A recent paper suggested that ‘climate sensitivity’ derived from a new paleo-CO2 record is around 7.2ºC (for equilibrium climate sensitivity ECS) and ~13.9ºC (Earth System Sensitivity – ESS) for a doubling of CO2. Some press has suggested that this means that “Earth’s Temperature Could Increase by 25 Degrees” (F). Huge if true! Fortunately these numbers should not be taken at face value, but we need to dig into the subtleties to see why.
The paper in question is Witkowski et al. (2024), which was published in Nature Communications. The meat of the paper is a reconstruction of paleo-CO2 from relatively new proxies – sterane and phytane δ13C ratios – derived from phytoplankton living in the ocean photic zone in the coastal ocean off of California.
The geochemistry here is quite involved, and I’m not qualified to assess how well this has been done, but it’s sufficient to take this as perfectly valid for the points I’ll make here. There are often somewhat heroic assumptions made in deriving paleo atmospheric CO2 from molecular markers, but the overall results (see left hand figure) – that CO2 went from 650 ppm 15 Million years ago (Ma) to 280 ppm in the most recent data point (close to the long term pre-industrial average), is not dramatically different from other recent compilations (such as CenCO2PIP (2023)) (right hand figure). The novelty here is (I think) that this change is calculated in a single core over the whole 15 Ma interval (albeit at a roughly 500,000 yr sampling interval).
The peak value roughly 15 Ma ago, corresponds the climate period sometimes referred to as the Miocene Climate Optimum (MCO), possibly the warmest period in the last 20 million years, with very little remaining glacial ice, and roughly 8ºC above the pre-industrial in the global mean surface temperature (Ring et al, 2022).
Astute readers will perhaps have already have done a quick back of the envelope calculation, given that the radiative forcing from 280 ppm to 650 ppm is around 4.7 W/m2 (using the Etminan et al. (2016) formula and assuming an average N2O value of 272 ppb – roughly 25% larger than the value for 2xCO2, 3.8 W/m2), to get a naive ‘Earth System Sensitivity’ of 8/4.7*3.8 = 6.5ºC for a doubling of CO2. This is quite a bit less than the Witkowski et al conclusion. So what is going on?
Sensitivity, Schmensitivity
First off, we need to be crystal clear about what our definition of climate sensitivity is: It is the change of global mean temperatures expected after a doubling of CO2. However, we frequently assume that some things remain constant. For instance, the standard ‘Charney Sensitivity’ or Equilibrium Climate Sensitivity (ECS) assumes that ice sheets don’t change. The broader concept of Earth System Sensitivity (ESS) allows for responses in the ice sheets, vegetation etc. Responses in atmospheric composition (dust, ozone, aerosols etc.) are sometimes included (or not!). Indeed, one can define a whole series of climate sensitivities depending on what feedbacks are included and over what time-scale:
So what are we dealing with here? Clearly, over the last 15 Ma, there have been big changes in the ice sheets, sea level (and presumably vegetation, and atmospheric composition), and some changes in solar irradiance as well as variations in continental configurations, so we should factor these things in to get to an ECS that is commensurate with what we talk about in the modern period. The authors make some attempt to do that by assuming a forcing of roughly 2 W/m2 (=66 m * 0.0308 W/m3) associated with change of ice sheets from PI to MCO. That would reduce the implied sensitivity to CO2, to 8/(4.7+2)*3.8 = 4.5ºC. However, they don’t calculate the influence of the other factors – such as the Rocky mountain range and the Andes in the Americas being lower elevation, changing circulation patterns and temperatures independent of CO2 (paleogeography effects), and the solar irradiance changes.
In work that we did a while ago on the Pliocene (3 Ma) Lunt et al, 2012, we calculated the paleogeography effect was worth 0.7ºC, and one might expect it to be greater for the earlier Miocene period (maybe 1ºC?). The solar irradiance has increased about 4.4% over the Phanerozoic (540 Ma), and so over 15Ma, that’s about 1.6 W/m2 in TSI, and thus about 1.6*0.7/4 = 0.3 W/m2 in solar forcing. Combining these effects with the prior calculation, you get (8-1)/(4.7+2-0.3)*3.8 = 4.2ºC – well within the scope of other ECS estimates. Note that here we are implicitly assuming that any vegetation or composition changes (including CH4, N2O, ozone and aerosols) are only changing because of changes in temperature and are thus feedbacks, not independent forcings – that’s different from how these are treated in historically-based estimates (where they have changed directly due to human activities). We could instead try to scale the N2O and CH4 changes (including indirect effects) based on glacial to interglacial transitions, and that would imply an ~25% increase in the forcing. So then we’d end up with (8-1)/(4.7*1.25+2-0.3)*3.8 = 3.5ºC for a sensitivity not including those feedbacks. Again, not too different from what one would expect.
Similarly, we could estimate the ESS (by not including the ice sheet term, and assuming that all composition change was a feedback too) as 7/(4.7-0.3)*3.8=6.0ºC, again, not so far off existing estimates. Of course, there are significant uncertainties in all of this that need to be taken into account, so the constraints are not as tight as one might like (and I haven’t mentioned the possibility that ESS/ECS might be varying as a function of the base state…).
But…
I’ve shown that neither the existing temperature reconstructions nor the new CO2 reconstructions for the Miocene obviously suggest some massive climate sensitivity, so where do the Witkowski authors get their numbers from? They do two things that are somewhat non-standard. First, they separate out different latitudinal bands (SH and NH mid-latitudes, tropics, and the NH high latitudes – and from Table 1, it’s clear that they assume the (unsampled) SH high latitudes are changing the same as the NH high latitudes). This isn’t such an obvious assumption. Second, they calculate the sensitivities by regressing the regional temperature reconstructions with radiative forcing calculated from the CO2 changes, and then estimate the global sensitivity using a weighted mean of the regional regressions.
The authors used a (slightly non-standard) linear regression method between CO2 forcing and T that takes into account varying uncertainties in both the sets of values (unlike ordinary least squares). The specific algorithm they use is ‘fitexy‘ which comes from Numerical Recipes (1992). It was not immediately obvious (to me, a non-statistician) what this is based on, but I think it’s related to a special case of what is now called York regression (with uncorrelated uncertainties). There are two consequences of this choice; first, it’s important to have reasonable estimates for the uncertainties (which can be hard), and second, it’s not linear i.e. the regression for the global mean, doesn’t equal the global mean of the regional regressions (I’ll demonstrate that below). Finally, and this will be important, the uncertainties on the regression can be quite large.
