by Nic Lewis
Michael Mann has had a paper on the Atlantic Multidecadal Oscillation (AMO) accepted by Geophysical Research Letters. The paper seeks to overturn the current understanding of the AMO. But on my reading of the paper Mann’s case is built on results that do not support his contentions.
Introduction
Michael Mann has had a paper on the Atlantic Multidecadal Oscillation (AMO) accepted by Geophysical Research Letters: “On forced temperature changes, internal variability, and the AMO”. The abstract and access to Supplementary Information is here . Mann has made a preprint of the paper available, here . More importantly, and very commendably, he has made full data and Matlab code available.
The paper seeks to overturn the current understanding of the AMO, and provides what on the surface appears to be impressive evidence. But on my reading of the paper Mann’s case is built on results that do not support his contentions. Had I been a reviewer, I would have pointed this out and recommended rejection.
In this article, I first set out the background to the debate about the AMO and present Mann’s claims. I then examine Mann’s evidence for his claims in detail, and demonstrate that it is illusory. I end with a discussion of the AMO. All the links I give provide access to the full text of the papers cited, not just to their abstracts.
The conventional view of the AMO
NOAA, which provides an AMO index, has a helpful FAQ on the AMO that says:
The AMO is an ongoing series of long-duration changes in the sea surface temperature of the North Atlantic Ocean, with cool and warm phases that may last for 20-40 years at a time and a difference of about 1°F between extremes. These changes are natural and have been occurring for at least the last 1,000 years… Since the mid-1990s we have been in a warm phase. The AMO has affected air temperatures and rainfall over much of the Northern Hemisphere… It alternately obscures and exaggerates the global increase in temperatures due to human-induced global warming.
The AMO is thought to be quasi-periodic with a typical cycle length of 60–70 years. It reached its nadir in the mid 1970s and, after reaching positive ground in 1995, may have peaked in the mid 2000s. NOAA’s AMO index[i] is a detrended average of mean North Atlantic (0°–70°N) sea surface temperature (SST) from the Kaplan dataset. Figure 1 shows that AMO index on both annual and centred 5-year mean bases.
Although the NOAA AMO index is based only on North Atlantic SST, both northern hemisphere (NH) temperature and global mean surface temperature (GMST) are quite strongly correlated with it. Something of the order of 0.2°C of the 0.5–0.6°C increase in GMST since the mid 1970s might be due to the strengthening AMO rather than to increasing anthropogenic radiative forcing. Consistent with this suggestion, a recent paper by Chylek et al concluded, using regression analysis, that about one-third of the post-1975 increase in GMST was likely due to the AMO. A 2013 paper by Zhou & Tung found an even stronger influence of the AMO on the post-1980 GMST trend.
Fig 1. NOAA AMO Index, annual (thin cyan line) and 5-year mean (thick green line), based on detrended North Atlantic (0°–70°N) SST from the Kaplan dataset.
Assuming that the AMO is natural, and it has had a positive influence on the increase in GMST over the last few decades, it follows that estimation of anthropogenic warming rates and the transient climate response (TCR) from post-1975 temperature changes will be biased upwards, showing high sensitivity, fast-warming climate models (CMIP5 GCMs, in particular) in an artificially favourable light, unless the AMO’s influence is adjusted for. A paper under discussion at Earth System Dynamics, here, makes just that point. It concludes that, adjusting for the influence of the AMO, global warming over the last 30 years indicates a best estimate for TCR of ~1.3°C. That is in line with the results of several studies based on warming since the second half of the 19th century – the trend of which will have been much less affected by the AMO – but well below the 1.8°C average TCR of current generation CMIP5 GCMs.
Did aerosols rather than the AMO drive 20th century Atlantic SST variations?
In 2012 a team of scientists at the UK Met Office published a paper claiming that anthropogenic aerosol indirect forcing, rather than natural variability, drove much of the 20th century variability in North Atlantic SST attributed to the AMO. This claim was based on simulations using the HadGEM2-ES climate model. However, in 2013 a team of scientists from GFDL and elsewhere published a counter-paper entitled “Have Aerosols Caused the Observed Atlantic Multidecadal Variability?“, which showed major discrepancies between the HadGEM2-ES simulations and observations in the North Atlantic.
Mann himself had argued that anthropogenic aerosols rather than the AMO drove variability in tropical Atlantic SST in a short 2006 paper, here . However, he accepted therein that his analysis relied upon the AMO having no influence on GMST, and he also used what is arguably a questionable statistical model. AR5 didn’t mention this paper when discussing the AMO (in Section 10.3.1.1.3).
Now, however, Mann has returned to this issue, making the extraordinary claim that trends forced by anthropogenic greenhouse gas and sulphate etc. emissions masqueraded as an apparent oscillation, and that rather than warming the NH:
“The true AMO signal, instead, appears likely to have been in a cooling phase in recent decades, offsetting some of the anthropogenic warming temporarily.”
Mann’s other claims
The press release for the paper also says:
According to Mann, the problem with the earlier estimates stems from having defined the AMO as the low frequency component that is left after statistically accounting for the long-term temperature trends, referred to as detrending.
Mann and his colleagues took a different approach in defining the AMO… They compared observed temperature variation with a variety of historic model simulations to create a model for internal variability of the AMO that minimizes the influence of external forcing — including greenhouse gases and aerosols. They call this the differenced-AMO because the internal variability comes from the difference between observations and the models’ estimates of the forced component of North Atlantic temperature change.
They also constructed plausible synthetic Northern Hemispheric mean temperature histories against which to test the differenced-AMO approaches. Because the researchers know the true AMO signal for their synthetic data from the beginning, they could demonstrate that the differenced-AMO approach yielded the correct signal. They also tested the detrended-AMO approach and found that it did not come up with the known internal variability.
While the detrended-AMO approach produces a spurious temperature increase in recent decades, the differenced approach instead shows a warm peak in the 1990s and a steady cooling since.
That is certainly a novel approach. By defining the AMO as the part of the smoothed temperature change simulated by the models that is not observed, the problem of models warming far too fast since ~2000 largely disappears. So does the inconvenient possibility that the fast model-simulated warming in the 1980s and 1990s might have only been matched in the real world due to a significant contribution from the AMO. Mann’s differenced-AMO is a high-sensitivity climate modeller’s dream. If climate models were perfect apart from not simulating the AMO, then the differenced-AMO approach would make sense. But models are by no means perfect – and if they were then they would simulate the AMO.
Mann’s differenced-AMO merely reflects, on a smoothed basis, the extent to which the observed NH temperature outpaces climate model simulated NH temperature, going negative when models simulate an unrealistically high temperature rise. It seems likely that it will represent model failings and unrealistic forcings to a greater extent than unforced multidecadal internal climate system variability. The CMIP5 models typically have very high aerosol forcing, and as aerosol forcing grew fast from 1950 to the mid/late 1970s it seems that their high aerosol forcing typically more than compensated for their high transient sensitivity, so that they partially emulated the effects of the AMO downswing.
After defining the differenced-AMO, Mann purports to show – using synthetic temperature histories containing a known AMO signal – that his differenced-AMO approach yields the correct signal, whereas the detrended-AMO approach does not. So how does Mann achieve this impressive feat?
The graphs in Mann’s paper are largely based on a simulation by a simple energy balance model (EBM). He obtains broadly similar, but less impressive, results using instead the GISS-E2-R GCM and the average of the full 40-model CMIP5 GCM ensemble. I’ll concentrate on his EBM simulation here, as it best illustrates how he achieves his surprising results.
Mann deals entirely with Northern Hemisphere, not global, temperatures. Figure 2 shows the evolution of NH surface temperature simulated by his EBM (blue line) when his code is run, compared to the HadCRUT4 observational record (black line). It also shows an alternative simulation by a low sensitivity EBM of my own specification (red line). The lines are aligned to all have the same overall mean. For HadCRUT4 the zero line is intended to represent preindustrial temperatures.
Fig 2. NH temperature anomalies from 1850–2012 per HadCRUT4 (black) and as simulated by Mann’s EBM (blue) and the alternative low sensitivity EBM (red)
Mann’s high sensitivity EBM and my alternative EBM
Mann’s EBM has an equilibrium/effective climate sensitivity (ECS) of 3.0°C and, unusually, no allowance for heat uptake by the ocean apart from in a 70 m deep mixed layer. As a result, its TCR – the simulated temperature rise from CO₂ concentrations doubling over 70 years as a result of 1% p.a. growth – is 2.8°C, very little lower than its ECS. His EBM uses a modest aerosol forcing that becomes only 0.3 W/m² more negative over 1950–1975. So why does its simulated temperature rise from 1920–1950, during the AMO’s upswing, but fall from 1950 to 1975, over which period the AMO was in a downswing but anthropogenic forcing excluding aerosols rose by over 0.7 W/m² (per AR5)?
The explanation is that Mann makes only a very modest allowance for the increase in non-CO₂ greenhouse gases and other non-aerosol anthropogenic forcings over 1950–1975, so his increase in total anthropogenic forcing over that period is only 0.4 W/m², 0.32 W/m² below AR5’s best estimate. During that period solar and volcanic forcings both had negative influences – totalling -0.2 W/m² per Mann’s data and -0.3 W/m² per AR5, taking trailing 5-year means to allow for the time constant of the ocean mixed layer. There was also sizeable negative volcanic forcing in 1963-64, again larger per AR5 than in Mann’s data. Therefore, Mann’s EBM had a negative forcing trend over 1950-1975 and shows cooling during that period.
On the other hand, during 1920–1950 the increasing trend in negative aerosol forcing was more than offset by trends in solar and volcanic forcings, and the very high TCR of Mann’s EBM made up for the shortfall in non-CO₂ greenhouse gas forcing and other non-aerosol anthropogenic forcings. After 1975, during the AMO upswing, much the same occurred, but by then the rise in CO₂ forcing was faster and more dominant, so Mann’s EBM simulated temperature rose fast. After 2000, since when the rise in CO₂ has strongly dominated changes in other forcings, Mann’s sensitive EBM outpaces HadCRUT4.
As a result of the particular forcing history used, Mann’s EBM, despite its very high TCR, is able to match – very closely on a smoothed basis – not only the overall HadCRUT4 20th century NH record but also its AMO-influenced ups and downs – very closely on a smoothed basis. But Mann chose the scaling for aerosol and solar forcing to optimise the fit, so it is not very surprising that it is good. The result is that his differenced-AMO smoothed time series is fairly flat over the 20th century, and declining post 2000.
My alternative, low-sensitivity, EBM is driven by the AR5 forcing best estimate time series. As is common when using a simple global model, volcanic forcing is scaled down, here by a factor of 0.5. It remains higher than the volcanic forcing series Mann uses for his EBM. The low-sensitivity EBM has the same ocean mixed layer depth as Mann’s EBM, but it is a 2-box model with the rest of the ocean’s heat capacity represented as well. The EBM has an ECS of only 1.65°C, in line with my best estimate using AR5 forcing and heat uptake data. One might expect a higher sensitivity (or a scaling of the simulated temperature) to be needed to match the faster warming in the NH, which is faster than the global rate, but different ocean parameters from those used for global temperature simulations suffice to allow for this.
The low-sensitivity EBM’s deep-ocean heat uptake coefficient is chosen to produce a TCR of 1.37°C which, on adding to the simulated temperatures a suitably scaled version of the 5-year mean NOAA AMO index, gives the best fit to the HadCRUT4 NH surface temperature record. That AMO index increases only modestly between the start and end of the simulation. The NH temperature simulated by my low-sensitivity EBM matches the overall NH temperature rise exhibited by Mann’s EBM up to the late 1990s, and matches the overall 1850–2012 observed (HadCRUT4) rise more closely. However, without the addition of the scaled 5-year mean NOAA AMO index the low-sensitivity EBM simulation’s fit to NH observations is a little worse than Mann’s in terms of mean square error, as it does not emulate the AMO’s fluctuations.
Mann’s differenced-AMO vs detrended-AMO
To recap, Mann’s differenced-AMO just represents actual minus model-simulated forced NH (not, as stated in the press release, North Atlantic) surface temperature. And whilst NOAA’s AMO Index is a detrended average of mean North Atlantic SST, for some unexplained reason Mann instead defines his detrended-AMO as the detrended average of mean NH temperature. In both cases, the AMO signal is smoothed by a 50-year low-pass optimising filter of Mann’s design – using slightly different variants in the two cases. Figure 3 shows the differenced-AMO (black) and the detrended-AMO (red), along with the unsmoothed annual time series that they are derived from.
Notice how Mann’s differenced-AMO, based on his EBM simulation, has a gentle peak just before 1990 before declining noticeably, so that it falls slightly from the mid-1970s to 2012. By contrast, Mann’s detrended-AMO rises strongly throughout that period. The smooth thick blue line shows the results of applying the detrended-AMO approach to the NH temperature evolution as simulated by Mann’s EBM. Its near coincidence with the smooth thick red actual detrended-AMO line shows how successful Mann has been in fitting his EBM to match the multidecadal fluctuations in NH surface temperature.
Fig 3. Version of Mann’s figure 2a. Estimated NH temperature anomaly variability: thin and thick lines are respectively annual, and 50-year low-passed smoothed, time series. The red lines show detrended observed (HadCRUT4) NH anomalies, the thick line being Mann’s detrended-AMO. The black lines show the observed NH temperature anomaly minus Mann’s EBM simulation, the thick line being the differenced-AMO. The blue lines show detrended anomalies from Mann’s EBM simulation, the thick line being what the detrended-AMO would be if based on the EBM-simulated rather than observed temperatures.
In Figure 2.a) of Mann’s actual paper (reproduced here as Figure 4), the smooth differenced-AMO line (grey dashed line in his figure) has a somewhat different shape, starting at a high level and ending at a lower level, with a peak around 1945 and minimum around 1965 that are missing when I run his code. The smooth blue line (in this case dashed rather than thickened) showing the results of applying the detrended-AMO approach to Mann’s EBM simulation is also marginally different. The EBM and smoothing code is deterministic so there should be no discrepancies.
Fig 4. Reproduction of Figure 2.a) from Mann’s GRL paper. This shows the same time series as Figure 3 and should be identical to it, but with grey lines in place of black lines and black lines in place of red lines. Dashed rather than thick lines are used to show the smoothed AMO-like signal versions of the annual time series.
As the jagged blue lines (the detrended EBM simulation anomalies) do not differ visually between my and Mann’s paper’s version of his Figure 2a, it seems possible that the difference lies in the smoothing used. Figure 5 shows the effect of changing the cut-off frequency of Mann’s low-pass filtering from the “freq0=0.02; % low-freq cutoff in cycles/year” in his archived code to freq0=0.025. That changes it from 50-year to 40-year low-pass filtering, which is in line with what the code comment says:
% determine multidecadal compoments via 40 year lowpassed versions of the residual series
The results, shown in Figure 5, are indeed much closer to those shown in Mann’s paper, although not identical. However, with 40-year low-pass filtering Mann’s results, as reflected in his subsequent figures, differ noticeably from those in his paper (and are slightly less impressive). I will leave this mystery for the future and continue for the rest of my present investigation making use of the 50-year low-pass filtering specified in Mann’s paper (resetting freq0 to 0.02). That filtering has broadly similar effects, leaving aside endpoints, to smoothing by a 15 or 20 year moving average, but it suppresses shorter-term fluctuations much more strongly.
Fig 5. Same as Figure 3 but using 40-year rather than 50-year low-pass filtering
Mann’s case against the detrended-AMO
Mann’s key claim is that, where the signal is known a priori, the detrended-AMO approach to estimating AMO-related variability fails to isolate the true internal variability, and yields an excessive and out-of-phase estimate of the true AMO signal. His Figure 3a, a version of which based on running his code is reproduced as Figure 6a, shows the differenced-AMO signal from five noisy variants of his EBM-simulated temperature time series with random realisations of red noise added – the noisy series being treated as surrogate NH temperature observations – (coloured lines), and the differenced-AMO based on actual NH temperature observations (black line). In all cases the differenced-AMO calculation deducts the noise-free EBM-simulated temperature time series from the noisy series (leaving just the red noise) and then applies low-pass filtering. Mann points out that the differenced-AMO signals represent independent realisations of multidecadal noise and are therefore uncorrelated, with random relative phases and a small amplitude. That is obviously so.
Mann’s Figure 3.b), a version of which based on running his code is presented as Figure 6b, shows detrended-AMO signal estimates from the same five noisy EBM simulations (thin coloured lines) and based on observed temperatures (red line of Figure 3) (black).
Mann writes in his paper:
The random surrogates are qualitatively similar in their attributes to the differenced-AMO estimate of the real-world AMO series. By contrast, the detrended-AMO signals (Figure 3b [here 6b]) show amplitudes ~0.25°C that are inflated by more than a factor of two. Further, they are largely all in phase with the detrended-AMO signal diagnosed from observations (Figure 2 [here 3]), an artifact of the common forced signal masquerading as coherent low-frequency noise.
a)
b)
Fig 6. Version of Mann’s Figure 3. Comparison of (a) “true” pseudo-NH AMO signal (as a priori defined using the differenced-AMO approach, not the real AMO) and (b) NH AMO signal as estimated by detrended-AMO procedure, applied to surrogate observational time series consisting of five noisy variants of Mann’s EBM simulation. (a) The differenced-AMO signal estimates relative to the noise-free EBM simulation: from the noisy simulations (thin coloured lines) and from the actual observed NH temperature time series (black; same as Figure 3 black line, but different scale). (b) The detrended-AMO signal estimates: from the noisy simulations (thin coloured lines); based on observed temperatures (red line of Figure 3) (black); and from the noise-free EBM simulation (blue dashed; same as Figure 3 blue line: omitted in Mann’s Figure 3).
