but that’s another thread.)

    We know that climate behaves in steady-state mode from stable levels of 190 ppm CO2 to over 1,200 ppm. Why would the addition of 1.8 W/m2 each year, when we agree that 93% of that already disappears into the ocean and few percent each melt solid water and warm the ground, why would say 0.07 W/m2, stay in an atmosphere circulating above the ocean, when water contains around 3,200 times the heat capacity of air by volume and the ocean has a thermal conductivity 24 times that of the atmosphere? The dynamic of El Nino and La Nina exchanging energy between the surface and the top of the atmosphere already acts as a pressure cooker absorption-release mechanism. Why would a few extra greenhouse gases change that? (As a note, when greenhouses gases increased after the last glacial maximum, many, perhaps most of the palaeoclimatic changes detected with appropriate resolution have been step-like, when the current statistical model would predict trend-like change)

    The annual circulation of the atmosphere over the ocean is equivalent mixing to 90 m depth, but the whole energy capacity of the atmosphere can be met by the top 2.3 m. Absorption of the added heat generated by greenhouse gases into the ocean is therefore not energy limited. The atmosphere can warm by itself due to changes in greenhouse forcing on Venus and Mars but not on Earth. The ocean sucks up the lot, because water is greedier than air. We know this with high confidence because lake energy balance models work in exactly the same way. Much of the heat absorbed by the global ocean is absorbed in the Pacific and is transported west into the western Pacific Warm Pool.

    The resting state of the ocean-atmosphere system is a steady-state regime between the atmosphere and shallow ocean. When one regime becomes unstable, either regionally or globally, it switches into another. In a stable climate, correlated variables that reflect the prevailing energy state are unchanged, only their distribution is changed. In a warming climate, the additional heat in the atmosphere results in a regime change where climate variables shift into a more energetic state; e.g., max temperature on land increases relative to rainfall. The mechanism is centred on the west Pacific Warm Pool, which acts as a heat engine, and when it becomes unstable by accumulating too much heat, releases it in an El Nino event. Contemporaneous regime shifts at various places around the planet raise ocean surface temperatures, sustaining this heat in the atmosphere, and preventing its return into the ocean because a new steady state is being maintained.

    Climate change is enhanced climate variability. It proceeds as a series of steady state regimes separated by step changes. Over the long term this converts to a complex trend. It is always possible to analyse these changes using trend analysis, but that is not what is actually going on in shallow ocean – atmsophere.

    The deep ocean shows a clear warming trend that is gradual because of the mixing process required to get the heat down there. The atmosphere, especially represented as satellite data, was in a steady-state regime globally between 1997 and 2014, though there is evidence of some shifts locally (e.g., 2006 in the Arctic). You could call this a pause or a hiatus, but I prefer climate regime. During 2014-2016, globally we experienced another shift. We have entered a steady-state regime of warmer temperatures because of that, and it is important to pinpoint the regions where the biggest changes have occurred, because they may be in some strife going forward.

    The greater the forcing, the shorter the intervals between regime changes are likely to be. We got lucky with 1997-2014. The next shift will be much sooner than that.

  38. The Very Reverend Jebediah Hypotenuse says:


    the change point analysis conducted by Rahmstorf et al. is flawed, as are all the papers they cite in the introduction. Why? They are all based on the premise that step-like change is surface/atmospheric warming cannot occur under gradual forcing, so none of them analyse for it. Having assumed nothing can happen, then conducting an analysis that proves nothing, is easy. It’s a good thing for them that global warming is real, otherwise they could never get away with such poor reasoning.

    It’s a good thing that this far-reaching and obliquely ad hominem claim appears in the form of a blog comment, otherwise someone might suggest that the premise that discontinuous step-like changes occur in warming should require a citation, or several…


    When one regime becomes unstable, either regionally or globally, it switches into another…
    Climate change is enhanced climate variability. It proceeds as a series of steady state regimes separated by step changes. Over the long term this converts to a complex trend. It is always possible to analyse these changes using trend analysis, but that is not what is actually going on in shallow ocean – atmsophere….
    We have entered a steady-state regime of warmer temperatures…

    Natura non saltum facit.

    If the climate “regime” lasts but a few years, it is hardly a regime, climate-wise. More like a transitional form…

    Gradualism versus saltationism – It could be a question of scale.