Adventures in replication
We’ve often discussed the ease and utility of replication, and this paper is a good example of why it’s important. In order to to see why the chosen procedure gives the numbers it does, we need to work through the calculations, and perhaps test some of the assumptions. Unfortunately, the sensitivity calculations were not part of the supplementary material (IMO they should have been) but two coauthors of the paper were helpful and sent me a spreadsheet of these results and clarified a few details.
The first thing to look at is the radiative forcing for the CO2. The authors used the formula (their Eqn. 3), which is taken from Etminan et al. (2016). [Note that the equation as published in this paper has two typos in the coefficients: a1 and c1 should be negative not positive]. Secondly, there is a small dependency in this formula on the average N2O concentration over the period, which is unknown, and the authors don’t mention what they used. Through a bit of trial and error, I found that I could match their calculation assuming N0=272 ppb and C0 = 278 ppm (reasonable pre-industrial levels), so the radiative forcing for 2xCO2 is 3.8 W/m2, and the forcing at 650 ppm is 4.7 W/m2. The uncertainties in the CO2 are given as almost constant % differences for the one sigma lower (33%) and upper bounds (28.5%) and are thus quite large.
Temperatures
The temperatures being used are from Herbert et al (2016) who produced stacked estimates of changes from the Miocene to present for the different regions mentioned above (all available in their supplementary material). These temperatures don’t appear to be inconsistent with the global estimates mentioned above, but are usefully segregated by broad latitude bands, and come with an uncertainty based on the standard deviation of the estimates of the temperatures that go into each stacked average. I found a couple of errors in this spreadsheet, but was able to interpolate these stacked values and their uncertainty to get something close to what the Witkowski et al authors used. Note that the tropical data is perhaps not accurate before ~8 Ma, so the authors only use the tropical regression over 0-8Ma, while the other regions use most of the last 15 Ma.
Drum roll please…
With just a few lines of R script I was then able to use the york function using the given CO2 and it’s uncertainties, and the temperatures and their standard deviation as given by Herbert et al. I’m not sure this is correct – surely it should be the standard error on the stacked temperatures that should be used? but this turns out to be basically irrelevant because the dominant uncertainty is in the CO2. [Replicating this also revealed that in Figure 3 two lines are mislabeled (the NH mid-latitudes is actually green, and the SH mid latitudes is cyan), and that Figure S5 (panel c) is plotting the wrong regression.]
For the first calculation, simply correlating the regional temperatures to CO2 and then area-averaging the regressions to calculate a naive global ‘ESS’, I get similar values to Witkowski et al., roughly 3.8 K/(W/m2), which once you convert by multiplying by 3.8 W/m2, is roughly 14.6ºC for a doubling of CO2 (Note Witkowski et al use 3.7W/m2, which is inconsistent with what they use for the forcing in the regression). However, the uncertainty on this number is huge: ±15.3ºC (95% CI)!! Using the land-ice correction as the authors did, I get the ‘ECS’ as 7.2±3.1ºC (95% CI) – again a very high (though proportionately slightly smaller) uncertainty. Basically the fits for the regressions are not very good, though it’s a little better for the land-ice-corrected calculation.
I mentioned above that York regression is not a linear operator: if I take the global mean of the regional regressions, it does not equal the regression of the global mean. I can show this doing the regressions on just the 0-8Ma segments where I can calculate a global mean temperature (and with suitably weighted uncertainties) and compare that to a global mean of the regional regressions. Note that in all of these estimates there is an assumption that the SH high latitudes are changing just like the NH high latitudes. I get that for the global ECS regression, a sensitivity of 7.1±4.2 ºC, while for the global mean of the regional regressions, I get 6.6±7.0 ºC – similar, but not the same. Both these estimates use the same raw data and it’s uncertainties, and so this raises questions about what the right method to use is if the goal is constrain the global mean sensitivity.
Nonetheless, the global temperatures allow us to see quite easily why the uncertainties in the regression coefficients are so large. As in the paper, I plot the global mean temperatures (including their one-sigma standard deviation) against the estimated CO2 level and its uncertainty. As in the paper too, I don’t use the data earlier than 8Ma (black open circles) because of the reported problems with the tropical temperature proxy. I plot both the York regression and what you’d get with OLS for reference.
In both cases the errors in the CO2 estimates dominate the uncertainty (making the issue of what sigma to use for the temperatures moot). Indeed, the errors are so broad that the results don’t even preclude a negative ESS!
As I mentioned above, more sophisticated estimates of both the ESS and ECS could be made using corrections for paleogeography change and the solar irradiance increase, and that would likely reduce the values, but the bottom line from this replication is that the uncertainties in this methodology with this data, are just too large to be useful constraints.
Interestingly, the peer review for the paper is online here, and (perhaps unsurprisingly) the reviewers didn’t discuss whether these calculations would be easily replicable nor what the uncertainties in the sensitivity were. Given the dramatic results, I think this was a bit of an oversight.
What it means
Papers like this – which have good new primary data and somewhat overconfident implications – are relatively common. Digging into why seemingly dramatic results are so overconfident often needs a deep dive into the calculations, and this should be something that could be checked in peer review. However, this is probably too much to ask reviewers to check as a matter of course (since it takes far more time and could just further decrease the acceptance rate for review requests), but maybe editors could commission special replicators to check this stuff specifically (and maybe even pay them for the service!).
Bottom line: this paper usefully adds to the database for paleo-CO2 value, but on its own does not further constrain actual global ESS and ECS estimates, breathless headlines notwithstanding!