The flaws in Mann’s case
The first part of what Mann writes is obviously true, but are his conclusions warranted? It is true that the detrended-AMO signals diagnosed from the noisy EBM simulations are indeed largely all in phase with, and very similar in amplitude to, the detrended-AMO signal diagnosed from observations (the black line). But their real such relationship is to the detrended-AMO signal diagnosed from the noise-free EBM simulation. Although that signal is not shown in Mann’s published Figure 3b, it is actually plotted by his code, and is shown by the blue dashed line in Figure 6b (same as Figure 3 thick blue line). As can be seen both there and in Figure 3 above, the low-passed detrended-AMO signal diagnosed from observations and the low-passed detrended-AMO signal diagnosed from the noise-free EBM simulation are almost identical, reflecting the success of Mann’s fitting of his EBM simulation to the smoothed observations. Therefore, the detrended-AMO signals diagnosed from the noisy EBM simulations appear also to be related to the detrended-AMO signal diagnosed from observations. But that apparent relationship is purely an artefact of the similarity of the detrended-AMO signal diagnosed from observations and the detrended-AMO signal diagnosed from the noise-free EBM simulation.
Mann’s random red-noise series have low-passed components typically only a quarter as large as the smoothed signal from applying his detrended-AMO approach to the EBM forced simulation (compare coloured lines in Fig 6a with blue dashed line in Fig 6b, noting different scales). So it is unsurprising that one recovers something close to that signal (as in Fig 6b) – and hence close to the nearly identical detrended-AMO from observed temperatures (black line in Fig 6b) – when applying the detrended-AMO approach to the EBM forced simulation with the random red-noise added, whatever realisation of noise is used.
So Figure 6 does not prove Mann’s claim. The detrended-AMO signals are in reality largely all in phase with, and of similar amplitude to, the detrended-AMO signal diagnosed from the noise-free EBM simulation, not (as Mann claims) with that signal derived from observations. One would expect to end up with something close to a smoothed version of the signal when adding a noise component with a small low-frequency amplitude to a signal with a ~4 times larger low-frequency amplitude and low-pass smoothing their sum, where there are only two cycles of signal in the pass band.
Figure S7.b3 in Mann’s Supplementary Information, reproduced as Figure 7, very much supports my conclusion. It shows the results that when an alternative volcanic forcing series (Crowley) is used. When that is done, results in the application of the detrended-AMO approach to Mann’s EBM simulation gives a significantly different signal (blue line – present, but not identified, in Mann’s SI graphs) from when it is applied to the actual temperature observations (black line), and the coloured lines cluster closely around the blue line rather than the black line.
Fig 7. Reproduction of Mann’s Figure S7.b3: as Figure 3.b in his main article but using the Crowley volcanic forcing series. The detrended-AMO signal estimates: from the noisy EBM simulations (red, green, cyan, yellow and magenta lines); from observed temperatures (black line); and from the noise-free EBM simulation (blue line)
Mann’s attack on Stadium Waves
Essentially the same arguments apply to Mann’s critique of the “stadium wave” theory (Wyatt et al, 2012; Wyatt and Curry, 2013), about which the press release says:
Mann and his team also looked at supposed “stadium waves” suggested by some researchers to explain recent climate trends. The climate stadium wave supposedly occurs when the AMO and other related climate indicators synchronize, peaking and waning together. Mann and his team show that this apparent synchronicity is likely a statistical artefact of using the problematic detrended-AMO approach.
Mann applies a similar procedure to what he terms synthetic AMO-related indices, which are pretty well the same as the noisy EBM simulations used already but with noise of a larger amplitude added. Figure 8, a version of Figure 4 in Mann’s paper produced by running his code, shows the outcome. Mann writes in his paper:
Indeed, the detrended-AMO approach (Figure 4b [here 8b]) yields an apparent multidecadal AMO oscillation that is coherent across the indices, an artifact of the residual forced signal masquerading as an apparent low frequency oscillation. The apparent AMO signal is most coherent across indices during the most recent half century, when the forcing is largest. Another important feature apparent in this comparison is that the low-frequency noise leads to substantial perturbations in the overall “phase” of the apparent AMO signal (Figure 4b [here 8b]) giving the appearance of a propagating wave or stadium wave in the parlance of Wyatt et al. [2012].
However, the thick blue line in Figure 8b, plotted by Mann’s code but missing from his published figure, shows the AMO signal as estimated by Mann’s detrended-AMO procedure applied to the noise-free EBM simulation, gives the lie to this claim. Rather than being “an artifact of the residual forced signal masquerading as an apparent low frequency oscillation”, the thin coloured lines are seen as modified, phase-shifted versions of the signal from applying the detrended-AMO approach to the noise-free EBM simulation.
a)
b)
Fig 8. Version of Mann’s Figure 4. Comparison of (a) true pseudo-NH AMO signal (as a priori defined using the differenced-AMO approach) and (b) NH AMO signal as estimated by detrended-AMO procedure. In both cases, no actual observational data is used: results are shown for the five synthetic standardized climate indices as described in Mann’s text, derived using his EBM simulation with added noise realisations (thin coloured lines). In (b) the result of applying the detrended-AMO approach to the noise-free EBM simulation is also shown (thick blue line; scaled version of that in Figure 3: omitted in Mann’s Figure 4). Series are standardized to have unit variance.
The results shown in Figure 8b are what one would expect to arise: a noise amplitude that is greater relative to the signal than before causes more modification and phase-shifting of the clean signal: (compare Figure 8b with Figure 6b). The extent of the differences between the coloured lines in Figure 8b derived from the noisy synthetic AMO-related indices and the blue line derived from the noise-free EBM simulation varies with the random realisations of noise, and can be much greater. The corresponding graphs (Figures S8.b9 and S8.b10) based on the GISS-E2-R and CMIP5 Ensemble simulations show a gradual loss of coherency between the five noisy versions and the detrended-AMO based on the forced simulations (the blue lines, which do appear in the graphs in Mann’s Supplementary Information). Before ~1960, the GISS-E2-R and CMIP5 Ensemble simulations do not follow the real-world detrended-AMO signal as well as Mann’s EBM simulation does.
Results using the low-sensitivity EBM
So far, I’ve been repeating Mann’s analysis using his EBM simulation. Now I’ll look at what happens when my low-sensitivity EBM simulation is used instead. Figure 9 shows the same as Figure 3 (my version of Mann’s Figure 2a) save for my low-sensitivity EBM simulation being used instead of Mann’s EBM simulation. Unlike the situation with Mann’s EBM simulation, the thick blue line (detrended-AMO based on EBM simulation) is not almost identical to the thick red observational detrended-AMO line, and the thick black line – the differenced-AMO – does bear a resemblance to the observational detrended-AMO.
Fig 9.Estimated NH temperature anomaly variability 1900-2012: thin and thick lines are respectively annual, and 50-year low-passed smoothed, time series. The red lines show detrended observed (HadCRUT4) NH anomalies, the thick line being the detrended-AMO. The black lines show the observed NH temperature anomaly minus the low-sensitivity EBM simulated temperature, the thick line being the differenced-AMO. The blue lines show detrended anomalies from the low-sensitivity EBM simulation, the thick line being what the detrended-AMO would be if based on the EBM-simulated rather than observed temperatures.
Figure 10 shows the same as Figure 6b (Mann’s Figure 3b) but using the low-sensitivity EBM simulation instead of that from his EBM. It is now fairly obvious visually that the coloured lines resemble the blue dashed line that represents an application of the detrended-AMO approach to the EBM-simulated temperatures, rather than resembling the black line representing the detrended-AMO derived from observed NH temperatures. That is confirmatory evidence that my analysis of what is going on is correct.
Fig 10. Version of Figure 6.b) based on the low-sensitivity EBM simulation
Is the detrended-AMO nevertheless questionable?
The detrended-AMO approach is not perfect, even when applied – as is standard – to SST temperatures in the North Atlantic, not to the full NH land and ocean surface temperature as Mann does. When the rate of increase in forcing secularly increases, as it has over the last hundred years, it is possible that the detrended-AMO may be biased towards high strengthening in recent decades. A comparison of the post mid-1970s segments of the red line (detrended-AMO from observations) and the black line (differenced-AMO from low-sensitivity EBM simulation) in Figure 9 illustrates this point. However, the basic shapes of the two lines are similar, and the differenced-AMO still accounts for about a 0.2°C rise in NH temperature over the last thirty or so years.
It would be preferable to find a way of estimating the AMO that was more independent of forced temperature trends. That is, in effect, what Delsole et al (2011) did in estimating their internal multidecadal pattern (IMP) in global SST. They employed a sophisticated statistical method based on maximising average predictability time, using simulations by a number of CMIP3 coupled GCMs as well as observed SST, to separate forced and unforced variability in SST. Although their method applies globally, the IMP they detect is remarkably similar to the standard NOAA detrended-AMO index. Figure 11, a reproduction of Figure 4 from Delsole et al’s paper, compares NOAA’s AMO index, suitably rescaled, (red line) with the ±1 standard deviation uncertainty range of their estimated IMP (shaded grey). The fit is remarkably close.
Using a different sophisticated statistical approach, Swanson et al (2009) also found an AMO-like pattern of multidecadal unforced variability, here in GMST rather than global SST, although with a somewhat lower recent level.
Fig. 11. Reproduction of Figure 4 from Delsole et al (2011). ±1 standard deviation uncertainty range of their estimated IMP (shaded grey) and scaled AMO index from NOAA based on detrended North Atlantic SST (red line). The vertical scale is arbitrary.
Finding a physical explanation for the AMO is of course desirable, and likely to lead to better estimation of its influence on temperatures and other climate phenomena both globally and regionally. That is a major attraction of the stadium wave theory. If it holds up under further examination, it promises a better understanding and estimation of multidecadal internal climate variability. Other papers, such as Dima & Lohmann (2007), have also put forward possible natural physical mechanisms for the AMO.
Conclusions
I have shown that the evidence Mann claims disproves the detrended-AMO, and supports his differenced-AMO, is illusory. I have also shown that his code produces different results from those shown in his accepted paper. I have pointed out that graph lines produced by his code that would have made it much easier to spot the flaws in Mann’s evidence, although appearing in the figures in his Supplementary Information, were omitted from the figures in his main paper.
A differenced-AMO approach has attractions in principle, but only makes sense if climate models are near-perfect, which is far from the case. The ease with which a simple EBM model can have its parameters adjusted to produce a nearly flat differenced-AMO shows the very low number of degrees of freedom involved, with only two full AMO cycles during the instrumental period. The very heavy, 50-year low-pass, smoothing applied by Mann arguably exacerbates this problem.
The detrended-AMO approach is not perfect, but the pattern exhibited by NOAA’s standard detrended AMO index based on North Atlantic SST appears to be supported by much more sophisticated approaches. The stadium wave theory, if it holds up, offers physical insight into the mechanisms underlying the AMO and may lead to more reliable estimation of its state and influence on surface temperatures and other climate variables.
[i]Enfield, D.B., A.M. Mestas-Nunez, and P.J. Trimble, 2001: The Atlantic Multidecadal Oscillation and its relationship to rainfall and river flows in the continental U.S., Geophys. Res. Lett., 28: 2077-2080
JC comments: This paper is also cross posted at Climate Audit. I have been discussing this article with Nic Lewis via email for the past several weeks. As with all guest posts, please keep your comments civil and relevant.
Nic, will you try to get this published in GRL? Very compelling rebuttal.
I’m glad there is a Nic Lewis around that can do this work and holler bulls**t when needed.
It would be interesting to contrast Mann’s funding level and sources vs. Nic’s for doing this work.
As the old British plod would say, “Hollow, hollow, hollow, what’s all this then?”
Not much, I’d say.
Ooops, meant to follow manacker @ 8.34. I see that kim has now filled the gap.
The importance of Dr Mann’s accepted paper is the inclusion of his references, data and especially his Matlab code. Other scientists (such as Nic Lewis) can use this detail to try to duplicate Dr. Mann’s results. I see this as essential to furthering the science behind CAGW. This should bring to light differences of approach to the stated goals of the IPCC. The resulting analysis will push science further toward conclusion of this important topic!
Thank you Nic Lewis
‘Other scientists (such as Nic Lewis) can use this detail to try to duplicate Dr. Mann’s results.’
And once they do you can see why Mann has avoided this before .
I think it will be very interesting to see both Mann’s rebuttal to this (if he supplies one) as well as 3rd party reviews of both. This is indeed how science progresses.
For me, regardless of who is right on this topic, the broader issue of the modulation of so-called “natural variability” is certainly part of the “wicked” nature of anthropogenic climate change. No “natural variability” of the climate system, except perhaps solar, exists in a vacuum, untouched by the fingerprints of the huge changes that human activity is making upon that system. The stadium-wave hypothesis might indeed be more than Mann would posit, but it certainly could be modulated by the highest GH gas levels in millions of years. The trick is trying to separate the truly “natural” variability of the system from the anthropogenic influences on that natural variability.
R Gates, why has the rate of warming dropped after 1945 despite higher man-made CO2?
“R Gates, why has the rate of warming dropped after 1945 despite higher man-made CO2?”
_____
Of course this is a completely incorrect assessment on the gains of energy to the climate system, and either the person making this statement is truly confused about what the data is showing, or is purposely trying to paint a false picture. The best proxy measurements for gains in the energy of the climate system would show very robust increases without pause for the last half of the 2oth century and the first 14 years of the 21st. A myopic, un-scientific focus on sensible tropospheric heat seems to be the last refuge for the fake-skeptics trying to run from the escapable conclusion the to a very high degree of liklilhood, the anthropogogenic forcing on the climate is robust and indeed, the dominant forcing now and into the forseeable future.
R.Gates,
“A myopic, un-scientific focus on sensible tropospheric heat seems to be the last refuge for the fake-skeptics trying to run from….”
A unscientific focus on sensible tropospheric heat.
This after two decades of globalclimatewarmingchange defined by the consensus as that same pi** poor proxy of “sensible tropospheric heat.”
This while the consensus still defines climate sensitivity in terms of STH.
And while the consensus waits with bated breath for another El Nino to send the curve of the graph of STH upward for the first time in 15+ years.
I think it is a bit harsh for R.Gates to be claiming that the IPCC and its foot soldiers have been myopic and unscientific for so long. But whom am I to disagree?
“I think it is a bit harsh for R.Gates to be claiming that the IPCC and its foot soldiers have been myopic and unscientific for so long. But whom am I to disagree?”
____
Fortunately, I have no allegiance to the IPCC, and in fact, think their watered- down political process probably has been understating the effects of anthropogenic climate change.
Regarding the use of sensible tropospheric heat as the proxy for energy being added to the climate system. It is only useful over long time frames with the minimum being at the decadal average. It is the ocean that warms the atmosphere and the flow of energy from ocean to atmosphere is highly influenced by natural variability, with the largest factor being ENSO. The upshot is, the best current proxy we have for energy being added to the climate system is OHC, and since we’ve only had ARGO for about a decade now, and a full ARGO float deployment for about 7 years, adopting OHC has a more stable long-term proxy for both climate sensitivity and energy gains in the system will take a while, but could happen. Tropospheric sensible heat was all we had and so we used it, but, especially has ARGO will be expanding to greater depths and more floats (assuming funding is approved), then it will be the better proxy.
“…the IPCC, and … their watered- down political process probably has been understating the effects of anthropogenic climate change.”
Glad to see you coming out from behind your faux skeptic facade with such clarity. I bet it was finding yourself in agreement with me twice in the period of a week that did it.
R. Gates
“Gains (or losses) to the overall energy system” sounds great, but IPCC (up until recently recognized as the “gold standard” group for summarizing the science relating to anthropogenic greenhouse warming) has used the “globally and annually averaged land and sea surface temperature” as a more meaningful indicator of AGW. (After all, we humans life at the surface of our planet, not at the depths of its ocean.)
Key indicators, such as the2xCO2 “equilibrium climate sensitivity” (ECS) or “transient climate response” (TCR) are based on this metric.
But now that this indicator has stopped warming since the end of the past millennium, you suddenly want to change the measuring stick to an indicator, which is much less meaningful for the human inhabitants of this planet (and much more difficult to quantify with actual observed measurements).
Methinks I hear the sound of goalposts being moved here, Gates.
Max
“Methinks I hear the sound of goalposts being moved here, Gates”
_____
Such is the nature of the advancement of science. When the goal posts are in the concession stands because that’s the only place we could put them, you take what you can get. Now that we can move the posts to the field (i.e. the ocean), isn’t it better to measure the thing that causes the majority of tropospheric sensible heat fluctuations (i.e. the OCEAN!)
R. Gates
You may personally be naïve enough to think that the switch from GMST to OHC was the result of an advancement of science, but I sort of doubt it.
If one is interested only in the purely scientific notion of the entire Earth’s energy budget and balance, then I would agree with you (and many others including Pielke) that OHC plus GMT(surface and troposphere) is a more pertinent overall indicator.
But wnen we are discussing the effects and impacts on humanity of AGW, we are NOT talking about a multi-century scale warming of the ocean by a few hundredths of a degree (which would be unnoticeable to humans) but a warming of the surface of the Earth (where humanity lives) by several degrees, which could result in perceptible negative impacts for humanity and our environment.
And that was the prime indicator used by IPCC to demonstrate the potentially serious effects of global warming caused by human GHG emissions.
And, now that this indicator no longer shows any warming, there is a mad scramble to find another indicator that does, even if minute changes in this indicator will have no impact on humanity, there are no meaningful measurements of this indicator prior to ARGO and even the ARGO measurements are limited and questionable so far.
Moving the goalposts in the middle of the game does not go unnoticed, Gates.
It’s a commonly used ploy when predictions do not materialize as expected.
Your attempts to justify it are hollow.
Max
Fill up that hollow with ocean heat content; we’ll need it before long. Oh, wait, the missing heat is probably traversing the galaxy. Dangit.
===============
kim, while you were drafting, I was mis-posting on the previous sub-thread rather than post-manacker. To whit (or not, as the case may be),
As the old British plod would say, “Hollow, hollow, hollow, what’s all this then?”
Not much, I’d say.
‘Mann’s differenced-AMO is a high-sensitivity climate modeller’s dream.’