    Referencing the same sort of “versus”, S. J. Gould stated:

    Since we proposed punctuated equilibria to explain trends, it is infuriating to be quoted again and again by creationists—whether through design or stupidity, I do not know—as admitting that the fossil record includes no transitional forms. Transitional forms are generally lacking at the species level, but they are abundant between larger groups.

    And of course, there are always many ways to parse any complex signal into ‘regimes’.

  39. John Hartz says:

    Roger Jones: Citations please.

  40. Everett F Sargent says:

    Mal Adapted,
    the change point analysis conducted by Rahmstorf et al. is NOT flawed, as are all the papers they cite in the introduction. Why? Thet use lower DOF’s than Jones and (mostly) Ricketts use see …
    http://www.vises.org.au/documents/climate/
    Reports 31-39 (9 tries even)

    See …
    Reconciling the signal and noise of atmospheric warming on decadal timescales
    https://www.earth-syst-dynam.net/8/177/2017/
    (please read the reviewer comments)

    Basically it’s like the SkS staircase/escalator analysis.

    Change point analysis is not even C0 continuous (it has a vertical break and jump in slope), Join point analysis is C0 (no vertical change, just a change in slope) continuous, Tamino uses it exclusively as do most real climate scientists and the NIH uses it …
    https://surveillance.cancer.gov/joinpoint/

    If one claims a regime change discontinuity or even just a change in slope. then they have better have an underlying quantifiable physical basis. Otherwise, it’s just statistics with no underlying physical basis (Like NINO or volcanoes.) whatsoever.

    Just be careful of those self promoting their own ideas over other ideas that are currently most often used. Paradigm shift? Who really knows until after the fact. That is all.

  41. Roger Jones said:

    “The mechanism is centred on the west Pacific Warm Pool, which acts as a heat engine, and when it becomes unstable by accumulating too much heat, releases it in an El Nino event. Contemporaneous regime shifts at various places around the planet raise ocean surface temperatures, sustaining this heat in the atmosphere, and preventing its return into the ocean because a new steady state is being maintained.”

    Discussion of “regime shifts” and discontinuities is an indication that the geophysics mechanisms are not understood

    I had not heard this term mentioned by TVRJH:

    “Gradualism versus saltationism – It could be a question of scale.”

    The best example of gradualism are the effect of lunar tidal forcing. This has gradual effects on every scale, from the daily ocean tides to the decadal long-term deep-ocean mixing described by Munk and Wunsch. Yet, even though apparently no one has ever attempted to apply the lunar gravitational forcing to the sensitive reduced-effective gravity interface of the Pacific ocean thermocline, it shouldn’t be surprising that would work as well. And it does http://contextearth.com/2017/11/22/the-enso-forcing-potential-cheaper-faster-and-better/

    Everett F Sargent said:

    “If one claims a regime change discontinuity or even just a change in slope. then they have better have an underlying quantifiable physical basis. Otherwise, it’s just statistics with no underlying physical basis (Like NINO or volcanoes.) whatsoever.”

    I agree. The starting point for modeling a behavior such as ENSO is a potentially valid geophysical mechanism. Lindzen has said that “It is unlikely that lunar periods could be produced by anything other than the lunar tidal potential” and “For oscillations of tidal periods, the nature of the forcing is clear”. The lunisolar cycles are such a precise clock that it is very easy to dismiss that mechanism if one can’t find a match. But if the match is there, as happens with straightforward gravitational forcing for ENSO and QBO, then the lunisolar cycle needs to be considered as a valid underlying physical basis.

    Do this and we can avoid having to listen to vague discussions of “regime shifts” or more red noise models and get on with the business of applying physics to understanding variability in climate.

  42. Pingback: Estadounidenses están preocupados por el cambio climático | Futuro Verde

  43. angech says:

    What he said.
    Though “Natura non saltum facit.” is a comforting thought both Skeptics and AGW people persist in talks of regime change and jumps particularly with El Nino recent events.
    I think natural variation will lead to seeming jumps at times but if we had better understanding then the steady change hypothesis is more likely.

    Willard
    “Since we proposed punctuated equilibria to explain trends”. Sounds like you ar being channeled somewhat.

  44. JCH says:

    Jumps go up and down; ACO2 goes up.

  45. BBD says:

    The troposphere ≠ the climate system.

  46. JCH says:

    They conclude the warming trend is currently .17 ℃ per/yr. This after NV is removed. I keep seeing papers suggesting the AMO is a driver, so I seriously question that NV has actually been accurately removed. I suspect NV has, on net, suppressed AGW since around 1985, and I believe that means the climate could be more sensitive to ACO2 than many currently think. Which is why I do not get the resistance to Roger Jones. Knutson at the GFDL modeled this and found that pretty large step change, if that is what you want call it, is possible.