References
- C.R. Witkowski, A.S. von der Heydt, P.J. Valdes, M.T.J. van der Meer, S. Schouten, and J.S. Sinninghe Damsté, "Continuous sterane and phytane δ13C record reveals a substantial pCO2 decline since the mid-Miocene", Nature Communications, vol. 15, 2024. http://dx.doi.org/10.1038/s41467-024-47676-9
- . , B. Hönisch, D.L. Royer, D.O. Breecker, P.J. Polissar, G.J. Bowen, M.J. Henehan, Y. Cui, M. Steinthorsdottir, J.C. McElwain, M.J. Kohn, A. Pearson, S.R. Phelps, K.T. Uno, A. Ridgwell, E. Anagnostou, J. Austermann, M.P.S. Badger, R.S. Barclay, P.K. Bijl, T.B. Chalk, C.R. Scotese, E. de la Vega, R.M. DeConto, K.A. Dyez, V. Ferrini, P.J. Franks, C.F. Giulivi, M. Gutjahr, D.T. Harper, L.L. Haynes, M. Huber, K.E. Snell, B.A. Keisling, W. Konrad, T.K. Lowenstein, A. Malinverno, M. Guillermic, L.M. Mejía, J.N. Milligan, J.J. Morton, L. Nordt, R. Whiteford, A. Roth-Nebelsick, J.K.C. Rugenstein, M.F. Schaller, N.D. Sheldon, S. Sosdian, E.B. Wilkes, C.R. Witkowski, Y.G. Zhang, L. Anderson, D.J. Beerling, C. Bolton, T.E. Cerling, J.M. Cotton, J. Da, D.D. Ekart, G.L. Foster, D.R. Greenwood, E.G. Hyland, E.A. Jagniecki, J.P. Jasper, J.B. Kowalczyk, L. Kunzmann, W.M. Kürschner, C.E. Lawrence, C.H. Lear, M.A. Martínez-Botí, D.P. Maxbauer, P. Montagna, B.D.A. Naafs, J.W.B. Rae, M. Raitzsch, G.J. Retallack, S.J. Ring, O. Seki, J. Sepúlveda, A. Sinha, T.F. Tesfamichael, A. Tripati, J. van der Burgh, J. Yu, J.C. Zachos, and L. Zhang, "Toward a Cenozoic history of atmospheric CO 2", Science, vol. 382, 2023. http://dx.doi.org/10.1126/science.adi5177
- S.J. Ring, S.G. Mutz, and T.A. Ehlers, "Cenozoic Proxy Constraints on Earth System Sensitivity to Greenhouse Gases", Paleoceanography and Paleoclimatology, vol. 37, 2022. http://dx.doi.org/10.1029/2021PA004364
- M. Etminan, G. Myhre, E.J. Highwood, and K.P. Shine, "Radiative forcing of carbon dioxide, methane, and nitrous oxide: A significant revision of the methane radiative forcing", Geophysical Research Letters, vol. 43, 2016. http://dx.doi.org/10.1002/2016GL071930
- D.J. Lunt, A.M. Haywood, G.A. Schmidt, U. Salzmann, P.J. Valdes, H.J. Dowsett, and C.A. Loptson, "On the causes of mid-Pliocene warmth and polar amplification", Earth and Planetary Science Letters, vol. 321-322, pp. 128-138, 2012. http://dx.doi.org/10.1016/j.epsl.2011.12.042
- T.D. Herbert, K.T. Lawrence, A. Tzanova, L.C. Peterson, R. Caballero-Gill, and C.S. Kelly, "Late Miocene global cooling and the rise of modern ecosystems", Nature Geoscience, vol. 9, pp. 843-847, 2016. http://dx.doi.org/10.1038/ngeo2813
Good timing, Gavin, given that in the Unforced Variations thread we have a raging discussion on whether one could extrapolate past rates of SLR rise to the near future – despite the different conditions and mechanisms in the past (coming off the glaciations) vs. those in the future, where we already at the top, or moving past the historical peaks of deglaciation.
Gavin: on its own does not further constrain actual global ESS and ECS estimates, breathless headlines notwithstanding!
That would be …. secondary headlines, right? The actual title in Science is rather … underwhelming:
“ Continuous sterane and phytane δ13C record reveals a substantial pCO2 decline since the mid-Miocene” Maybe realizing the limitation of their study to the ESS and ECS they didn’t want to push it into the headline? ;-)
Gavin:” they don’t calculate the influence of the other factors – such as the Rocky mountain range and the Andes in the Americas being lower elevation, changing circulation patterns and temperatures independent of CO2 (paleogeography effects), and the solar irradiance changes.”
By “circulation” patterns you mean “oceanic circulations”. This may be problematic – as I recall, the onset of the current glaciation in Pleistocene has been often linked to the changes in the circulation – closing the Panama isthmus led to an increase in Salinity in N Atlantic – which in turn may have started AMOC in its current configuration (sinking of the cold water near Greenland) – which resulted in the massive increase in deep water production, explaining the pronounced cooling of the deep ocean, and the drop of atm. CO2 to the very low glaciation levels.
The other question mark for me is their use of phytoplankton C-13 as proxy for CO2. CO2 in the biologically productive waters of the ocean are much more temporarily variable than the well mixed atm. above it – upwelling increase pCO2 in seawater above the atm. values, phytoplankton bloom reduces below it. Most of the sediments are formed by algae from the periods of bloom, i.e. from the periods where the surrounding water may be undersaturated with CO2 as result of algal uptake.
I’ll have to have a closer look at the paper to see whether the shorter-time cores from other parts of the ocean show similar patterns in atm. CO2 – if yes – this could assuage some of these questions.
Folks a lot of this is way beyond me.I am an attorney and a substitute teacher.About 8 years ago I commented in RealClimate about the potential catastrophic melting of the frozen peat moss, the melting of methal hydrates on the ocean floor, the increasing methane pollution,the massive forest fires in the Boreal forest and Amazon, and the massive fires in the Pantanal wetland region in South America.I think I asked all of you if these 4 factors would get worse (and if they all might converge in 4 tipping points) with a massive 2 or 3 decade long outgassing from the permafrost, the Boreal forests, and the Pantanal fires, andvthe methal hydrates,and that all might cause a massive and quick shift in climate leading to a 13 C rise within the next 300 years.Seems recently all these items have been getting much worse. Was I incorrect?Seems from the article above a 25F increase is now not to be ruled out.Runaway greenhouse effect quite possibleIn my humble amateur opinion.Tick tock goes the clock.If my comment is too amateur please feel free to delete.I know I am not a scientist.