A pipe dream at that…
Nic writes: “I have shown that the evidence Mann claims disproves the detrended-AMO, and supports his differenced-AMO, is illusory.”
Nothing surprising there.
Mann is a genius in coming up with new ways to misuse statistics. If I didn’t know better, I’d say he was doing it on purpose.
Nic is too polite to say so, but Mann has effectively defined “truth” as the model output. No number of statistical tests can eliminate that essential error.
Abstract “When I use a word,” Humpty Dumpty said in rather a scornful tone, “it means just what I choose it to mean – neither more nor less.”
We estimate the low-frequency internal variability of Northern Hemisphere (NH) mean temperature using observed temperature variations, which include both forced and internal variability components, OK
and several alternative model simulations of the (natural + anthropogenic) forced component alone. Make up a model
We then generate an ensemble of alternative historical temperature histories based on the statistics of the estimated internal variability.
Make up more models
Using this ensemble, we show, first, that recent NH mean temperatures fall within the range of expected multidecadal variability
Make sure the models match initially
. Using the synthetic temperature histories, we also show that certain procedures used in past studies to estimate internal variability, and in particular, an internal multidecadal oscillation termed the “AMO”, fail to isolate the true internal variability when it is a priori known.
Make the model or synthetic data disagree with the real data where the real data is inconvenient
Such procedures [real data] yield an AMO signal with an inflated amplitude and biased phase,attributing some of the recent NH mean temperature rise to the AMO.
which we disprove with our models
Hence we can claim
The true AMO signal, instead, appears likely to have been in a cooling phase in recent decades, offsetting some of the anthropogenic warming
brilliant.
Will anyone else with the maths and prestige be able to call him out on this?
Exactly. Very good analysis.
Perhaps Cowtan and Way
A good fundamentalist theologian like Mann starts from the dogma and works back. (We even have the windmills now for some medieval ambience. Who even misses that silly Enlightenment?)
Tony said:
“How good this paper is I cannot say but it surely doesn’t merit the concerted attention Of four major blogs?”
____
Actually, should the Mann paper on the AMO turn out to be correct (and I am certainly not qualified to assess that), it is a very big deal, as it would show:
1) The natural tendency of the AMO is toward cooling over the period of the “pause”, and has been “forced’ to appear to be in a natural warming mode due to GH gas forcing.
2) In addition to a cool phase of the PDO, the actual cool phase of the AMO would have led to a much cooling period were it not for anthropogenic forcing.
3) Climate sensitivity to GH gas forcing is likely toward the higher end of the range, certainly 3C or above for ECS.
That’s funny RGates. Unqualified to assess it but qualified to think it might be a “very big deal”
To steal an idea from others here, unicorns have the same potential.
R. Gates
It appears to me that the odds are very great that the Mann AMO paper will NOT be a “big deal”, but rather another “:big flop”.
Since this is a technical thread, I’ll try to get back to the conclusions originally reached by Mann and the summary by Lewis of why these conclusions and the method used to arrive at them were flawed. The simplified explanation over at Bishop Hill helps non-climatologists understand this a bit more easily. Mann simply used some statistical tricks to try to make the observed facts force-fit his estimate of ECS.
Rud Istvan made a good comment over at Bishop Hill, which I’ll copy here
Looks to me like another botched job by Mann, rather than a “big deal”.
Max
Michael Mann goes into the doctor…
Mann: Doc, when I lie it hurts.
Doc: Then don’t lie.
Mann: But it’s all I know how to do.
Doc: Then its gonna hurt.
Mark Steyn: Yup, sure is…
Isnt there some other Journal other than the warmist “gated” GRL that could accept publication of skeptical articles like this?
Agree or disagree, this blog post does rather raise the bar. Bookmarking as a template for future reference.
BartR
I agree. Sadly I suspect that people will once again fall into one camp or the other regardless of what the data says and the sad truth is that this is a highly technical post and most of us do not have the technical expertise to pass an objective comment.
Now, if it had been about Dr Mann’s paper trying to explain away the apparent underestimation of volcanic forcing in tree rings relative to the 1258 super volcano I would have an opinion…. But it isn’t, so I shall sit on the side-lines with my popcorn and see if anyone steps outside their box.
tonyb
climatereason | May 19, 2014 at 11:17 am |
Wise choice.
It would take me many weeks to fully disentangle the cases and do any justice to the arguments, so pretty much any comment made on the technical aspects before June would be ambitious on my part, too. It’s not like knocking down Wyatt & Curry’s stadium wave, which is so patently flawed it doesn’t take more than a few moments to deprecate.
At first blush, the word “illusory” seems too strong, and the tone of certainty is rather strong. Also, I could see no case for a reviewer recommending rejection based on the above line of argument, though heavy revision would be warranted, were the strength of Nic Lewis’ claims verified. What isn’t mentioned is just how heavily Mann’s technique for estimating amplitude of influence is relied on conventionally across the sciences: Mann’s is a standard treatment, and if this criticism holds, it will upend rather a lot of conventional thinking.
Tony,
Mann has a history which reflects poorly on both his competence, and his character. If i were a betting man….oh wait….I’d put my chips on Nic.
Incidentally, the Bish has a nice synopsis of the critique which even I can follow…
Pokerguy
You forget that I did a thorough analysis of his historic climate related work for one of my articles so I know his work better than most
My point is that few of us are qualified to comment on his highly technical subject. That many see this as a bash the Mann opportunity can be seen in the fact that extraordinarily nic’s post is being carried simultaneously here, Wuwt, bishop hill and climate audit.
It would not warrant that level of attention for anyone except Mann. the work I have seen of his in the field I understand is mediocre. How good this paper is I cannot say but it surely doesn’t merit the concerted attention Of four major blogs?
Tonyb
Tony said:
“How good this paper is I cannot say but it surely doesn’t merit the concerted attention Of four major blogs?”
____
Actually, should the Mann paper on the AMO turn out to be correct (and I am certainly not qualified to assess that), it is a very big deal, as it would show:
1) The natural tendency of the AMO is toward cooling over the period of the “pause”, and has been “forced’ to appear to be in a natural warming mode due to GH gas forcing.
2) In addition to a cool phase of the PDO, the actual cool phase of the AMO would have led to a much cooling period were it not for anthropogenic forcing.
3) Climate sensitivity to GH gas forcing is likely toward the higher end of the range, certainly 3C or above for ECS.
tony,
I have no opinion on Dr Mann’s latest paper, other than to acknowledge and commend him for making his data and code available. I figure (or maybe hope is a better term) that it will stand or fall based on its merits, the way any paper should.
tonyb,
“… it surely doesn’t merit the concerted attention Of four major blogs?”
Michael Mann has insisted on making himself the central issue in much of the climate debate. Suing Mark Steyn and NRO being just one of the latest examples. It is no surprise his latest foray into the wonderful world of statistics, for which he has such a grand reputation, is is gathering such broad attention.
I believe all four blogs have covered his suit against Steyn, his claim to a Nobel prize, his repeated defenses of the hokey stick, including inverted Tijlander in all its glory, etc. I see no over reaction here. If he wants to be the clown at the party, there is no reason for those in attendance to ignore him.
More to the point, Steyn and NRO are not the only targets in his assault on free speech. Not to mention, I think he has had the occasional unfriendly word for Watts, Curry, McIntyre and the Bishop himself.
He merits all the negative attention he receives.
timg56
I agree. Let it stand or fall on its merits
Gary said;
‘Not to mention, I think he has had the occasional unfriendly word for Watts, Curry, McIntyre and the Bishop himself.’
With that, I think you have just answered my question as to why the paper is playing on four channels simultaneously.
tonyb
“How good this paper is I cannot say but it surely doesn’t merit the concerted attention Of four major blogs?”
That’s a good question Tony. Whether merited or not is of course a judgment call. But it’s certainly understandable. Close minded, contemptuous, mendacious, and bullying, Mann more than anyone else I can think of, embodies the very things we skeptics find so hard to take among the alarmists.
He is the most divisive figure I can think of in the climate debates…even among his own peers…with the possible exception of the of the President of the U.S.. The iconic, now infamous hockey stick chart galvanized the world around the issue of global warming to use the quaint phrase of yesteryear. Including yours truly for a time. I remember thinking to myself, well hell, this has to be the real deal after all. And it turns out to be, to be polite, a bunch of cr**.
Little wonder that anything Mann publishes is going to attract outsized attention.
It is also a very big deal if the paper turns out to be wrong, and if the chicanery by which Mann claims it to be right can be demonstrated to be deliberate. A tall order, but it may be easy to fill, given the history of his aforethought deceit.
So far, I’m convinced by the little tricks pointed out by Nic, but hey, I’m biased.
=====================
Maybe he needs a Matlab course from Steig. Or maybe he got one.
===========
You’re all being rather circumspect here. The point really isn’t that a skeptic (Lewis) is trying to demolish a bogeyman (Mann). The interesting thing is that Mann seems to be trying to overturn some well accepted science, presumably there are a relatively large number of mainstream scientists that research this aspect of the climate system. One might expect that beyond the borders of skepticism that quite a few individuals would have thoughts about this work.
The expectation is the bar should be set quite high from within the climate community for this type of groundbreaking work. The question might be whether the review process did that. Although having said that I’m happy with a publish and be damned approach as well.
Mr. B –
Nice series of comments.
Just to add a sense of moderation to my last comment it seems Mann has been working (and publishing) on this issue since the mid-2000’s so I guess this isn’t straight out of the blue and it would seem sections of the climate community have been critiquing that work.
Tony
How many channels did the 12 foot sea level Antarctic glacier imminent collapse in a thousand years after already experiencing thousands of years of melting get papers get?
Statistically torturing the data until it shows what you wish to see is not science. That’s the history of AGW in a nutshell.
“Had I been a reviewer, I would have pointed this out and recommended rejection.”
This speaks for itself, on several levels.
As Mann might taunt had he any wit, style,and breadth of knowledge… “But you weren’t Blanche! You weren’t!”
(H/T and apologies to “What Ever Happened to Baby Jane”)
Alas, he has not wit, style, nor breadth of knowledge
It’s my opinion that Mann is so narcissistically self-deluded that he’s convinced he’s an excellent scientist who deserves that Nobel Prize he falsely claimed was his. He also seems to genuinely believe that any criticism of his work is not only unwarranted, but prima facie evidence of bad faith.
He’s really quite a remarkable specimen.
He is not deluded, poker. He is deliberately devious. He comes up with a conclusion for his paper and then does whatever he has to do to support the conclusion.
More and more he exhibits similarities to that other theoretical physicist, Sheldon Cooper.
Don,
Of course you might well be right. Like anyone, I can only guess at what goes on in that unpleasant brain of his. Maybe it’s that I’d prefer to think he’s mentally ill instead of just an appallingly bad person…
pokerguy
“specimen?”
I hope you were not talking in the medical sense…
Max
pokerguy
Ya gotta choose one or the other?
Max
He’s really quite a remarkable specimen. Indeed one thing that marks him out from the crowd is not his massive ego nor his poor science has their plenty working in this area with those. But that he is so nasty to everyone , even others on ‘the Team ‘ should their dare not to fully agree with him. Its why when he falls we will be surprised to see who lines up to kick him on the way down. And the day the others throw him under the bus to save themselves , will be a good day.
“I have pointed out that graph lines produced by his code that would have made it much easier to spot the flaws in Mann’s evidence, although appearing in the figures in his Supplementary Information, were omitted from the figures in his main paper”.
Pretty much sums up Mann’s MO, except this time, he actually made the raw data available.
I will wager that that he already has in hand the outline of a rebuttal to criticism based on his data. IMO, he is that devious.
“It seems the most natural thing in the world to take some clay and mould it into a ball, a little clay figure, a cup, a pit house. At first we feel that the shape of nature has been given us by this. But, of course, it has not. This is the man-made shape. What the pot does is to reflect the cupped hand; what the pit house does is to reflect the shaping action of man. And nothing has been discovered about nature herself when man imposes these warm, rounded, feminine artistic shapes on her. The only thing that you reflect is the shape of your own hand.
But there is another action of the human hand which is different and opposite. That is the splitting of wood or stone; for by that action the hand (armed with a tool) probes and explores beneath the surface, … Now the hand no longer imposes itself on the shape of things. Instead it becomes an instrument of discovery…”
–J.R. Bronowski, The Ascent of Man
The manipulation of constants described above appears to me to be pottery.
I don’t normally comment on here but as this is a highly technical discussion I thought reading the comments was interesting. Some have been honest enough to say that to follow this debate requires hard work. It’s rightful place is in the scientific literature following expert review. It is interesting that others have taken the opportunity to hurl insults. Very revealing
TomC;
I hear your point, on the other hand the by accepting every technical nuance and following it to its natural ends actually distracts from what a the more fundamental drivers of climate debate and in this case Michael Mann’s role in the debate;
What is really comes down to, due to left-wing academic corruption in general, is that we need to poll and reveal the political “ID” of the “science” communities as they are quotes in political policy discussions;
http://www.washingtonpost.com/blogs/the-fix/wp/2014/05/06/just-7-percent-of-journalists-are-republicans-thats-far-less-than-even-a-decade-ago/
http://www.telegraph.co.uk/science/science-news/10837146/Climate-change-science-has-become-blind-to-green-bias.html
Climate science is a pretty poisoned well that can’t be trusted at so many levels. Michael Mann is a party who has lost objective credibility due to his own partisan activity. By focusing on papers like this strictly on academic claims is a form (intentional or not) of disinformation. You can focus on “insults” but the objective truth that this is a disqualified activist not a scientist. The process of treating every submitted paper as a tax-return to be reviewed as if it is good faith report has worn out for some.
People can argue the spaghetti charts as much as they like, just don’t pretend this is the core climate debate or will ever be decisive to either faction.
I go out of my way to stay off the deeply self enamored threads that view themselves as deeply “technical”. I made the exception here as the premise of ignoring the subject writer and his history is beyond reasonable. The “about science” meme of both advocate and dissent carried too far yet again. Michael Mann’s technical opinion is always per-determined based on his ideology, dissent that ignores that is disingenuous.
I want people to imagine how the debate would differ if more skeptics followed the lead of mcIntyre, Watts, Lewis, Odonnell, masters, etc
and actually did work that was publishable and then tried to publish.
read more comment less.
or if you are super busy make short cryptic comments at WUWT and watch people try to figure out the mystery
“I don’t normally comment on here but as this is a highly technical discussion I thought reading the comments was interesting.”
I could be wrong about this, because as you say the discussion is highly technical. The argument of the paper seems to me to be “Models vs. Observation.” Mann’s claim (again, if I’m reading right), that observations of the AMO are wrong, but you can get them right if you tweak a model, and then look at what the AMO must have been doing.
The argument we can’t wait for the observations because people are changing the system so fast, you have to do something now, is failing for practical considerations. Only the West has done much to abate CO2 production, and even that doesn’t seem meaningful (watching one of Barbara Boxer’s Global Warming forums, one guy pointed out that
Great Britain is actually producing more CO2 when CO2 production for imported goods are accounted for on Britain’s ledger).
CO2 will increase, no one can stop it, and so Climate Scientists will be able to observe how the world’s Climate System reacts. It doesn’t matter what Mann says, or anyone else. It doesn’t matter what the models claim, except at some point in the future, we can all look back and see how good they were in their simulations. Or how right or wrong Mann was.
Mosher: to hell with the quality of the debate. The issue here isn’t this paper or Mann. It is agenda-driven science, which is a phenomena of government-funded science.
Imagine how much better the SCIENCE would be if it wasn’t government funded to go after problems that are so complex it is always difficult (likely near impossible) to separate the signal from the noise given our current state of technology.
Don’t believe me? Take a look at the recent development on the “saturated fat is bad for you” science and tell me why that is different than this.
It is time to call a spade a spade: this “research” is driven by people with agendas torturing data, models and statistics to get the answer they prefer. Period.
““I have pointed out that graph lines produced by his code that would have made it much easier to spot the flaws in Mann’s evidence, although appearing in the figures in his Supplementary Information, were omitted from the figures in his main paper”.
Now perhaps people can see why I ask that the data AS USED and the code AS RUN be supplied with every paper.
Sad fact. In empirical studies where scientists were asked to reproduce their own work a substantial number are unable to reproduce the very work they published.
How do you think that would have worked out for those scientists if they were funded by industry? I suspect no company would have put up with that type of error more than once.
–Rob Starkey
“I suspect no company would have put up with that type of error more than once.”
Be realistic. That would more than likely depend on who makes the errors.
;O)
-Steven Mosher
“Now perhaps people can see why I ask that the data AS USED and the code AS RUN be supplied with every paper.”
Been burned before, huh?
“How do you think that would have worked out for those scientists if they were funded by industry? ”
the best examples DO come from INDUSTRY. the medical industry.
http://online.wsj.com/news/articles/SB10001424052970203764804577059841672541590
This is not a free market science versus government science issue.
This is a fundamental issue in all science.
Not a good link for making a determination but after checking, I’ll agree that Brigham and Women’s Hospital is a largely-non govermental institution.
Er, no… It’s a fundamental issue with all data processing. I can remember working for a large bank, having to create ad hoc reports in a hurry and brushing through it without saving every iteration of my JCL and code while tweaking to meet changing requirements. The whole project might be done in a day or two, with frequent consultations with the business manager (at my desk).
If I had to re-create the report later, it often took me several days just to backtrack through what I’d done to recreate the different data from (often different iterations) of the report. I learned the hard way to do everything in a repeatable format fully automated processes that would re-create every piece of data every time I ran it. Only that way could I be sure I could re-run the “one-time” report the next month when the business discovered they needed it again.
I was never able to train anybody to do it that way, so re-creating an ad hoc report often ended up taking more time than the original.
-AK
JCL. Gack! Doppelgack!
Seriously, I wonder if how easier interaction with computers over the years has in a number of ways made us more careless with that resource and by extension those things to which it is applied.