  47. Mal Adapted says:

    angech:

    I would be happy with a definition of a pause, in general, to be a zero slope trend for any graph with a time base over any reasonable fraction of the presented graph.
    This is not a standard definition but since we are discussing unicorns this is the sort of definition I would prefer.

    Angech highlights the requirement to disambiguate ‘pause’ scrupulously. AFAIK, the Oxford English Dictionary curates the ‘standard’ definition of English language words. It offers the following for pause:

    NOUN

    1 A temporary stop in action or speech.

    That seems consistent with the definition both angech and I are using, i.e. “a zero slope trend for any graph with a time base over any reasonable fraction of the presented graph”.

    The OED’s definition is further consistent with the relentless undead AGW-denialist meme of a ‘pause’ in global warming, as represented by a jaw-dropping iteration I’m loathe to link here, posted on the AGW-denier flagship Climate Depot two years ago by infamous unicorn hunter Marc Morano: it’s titled “No global warming at all for 18 years 9 months – a new record – The Pause lengthens again – just in time for UN Summit in Paris”.

    So, the standard professional AGW-denier’s use of ‘pause’ in the preposterous lie of “No global warming at all for 18 years 9 months” matches the OED definition; and also angech’s and mine, which expressly applies to statistical hypothesis testing.

    Non-duplicitous interpretations of ‘pause’, OTOH, can be found in the peer community of climate scientists, some of whom are following up their eyeball inferences to elucidate the physical sources of short-term variation in the long-term trend of GMST. The ensuing refinements to coupled GCMs are paradigmatic of scientific progress.

  48. Mal Adapted says:

    Roger Jones:

    Mal Adapted,
    the change point analysis conducted by Rahmstorf et al. is flawed, as are all the papers they cite in the introduction. Why? They are all based on the premise that step-like change is surface/atmospheric warming cannot occur under gradual forcing, so none of them analyse for it. Having assumed nothing can happen, then conducting an analysis that proves nothing, is easy. It’s a good thing for them that global warming is real, otherwise they could never get away with such poor reasoning.

    Roger, in all candor I’m not qualified to evaluate your argument with confidence. Yet as I understand it, Rahmstorf et al. challenged the transparently mercenary null hypothesis that “the trend of GMST in the interval 1998 to 2013 did not deviate from 0”. Using what they referred to as change point analysis, they tested the null hypothesis that “the trend of that interval did not deviate from the long-term trend of the previous 30 years”, and found no significant deviation. As far as I can tell from my ‘semi-doctoral’ understanding of statistics, they successfully refuted the AGW-denialists claim of a ‘pause’ in global warming. Bravo!

    As angech illustrates, the AGW-denialist ‘pause’ meme refuses to lie quietly in its grave nonetheless. Science is no match for magic, I fear.

  49. Ragnaar says:

    I also think Roger Jones had a good explanation above.

    “The IPCC AR5 notes the lack of warming since 1998:
    [T]he rate of warming over the past 15 years (1998–2012) [is] 0.05 [–0.05 to +0.15] °C per decade)which is smaller than the rate calculated since 1951 (1951–2012) [of] 0.12 [0.08 to 0.14] °C per decade.” – Curry

    SkS explain this about 3 years ago as Hiroshima bombs of energy.

    While I explain it as almost 4 kilometers of water over 2/3s of the surface, even 90 meters is about 30 times the mass of the atmosphere. Opinions vary as to how much depth easily exchanges with the atmosphere? Or as I expect, the oceans draw a lot in, in the long run and this draw increases the greater the differential.

    The pause as I see it, not being in this discussion as long as most, told people to look in the oceans. To now add much more thermal mass to their models, and make them much more complex. The ENSO SST forcing paper helped me reach that conclusion. And think there was another paper that forced all SSTs. And those models I think kicked butt. But they forced a lot. Huge amounts of joules mostly entering the atmosphere. So when you know what you haven’t modeled yet, it works great.

  50. kribaez says:

    ATTP,
    If you are holding my previous attempts to post a comment. please delete them all without publishing. I have written to Karsten directly.
    Thanks

  51. kribaez,
    Okay, thanks for letting me know.

  52. angech says:

    At least we can communicate with a standard definition.
    Mind you that only makes 2 of us as others will explain.

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