Mark: “Runaway greenhouse effect quite possibleIn my humble amateur opinion”
Humbly acknowledging your amateur status means you’re able to learn what genuine experts know. Beware the Dunning-Kruger effect! Like many commenters on RC, I consider myself an educated amateur on the subject. I was scientifically trained to the doctoral level before I found an easier way to make a living. That left me a comprehensive non-expert, but has helped me understand something of the history and current state of climate-related physical and biological science. What I understand is that a runaway greenhouse hasn’t been ruled out, but is considered so unlikely that it’s left out of any realistic scenario. Not only that, but IIUC, so little quantitative data is available about runaway scenarios that professional climate scientists haven’t made much effort to model them. I did find a 12-year-old RC post, An Arctic methane worst-case scenario with some back-of-envelope calculations, that concludes:
But the methane worst case does not suddenly spell the extinction of human life on Earth. It does not lead to a runaway greenhouse. The worst-case methane scenario stands comparable to what CO2 can do. What CO2 will do, under business-as-usual, not in a wild blow-the-doors-off unpleasant surprise, but just in the absence of any pleasant surprises (like emission controls). At worst comparable to CO2 except that CO2 lasts essentially forever.
And here’s a 2020 announcement from the National Science Foundation, which funds a lot of climate science:
A long-feared scenario in which global warming causes Arctic permafrost to melt and release enough methane—a potent greenhouse gas–to accelerate warming and cause catastrophe probably won’t happen.
That’s based on a paper in Science titled “Old carbon reservoirs were not important in the deglacial methane budget“. Probably won’t happen” may be as much assurance as we’ll get. I expect other educated commenters, if not the blog’s authors, will have more to say about this.
Mark. I agree that anthropogenic climate change is looking very bad. I’m no climate expert, but my understanding is the arctic permafrost varies from one metre deep to about 1,500M deep and is is typically hundreds of metres deep. Even with warming around 3 degrees it would clearly take a very long time for that to melt completely, if you look at information on rates of surface melting, maybe hundreds to thousands of years. It will release methane and C02 and act as a feedback and enhance the overall rate of warming – but its hard to describe it as a methane bomb, in the sense of something big unfolding catastrophically in a matter of decades towards a single century.
Forest fires emit some methane but again even in worst case scenarios combining with melting permafrost its not enough to create a methane bomb as such. The ocean based methane hydrate issue is a bit harder to understand but the experts think its unlikely to be an issue. Although ‘unlikely’ is not that reassuring. However the real issue is more likely the slowly creeping increase in general methane emissions from natural sources as they warm, gas pipe leaks, forest fires etc,etc. While its slowly creeping, it does add up and combine with CO2 to be a very serious concern.
Mark J. Fiore, Mal Adapted, Nigelj,
Referencing Mark’s initial comments/questions on methane release, and Mal’s and Nigelj’s replies, I came across this today and thought it might be of interest to you three (unless already been aware) –
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From Inside Climate News, Aug 28th by Bob Berwyn: “Surging Methane Emissions Could be Sign of a Major Climate Shift”:
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https://insideclimatenews.org/news/28082024/surging-methane-emissions-major-climate-shift/
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And here’s the paper, “The Methane Imperative” Shindell et al (2024):
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https://www.frontiersin.org/journals/science/articles/10.3389/fsci.2024.1349770/full
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Gavin Schmidt is one the authors and is referenced in the news story.
Mark,
As Mal & Nigelj already show, I’d offer that as one of RC’s most recent frequent commenters (and surely the dumbest! :-), I can say I’ve found this is a pretty decent place to share thoughts/questions.
So welcome and tell your friends.
MJF: Runaway greenhouse effect quite possibleIn my humble amateur opinion.
BPL: Probably not. Earth’s mean global annual temperature would have to hit at least 320-340 K to start a “moist greenhouse.”
When runaway greenhouse effect morphs into a moist greenhouse. I’m wet with anticipation.
A moist greenhouse happens at a lower temperature than a runaway greenhouse. It is characterized by water entering the stratosphere, which it can’t normally do in great quantities due to the “cold trap.” In a runaway greenhouse, which requires a higher temperature, the entire world ocean evaporates and water is lost at the top of atmosphere by photolysis. Neither state is habitable.
But isn’t there a little problem with WV feedback, a key ingredient to climate sensitivity?
I certainly have not read all the papers, but some, and I think I understand where the canonical 1.8W/m2 figure comes from. Ramanathan, Inamdar 2006 (I know it is not article) for instance give a nice overview.
http://ruby.fgcu.edu/courses/twimberley/envirophilo/Forcing.pdf
Basically it is about relating OLR (outgoing longwave radiation) to surface temperature, or Ts. The analysis comes in 3 flavours: geographical (by latitude), seasonal and inter-annual variations of Ts. The relation dOLR/dTs is well below the Planck feedback in all three cases, and in similar magnitudes, indicating a strong fast feedback that could only be due to WV.
A vital component of the interpretation of these results, is the assumption of a respective lapse rate feedback. If it gets warmer, the lapse rate shrinks (cause more latent heat) and so the tropospheric temperature (Ta) increases even more. The same happens in reverse if Ts shrinks. This factor should push the dOLR/dTs relation well beyond the Planck feedback and given it is actually observed to be much smaller, the explicit WV feedback must even larger, bringing us towards these 1.8W/m2.
One problem here was already pointed out by A. Dessler et al 2008 with respect to the geographic approach:
“This is a quantitative estimate of the effect of the changing lapse rate on dOLR/dTs, and it shows that it is negative for almost all values of Ts. In other words, as Ts increases, so does the lapse rate, and the general effect of this is to reduce dOLR/dTs, and therefore OLR, below what they would be if the atmosphere maintained a constant lapse rate.
In most climate-change scenarios, the upper troposphere is expected to warm more than the surface, and the additional radiation from a warmer upper troposphere will act as a negative feedback on the warming.
This result demonstrates the unsuitability of using variations in different regions in our present climate as a proxy for climate change.”
In other words, the changes in Ta do not exceed that of Ts, but rather it is the opposite. This will push the dOLR/dTs relation well below the Planck feedback, thus NOT indicating WV feedback.
Doing my own research, I found the same problem occurs with seasonal variation in Ts. Again dTa dTs. That makes seasonal variations of Ts equally unsuitable as a proxy for WV feedback. And although there is a poor data basis for this, the same seems to be true for inter-annual variations.
On top of that, radiative transfer models barely seem to support a positive WV feedback (after considering negative lapse rate feedback) either. And eventually there seems to be a little problem with the assumption of constant relative humidity, which fails to materialize.