I also think that ease in computation has lead to an unfortunate blurring of the concept of models and a computer implementations at times by both advocates and critics. Somehow science is lost.
Well, I was usually running on MVS in those days, but even today I’ll automate a process with a script (often running in a cmd window) rather than perform a manual process. It actually ends up taking less time usually when you include full regression testing of whatever you’re
doingtrying to do.You’re probably right. At least, using complex systems with manual controls doesn’t usually make for a reliably repeatable process. Thus, for instance, in Photoshop I’ll often create an action for something I am trying to do, rather than doing it manually. If it takes 10 times as long to set up and test an action than to run the process manually, it works out to a time savings vs. 3-4 instances of the manual process, when you factor in errors, forgotten steps, etc.
Duh, if they keep records, someone may find the records, Climate Gate again!
“Sad fact. In empirical studies where scientists were asked to reproduce their own work a substantial number are unable to reproduce the very work they published.”
Partly because they publish too soon, as they need to be seen to be productive, ignoring artifacts. I have loads of data that I can’t reproduce, some times I know why, but often I don’t.
-Doc Martyn
“I have loads of data that I can’t reproduce, some times I know why, but often I don’t.”
I suspect there are real human limits at play: the capacity to compute exceeds the capacity to assimilate–at least under time constraints and sometimes without. There is a temptation to meta-grok and sling it out the door.
Simple solution: Make reproducibility a condition of publication.
Mosher: This is not a free market science versus government science issue.
——–
Wrong, it is an ACCOUNTABILITY issue. And, in general, governments and non-profits are far less accountable than for-profits.
Ask someone who worked or works for one of the premier consulting firms in the world (McKinsey, Bain, …). They will tell you one data error in a report to a client is game over.
Ask someone who works for the many of the major companies in the US… one integrity violation and it’s game over.
So how about if Mann’s result aren’t replicable we ban him from the journal for life? Think that might change his work habits a bit?
“k scott denison | May 19, 2014 at 7:48 pm |
Simple solution: Make reproducibility a condition of publication.”
My last mouse drug experiment took 315 days from first injection and took me more than four months to do the histology.
You want me to do it again?
Rob Starkey,
I’m not sure that industry would even bother to reproduce their results if the first set of data shows what they want to see. You do (pay for) the minimum demanded of you.
Well, HR, you might be surprised that various industries frequently have standards bodies and standardized tests. Your snobbish slight of industry belies your true colors.
Heres’ one such body:
http://www.astm.org/
From the link:
Setting the Standard
ASTM provides technical standards and related services for an ever-changing global marketplace. Learn more about ASTM.
DocMartyn | May 19, 2014 at 8:32 pm |
“k scott denison | May 19, 2014 at 7:48 pm |
Simple solution: Make reproducibility a condition of publication.”
My last mouse drug experiment took 315 days from first injection and took me more than four months to do the histology.
You want me to do it again?
____________
Yes.
Does anybody know the error bounds of Mann’s “simple energy balance model?” As he seems to adjust different parameters on the fly with a remarkable ease, he should be able to achieve any desired result.
Steven Mosher | May 19, 2014 at 12:53 pm |
/
This is a fundamental issue in all science.
————————————————————————-
Why is it that we have seen a precipitous jump in the refusal rates to share data and code with respect to climate related papers, even under FOIA scenarios?
Is it just a trained defensive tactic or weak science hole hiding?
normal behavior amplified by the importance of the topic
“normal behavior amplified by the importance of the topic”
One would think that, given the importance of the topic, the onus would be on those providing the ‘science for policymakers’ and the policymakers paying for the science to be COMPLETELY TRANSPARENT to the public that is paying for said policy.
There seems to be plenty who understand the science as it stands at the moment, tho only one side gets press. And the rest, if they have the right to vote, should understand the restrictions on their lives over something as innocuous as a trace gas that is the basic food for practically all life on this planet.
Please explain to me why outright lies and subterfuge pass as normal behavior given the importance of the topic if it is not politics and power grab, pure and simple.
“Two unbiased estimators were sitting in a bar. The first says, So how do you like married life? The other replies, It’s pretty good if you don’t mind giving up that one degreee of freedom!” ~Bert Bishop
Nic Lewis, thank you for a good post. A very good post.
Steven Mosher: Now perhaps people can see why I ask that the data AS USED and the code AS RUN be supplied with every paper.
Spot on. It illustrates as well why people don’t want to share.
Academic squabbles regarding statistics-only dubious-confidence phenomenological models may be nugatory, eh Climate Etc readers?
Science by oceanographers, awsome Godzilla graphics supplied by FOMD, predictions coming true per James Hansen’s communication of last January 21.
`Cuz prediction is the name of the game in science, eh eh Climate Etc readers? In this regard, pure-statistics climate-models historically historically have performed poorly, isn’t that right? Whereas Hansen-style thermodynamical climate-models have performed pretty d*rn well over the decades?
Conclusion I What matters in the long run is the strongest science (which isn’t Mann’s or Curry’s statistical analysis) subjected to the strongest criticism (which isn’t Nic Lewis’ counter-statistical analysis).
Conclusion II Record-setting pause-ending global temperatures in 2014-2015 will spell “game over” for quibbling willfully ignorant climate-change denialism.
That’s solid science *and common-sense!
“Conclusion II Record-setting pause-ending global temperatures in 2014-2015 will spell “game over” for quibbling willfully ignorant climate-change denialism. ”
____
Sadly, that would not be the case. They will simply do a Tisdale, and point the El Nino as the source of the warming. It will be at least another 20 years before all the fake-skeptic arguments against anthropogenic climate change have been thoroughly de-bunked.
Can’t wait to hear yours, Hansen’s and other true believers’ sputtering excuses when Super El Nino fails to materialize again and instead an El Nino Modiki materializes and quickly fades away by next Spring.
http://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-cpc_plume
Chuck L.,
As I am not one who puts much stock in the notion that one El Nino induced tropospheric warming spike tells us much about ANW, you’ll have to pardon me for discounting that your comment has any meaning for me.
“‘Conclusion II Record-setting pause-ending global temperatures in 2014-2015 will spell “game over” for quibbling willfully ignorant climate-change denialism.’
____
Sadly, that would not be the case.”
Sadly? And here I thought R.Gates was not a member of the reflexive, wholly unskeptical consensus.
Why would it be sad for skeptics not to take an uptick in, what was it you called it, sensible tropospheric heat, as evidence that the “pause” was over? And here you were doing so well portraying an open minded, almost lukewarmish progressive.
Are we now seeing the hard core decarbonizationist zealotry coming out?
Funny, as Mosher is writing more reasonable comments lately, R.Gates is going the full warmist. Maybe they are simply out of phase, like the Arctic and Antarctica?
Gates, I was responding to FOMD’s post, not yours. I agree that El Nino/La Nina should not be used as “proof” of warming or cooling since both phases seem to be more affected by the PDO than anything else.
a fan of *MORE* discourse: Academic squabbles regarding statistics-only dubious-confidence phenomenological models may be nugatory, eh Climate Etc readers?
Monster El Nino
Emerging From the Depths:
Nose of Massive Kelvin Wave Breaks Surface
in Eastern Pacific
A good read. Thanks for the link.
Here is the final paragraph:
Should the rest of the Kelvin wave follow, temperature anomalies in this region will spike well above 4 C and possibly has high as 5-6 C. Such an event would be even stronger than the one seen in 1997-98, drive global temperatures about .05 to .2 C hotter than previous records in a single year, and set off a series of extreme weather that, when combined with the already severe conditions set in place by human-caused warming, may well be far in excess of those seen during past events.
It opens with a conditional and ends with a “may well be”. Something to watch, as this and other blogs are doing..
“Why would it be sad for skeptics not to take an uptick in, what was it you called it, sensible tropospheric heat, as evidence that the “pause” was over?”
_____
Any unwarranted focus on tropospheric temperatures takes away from the accurate long-term perspective. El Nino focus in general is a huge red-herring that distracts from the larger issue of long-term gain of energy in Earth’s climate system. El Nino’s don’t increase energy of the system, so focusing on it simply distracts.
Im always more reasonable. Its just that when you are wrong you need some excuse not to change your beliefs
It is amazing how you can use graphics to completely misrepresent data.
If you change the depth of the thermocline you get a massive change in the ‘anomaly’, even though you are only sloshing heat around the system.
Look at the cartography style absolute temperatures.
http://i33.tinypic.com/2jfakcm.jpg
Temperature anomalies can be highly misleading.
“Can’t wait to hear yours, Hansen’s and other true believers’ sputtering excuses when Super El Nino fails to materialize again and instead an El Nino Modiki materializes and quickly fades away by next Spring.”
____
You apparently still don’t get it—the appearance or not of an El Nino and the resultant spike in tropospheric sensible heat tells us next to nothing about the longer-term forcing from GH gas increases. Tropospheric sensible heat is a very poor proxy for measuring this forcing over anything less than decadal average temperatures in the troposphere. If the big El Nino hits, it just helps to raise the decadal average temperatures, ensuring the likelihood that the trend of each decade being warmer than the last continues. But the better proxy for gains in Earth’s climate energy system is ocean heat content anyway, and for the past 4 or 5 or even 6 decades it has been going higher—without pause.
Doc said:
“It is amazing how you can use graphics to completely misrepresent data.”
____
What is your essential point here? The “sloshing” around of energy in the system sloshes a bit more from ocean to atmosphere during an El Nino, and the graphics tell us a great deal about this. But, despite what many on both sides of the issue seemed to want to insist on—El Nino activity tells us very little about the longer-term forcing from GH gases, except perhaps how El Nino/La Nina activity might change as a result of this external forcing.
“El Nino activity tells us very little about the longer-term forcing from GH gases, ”
I absolutely agree. This is why I for one have wanted people to do actual science. I wish to know how light of different frequencies, but at the same power, interacts with the planet. I want someone in a lab, with a large, deep saline tank, to shine photons from 400 nm to 25 micron and work out where the water is thermalized and its effect on evaporation.
Sadly, the physicist appear to have given up on examining basic phenomena, as Pekka says, it is in a text book somewhere, and is all know.
Query by DocMartyn, Super-Kamiokande photos by FOMD!
Seriously DocMartyn, even the purest triple-distilled water is surprisingly opaque at most wavelengths; for ordinary sea-water (which is laden with salts and particulates) essentially all incident solar energy is absorbed in the top ten meters.
FOMD, you are real JC SNIP, as always.
“I am a medical researcher and quantum systems engineer, ……….., in service of applications in regenerative medicine.”
http://mathoverflow.net/users/11394/john-sidles
I know what the absorbtion spectrum of pure water is, all the way out to the IR. The question is dose an IR packet at 10.5 microns have different thermalization and evaporative properties than do an packet of equal energy at 550nm?
I would say no. I would expect the relationship between photon flux and salt water temperature profiles to be wavelength dependent, so as to make a mocker of the term ‘forcings’. Than again, I thing rain is wet so what do I know.
Seriously DocMartyn, even the purest triple-distilled water is surprisingly opaque at most wavelengths; for ordinary sea-water (which is laden with salts and particulates) essentially all incident solar energy is absorbed in the top ten meters.
The optical clearest waters are in the sector of the Sp anticyclonic gyre east of rapanui.eg morel.
http://www.obs-vlfr.fr/LOV/OMT/fichiers_PDF/Morel_et_al_LO_07.pdf
FOMD is guessing again.
Thank you for that outstandingly excellent reference maksimovich! It is an awesome experience to dive from a open-ocean boat into those empty pellucid central-pacific waters! So clear! So blue! So infinitely deep!
The “super-blueness” of the clearest open-ocean water comes because even those hyper-pure waters are relatively opaque at optical wavelengths longer than (about) four hundred nanometers. Indeed the color “red” is lost within a couple of meters of sea-water, whereas infra-red (heat) wavelengths are absorbed within centimeters. In terms of energy, essentially all solar energy is carried by optical wavelengths at which even the purest sea-water is strongly absorbing.
The nature of DocMartyn’s objections is far from clear, but those who seek deeper explanations of these intricate optical phenomena are well-advised to read Howard Carmichael’s texts on quantum optics, and to reflect upon his advice
Truly, quantum thermodynamics is “a piece of 21st century science that fell by accident into the 19th century.”
On the other hand, there’s not much mystery about the optical wavelengths at which the sun transmits energy and seawater absorbs energy. That’s why at (long) infrared wavelengths, water looks dark (as wildlife photographers know).
Thank you again, maksimovich!
It’ll also be interesting if we have another weak polar vortex and wavy jet stream. Maybe a bunch of that moisture and heat will end up in unusual places, like the arctic. Maybe we won’t get the albedo decrease that Spencer believes is part of el Nino. Maybe we’ll see even more clouds over the pacific (cold air from the arctic or more CCN from asia over the pacific)…
“The nature of DocMartyn’s objections is far from clear”
At 283K the Wien peak is at 10.24 um; just how far do half the photons at 10.24 um make it through saline?.
So what is the interaction of photons from a black body at 283K on a tank of saline?
How does evaporation and thermalization of these photons differ from the solar spectrum?
DocMartyn, liquid water at infrared wavelengths is comparably black (that is, light-absorbing) as coal at optical wavelengths.
Consequence Much depends on surface mixing. As surfers and water-skiers both appreciate, the top few centimeters of surface-water warm considerably more on a (sunny) still day than on a (sunny) windy day.
In tropical latitudes, increased surface mixing associated to windier weather (due to AGW?) acts to decrease surface-layer water temperatures, hence decrease surface-layer IR energy emission, hence increase the aggregate Hansen-style Godzilla-level energy imbalance.
Thank you for your question, DocMartyn.
That blog reads too much like a warmist rendition of Harry Potter for me to take it seriously. More data and less emotionalism would be helpful.
“That’s solid science *and common-sense!”
Interesting statement, I find neither above.
Well Done Nic. A shame that the journals cannot do a real peer review. Otherwise the problems would have been seen before publication.
“The stadium wave theory, if it holds up, offers physical insight into the mechanisms underlying the AMO and may lead to more reliable estimation of its state and influence on surface temperatures and other climate variables.”
Right, the stadium wave hypothesis posits a physical sequence, the wave moving around the stadium, which stands as a falsifiable physical hypothesis. That part is not analogous to Tinker Toys and cannot be replaced by an never ending sequence of “ad hoc” hypotheses. Of course, the stadium wave hypothesis is in process of articulation and, as such, encourages empirical research to discover the several connections among the physical phenomena that constitute the wave. Genuine science is such a joy.
Without judging the overall validity of Mann’s analysis or Nic Lewis’s critique, I think it’s worth pointing out an apparent inconsistency among a set of values Nic cites as possibly relevant – his EBM-based value of 1.65 K for equilibrium sensitivity, the contribution to global warming from internal variability since the mid-70s, which he suggests might be 0.2 KC out of a total of 0.6 KC, and values for change in ocean heat content (OHC).
The equation for the energy balance model is N = F – λ ΔT, where N is the planetary energy imbalance (mainly derived from OHC data), F is the forcing during the relevant interval, and ΔT is the interval temperature change. The feedback parameter, λ, quantifies the extent to which a temperature rise (fall) increases (reduces) the rate of heat loss to space. At equilibrium, N is 0 and so ΔT = F/ λ. For doubled CO2, ECS is therefore 3.7/ λ. For an ECS estimate of 1.65 K, this translates into a λ of 2.24 W/m-2/K-1. When the surface warms, some of the heat is retained by the ocean, and some escapes to space as exemplified by the 2.24 value cited above. How much does the ocean retain? A typical value is about 0.7 W/m-2/k-1, which is consistent with estimates of OHC uptake from OHC measurements. If OHC uptake is actually less than typically estimated, the heat uptake value would be less than 0.7 – these are reasonable approximations only.
We can now ask what would happen to the planetary imbalance, or its surrogate, OHC change, if 0.2 K of warming came from internal variability and 0.4 K from a forced response, the latter of which during this interval was almost entirely anthropogenic. For a 0.2 K rise due to an internal source – i.e., heat coming out of the ocean – the loss to space would be 0.2 x 2.24 = 0.45 W/m-2/K-1. For a 0.4 K rise from external forcing, the gain in OHC would be 0.7 x 0.4 = 0.28 W/m-2/K-1. The difference is 0.45 – 0.28 = 0.17 W/m-2/K-1 net loss of OHC – i.e., the ocean would have been losing heat since the mid-70s. Instead, all measurement-based estimates of OHC change show a very substantial heat gain – e.g., Ocean Heat Content. The observed heat gain would require a far lower λ (i.e., a far greater ECS) to balance the energy budget.
All of the above involves estimates and assumptions – they are approximations – but as far as I know, there is no plausible way for the OHC or ΔT data to be so widely wrong as to permit us to reconcile all the values described. My own interpretation, which I’ve stated elsewhere but won’t try to defend here, is that estimated 0.2 K contribution from internal variability is too high (if AMO warming is claimed to be an estimate of warming due to internal variability), that the cited value of λ may also be too high (i.e., the estimated “ECS” too low) due to erroneous values for aerosol forcing and OHC, and that λ derived from non-equilibrium conditions is likely to differ from λ at equilibrium. It is the latter difference that prompts me to suggest that EBM-based climate sensitivity values be referred to as “effective climate sensitivity” (EFS), a term commonly used, and not as ECS, with of course the option for authors to justify any proposed relationship between the two.
” but as far as I know, there is no plausible way for the OHC or ΔT data to be so widely wrong as to permit us to reconcile all the values described.”
http://judithcurry.com/2012/11/05/uncertainty-in-observations-of-the-earths-energy-balance/
Fred, “You might want to test this with trial values for all of these, as well as ECS.”
I have. Most likely there is a small ocean imbalance on the order of 0.3 Wm-2, but with an uncertain range of roughly +/- 0.4 Wm-2 after serious statistical manipulation, I would not be overly confident that it can’t go negative for a decade or two.
Maybe the variability doesn’t involve energy release from the ocean, but a reduction in energy uptake by the ocean, which in turn drives the surface temperature up? I see the ocean as a heat sink, because (in general) the surface has been warming for over 15 thousand years. If my perception is right, the deep ocean layers absorb geothermal energy from below and also absorb energy from above. The geothermal energy flow is a constant, so let’s discard it for this discussion.
Now I picture in my mind a heat transfer process from the surface into deep water which has variable heat transfer rates. If the process slows down the earth’s surface warms up, this changes feedbacks, thus the energy input from above (the sun) changes because the atmosphere and the surface change (I suppose the humidity goes up and this changes clouds, ice, etc).
I can visualize this system as a simple box, but I imagine the real world system is amazingly complex and has all sorts of parameters which change in complex and probably chaotic fashion? This means I don’t dare venture a guess as to why the current regime involves reduced forcing, or why the forcing may have been higher in the last few decades of the 20th century. However, it sure looks like forcing did change. Either that or the ocean heat content wasn’t being measured so well in the past.
Fernando,
It’s nice to see someone else saying this.
Fred, you’re assume the albedo change is a response to temperature rather than weather.
Fred Moolten, I am glad to see you back. I hope to respond in a day or two.
Fred Moolten, I have read through your post a few times, and I do not see where you have called into question any of Nic Lewis’ comments about Mann’s papers. I also do not see where you have actually critiqued Nic Lewis’s post at all.
You wrote this: All of the above involves estimates and assumptions – they are approximations – but as far as I know, there is no plausible way for the OHC or ΔT data to be so widely wrong as to permit us to reconcile all the values described.
How does that affect our understanding of Nic Lewis’ post. It does not seem to at all.
I have often pointed to holes in the scientific evidence, the “case” that future CO2 increases will cause future warming. It looks to me like you have described some discrepancies that can’t be resolved with current knowledge.
Hi Matthew – I’ll address mainly your above comment. In further comments down below, you raise issues about the process of estimating climate responses, including concerns about the hydrological cycle. I believe most of those can be answered, which would require considerable detail and time, but I’ll suggest they are not really relevant to my main point – the apparent inconsistency among statements in Nic’s post.
Using the energy balance model described in my comment, Nic has estimated climate sensitivity to be about 1.65 C, an estimate that involves evidence he used that the ocean has been gaining heat since 1975. and he has also suggested that 0.2 C of the 0.6 C warming since 1975 may have been due to internal variability. All of these entities entail numbers that can be entered into his model, and when that happens, they can’t be reconciled with each other. As I pointed out, we know that the total temperature increase (about 0.6 C) is correct, and we know it’s correct that the ocean has been warming. The problem arises when we try to assign 0.2 C to internal variability and 0.4 C to external forcing on the basis of an ECS of 1.65. That leads to the conclusion that the ocean should have been cooling instead of the warming that has been observed.
This is unrelated to other models or other means of evaluating climate responses. It’s an inherent result emanating from the model he employs. That model has some uses, but also problems, some of which deserve more discussion. In this case, we can speculate as to which of the numbers used should be changed to make all the values internally consistent. In my view, the 0.2 C internal contribution is probably much too high, and the ECS may be too low, but that too is the subject for a different discussion.
Fred Moolten, Nic Lewis says this about Mann: Mann’s EBM has an equilibrium/effective climate sensitivity (ECS) of 3.0°C and, unusually, no allowance for heat uptake by the ocean apart from in a 70 m deep mixed layer. As a result, its TCR – the simulated temperature rise from CO₂ concentrations doubling over 70 years as a result of 1% p.a. growth – is 2.8°C, very little lower than its ECS.
You wrote this: The problem arises when we try to assign 0.2 C to internal variability and 0.4 C to external forcing on the basis of an ECS of 1.65.
…
In my view, the 0.2 C internal contribution is probably much too high, and the ECS may be too low, but that too is the subject for a different discussion.
0.2 C can’t be very much too high, can it? Have you essentially written that your critique hardly affects Nic Lewis’ critique of Mann at all? Especially if Nic Lewis’ estimate of ECS “may” be too low?
Matthew – the internal contribution may be zero or close to it. As to whether my critique affects Nic’s critique of Mann, it may not, but I have to confess I would have to study Nic’s very detailed evaluation for more thoroughly to judge. As for ECS, even 3 C would be too low to reconcile all the numbers. If you want to try this out, calculate λ from an ECS of 3 C, and then go through the other calculations to compare ocean heat loss with heat gain.
Fred Moolten: As for ECS, even 3 C would be too low to reconcile all the numbers. If you want to try this out, calculate λ from an ECS of 3 C, and then go through the other calculations to compare ocean heat loss with heat gain.
Since the system is never in equilibrium, I doubt that the diverse discrepancies resulting from assuming an equilibrium can be resolved by assuming it is in equilibrium. As I wrote, the increase in latent heat carried from surface to upper troposphere caused by an increase in CO2 is ignored in equilibrium models, so they overestimate the warming of the surface and underestimate the increase in heat radiated from the upper troposphere; besides being totally inadequate in modeling changes in cloud cover. If I am correct (and I am hardly alone in describing some of these unsolved problems in modeling the dynamics of the response to CO2), then 3C is too high; quantitatively how much too high can’t be computed on present knowledge.
“Since the system is never in equilibrium, I doubt that the diverse discrepancies resulting from assuming an equilibrium can be resolved by assuming it is in equilibrium. “.
Hi Matthew – The energy balance model commonly used by Nic and many others is based on the assumption that ECS can be estimated from data derived under non-equilibrium conditions. This is probably wrong, but how wrong is a matter of uncertainty. If wrong, it is likely to underestimate the true value for ECS. This is discussed extensively in most of the recent blogs addressing climate sensitivity.
“As I wrote, the increase in latent heat carried from surface to upper troposphere caused by an increase in CO2 is ignored in equilibrium models, so they overestimate the warming of the surface and underestimate the increase in heat radiated from the upper troposphere;”
That’s not correct. The models do incorporate latent heat into their estimates.
“besides being totally inadequate in modeling changes in cloud cover. If I am correct , then 3C is too high”
The 3 C value may or may not be too high (or too low), but it has been derived from methods not involving GCM modeling of cloud feedbacks – e.g., paleoclimate studies. There is no ideal method for estimating ECS. Finally, though, I should clarify my earlier point. I was not proposing a specific value for ECS, but pointing out the inconsistency among all the variables that is not resolved by raising ECS estimates from 1.65 to 3 C. That inconsistency is created by any claim that as much as 0.2 C out of 0.6 C warming since the mid-70’s is due to internal variability. Once that claim is eliminated, a broad range of ECS estimates is compatible with the other numbers.
K not KC in the above values for temperature
Captdallas – As long as there is a claim that temperature change, OHC change, and a significant contribution from internal variability are all positive, the uncertainties appear insufficient to reconcile the values. You might want to test this with trial values for all of these, as well as ECS.
Fred, you start with the assumption that the AMO doesn’t change the energy budget. I don’t think that is a very supportable assumption. It would mean that all the weather pattern changes that are attributed to changes in the AMO don’t affect the global albedo or water vapor concentrations.
Steven – My comment assumed that the AMO does change the energy budget. That is what leads to the difficulty in reconciling the numbers.
Fred, you only assume it changes the budget on the way out. What about the changes on the way in? There is no reason why you should assume the ocean has to lose heat content in order for the atmosphere to warm. There could be more energy going into the ocean due to changes in albedo and water vapor.
Steven – I’m not sure exactly what you have in mind, but one suggestion is to try the calculations with any value of ECS (i.e. λ) and any source of warming you want to test among those known to play a role in temperature change.
Fred, rough numbers but good enough for government work. A 1% change in the Earth’s albedo would cause about a 1C change in global temperature. That means a swing in the AMO from a positive to a negative phase would only have to change the Earth’s albedo by 0.4% in order to cause a 0.4 C swing in temperatures.
Steven – Surface warming from AMO-induced heat loss from the ocean could in theory induce an albedo reduction feedback that outweighed the ocean heat loss by allowing more solar heat to be absorbed, thereby turning ocean heat loss into the heat gain observed. The problem with this is that it requires a very high climate sensitivity – above the IPCC upper limit. I suppose one could postulate that climate sensitivity to CO2 is low but climate sensitivity to internal variability is very high. There’s no evidence for this in the pattern of recent climate change, but anything is possible. That’s why the IPCC can assign a 95% probability to the role of GHGs in recent warming but not a 100% probability.
A higher sensitivity or a greater change in albedo. 0.4% is rather small when you consider the short data base we have for such changes.
It’s not either/or. A greater albedo change in response to a given temperature change requires a higher climate sensitivity.
It seems to me that a difficulty in this discussion is that the variables are invoked piecemeal rather than as a package. My take is that Mann’s analysis may have problems, but I’m not sure Nic’s alternative stands up to scrutiny either. In particular, a claim that internal variability may have contributed as much as a 0.2 C rise is hard to reconcile with the other variables. I hope that anyone who disagrees, including Dr. Curry, will review my calculations and state why they lead to a wrong conclusion. To do this, I would hope they will redo the calculations using their own values for the variables, but they should include everything in presenting their results. This includes forcing from doubled CO2, λ and the consequent ECS, ΔT, the fraction of ΔT assigned to internal variability, OHC uptake, and the efficiency of ocean heat uptake. The challenge will to make all of these compatible with each other and with the real world data.
Parenthetically, I should note that a significant warming from the AMO would not create difficulties if it were negated by internal variability elsewhere in the opposite direction. It’s the net contribution from internal variability that’s problematic.
Fred, a higher albedo doesn’t require a higher sensitivity. It could very easily be a change in location of heat. Take a look at studies of changes in ocean heat transport. I know I have linked at least one at you before. There are many more out there. You would have to assume that the change in heat transport is forced for your argument to be sound and then we could start worrying about differences in efficacy to differnt forcings.
A change in heat transport leading to a greater albedo change is a change in climate sensitivity.
Steven – could I urge you (and others) to accept my invitation to do all the energy budget calculations using numbers of your own choice? Otherwise, we’re likely to go around in circles. I would like to refrain from addressing single points if that isn’t done. Thanks.
Fred is suggesting we follow the lead of climate scientists and just pick our own numbers. Seems to be working for them so far – at least as far as Obama goes.
Fred, I’m not sure how, if it is internal variability, it becomes part of climate sensitivity but I can tell you would prefer to just do it your way so calculate away :).
“Fred is suggesting we follow the lead of climate scientists and just pick our own numbers. Seems to be working for them so far – at least as far as Obama goes.”
No, he’s suggesting that you check that your own beliefs are consistent with one another. It’s easy to rebuke results from climate science, and propose alternate values for climate sensitivity, natural variability attribution, OHC, etc., if your doing so can be done with no concern with the logical compatibility of the proposed alternate values. Theories that aren’t self-consistent are a dime a dozen and have zero chances of being true.
Pierre-Normand, no, what Fred is doing is saying check your believes with his assumptions to see if they are practical.
“Pierre-Normand, no, what Fred is doing is saying check your believes with his assumptions to see if they are practical.”
If you think it is some assumption of his that makes your beliefs merely seem inconsistent, then you (or someone else) will have no trouble answering his challenge and showing which of his assumption must be rejected. But I’ve never seen any skeptic present a coherent alternative picture, so far, while accounting for all the variables he has mentioned.
Pierre-Norman, how much would you like attributed to the AMO? I just have to adjust the amount of albedo accordingly. That is why the value has been determined by statistical methods. We don’t have the data to do it directly.
N.Lewis’s analysis does not hold up to scrutiny. Bank on it.
Let’s see…
Isn’t this the paper WebNut has been touting loudly as “debunking” the Stadium Wave hypothesis? So much so that he insists the papers describing it ought to be withdrawn?
So, when after enough time for somebody to actually produce a well-thought-out rebuttal that rebuttal appears, all he has to say is the “analysis does not hold up to scrutiny.” What I’m willing to “Bank on” is that the vast majority of “quick-response” opportunistic uses of just-appeared papers to attack disliked hypotheses will turn out to be wrong.
And yes, Joshua, that applies to both sides of the “debate”.
“Pierre-Norman, how much would you like attributed to the AMO? I just have to adjust the amount of albedo accordingly.”
You can’t posit arbitrary responses of the cloud albedo to internally generated surface warming (due to AMO, PDO/ENSO, etc.) without this impacting climate sensitivity to CO2 forcing at all. It seems that many skeptics want both to say that climate sensitivity is very high, or that it is very low, depending on what forcing is at issue. But a couple decades after the primary forcing (either internally or externally applied) has produced a general warming of the ocean surface, it’s hard to argue that the cloud feedback will remain selective depending on what the forcing has been that caused the surface temperature to increase in the first place.
Pierre-Normand, I’m not sure how you make the leap that if the albedo response to an internal variation in ocean heat transport is greater the climate sensitivity must also be greater. Greater than what? Can you show what the expectations were for a change in albedo due to a change in phase of the AMO? Can you show how this directly relates to an expectation in ocean heat transport changing due to a forcing?
Pierre-Norman, the last I heard AGW was supposed to slow the AMOC not speed it up. If this is the case the greater you make the albedo change the more positive the response is to internal variation and the more negative is the response to forcing.
Sorry about losing your d again. I can assure you I am well known for sloppy typing.
AK
–> “And yes, Joshua, that applies to both sides of the “debate”.”
http://judithcurry.com/2014/05/19/critique-of-manns-new-paper-characterizing-the-amo/#comment-560474
Read that discussion between Bart and tonyb here (and ignore the input from a few other participants in the subthread) and you can see the rare Climate Etc. exchange where people on both “sides” recognize your point.
I had to double-check to make sure I was still at Judy’s when I read that exchange.
Well, Joshua, I guess the fact that (some) better-informed participants in the “debate” are willing to wait for more rigorous analyses before jumping to conclusions would stand out most to you, given your perspective.
My view is that the vast majority of current “climate science” is based on an obsolete paradigm (due to the usually tacit assumption that small divergences will “cancel out” on a larger scale) and efforts to construct a new paradigm are still in a very early stage (in Kuhnian terms). The “Stadium Wave” hypothesis is a good step in the right direction, attempting to deconstruct the massive noise of the overall system into elements that might be related to actual “causation”.
So was M&M’s demonstration that analytical methods that appear to find a signal in real-world noise might actually produce a similar signal in artificially generated “noise” of some sort (e.g. color). I’ve seen many claims that the method in Mann et al. (2014) is a development from that, which I’ll provisionally accept.
The rebuttal here fits into the same category, of efforts to extend a scientific field “beyond the paradigm”. What stands out to me is that such terms as “proof”, “falsification”, and the like are actually defined within the paradigm, so when work goes beyond it arguments over its “scientific” applicability often turn into people talking (shouting) past one another. This often opens the door for pursuit of non-scientific agendas.
When considering hyper-complex non-linear systems, it’s important to remember that even such “basic” terms as “cause and effect” are really myths: metaphors that are often useful but don’t necessarily apply to any specific issue/question. The universe evolves from present to future “state” (actually a superposition of many states if I understand the quantum theory correctly), and any difference in the present “state” will have some potential difference in the future.
“Cause and Effect”, OTOH, includes the usually tacit assumption that the difference being labeled “cause” is the only difference, “all other things are equal”. Which they never are.
“Isn’t this the paper WebNut has been touting loudly as “debunking” the Stadium Wave hypothesis? So much so that he insists the papers describing it ought to be withdrawn?”
Wasn’t that Gates? I’m likely confused. They all sound so alike to me.
Fred, you’re assume the albedo change is a response to temperature rather than weather.
Aaron – If you or others do the calculations I suggest, using any numbers you want to test, I think you’ll see why what you suggest doesn’t work.
Incidentally, I apologize for sloppy units in my first comment. The units for radiative loss and ocean uptake efficiency should be expressed as W/m2/K
Also, the gain or loss in radiative and OHC heating or cooling for a specified temperature change should be W/m2.
Fred, what’s behind the blue line?
========
Pierre-Normand, I was trying to think of why I couldn’t comprehend your and Fred’s argument and then it occurred to me iit is just the simplisity of my thought process. You see, if you increase the forcing but don’t change the reponse you get a smaller sensitivity. I don’t see how I will ever be able to get beyond this mental block to understand why the AMO having reduced the albedo, if it did, would point to a higher climate sensitivity.
Steven wrote: “Pierre-Normand, I’m not sure how you make the leap that if the albedo response to an internal variation in ocean heat transport is greater the climate sensitivity must also be greater.”
I agree that’s a leap I can’t make. I got convinced of this in recent discussions about El Nino. But I am not making it (anymore). I grant you that different localized mechanism for surface warming can have different feedbacks associated with them. I am talking about what occurs some time after the internally generated forcing isn’t applied anymore or has stopped increasing for a while.
The usual internal cycles that are invoked as alternate culprits for the warming that occurred in recent decades tend to switch phase at some point (i.e. PDO/ENSO or AMO/Stadium Wave, etc.) When this occurs the initially localized pattern of warming tends to spread and become more homogeneous. This is exemplified both in the case of ENSO and AMO. The Earth tends to warm or cool as a whole over a few decades. If the temperatures don’t fall back but rather continue to rise (even at a slower pace) after the internally generated forcing that initially contributed to the rise is falling back, then this suggests that something strong *still* is counteracting the Planck response and actively prevents the Earth to cool. This can be a high global climate sensitivity to CO2 forcing. It could also be a very strong delayed global feedback response still amplifying the initial warming that has now be redistributed around the globe. But the second mechanisms can hardly be at work while being insensitive to CO2 forcing since it is a response to the effect — the global warming — and not its initial localized cause. And if it is indeed sensitive to both, then, when you work out the numbers, accounting for both surface temperature rise and increase in ocean heat content, you end up *attributing* more warming to CO2 and natural variability together than has actually occurred.