In Re to E. Schaffer, 28 Aug 2024 at 11:46 PM,
Dear Sir,
Thank you very much for your reference to Ramanathan.
In view of recent publications by Lague et al
https://iopscience.iop.org/article/10.1088/1748-9326/acdbe1/pdf
and Makarieva et al
https://www.frontiersin.org/journals/forests-and-global-change/articles/10.3389/ffgc.2023.1150191/full
and
https://arxiv.org/pdf/2205.14646 ,
I asked on this forum a question if climate sensitivity towards forcings like changes in GHG atmospheric concentration, atmospheric aerosol concentration, surface albedo, or Earth insolation may perhaps depend on parameters like water availability for evaporation from the land.
The incentive for this question were the hints provided by the above mentioned publications which suggest that a change in water availability for evaporation from the land can change global mean surface temperature.
These hints inspired, first, questions if so called water vapour feedback (to other forcings like changing GHG concentration) and/or so called cloud feedback can depend on water availability for evaporation too.
The question regarding climate sensitivity then arose from my assumption that climate sensitivity to forcings like GHG concentration depends also on the above mentioned water vapour feedback and/or cloud feedback.
In Ramanathan, I have not found any clue to these questions. Are you aware of newer publications that reflect the progress achieved in this direction during 18 years following Ramanathan’s review article?
Thank you in advance and best regards
Tomáš Kalisz
Ocean Heat Content:
Nowadays the biggest sink of heat resultante of the enhanced greenhouse effect.
Is there a paleo-OCH analysis?.
https://doi.org/10.1038/s41561-023-01250-y gives a paleo-analysis of Earth energy imbalance (EEI).
At present, a large majority of the EEI is going into increasing ocean heat content. However, a much larger share of it can go into melting ice, especially coming out of glaciation into an interglacial.
One finding of the research was that a positive EEI of around 0.3 W/m^2 was enough to go from a full glacial period to an interglacial warm period, when sustained. Very sobering when we see that the OHC rise in the past couple of decades has been at least twice that rate, and some estimates of current EEI are quite a bit higher.
Coincidentally, having recently finished reading Michael Mann’s “Our Fragile Moment”, my bedtime climate reading has just moved on to Peter Wadhams “A Farewell to Ice” (2016.) With the former still fresh in my mind, I’ve scribbl;ed quite a few “??” and “eh?” notes in the margin; last night I reached this passage (the context is the onset of regular ice ages in the Pleistocene):
(To be fair he notes that he’ll dsicuss this result in a later chapter that I haven’t read yet, hopefully explaining why it’s so far from the current consensus of ~ 1.5-5 degC.)
The great thing about climatology for this interested layperson is that there’s always so much more to learn about. It’s the gift that keeps on giving — rather like fossil fuel deposits…
It’s the Eocene, not the Miocene…
Nature 461, 1110-1113 (22 October 2009)
Atmospheric carbon dioxide through the Eocene–Oligocene climate transition
Paul N. Pearson, Gavin L. Foster, Bridget S. Wade
“Geological and geochemical evidence indicates that the Antarctic ice sheet formed during the Eocene–Oligocene transition 33.5–34.0 million years ago. Modelling studies suggest that such ice-sheet formation might have been triggered when atmospheric carbon dioxide levels fell below a critical threshold of ~750 p.p.m.v. During maximum ice-sheet growth, pCO2 was between 450 and 1,500 p.p.m.v., with a central estimate of 760 p.p.m.v.”
CO2 was higher than it is now and the Eocene climate was warmer but life on land and the plankton in the oceans diversified, even as the pH was about one unit lower than now. No “acidification” and the polar ice sheets began to form.
We’re talking about changes occurring over millions of years. Species evolved and went extinct as CO2 concentrations in the atmosphere and oceans rose and fell. Continents were moving. The Antarctic Circumpolar Current formed.
Climate is changing orders of magnitude faster now. We know with more than adequate confidence that ~300 years of economically-driven (i.e. anthropogenic) transfer of fossil carbon to the atmosphere is the principal driver of the contemporaneous rise of global heat content. And we know that the resulting costs in human treasure and tragedy (to say nothing of accelerating biodiversity loss) are already being paid by people around the world, whose own fossil carbon emissions are minuscule compared to the average American’s. Nor are Americans exempt from paying, in money and grief. If the burning of fossil carbon by the 10s of gigatonnes annually continues, the cumulative social and biodiversity costs will not only become more disastrous rapidly, but will be open-ended. Only collective (i.e. government) intervention in the global energy market can cap the tragic trend, by taking the profit out of selling fossil fuels, thereby driving the global economy to carbon-neutrality. Since there is no effective international government, individual nations must decarbonize their own economies first, while doing what’s possible to influence their trading partners to follow their example. If you are a US voter, please vote Democratic in November.
Any questions?
Broadlands “CO2 was higher than it is now and the Eocene climate was warmer but life on land and the plankton in the oceans diversified”
Aaa – another denier cliche: “CO2 is good for us!” Except that life can adapt if the change is gradual – so the tree-line has enough time to migrate North, and there is enough time for species to evolve adaptation. Here is
of your favourite geological epoch:
From it dT/dt ~= 5C/10 mln – i.e. 0.5C/mln yr. Today we get the same 0.5C in a few decades. If you want to find similar rates in the past – probably you need to go to the non-asteroid mass extinctions. Not exactly poster boys for thriving and diversification.
And since you are posting on a human forum – there were no humans during the Eocene, much less a human civilization. Not surprisingly – human civilization depends critically on the agriculture able to feed billions – and agriculture requires stable and predictable climate, with as few extremes as possible.
Interestingly, many of the main humanity staple grains have been domesticated in relatively cold climates, and often require a period of colder air for the seed germination. And even if they germinate – when subject to heat waves – they suffer massive drops in yield:
IPCC 2007, on the 2003 Heat wave in Western Europe:
“ A record drop in crop yield of 36% occurred in Italy for maize grown in the Po valley, where extremely high temperatures prevailed (Ciais et al., 2005). In France, compared to 2002, the maize grain crop was reduced by 30% and fruit harvests declined by 25%. Winter crops (wheat) had nearly achieved maturity by the time of the heatwave and therefore suffered less yield reduction (21% decline in France) than summer crops (e.g., maize, fruit trees and vines) undergoing maximum foliar development (Ciais et al., 2005). Forage production was reduced on average by 30% in France and hay and silage stocks for winter were partly used during the summer
Add to this at least 30,000 deaths.