Steven – the following website might be useful to you in seeing these relationships, particularly Table 1 – Soden and Held 2006. Notice that in the absence of positive feedbacks, a warming is dissipated to space exclusively by the Planck Response, at about -3.2 W/m2/K. Positive feedbacks partially counteract the Planck Response by reducing the rate at which heat is lost to space, thereby increasing its ability to warm the climate system, which is the broad definition of climate sensitivity. When warming from any source, internal or externally forced, reduces albedo and thus amplifies the warming, it is inducing a positive feedback, which in the paper, is in the order of about 0.3 W/m2/K. According to the calculations I described in my first comment, a sensitivity of 1.65 is too low to balance the heat loss involved when internal variability causes ocean heat to warm the surface and thus lose some of the heat to space – see those calculations for the details. Also note that the albedo feedback is modest, and it would require an enormous percent increase in that particular feedback (expressed as W/m2/K) to even reach a balance, much less result in a positive rate of OHC increase. In any case, the increase would be such as to greatly increase climate sensitivity – again, try it out with different values for feedback strength to see how great an increase in sensitivity would be required. (For reference, ECS is defined as 3.7/λ, where λ denotes the rate heat loss rises in response to warming, and in Table 1 is the Planck Response minus the net feedbacks, but conventionally expressed as a positive rather than negative value in energy balance equations written as I described).
‘What defines a climate change as abrupt? Technically, an abrupt climate change occurs when the climate system is forced to cross some threshold, triggering a transition to a new state at a rate determined by the climate system itself and faster than the cause. Chaotic processes in the climate system may allow the cause of such an abrupt climate change to be undetectably small.’ NAS – Abrupt climate change: inevitable surprises.
Rather than challenge absurdly simplistic calculations or even sillier narrative – the entire global warming paradigm has collapsed in a screaming heap to be reanimated as a blogospheric zombie.
Rather than an average of weather – climate is an emergent property of a deterministically chaotic system. In this paradigm ocean and atmosphere patterns shift abruptly and produce large variability in the Earth’s energy budget. In this paradigm sensitivity is dynamic rather than static. It is large in the vicinity of climate shifts but not otherwise.
The evidence is clearly there – but almost entirely absent from the run of the mill blogifications. TOA radiant flux anomalies are remarkably accurate.
‘Climate forcing results in an imbalance in the TOA radiation budget that has direct implications for global climate, but the large natural variability in the Earth’s radiation budget due to fluctuations in atmospheric and ocean dynamics complicates this picture.’ http://meteora.ucsd.edu/~jnorris/reprints/Loeb_et_al_ISSI_Surv_Geophys_2012.pdf
The evidence shows that large radiaitve effects of natural variation are the most obvious feature of the recent global energy budget. No ifs – no buts – no maybes. These change with decadal – and presumably longer term – climate shifts.
e.g http://s1114.photobucket.com/user/Chief_Hydrologist/media/Clementetal2009.png.html?sort=3&o=151
Of course science both explains observations and makes predictions. Deterministic chaos explains climate shifts around 1910, the 1940’s, 1976/1977 and 1998/2001.
Anastasios Tsonis, of the Atmospheric Sciences Group at University of Wisconsin, Milwaukee, and colleagues used a mathematical network approach to analyse abrupt climate change on decadal timescales. Ocean and atmospheric indices – in this case the El Niño Southern Oscillation, the Pacific Decadal Oscillation, the North Atlantic Oscillation and the North Pacific Oscillation – can be thought of as chaotic oscillators that capture the major modes of climate variability. Tsonis and colleagues calculated the ‘distance’ between the indices. It was found that they would synchronise at certain times and then shift into a new state.
It is no coincidence that shifts in ocean and atmospheric indices occur at the same time as changes in the trajectory of global surface temperature. Our ‘interest is to understand – first the natural variability of climate – and then take it from there. So we were very excited when we realized a lot of changes in the past century from warmer to cooler and then back to warmer were all natural,’ Tsonis said.
I predicted non-warming for decades more – publicity high profile – in 2007. I was not the first and have been joined by many since.
e.g. http://s1114.photobucket.com/user/Chief_Hydrologist/media/rc_fig1_zpsf24786ae.jpg.html?sort=3&o=100
Tortuous deductive reasoning supported by anachronistic algebra by Fred – real data by me.
Why ocean heat transport warms the global mean climate
Herweijer et al 2005
Why tropical sea surface temperature is insensitive to ocean heat transport changes
Koll & Abbot 2013
Ocean heat transport and water vapor greenhouse in a warm equable climate: a new look at the low gradient paradox
Rose & Ferreira 2013
Fred, I must admit I am perplexed why I should take a radiative forcing model and attempt to determine what the feedbacks to a change in ocean heat transport would be when there are model studies that are designed for just this purpose such as those above.
Steven, “Rose & Ferreira 2013”
Good reference.
Steven – I don’t mean to sound patronizing but I was trying to help you by asking you to go through the calculations rather than throw out piecemeal suggestions. If you do the calculations, you’ll see why your suggestions don’t resolve the problem. I can’t think of any new way to explain beyond that. I may not comment more on this with you until then unless something very unexpected turns up.
Fred Moolten:
Notice that in the absence of positive feedbacks, a warming is dissipated to space exclusively by the Planck Response…
…a sensitivity of 1.65 is too low to balance the heat loss involved when internal variability causes ocean heat to warm the surface and thus lose some of the heat to space…
I think I see what you’re saying. That the models are closer with the higher sensitivity values. If the only thing is the Planck response, that seems like a big homogenized system where change happens slowly. The GAT seems to jump around quite a bit and higher sensitivities are a plausible answer. Another poster on the recent Climate Sensitivity post made a comment along the lines of what you said.
Here:
http://climateaudit.files.wordpress.com/2013/07/model-comparison21.png
I think we can see the homogenized model.
Fred, that’s fine. Lets drop it. I wouldn’t want to force you into being patronizing.
Dallas, I fnd Rose to have interesting arguments. I’ve watched his video on that paper several times.
WebHubTelescope: N.Lewis’s analysis does not hold up to scrutiny. Bank on it.
Nic Lewis has shown that Michael Mann has done what you can always do: if you are sure you know the signal in the time series: you can re-estimate the noise to re-estimated the data closely as data = “model” + “noise” (plus a small amount of pure “randomness” such as instrument fluctuation.) In this case, Mann has focused on re-estimating the part of the fluctuation that is independent of CO2 that is called the AMO. That part of Lewis’ analysis is solid. Mann’s effort is a classic effort to “rescue” the hypothesis when it has apparently failed a straightforward test. The doubtful parts of Lewis’ analysis are whether Lewis anywhere presents a “model” and corresponding “noise” that are demonstrably better than Mann’s. That might be debatable.
Steven – OK, I apologize for being patronizing while claiming I don’t want to be, but I am finding it hard to address your points when they’re made in isolation without reference to the whole. I’ll try to be more explicit this time regarding your most recent comment about heat transport. This phenomenon is included in estimating climate sensitivity to CO2 and undoubtedly affects climate sensitivity to the AMO. However, if you are suggesting that the AMO exhibits so much greater heat transport (and hence such a higher climate sensitivity) than the sensitivity value Nic cites, or IPCC values for that matter, then you should explain how that might come about and cite some real world evidence. Equally important, you should calculate what sensitivity would be required to reverse the negative OHC trend I found inconsistent in my first comment and convert it to a positive OHC trend matching observations. I think you will find it extraordinarily high (i.e., the value of λ extraordinarily low) – far higher than the upper IPCC boundary – and you will have trouble assigning realistic numbers to the specified feedbacks in order to reach that value. Geographic differences in feedbacks, and thus in λ, are known to exist, but there is nothing to suggest anything of the order you want to consider as a mechanism to amplify feedbacks. That’s why I’ve been appealing to you to do the calculations.
Fred, what’s behind the blue line? Is it something bad or good?
=========
Fred, ok let me explain where your assumptions are in error.
First you are working with a static model. Ocean heat transport is not static. It changes a lot of things. I like using albedo because albedo is simple and everyone understands albedo plus it is all that the earlier simpler models used. Let me show you what changes this study shows at the tropics which would be the source of the transport
Why Tropical Sea Surface Temperature is Insensitive to Ocean Heat Transport Changes
Daniel D. B. Koll and Dorian S. Abbot
Previous studies have shown that increases in poleward ocean heat transport (OHT) do not strongly affect tropical SST. The goal of this paper is to explain this observation. To do so, the authors force two atmospheric global climate models (GCMs) in aquaplanet configuration with a variety of prescribed OHTs. It is found that increased OHT weakens the Hadley circulation, which decreases equatorial cloud cover and shortwave reflection, as well as reduces surface winds and evaporation, which both limit changes in tropical SST. The authors also modify one of the GCMs by alternatively setting the radiative effect of clouds to zero and disabling wind-driven evaporation changes to show that the cloud feedback is more important than the wind–evaporation feedback for maintaining constant equatorial SST as OHT changes. This work highlights the fact that OHT can reduce the meridional SST gradient without affecting tropical SST and could therefore serve as an additional degree of freedom for explaining past warm climates.
So there you have it. This study states that the source of the heat does not lose energy just because it transports energy out due to other factors being involved.
So what happens with that heat that is transported? Well the newer models show that it increases atmospheric water vapor and reduces albedo. I think you would agree that both of those cause warming. The older models as I stated before show mostly albedo changes but even a small change in albedo can cause significant changes in climate.
What about ocean heat content? Well we have already determined we aren’t losing OHC at the tropics because of the changes that occur there. I have yet to see an ocean heat transport model study that makes the claim that any warming from transport does cause a loss in OHC although I’m sure with some effort you could find one. So are going to lose OHC where the additional heat is being pumped to? Seems unlikely and observations indicate that you don’t. In fact observations indicate that the greatest factor in determining what ocean heat content will do is the amount of ocean heat transport. Sonnewald et al 2013.
Now as far as how much the AMO actually causes I didn’t actually state. I used an example of 0.4 C which is 0.1 C higher than the highest estimate I have seen and is probably unlikely, but not for the reasons you were claiming which was what I considered my important point. Is it possible? I see no reason why it isn’t. Measurements of poleward heat transport in the Atlantic have been estimated to have reduced by 10-15% in just the last decade. Smeed et al 2013. According to the Rind and Chandler model 1991 a 15% increase in poleward heat transport could cause a change of 2 C globally. The AMO isn’t global but I don’t see 0.4 C out of the range of possibilities.
So Fred, I am perfectly willing to drop this topic with you but if we are going to discuss it lets at least get on the right models first.
Steven – By all means let’s drop it. Climate physics is a quantitative discipline, so invoking concepts or phenomena without numbers is more or less meaningless. I’ll end though by encouraging Dr. Curry to go through the calculations, since they are the same type that demonstrate the validity of the IPCC attribution (in a quantifying diagram) of almost all post-1950 warming to anthropogenic forcing. In facts, these calculations demonstrate the unimportance of internal variability during this interval more convincingly than the IPCC use of GCM-based simulations. This point has been noted by a number of the experts who rely more on the mathematics than the GCMs.
Fred, I doubt those papers made it through peer review without any numbers. May I suggest you go look at the numbers and tell them why they are wrong and you are right. I suspect they will tell you to stop looking at the wrong models.
Fred Moolten: A greater albedo change in response to a given temperature change requires a higher climate sensitivity.
the problem here, imo, comes from focusing on the hypothetical equilibrium without consideration of the (poorly studied) dynamic response of the hydrological cycle to an increase in atmospheric CO2. As the Earth turns, the ground warms and cools each day, as sunshine alternates with shade, as everyone knows. If the atmospheric CO2 were to increase (double, as the standard study case), the daily am burst of downwelling LWIR would be increased, and on the 85% or so of the non-dry Earth surface would undergo a mixture of increased evaporation and increased warming. The increased evaporation happens faster than the atmosphere can equilibrate to, as can be observed everywhere there are thunderclouds followed by rainfall. How much of the energy in that increased downwelling LWIR is carried to the upper troposphere by radiation and how much (as latent heat) is carried by the wet thermals is not known, but as long as the increase in the latent heat transport is unaccounted for so far, the estimate of the increase in Earth surface warming is too high; and it is possible for the cloud cover (hence albedo) to increase more than is currently estimated, even though the surface and lower troposphere warm less than is currently estimated.
On present knowledge, aka “present ignorance”, increased CO2 could produce both a higher albedo increase and a lower temperature increase than the equilibrium models yield from the equilibrium assumption.
Fred Moolten: . Climate physics is a quantitative discipline, so invoking concepts or phenomena without numbers is more or less meaningless.
It’s worse than that! The calculations that can be made are based on the equilibrium assumptions, which are counterfactual since the Earth is clearly never in equilibrium. They could be accurate enough to achieve some goal or another, but that has not been shown: that is, nowhere has it been shown that the equilibrium model is sufficiently accurate to account for a less than 1% change in absolute mean temperature resulting from a less than 1% change in downwelling radiation. The effects of increased CO2 on the rates of the processes sketched by Fasullo and Trenberth and G. Stephens et al are not known quantitatively, so none of the short-term or long-term quantitative effects of doubling CO2 can be calculated.
I did listen to Michael lecture. I did talk to him afterward. I also talked to some of his former students. I did talk to them about Ewing and Donn Climate Theory. They did not know what that was. These Climate Scientists have not studied Climate Theory History. They only know the modern Consensus Stuff.
It is how courses are taught nowadays, in my day we were taught the history of discovery and why people believed what they did or why they were constrained by equipment. Nowadays they are given information, no stories.
My only critic to stadium wave theory is that uncertainties in knowing global (or NH) temperatures grow as long as we move to the 1850’s. (See fig.11).
My critic to Mann’s (et al) article are many: why using an ECS of 3K?, are the ERF values based also in invented-consensed values or in actual measurement (because in those measurements uncertainties also grow as we move to the 1850’s)?, why defining AMO as a low-frequency component (for multidecadal = 50 years)?.
Spetial menction has the phrase: “The use of independent noise realizations reflects the null hypothesis that the various climate indices are impacted by different noise processes”, are these lads serious?, have they passed a 1st course in statistics?.
Furthermore, nobody cares about my +900 years timescales.
In summary, if I were a judge, here there are my assigned probabilities: a 70% that nobody is right, a 29% that JC+Lewis are right and a 1% that Mann el al are right.
If a hypothetical Dr. Anti-Mann wrote a paper arguing the converse of his new paper, the CAGW truth police would no doubt be up in arms, screaming “But he’s a Dendro-chronologist! He’s not qualified to comment on AMO or the PDO!”
Mann was one of the scientists who discovered the AMO
LOLWOT – I didn’t way it would be justified
Iolwot
Citation please. I thought the amo was discovered in 1994 and not by Mann
The scientist concerned built on the extensive work carried out by Hubert lamb who identified its effects many years previously but did not name it.
Tonyb
tonyb, I think he is referring to this paper:
Mann, M.E.; Park, J. (1994). “Global scale modes of surface temperature variability on interannual to century time scales” (PDF). Journal of Geophysical Research 99: 25819–25833. doi:10.1029/94JD02396.
lolwot,
Really??
http://wattsupwiththat.com/2012/03/08/mann-and-coining-the-amo-and-claims-of-credit/
DCA
Thanks for that. This was identified years ago by people such as Lamb but quantified and named by others.
Perhaps Iolwot can come up with a better and more objective reference to support his claim than Mann’s own book?
Tonyb
‘The term was introduced in a summary by Kerr (Science, 2000) of a study by Delworth and Mann (2000). The index was defined by Enfield, Mestas-Nuñez, and Trimble (Geophys. Res. Lett., 2001) as the North Atlantic SST anomaly north of the equator.’
http://ioc-goos-oopc.org/state_of_the_ocean/atm/amo.php
Perhaps the term was coined by Mann, perhaps by Kerr, but it seems doubtful that Mann can claim to have discovered the phenomenon, any more than Al Gore invented the Internet. But I digress….
Did Mann make the claim – as opposed to winning the Noble Prize – or was this just more numbnut hyperbole?
whoops – Nobel Prize – although perhaps winning the Ig Noble Prize is just a matter of time.
http://www.improbable.com/ig/winners/
Strange how riled up everyone gets just because I point out the fact that Mann was one of the scientists who discovered the AMO.
It’s presumably hard to acknowledge the importance of Mann’s work in the field, but come on.
From the WUWT post linked in the comments:
The Atlantic Multidecadal Oscillation (AMO) was identified by Schlesinger and Ramankutty in 1994.[1]
Enfield, D.B., A. M. Mestas-Nunez and P.J. Trimble, 2001: The Atlantic multidecadal oscillation and it’s relation to rainfall and river flows in the continental U.S.. Geophysical Research Letters, Vol. 28, 2077-2080.
So it appears that when the phenomenon was identified in 1994 by Schlesinger and Ramankutty, the abbreviation didn’t get used until Dick Kerr suggested it for an article he was writing.
(end quote)
Maybe Al Gore will share the invention of the internet with Mann.
Why was Kerr having a phone call with Mann?
Maybe because Mann was one of the scientists who discovered the phenomenon that on that very call would become named AMO.
Sure odd that Mann would be talking to Kerr on that very subject if he had nothing to do with the phenomenon.
‘Bad’ or ‘Good’
What dybbuk should,
Or could,
Censor the would?
===========
H/t Jean S.
========
Looks like the Arctic is about to collapse
But it won’t collapse as quickly as CAGW.
If you believe century long predictions like this LOLWOT, I’ve got some Prime Florida Land for you.
From the article:
…
University of Washington researchers used detailed topography maps and computer modeling to show that the collapse appears to have already begun. The fast-moving Thwaites Glacier will likely disappear in a matter of centuries, researchers say, raising sea level by nearly 2 feet. That glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet (3 to 4 meters) of global sea level rise. The study will be published on May 16 in Science.
“There’s been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is under way,” said Ian Joughin, a glaciologist at the UW’s Applied Physics Laboratory. “This study provides a more quantitative idea of the rates at which the collapse could take place.”
The good news is that while the word “collapse” implies a sudden change, the fastest scenario is 200 years, and the longest is more than 1,000 years. The bad news is that such a collapse may be inevitable.
…
Read more at: http://phys.org/news/2014-05-west-antarctic-ice-sheet-collapse.html#jCp
The good news is that those who are predicting this don’t have a clue!!
Smiley Faces all around.
Perhaps you have a difficulty distinguishing between the “Arctic” and Antarctic?
LOLWOT – I meant to say “I didn’t say it would be justified”
R Gates
So the Mt Agung eruption managed to cool the land and sea temperature before it erupted and also cooled it in the 1940’s?
http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A.gif
As regards the 1257 volcano the evidence is that the cooling happened BEFORE the eruption and returned to normal the year after.
I am sorry but the volcanos are not an explanation either in the 1960’s/1970 or the 1250’s
tonyb
‘In summary, although there is independent evidence for decadal changes in TOA radiative fluxes over the last two decades, the evidence is equivocal. Changes in the planetary and tropical TOA radiative fluxes are consistent with independent global ocean heat-storage data, and are expected to be dominated by changes in cloud radiative forcing. To the extent that they are real, they may simply reflect natural low-frequency variability of the climate system.’ AR4 s3.4.4.1
e.g. http://s1114.photobucket.com/user/Chief_Hydrologist/media/Wong2006figure7.gif.html?sort=3&o=219
Hell – if two different instruments gave the same answer and It agreed with ocean heat content I’d assume – just for the sake of argument – that it was real and neglect land based cloud observations.
Combine it with a change in cloud cover seen in a third method in the 1998/2001 ‘climate shift’ and the eyebrows arch wryly.
‘ Earth’s global albedo, or reflectance, is a critical component of the global climate as this parameter, together with the solar constant, determines the amount of energy coming to Earth. Probably because of the lack of reliable data, traditionally the Earth’s albedo has been considered to be roughly constant, or studied theoretically as a feedback mechanism in response to a change in climate. Recently, however, several studies have shown large decadal variability in the Earth’s reflectance. Variations in terrestrial reflectance derive primarily from changes in cloud amount, thickness and location, all of which seem to have changed over decadal and longer scales.
A global and absolutely calibrated albedo can be determined by measuring the amount of sunlight reflected from the Earth and, in turn, back to the Earth from the dark portion of the face of the Moon (the `earthshine’ or `ashen light’).’
http://s1114.photobucket.com/user/Chief_Hydrologist/media/Earthshine-1.jpg.html?sort=3&o=138
‘Earthshine changes in albedo shown in blue, ISCCP-FD shown in black and CERES in red. A climatologically significant change before CERES followed by a long period of insignificant change.’ http://www.bbso.njit.edu/Research/EarthShine/
This is of course all data that is systematically marginalized.
It would suggest that we don’t really have much of a clue about the actual energy dynamic of the planet and Mann’s forcings that are a priori known are a bit of a nonsense.
But even then – it is undoubtedly wrong to assume that the only source of change in the global energy dynamic are greenhouse gases.
http://s1114.photobucket.com/user/Chief_Hydrologist/media/CERES-BAMS-2008-with-trend-lines1.gif.html?sort=3&o=208
“But even then – it is undoubtedly wrong to assume that the only source of change in the global energy dynamic are greenhouse gases.”
____
And since no climate scientist does assume this, then all is well.
No credible scientist should assume such – but that leaves you out in the cold Randall.
Most of the energy dynamic last decade was in SW – which is what the BAMS data shows. The so called missing energy. There is no longer any missing energy.
As I say – the oceans are warming meme both misunderstands what conclusions can reasonably be drawn from the data and is far too simplistic as to causality.
Skippy said:
“…the oceans are warming meme both misunderstands what conclusions can reasonably be drawn from the data and is far too simplistic as to causality.”
____
It is inconvenient for your own meme that it appears likely, based on all available data that the ocean are indeed accumulating energy, and have been doing so for many decades. Your own gross misinterpretation of the data is not unlike the half-truths that Tisdale brings here related to the ENSO cycle, where he mentions the IPWP, but seems to ignore the multi-decadal (no pause, no hiatus) gain in energy for this exceptionally important part the Earth’s climate system. There is not one bit of data that would call into question the basic notion as to whether the oceans are gaining energy, and quite robustly over the past decade, and there is not one expert on ocean heat content who would question that it is likely to highly likely the ocean are indeed gaining net energy. The real issue is one of how much and how deep. This is not unlike the issue of climate sensitivity, and is in fact, closely related. The conclusion across the board is that we need more data, both in extent and to greater depth (recent proposals are to send ARGO floats to at least 6000m) to begin to narrow the uncertainty in the how much and how deep questions.
Skippy said:
“Most of the energy dynamic last decade was in SW.”
____
This is just plain silly. The real story of the past decade is the rate of flow of sensible and latent heat out of the ocean (cool phase of the PDO has meant a reduced net flow). There has also been some reduction in net SW into the oceans from a sleepy sun and moderate increase in aerosols. So, as far as the oceans have been concerned…less energy in (your SW portion), but even less out (via sensible and latent heat flux), and thus, the net energy is set for accumulation, which is of course, exactly what we’ve seen.
The problem with fanatics of any stripe is that they are quite unable to review their assumptions in the light of evidence. Who knows – maybe they are just too thick to cope. What’s the old saying. Never posit groupthink when simple dumbness is usually the case?
If you are capable of reviewing the evidence objectively – the Lyman and Johnson 2013 and von Schuckmann and Le Traon 2011 discuss the problem of data handling – which relates to the problem of coverage. The Leuliette 2012 paper provides a steric sea level rise of 0.2mm+/-0.8mm.
The fact is that apart from the NODC – the data is looking particularly dodgy for the warminista narrative.
I covered this in detail – and merely covering the same ground over and over again is especially unsatisfying.
CERES data is much more satisfactory – errors are very tight – both Aqua and Terra agree – this is the data with trend lines.
http://s1114.photobucket.com/user/Chief_Hydrologist/media/CERES-BAMS-2008-with-trend-lines1.gif.html?sort=3&o=208
Reflected short wave declined last decade and IR was practically unchanged. There is a difference between looking at the data and understanding what it means and ignoring the data and telling yourself stories because you don’t have a freakin’ clue. It’s called science.
In a startling moment of clear self-reflection, Skippy intimates:
“The problem with fanatics of any stripe is that they are quite unable to review their assumptions in the light of evidence.”
Typical lack of self reflection there Randall – I keep showing data – you keep telling stories to yourself.
Despite Skippy’s insistence otherwise, here’s what the ocean heat content has likely been doing over the last half century:
http://www.epa.gov/climatechange/images/indicator_downloads/ocean-heat-download1-2013.png
This is probably a far better proxy for overall gain or loss of energy in the climate system, and also a better gauge for the sensitivity of the climate system to changes in GH forcing, which closely parallels this rise. Note: the 1960 to 1970 dip in ocean heat content was likely partially influenced by the eruption of Mt. Agung in 1963.
Rgates
Reference your graph. In this context at what depth is this ocean heat content being derived
Secondly how can you have a long term average when only 10 years of that period is average?
Thirdly, we had this conversation elsewhere on another thread and the data is uncertain, contradictory and according to the IPCC team we do not have the technology to monitor the heat properly and it is unlikely the trend is increasing.
tonyb
RGates
Hmm. It took 15 years for the ocean temperature to return to pre Mt Agung levels,. Don’t you think it highly unlikely this volcano had any meaningful effect either on ocean or land temperatures let alone be an explanation for this natural variability?
tonyb
Hi Tony,
Regarding Mt. Agung, you said:
“Don’t you think it highly unlikely this volcano had any meaningful effect either on ocean or land temperatures ”
——
No, I think it actually highly likely that this volcano had some impact on both ocean heat content as well as tropospheric temperatures. See:
http://blogs.edf.org/climate411/wp-content/files/2007/05/volcanoes_cooling.gif
And:
http://www.nature.com/nature/journal/v438/n7064/abs/nature04237.html
The location and size of Mt. Agung, right in the middle of the largest warm pool on the planet, makes it a good test case for volcanic effects on OHC. This eruption significantly reduced SW into that warm pool. And keep in mind that the 1257 eruption was in the same general region, but massively larger. It’s effects on OHC would have been commensurately larger.
Also, I think you overplay the uncertainty related to ocean heat content. Yes, the older data has a higher range of uncertainty, but the general decadal trends have a higher degree of certainty.
In fact, just a quick glance at ocean heat content data seems to show a clear reduction in OHC after both large volcanic eruptions and after a last ring El Niño. For volcanoes we get less energy into the ocean, for El Niño, a bit more out.
Reference your graph. In this context at what depth is this ocean heat content being derived
It should be labelled. Based on the csiro plot, it loos like 0-2000 meters.
Graph is 0-700m.
Again, a close correlation between 4 elements: OHC, GH Gas increases, Volcanic Activty, ENSO
1) OHC & GH gas increases (positively correleated)
2) OHC & Volcanic Activity (negatively correlated)
3) OHC & ENSO (especially large El Ninos, negatively correlated)
Tony,
A few things for you to consider.
First, here’s an article about the long-term effects of a large volcanic eruption on ocean heat content:
http://www.nature.com/nature/journal/v439/n7077/abs/439675a.html
Keep in mind the Krakatoa was considerably smaller than the 1257 event or the 1453 event. Keep in mind also that there were several events in the 1250 to 1300 AD time frame. That they would impact ocean heat content has a high probability. We can be pretty sure that Mt. Agung did in 1963, and this event was smaller than any of the three events previously mentioned.
Keep in mind the physics involved here. The ocean heat the troposphere, but the rate of flow of energy out of ocean to troposphere varies naturally from ENSO, but is dictated over the longer-term by GH gases. During a large volcanic eruption, the troposphere is impacted immediately by the lower SW, but because of the high thermal inertia of the oceans, they are impacted over a long period, as it takes a long while to make up for all that loss of SW heating. The cooler ocean will then impact the atmosphere over a longer-period with reduced outflow of latent and sensible heat.
I realize that you have convinced yourself that even large volcanic eruptions only impact the climate for a few years at the most, but I would encourage you to read the above article, and also google “Ocean heat content volcanoes” and see the many other research articles related to this.
What is not systematically marginalized is the ocean heat content data – but they inevitably refer only to one source.
The reality is much more complex. Lyman and Johnson discuss the influence of ‘climatologies’ on ocean heat analysis.
http://s1114.photobucket.com/user/Chief_Hydrologist/media/ERCOT-bauhighgascosts_zps9ff39dba.png.html?sort=3&o=78
http://www.pmel.noaa.gov/people/gjohnson/OHCA_1950_2011_final.pdf
Data handling and interannual variability likewise complicate interpretation of ARGO data.
e.g. http://s1114.photobucket.com/user/Chief_Hydrologist/media/vonSchuckannandLeTroan_zps45e82e5b.png.html?sort=3&o=17
But even then – it is undoubtedly wrong to assume that the only source of change in the global energy dynamic are greenhouse gases.
e.g. http://s1114.photobucket.com/user/Chief_Hydrologist/media/ERCOT-bauhighgascosts_zps9ff39dba.png.html?sort=3&o=78
SW and IR out decreasing and Net flux increasing is warming.
Damn – try to correct and mess it up again.
But even then – it is undoubtedly wrong to assume that the only source of change in the global energy dynamic are greenhouse gases.
http://s1114.photobucket.com/user/Chief_Hydrologist/media/CERES-BAMS-2008-with-trend-lines1.gif.html?sort=3&o=208
Leuliette 2012 -(http://www.star.nesdis.noaa.gov/sod/lsa/SeaLevelRise/documents/NOAA_NESDIS_Sea_Level_Rise_Budget_Report_2012.pdf – is showing a steric sea level rise of 0.2+/-0.8mm/yr. Implying that the data is a bit dodgy at best.
Zero trend is at least consistent with the full CERES record.
http://s1114.photobucket.com/user/Chief_Hydrologist/media/CERES_Net_zps9f7faaaa.png.html?sort=3&o=32
Perhaps I should say – a bit dodgy for drawing premature conclusions.
What happened to my nom de querre?
Typological diminuition – one of the lesser-known effects of global warming.
Generally, the ‘y’ diminuates. We have a particular exception.
===============
So, with all the conplaings about Mann’s paper, with GRL publish a rebuttal paper pointing out the errors?
Will one be written?
It strikes me that a rebuttal paper ought to be “original” and “add to the debate” and “innovative” if it knocks down ideas that were published BECAUSE they were considered to be original, adding the the debate and innovative.
Or is just claiming something the only original and useful part of scientific discourse? Perhaps proving – or disproving – is just the dull maneuvering of minor minds.
‘The essence of science is validation by observation. But it is not enough for scientific theories to fit only the observations that are already known. Theories should also fit additional observations that were not used in formulating the theories in the first place; that is, theories should have predictive power.’ http://www.project2061.org/publications/sfaa/online/chap1.htm
Rebuttal – schermuttal. The only thing that cuts any grass is scientific prediction.
‘The procedure attributes too large an amplitude to the AMO signal and a biased estimate of its phase. Wherein application of the flawed Detrended-AMO approach attributes some of the recent NH mean temperature rise to an AMO signal, the true AMO signal instead appears likely to have contributed to a relative cooling over the past decade, explaining some of the observed slowing of warming during that timeframe.’
I presume this means that the ‘slowing’ will continue? Shall we add Mann to FOMBS list of decadal deniers?
I suspect that the so-called AMO is not really an oscillation. Like the SOI, it is the mean affect of winds blowing over the ocean and sometimes causing peaks and dips in SST. Like the SOI it does not have a periodicity. So, in my opinion, it does not qualify as an oscillation. Yet the SOI has a well established affect on global climate and so may the AMO, but to a lesser degree.
All this talk of oscillation of SST tends to obscure the real effect of the on/off nature of climate change. It is clear that the absorption and emission of radiation in the IR depends on the vibration modes of the CO2 molecule. The 19th century of Arrhenius did not understand this, but the 20th century physics of Planck does. So discontinuous dynamic models are the way forward.
Alexander – Alexander – sigh.
I have no idea what you are talking about and I suspect you don’t either.
The physics of greenhouse gases is statistical. Let’s get back to that.
Overwhelmingly the carbon on the atmosphere is in the stable c12 form – but even then I am not sure that the number of neutrons determines the shape of the molecules – which is determined by sharing of electrons in an outer valence shell in a chemically stable form. The shape gives the resonance at particular frequencies and energies. When a photon strikes a CO2 molecule there are quantum vibrational transitions – an increase in kinetic temperature. This are communicated to adjacent molecules – which are primarily oxygen and nitrogen. Occasionally there is a quantum vibrational transitions to a lower energy state and a photon is emitted.
If there are more greenhouse gas molecules in the atmosphere any particular volume has a higher kinetic temperature – the increase is not additive but approximately logarithmic due to progressive closure of the IR window. The volume holds more energy at any time – statistically and all else being equal. Quantum vibrational transitions in a molecule do not result in quantum changes in the macroscopic – statistical – state.
Your ‘singularity’ is much more likely to result from changes in ocean and atmospheric circulation – including ENSO. I have no problem with the term oscillation applied to NSO – as long as it is understood that it is both aperiodic and non-stationary. Even the period changes – form 2 to 5 years pre 1900 to 2 to 7 years post – an intriguing question. The mean and variance changed around 1910, the mid 1940’s, 1976/1977 and 1998/2001.
What is the best way to model the AMO, if we do not detrend the SST temperature?
Are there a pair of station with long records that are at either side of the oscillating lineshape?
Can we look back at the periodocity using the deuterium record from a pair of ice cores on W/E Greenland?
Given that neither Mann’s paper, or Lewis rebuttal for that matter, make any reference to the seasonal evolution of Northern Hemisphere temperature anomalies during the past decade ( a point that even Tamino has picked up on), I’m afraid that both these pedantic pieces of waffle should be discarded.
Thanks.
http://xanonymousblog.files.wordpress.com/2014/05/seasonal.jpg
This is interesting, but I would like to see a plot of this back to 1930 before thinking about mechanisms. And since it focuses on NH, probably would need to look at HadCRUT4, Cowtan and Way, and Berekeley Earth data sets to understand uncertainty associated with assumptions made about the Arctic.
Dr. Curry – what is your take on the percent natural vs the 120 extra ppm of CO2 forcing? Do you think the AMO is all naturally driven?
It seems there could be room for the AMO to respond to extra CO2.
@jim2: It seems there could be room for the AMO to respond to extra CO2.
Evidence to the contrary can be found on slide 4 of my recent AGU Fall Meeting talk.
Interpreting HadCRUT4 as the (weighted) sum of LAND and SEA temperatures, the AMO corresponds to the three rises during 1860-1880, 1910-1940, and 1970-2000. For each of these three periods, when a trend line is fitted to the difference LAND − SEA surface temperature instead of the sum, the respective trends are (i) sharply down, (ii) barely down, and (iii) sharply up.
(At least) two conclusions may be drawn from this.
1. Contrary to what many claim, the three rises are of a qualitatively different character.
2. The first two rises in HadCRUT4 cannot be (primarily) caused by CO2 because such heating would be driven down into the ocean. This is contradicted by the first two declines in LAND − SEA, which slope downwards when CO2 heating would have driven them upwards. That the second decline is flatter suggests that CO2 is already having some impact even as early as 1910-1940.
Now that the 1994 paper of Schlesinger and Ramankutty describing the AMO (albeit not under that name) is getting serious attention in the climate blogs 20 years later, hopefully my wacky suggestion to fit trend lines to LAND − SEA will get some attention by 2034. My Mum lived to 91.5, this will motivate me to make it to 90 to see how the idea panned out. ;)
X Anonymous | May 19, 2014 at 8:33 pm | wrote: “( a point that even Tamino has picked up on)”
Would you be willing to point us to whatever Tamino has said about Mann/AMO?
OHT dropped during the last decade. OHC in the N Atlantic started dropping in 2007. It looks like winter temperatures are reacting to less heat being stored as a buffer.