And all these – in France, Italy, and Switzerland, affluent countries that are in much better position to protect their agriculture and people than the developing countries where the majority of the humanity lives.
But don’t let that stop you, Prof. Pangloss – after all, we live in the best of the possible worlds and that all is for the best , right?
P.S. I am sure that Saudi Arabia and Russia, whose economies, and therefore the affluence of their oligarchs, stability of the regimes, and ability to wage wars – critically depend on the world continuing to buy their oil and gas, appreciate your efforts.
Broadlands: “ the pH was about one unit lower than now”
Not to let the made-up numbers unchallenged – a simple calculation of the CO2 system in the equilibrium with atm pCO2: suggests that IF the pH in Eocene was “one unit lower than now” – the corresponding atm. CO2 would have to be
not “760 p.p.m.v.”, but …. 5,000 p.p.m.v.
So whoever sold you on that LIE, wasn’t your friend.
Still, you can learn something from that: you presumably think yourself a skeptic, somebody, who unlike others, can’t be easily fooled – so why weren’t you so skeptical to your source?
“CO2 was higher than it is now and the Eocene climate was warmer but life on land and the plankton in the oceans diversified”
Many people imagine the warmer climates of past epochs, with their elevated levels of major and minor trace gases, as times of enriched biodiversity and flourishing life. When ecosystems were left to respond freely, this conceivably represented a stabilizing feedback through biogeochemical and biogeophysical effects.
The headpost article attempts to demonstrate that the climate sensitivity of the distant past, when including factors like solar forcing, topographic configuration, and minor trace gases, is directly comparable to today’s conditions, with a fast ECS estimated at only 3.5°C.
However, this could be misleading. Left unperturbed, the paleo Earth had total freedom in biogeochemical and biogeophysical response. As you noted, as the CO2 rose, it’s likely that life diversified, soils enriched, and nutrient cycling intensified.
Today, the situation is markedly different. As humanity artificially drives up CO2 levels, life is being drastically diminished, soils are actively eroded, and biodiversity is in sharp decline. This by direct ongoing intervention. This is the exact opposite of what occurred in the past. Today’s unnatural and unprecedented combination of rising CO2 and declining biosystems suggests that paleo climate sensitivity estimates may not be directly comparable to those of today. Alarmingly, this implies that today’s climate sensitivity is likely higher than in the past.
to JCM
Today, the situation is markedly different. As humanity artificially drives up CO2 levels, life is being drastically diminished, soils are actively eroded, and biodiversity is in sharp decline. This by direct ongoing intervention. This is the exact opposite of what occurred in the past. Today’s unnatural and unprecedented combination of rising CO2 and declining biosystems suggests that paleo climate sensitivity estimates may not be directly comparable to those of today. Alarmingly, this implies that today’s climate sensitivity is likely higher than in the past.
Yes, well said.
Climate science keeps on saying and implying and suggesting that they know things they do not know. Then basing their recommendations out of the IPCC and other bodies based on this not knowing unproven guesswork and assumptions, guesses and opinions of the most outspoken who declare they are certain about things when they and the science is clearly uncertain and unproven.
Resulting in – “it’s ‘easy’ to stop global heating, just hit zet nero emissions by 2050 and the warming will be stopped! The UNFCCC agrees.”
That isn’t science. Or real.
E: Climate science keeps on saying and implying and suggesting that they know things they do not know. Then basing their recommendations out of the IPCC and other bodies based on this not knowing unproven guesswork and assumptions, guesses and opinions of the most outspoken who declare they are certain about things when they and the science is clearly uncertain and unproven.
BPL: Who says it’s uncertain and unproven? You? Show your work.
BPL: Who says it’s uncertain and unproven?
Science does. You do. Radge just did. And Gavin does, among uncountable others.
In fact Gavin specifically addressed the net zero ‘issue’ a few months back on the Climate Chat channel. What he said was posted here. Ask him or google is your friend.
And try to educate yourself better and improve your default negative attitude towards other people if possible.
https://jacobin.com/2024/08/climate-disinformation-green-transition-workers
Phrases with uncertainty and unproven are not dirty words in science. Please try not to pretend they are and stop assuming the people who use them are trying to spread disinformation when they are not.
[BPL: Who says it’s uncertain and unproven?]
E: Science does. You do. Radge just did. And Gavin does, among uncountable others.
BPL::
1. Everything comes with error bars. That’s not a weakness, it’s a strength.
2. Science doesn’t deal in proof. Proof is for formal logic or mathematics (and alcoholic beverages). Science is inductive, not deductive; it works with evidence, not pure logic.
3. Denigrating a whole science as “uncertain and unproven” simply shows you are not familiar with science in general (see 1 & 2), and with climate science specifically.
Pick up a climate science book and read it. Not a web site. Not a blog. A book, if you remember what those were. I can recommend some IF you want to learn. Or you may just prefer to keep randomly slandering everyone here.
Escobar wrote:
Huh? What does “not knowing unproven guesswork and assumption, guesses and opinions” actually even mean?
The IPCC exists to summarize the current state of the research art as pertinent to climate, which it undertakes on a recurring cycle as new information enters the literature. IMO, it’s one of the most remarkable scholarly endeavors ever.
Now, elsewhere he (?) says that unproven is not a dirty word in science. Well, that’s true. But actually, under the Popperian paradigm at least it’s not even a necessary word, because in that formulation nothing is *ever* “proven.” And equally, nothing is ever “certain,” either, excepting propositions that have been falsified.
Which leaves “not knowing”–grammatically incongruent, so we’ll just assign that as meaningless ‘null string’–“guesswork,” “assumption,” “guesses,” and “opinions.”
Well, you can find assumptions in primary literature, certainly. They are normally employed to constrain a conceptual framework in order to set the necessary boundary conditions and clearly identified as such because if they aren’t the analysis may not be comprehensible, in which case it’s unlikely to be published in the first place. However, assumptions are not conclusions.
You also sometimes find “opinions”, particularly in parts of Assessment Reports. “Opinion” is there referred to as “expert elicitation,” and seems to be employed in situations where there is no rigorous analytical technique available which can reliably calculate a probability for outcome X, Y or Z. Again, however, it is identified as such, because its ‘faute de mieux’ nature is important to be aware of.