I have to give Michael Mann kudos for supplying code and data.
That being said, it’s difficult to believe he used climate models that run too hot to determine another version of the AMO and also use the entire Northern Hemisphere as the data set for the (NON) Atlantic Multidecadal Oscillation. Just using the NH justifies him calling it something else. Using climate models definitely calls for some name other than AMO.
Just curious, when is the last time MM did not supply code and data?
It seems to me that it would be difficult to explain why the OHC of the N Atlantic was rising so much faster than the global average without invoking the increase in ocean heat transport that would be indicative of a positive AMO. I don’t see how observations could support an AMO on the decline before ~ 2007.
The AMO appears to be a mathematical definition. AFAICT, there is no physical motivation for it. For example, the variation in sunspot numbers has an underlying mechanism. I don’t know that the AMO has such a basis.
Jim, it seems impractical to me that changes in SSTs would come about without changing poleward heat transport. I think it is widely accepted that the AMO is a function of heat transport but I could be wrong. I do know that the mechanism is widely debated.
R. Gates | May 19, 2014 at 7:53 pm |
“Can’t wait to hear yours, Hansen’s and other true believers’ sputtering excuses when Super El Nino fails to materialize again and instead an El Nino Modiki materializes and quickly fades away by next Spring.”
Gates, even you must admit that most true believers like FOMD, not necessarily you personally, have been hoping for a “Super El Nino” which would spike the global temperatures and end the hiatus in warming. That was the point of my post. You are arguing with me when I was agreeing with you! Sheesh!
Yes, I would agree that a certain group of “warmists” are hoping for an El Nino spike to tropospheric temperatures to end the hiatus, though I am not one of those, as I really am not concerned with short-term proxies for energy in the climate system. It is s red-herring that serves only the side that happened to be benefiting from the ENSO/PDO cycle of the time. Under the very best of circumstances you can use decadal average tropospheric temperatures as a reasonable proxy for net gains/losses of energy in the system.
Since the ocean surface temp is the dog that wags the atmospheric tail, seems the atmospheric temp would be a good proxy. And luckily, we have some actual measurements there.
It’s more a case of “I told you so”
Statistically speaking there is no hiatus in warming. Skeptics have been relying on noisy data to claim global warming has paused, without any statistical support for that claim.
Yup, those nasty skeptics just look at the global mean temp.
Or, LOLWOT, do you refer to the millisecond-scale noise?
“Since the ocean surface temp is the dog that wags the atmospheric tail, seems the atmospheric temp would be a good proxy”
____
Thank you for using my metaphor of the ocean dog and atmospheric tail, but it is precisely because the tropospheric temperatures are dragged along with the ocean eventually that they make a poor proxy over the short-term (less than decadal average). Just a tail is wagging side to side, even if the dog moving forward, or backward, or even standing still, so too with tropospheric temperatures. If you really want to find out where the dog is going, best to follow the dog directly and ignore the tail. ARGO is our best current way to follow the ocean dog, with lot of confirmatory data from other proxies that closely follow ocean temperature over various time frames.
This combination of the synchronization of these dynamical modes in the climate, followed immediately afterward by significant increase in the fraction of strong trends (coupling) without exception marked shifts in the 20th century climate state. These shifts were accompanied by breaks in the global mean temperature trend with respect to time, presumably associated with either discontinuities in the global radiative budget due to the global reorganization of clouds and water vapor or dramatic changes in the uptake of heat by the deep ocean. https://pantherfile.uwm.edu/kswanson/www/publications/2008GL037022_all.pdf
In the second case there is alternate uptake and release of energy from the oceans that result in a residual surface warming of 0.05 degrees C/decade.
No particular problem but the oceans continue to warm.
I would opt for the first from satellite and Earthshine data.
On the one hand we continue to warm modestly on average after the 20 to 40 year hiatus – assuming no surprises. That makes me smile – surprise as the NAS who’s who of climate science says is inevitable. On the other hand surprise is all there is.
This apparently mainstream climate science apparently makes me a sceptic in the eyes of the Borg collective cult of AGW groupthink space cadets – who are busily debating dogs and tails. C’est la vie.
Skippy,
If you’d rather use your beloved Earthshine data, have at it. I’d rather put more ARGO floats in the ocean at greater depths and measure ocean heat content directly. I’ll hold that direct measurement up against your beloved Earthshine proxy data any day. If the ocean is the dog and the troposphere is the tail, then Earthshine would be the reflected light off the fleas on the tail of the dog.
Opting for real science and data – Randall. Earthshine is just one more data source. If it was inconsistent with satellite data – it would have shown up in the graph.
Just as Leuliette 2012 lack of ocean warming is consistent with CERES Aqua and Terra.
@Chuck L: most true believers like FOMD, not necessarily you personally, have been hoping for a “Super El Nino” which would spike the global temperatures and end the hiatus in warming.
While you guys have been trading insults the Super El Nino has come and gone!
According to Wikipedia, El Nino “happens at irregular intervals of two to seven years, and lasts nine months to two years. The average period length is five years. When this warming occurs for only seven to nine months, it is classified as El Niño “conditions”; when it occurs for more than that period, it is classified as El Niño “episodes”.”
The last 30 months of HadCRUT4 witnessed a rate of rise of 4.54 °C/century. If it goes down over the next 30 months it will have been an average five-year period. If it continues to rise it will have been longer than average.
Vaughan old buddy – I got no idea what you are talking about and I suspect you don’t either. Hitting the bottle a bit hard mate?
You do know it refers to sea surface temperature? And Wikipedia isn’t really helping. Perhaps Claus Wolter’s MEI is a better option.
http://www.esrl.noaa.gov/psd/enso/mei/ts.gif
Is anyone really expecting a ‘super El Nino’. Models certainly aren’t showing it.
http://www.bom.gov.au/climate/enso/#tabs=Outlooks
Gee I wonder what they base it on? Entrails? Tarot cards? I Ching?
I have a layman question from reading this N.Y. Times article from today’s edition: http://www.nytimes.com/2014/05/20/upshot/how-el-nino-might-alter-the-political-climate.html?src=twrhp&_r=0
Question: What will be the science response of AGW Skeptics if the spike in temperatures from an El Nino is statistically much greater than what occurred in 1997-98? (or any other previous El Nino’s).
What I have been hoping for is a purely ENSO neutral year that is the warmest year in the instrumental record. That would be a ball disrupting blow.
Steve, I’d be more interested in what the temperature does after the el Nino than the size (e.g. how much it goes back down after, giving us an upper bound on the GATS for GHG forcing).
But I doubt it will be larger than 98. I think RG’s belief in global CO2 forcing the IPWP heat content up is plain silly. I doubt it’s more than 98 and I don’t think the climate will respond to a large el Nino the same as it did during warm PDO phase.
I may be subjective here & if so…shame on me. But it sure seems to me that Mann has sought out a way to cleverly dismiss a big obstacle in the way of his views…that being any climate changes potentially tied to natural variation…ocean oscillation cycles being the larger domino. Let’s just be honest here & address the big elephant in the room; that’s what this is about. Climate model simulations are aiding him…but why not just stick to the raw data here? There’s just too much rewriting of climate history with this “Mann” for me to take his research seriously.
1. Proxies going the wrong way get truncated.
2. The MWP gets whacked.
3. The AMO heats up.
@Spencer: Climate model simulations are aiding him…but why not just stick to the raw data here?
Hear, hear. My position exactly.
My interpretation of the data is that it is exactly as understood by the majority. The minority need to misrepresent the data in order to support their arguments.
The light, which has been on generally, penetrates particularly. Open up a few more windows, Vaughn.
==========
The premise of the AMO seems to be that just by subtracting the linear trend since 1850 (0.05 C per decade) all you are left with is the natural internal variation of the Atlantic. This seems to be a very easy premise to attack (as Mann does). For one thing the forcing change in this period is far from linear. Just from CO2, it has risen from almost no trend in 1850 to 0.15 C per decade now. Other variability due to the sun and aerosols are also seen in decadal trends. How can it be even a premise that the AMO contains no forcing just by using linear detrending. Furthermore, the AMO is almost exactly the same in amplitude and phase as the NH detrended pattern, so it is not even a unique regional signal, and this makes it even more likely to be mostly global forcing. I think Mann is right.
http://www.woodfortrees.org/plot/hadcrut4nh/mean:80/mean:40/from:1850/detrend:0.8/offset:0.5/plot/esrl-amo/mean:80/mean:40
A linear-forcing assumption will overestimate the non-forcing trend by 0.1 C per decade in recent decades, so a downturn has to be added at the end of the AMO plot to correct for the real recent forcing.
I think most will decide based on what they want to see.
I am with jimmy dee, on this one. Mikey discovered the AMO way back when, so he should know. The NOAA et al got the wrong message somehow and settled on the belief that the AMO had been in a warm phase, since the mid 1990s. Mikey mischievously let them labor under that misconception for quite some time, but now he has decided to let it be known that the AMO was actually in a cool phase. (Shhh, we suspect that the pause made him do it.) Anyway, it’s all straightened out now and the science is settled…again. Mikey’s studious avoidance of avoiding confirmation bias and his ad hoc statistical methods that are designed to turn up useful artifacts continue to serve our wannabe Laureate well.
Jim D,
I agree that the premise is easy to attack, but not as Mann does. Detrending the North Atlantic SST and calling it AMO makes no sense. The secular trend is part of the quasi-periodic oscillation. Why stop at multidecadal? It’s logically and physically incoherent. Furthermore, the so-called AMO is almost exactly the same in amplitude and phase, not only as the NH detrended pattern, but also as the SH detrended pattern!
http://www.woodfortrees.org/plot/esrl-amo/plot/hadcrut4sh/detrend:0.74/plot/hadcrut4sh/detrend:0.74/trend
Why stop at regional or hemispheric when it’s clearly global? The pattern known as AMO is not only North Atlantic SST and it’s not only multidecadal. It should be called Global Climatic Oscillation (GCO).
The Global Climatic Oscillation (GCO) is an ongoing series fluctuations in the mean sea surface temperature of the EARTH. ALL of the global warming since the mid 1970s might be due to the strengthening GCO rather than to the increase in greenhouse gases. I think it is indeed all, but am open to any contradictory evidence and I haven’t seen any so far, except GHGs/CO2 and anthropogenic hand-waving.
I mean counter-evidence.
You’d have to believe the greenhouse effect doesn’t exist to claim there’s no counter-evidence.
I sure wish your community (and I mean both sides) would refer to the estimated forcing rather than the estimated temperature change at the surface.
The debate centers around energy imbalance, the nature of feedbacks which arise as conditions change due to the energy imbalance, and the methods used to chew up the data to put it in a presentable form.
I just saw something written by somebody arguing for an increased focus on energy rather than temperature, and as long as the buoy data is coming and the satellites aren´t accurate enough, then point forward the ocean´s energy content seems to be the key.
Do I see this right?
lolwot, clearly not. The increment in atmospheric CO2 could be to small to have any significant/measurable effect or the atmospheric GHE could be not properly understood…
I stick to the null hypotheses – no CO2 and no anthropogenic effects globally.
You’ve moved the goalposts again as a true dilettante, Jimmy old bean
You’ve completely ignored this:
“However, the thick blue line in Figure 8b, plotted by Mann’s code but missing from his published figure, shows the AMO signal as estimated by Mann’s detrended-AMO procedure applied to the noise-free EBM simulation, gives the lie to this claim”
Got it ? The jury is still out
Edim, to hold your view you have to object to any detrending at all, and just call the whole thing an “oscillation” otherwise you have to explain the trend as something other than an oscillation. Of course, this misses my point that detrending doesn’t remove all the forcing even to a good approximation, so the assumption made by Lewis that this simplistic definition of an AMO is all an unforced natural variation is plain wrong, and Mann goes as far as saying that almost none of it has to be natural when you look at real forcing changes within the limits of estimates.
Jim D, I have two points.
1) the mode of variability known as AMO is clearly global and not only North Atlantic (see the WFT link – AMO compared with the Southern Hemisphere surface temperature).
2) Obviously the quasi-periodicity of ‘AMO’ is widely acknowledged at multi-decadal timescales. I think it’s very likely that there are longer (than ~60 years) quasi-cycles as well.
“Had I been a reviewer, I would have pointed this out and recommended rejection.”
You’d have suppressed a result inconvenient to your fossil fuel cause?
Mann seems to churn out papers in which he atempts to reinforce his point of view using climate models. I have some experience running 3D dynamic models (in a very different field), and when I supervised youngsters trying to perform matches to existing data I used to check the model input, asumptions, and outputs using diagnostic maps, sections and graphs.
Sometimes I had them extract maps and sections which graphed parameters most of us ignored, and sometimes I found these diagnostics allowed us to see where the modeler(s) had tricked the model using subtle methods.
For example, one way to trick a model would be to use a simple layer scheme and then “block” mass and heat transfer between layers using goofy parameterizations. Such a scheme allows the layers exposed to energy inputs (what you guys call the external forcing) to warm up because they can´t release heat at the proper rate to the layers further away from the emergy source (this of course yields a weird set of transient/equilibrium conditions).
If a modeler (or a team) is given a free hand and sufficient time to trick the model, it takes a lot of digging to find the skeletons. And once we find the skeletons we have to ponder how do we punish the tricksters when it´s so common so trick a model anyway? Where do we draw the boundaries?
Modellers in cloud towers, fan,
tend ter ferget
their models jest ain’t
the reality.
Silk shirted coteries in
whispery corridors of power
do not concern themselves with
the uncertainties.
Cloud towers join the corridors of power.
The IPCC is gonna make the global
proletariat sit up, take notice and …
obey.
Beth-the-asto-turfing-serf.
Hello there … heh, I’m a climate modeller. This is jest ter say
that, well yeah, nothing I have hind-cast, fore-cast, extra –
polated or pro-jected in the last twenty-five years has come
true.
And, yeah, I’ve published nothing but what has been pal-
reviewed by me consensus friends, all of whom are sharing
me guvuhmint grants and research money.
Okay, so I admit I want ter take yr money and ruin yer fuchure
by raising energy costs and starving innocents, but – do – not
– listen – ter – others – who – maybe – are – more – skilled – and
-grounded – than – meself, because, hey, I’m a climate modeller.
Your sustained fact-free willfully ignorant anti-scientific abusive astro-turfing efforts are appreciated. beththeserf!
Such astro-turfing is well-grounded in ideology-first politics, needless to say!
Your longstanding commitment to sustaining willful anti-scientific ignorance in core voting segments is appreciated, beththeserf!
Fifteen seconds into the first round, Fan takes a fall.
========
Denialist braggadocio, scientific knockout!
They haven’t even sold their souls to big oil, they’ve given it away for free.
Mann, and many others, always seem to be oblivious to the implications of their work. His new hypothesis refutes his old work, since it means natural variability is far higher than he has concluded in the past. This also has implications such as “warming faster than…” and “warmer than the past…” If variation is as high as this hypothesis (or the stadium wave as well), these things can’t be true.
And that the feedbacks that would move warming to a rate that isn’t beneficial to us don’t exist.
Geophysical Research Letters did unspeakable damage to the warmist cause by publishing a paper with such flaws, therefore its Editor in Chief, Eric Calais should be fired as usual.
What’s in a name Beth or Bweth?
Nic, I saw it on WUWT and put in a short comment that is below:
“As far as I can see there is no satisfactory physical explanation for AMO. Futhermore, all graphical presetations of it that I have seen are a huge srtretch. It is time to stop imagining that it is an oscillation and realize that we are dealing with SST changes whose causes are unknown and periodicity non-existent. In contrast to that, ENSO does have a physical explanation and is traceable in all historic temperature records.”
Let me add that I wish people would not take the plethora of ill-defined long-period “oscillations” seriously and start critically analyzing them instead of taking them as givens and elaborating more nonsense about them.
Let me add that I am not for taking the plethora of ill-defined long-period “
Arno,
Maybe, but there does seem to be evidence linking the AMO to fluctuations in the AMOC, and for it having occurred over an extended historical period. I agree that a proper physical explanation/mechanism is required. I commend the Dima & Lohmann (2007) paper (link just above my Conclusions section) to you.
Looks like a lot of warmistas are praying for “the second coming of El Nino” to save the CAGW story as specifically outlined by IPCC.
A bit ironic.
Somewhere above, someone said let the paper rise or fall on its merits. Normally such a rise and fall would come from comments to the journal both providing additional evidence or debunking the claims. Such notes (see AMS policy) are reviewed. That is good but cumbersome and takes a while. The GRL policy is no comments on its papers. Once published a GRL paper is one Moses would be proud of. And who can argue with his 10 commandments. I have complained of this often and haven’t given up hope yet.
I have also advocated that the reviews and editors comments on a paper, especially a failed paper, be put on an sponsored internet site but that has not received accolades either.
When I think back to some of the unfortunate editorial issues that came during the email exposure (legal or not, still exposed) that editors do not want the treatment that some received for letting contra papers through. I don’t blame these guys too much as they have a real day job and dodging missiles is very distractiing. So choose the easier way. I think the problem is with the societies. It must be made clear that papers should be judged on their merits and that the societies have the back of the editors.
Now I haven’t read the Mann paper and will do. But as I brought up a religious example above, how can one argue with someone who has initials JC! I guess on one’s peril in the afterlife. Clearly to do so would give you a bad mark in St. Peter’s conduct book! Sorry my attempt at humor!
PW
Peter Webster wrote:
‘The GRL policy is no comments on its papers. Once published a GRL paper is one Moses would be proud of… I have complained of this often and haven’t given up hope yet.’
Many thanks for trying. If you can’t get it changed, there’s not much hope!
For another example of a poor paper recently accepted by GRL, and now being altered at the galley proof stage to finesse (unsatisfactorily IMO) blog criticism, see:
http://troyca.wordpress.com/2014/05/09/on-forcing-enhancement-efficacy-and-kummer-and-dessler-2014/
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