So, now we are at “guesses” and “guestwork.” Clearly, these are unnecessary and superfluous examples of unnecessary verbiage–near synonyms which function only to smuggle in a negative connotation which to smear their innocent verbal cousin, “assumptions.”
So, Escobar’s comment holds much less substance than meets the eye. It particularly leaves out everything that is known to a good degree of certainty–which is, if you look honestly, rather a lot.
B: CO2 was higher than it is now and the Eocene climate was warmer but life on land and the plankton in the oceans diversified, even as the pH was about one unit lower than now. No “acidification” and the polar ice sheets began to form.
BPL: But there was no human civilization dependent on a stable climate for its agriculture to keep working. Nor were there hundreds of millions of people living along seacoasts, or trillions of dollars worth of infrastructure ditto.
It is clear to me that one has to be careful while comparing the climatic effects of a changing tropospheric CO2-level in the distant past over millions of years to *the in comparison extrenely abrupt/fast and accelerating speed – a global “experiment” – in artificially adding enormous amounts of this and other greenhouse gases to the troposphere that we humans are conducting since around 1850*. The reasons for this is obvious: over millions of years other external factors like plate tectonics, changing volcanism etc. play a bigger role, difficult to quantify.
The main characteristic of our human “global climate experiment” is that we are changing the tropospheric greenhouse gas content *at least an order of magnitude – ten times or more – faster than during any known comparable event from the whole geological history*, fx. the end permian basalt volcanism creating the siberian traps 252 m. yrs BP and the PETM 56 m. yrs BP.
This means that we should not only be extremely reluctant continuing along this path, in fact we would be better off, the sooner we manage to put an end to this global experiment, which was unconsciously startet by our ancestors a couple of hundred years ago.
Our climate models of course may all be very sophisticated mathematically etc., but they clearly have this serious weakness: because our “experiment” lacks parallels in the geological history, we really can’t calibrate the model results with anything known. Compared to the reality our models are indeed very simplistic. Even our most sophisticated economic models are nowhere near predicting financial collapses like 2008, even if we have much more experience with them and material for their calibration.
Just the same: The IPCC have for long been using the climate models to create the completely unfounded opinion, especially among mainstream/neoliberal economists and almost all politicians regardless of their ideological viewpoints (neoliberal, neoconservative, reactionary/trumpist/authoritarian/putinist/fascist/stalinist, socialdemocratic…), that global heating is no big deal: they “vary” only from jubilant warmers like Trump and Putin, Xi and Modi etc. to lukewarmers like the EU, and the latter mainly do exact like the first mentioned: fossil business as extremely usual. In 1975 the fossil percentage of total global energy consumption was 75, today it is 82 (eightytwo…) – the socalled “green change” is pure mythology, fake news, it’s not even symbolic. Because in the same period of only around fifty years, *we have changed the tropospheric CO2-level backwards in earth-time to at least three to five, probably rather fifteen to twentyfive million years BP.
In fact nobody can have even the slightest idea what this could lead to of unforeseeable events concerning our life-supporting natural systems, which have been extremely and unusually stable and good for us during the holocene compared to earlier times. But most nonetheless act as if we were very safe. When the IPCC in 2013 calculated a warming/thawing rate of northern canadian permafrost in 2090 like the one researchers were measuring already in 2019, seventy years earlier, you get a sense of what this could imply. The scenery from “Titanic” spring to mind, or the chamberlainic proclamation of “peace in our time” in 1938, less than one year before WWII started.
It’s only five months since Gavin wrote that “we could be in uncharted territory” https://www.nature.com/articles/d41586-024-00816-z . Has any research suddenly changed that? Or is it Biden’s forced withdrawal? Surely not Trumps fantasies about “Jesus counting the votes in California”? Sorry if I’m being somewhat sarcastic.
BTW I miss this in the discissions: https://pubs.geoscienceworld.org/gsa/geology/article/48/9/888/586769/A-23-m-y-record-of-low-atmospheric-CO2 .
Karsten said:
I don’t want to call that statement “completely unfounded,” but it’s very much at odds with my perception, and I think it’s quite incorrect.
No. It’s in fact quite fundamental. There’s a lot of objective information available on this, and I don’t wish to multiple stats unnecessarily, but:
This doesn’t, of course, undo the damage already done. But it does mean that we are well into the process of ‘stopping the bleeding.’ And that is not merely “symbolic.”
I appreciate your contributions on RC, Kevin.
A number of commenters this summer accept enough of climate science to be aware of the rising risks to civilization and the biosphere, but are fearful of lower-probability, higher-cost outcomes lurking in the upper tail of the TCR and ECS PDFs, especially with the confirmed acceleration of the trend of GMST*. The reality-based regulars here have generally responded with “yeah, it’s bad and getting worse fast, but there’s reason to hope the global economy will decarbonize before the end of the century, making the worst-case scenarios tolerably unlikely for now.” Some frequent commenters appear to have lost patience with least-drama projections, and I for one acknowledge the non-zero probability they are right. But modal estimates of the trajectory of GMST under likely scenarios are quite scary enough IMHO. I’m horrified by the costs some have already paid in money and grief, far out of proportion to their own lifetime GHG emissions; this, after all, is why anthropogenic global warming is fundamentally a moral issue. I fully expect the cumulative social costs to rise with any warming trend, and I’m fully aware the current trend of GHG concentrations is still rising also. Ack!
OTOH, none of the forgoing is a reason to stop hoping. AFAIK, there is a finite chance that net-zero global emissions can be achieved by mid-century, driven by market responses to collective intervention around the world. I might even be alive then! At that point, the cumulative cost of anthropogenic global warming will already be immense, and already being paid by millions around the world, but will no longer be open-ended. Just what those final figures will be is as yet hard to predict: not an exercise for the faint-hearted. But we know damn well that however bad it gets, it will keep getting worse as long as there’s fossil carbon that’s profitable to sell.
Meanwhile, I want to see GMST stabilize in my lifetime! I’m aware my private carbon footprint is less than the US average, but greater than the global average. Boasting of one’s voluntary sacrifices is distasteful IMO, because everyone with any connection to the global economy has a positive carbon footprint. That’s why only collective action can mitigate the tragedy of the global climate commons. Ultimately, all I can do is vote Democratic and exhort otters to same. Those who urge more radical collective actions may have moral and even scientific justification, but must know the American masses don’t support them. And even if the American masses are deceived by the power of $trillions in carbon capital, I’m too old for street fighting! I’ll leave that to younger generations.
* A convenient proxy for global heat content, which some here argue is a more “real” metric. GMST is more closely tracked, however, and AFAICT is more accessible, thus more real, to the lay public.
Karsten V. Johansen: “ The IPCC have for long been using the climate models to create the completely unfounded opinion, ”
Glad you have found something in common with Trump. Maybe there is a hope for humanity, after all ;-)
The suspicion does enter the mind that since nobody’s good enough for him and evil is identical to good, if he were put in charge he’d run away, blaming everybody but himself.
Karsten V. Johansen: “ The IPCC have for long been using the climate models to create the completely unfounded opinion, ”
Piotr: Aug. 30 Glad you have found something in common with Trump.
Still, no second thought, on the fact that you share your anti-science views with Trump, MAGA, QAnon and antivaxers? Nothing, nada? Life unexamined IS worth living ?
Piotr: your own and some others here in fact are the ones using trumpist demagogery. I am not. I know that Trump is a late-capitalist kind of fascist backed by oligarchs like Peter Thiel, Elon Musk etc., organized in Project 2025 etc. But their screaming repetitions of “drill, baby drill!” doesn’t make the “inflation reduction act” etc. even one inch greener. Even if the two-party craptrap may create that illusion by means of the “lesser evil” tactic. *Politically you need to ask yourselves why the social democrats and the stalinists of 1920’s and early 1930’s werent able to stop Hitler? Why did they continue with their dogmas and sectarian infighting, while Hitler was planning his next coups and the first concentration camps together with the steel baron Fritz Thyssen, the big banker Hjalmar Schacht etc. (they were the Kochs, Thiels, Musks etc. of that miserable oligarchic age, see “The institute advocates free market policies.[19] The policy orientation of Heartland has been described as conservative, libertarian, and right wing.[11][20][21][22] The institute promotes climate change denial, advocates for smoker’s rights, for the privatization of public resources including school privatization, for school vouchers, for lower taxes and against subsidies and tax credits for individual businesses, and against an expanded federal role in health care, among other issues.[citation needed] In addition to lobbying activities, Heartland hosts an internet application called “Policybot”[23] which serves as a clearinghouse for research from other conservative organizations such as The Heritage Foundation, the American Legislative Exchange Council, and the Cato Institute.” https://en.m.wikipedia.org/wiki/Heartland_Institute , “In May 2022, the Heritage Foundation completely reversed its position supporting military aid to Ukraine in its attempt to repel the Russian invasion of the nation, which it had previously supported.[81] Following the reversal of its position on military aid to Ukraine, the foundation claimed, “Ukraine Aid Package Puts America Last”.[82] In September 2022, the foundation’s foreign policy director said the foundation ordered him to retract his earlier statements supporting aid to Ukraine; he subsequently left the organization.[83] In August 2023, Thomas Spoehr, the foundation’s Center for National Defense director, resigned his position over the dramatic policy change.[84]
In September 2022, one Heritage employee said he had been “required by management to remove a Twitter post condemning the January 6 storming of the Capitol.”[85]
In March 2023, the Heritage Foundation established a cooperative relationship with the Danube Institute, a Budapest-based state-funded think tank founded in 2013.[86]
On July 12, 2024, Heritage stated a conspiracy theory that Biden could attempt to remain in office following the 2024 election by force,[87] and that the 2024 election was illegitimate in advance.[88]” https://en.m.wikipedia.org/wiki/The_Heritage_Foundation https://web.archive.org/web/20230827202800/https://www.nytimes.com/2022/05/27/us/politics/ukraine-aid-heritage-foundation.html , https://www.theguardian.com/commentisfree/article/2024/aug/29/trump-project-2025-history
https://www.counterpunch.org/2024/08/29/project-2025-provides-a-gop-blueprint-for-destroying-americas-labor-unions/ “In July 2007, a BBC investigation reported that Prescott Bush, father of U.S. President George H. W. Bush and grandfather of then-president George W. Bush, was to have been a “key liaison” between the 1933 Business Plotters and the newly emerged Nazi regime in Germany,[51] although this has been disputed by Jonathan Katz as a misconception caused by a clerical research error (?? KJ).[52] According to Katz, “Prescott Bush was too involved with the actual Nazis to be involved with something that was so home grown as the Business Plot.”” https://en.m.wikipedia.org/wiki/Business_Plot “The Congressional committee kept the names of many of the participants under wraps and no criminal action was ever brought against them. But a few names have leaked out. And one is Prescott Bush, the grandfather of the incumbent president. Prescott Bush was of course deep into the business of the Hamburg-America Lines, and had tight relations throughout this period with the new Government that had come to power in Germany a year earlier under Chancellor Aldoph Hitler. It appears that Bush was to have formed a key liaison for the group with the new German government.”)
There is nothing new in Trump, And: *Reagan, Clinton, Bush politics – their “market” illusions, super PACery etc. led to Trump*, Thiel etc., 6. jan. 2021 and Project 2025! You can’t fight oligarchy with the same old clintonism styled in TikTok videoclips, playing “brat” etc. Time to wake up and face the reality.
Your invectives and mudslinging, your lack of argumentation provides no answer whatsoever to any of the facts. You are being enraged by the unpleasant facts I mention, not by me.
Why is the tropospheric CO2-level now in the antropocene rising faster than anytime known before, and even: faster in the 2020’s than in the 2010’s and 2000’s in which it rose faster than in the 1990’s, in which it rose faster than in the 1980’s, in which it rose faster than in the 1970’s etc.?
Is this relentless acceleration and our arrival in “uncharted territory” as Gavin correctly wrote in his march 2024 paper, a sign of even the slightest real “green change”? Any approaching “net zero” (whatever that airy expression might mean in the big theatrical speeches of the usual clintonic-reaganomist suspects or any other political showbiz pundits)?
Of course it isn’t, James Hansen warned of this “pure bullshit” – the Paris “agreement” (what is an agreement with no agreed actions like carbon fee and dividend, but just lofty “ambitions” which never are anything but empty words?) already in late november 2015, at the start of the Paris climate conference (which “accidentally” was interrupted from the very beginning and drowned in media frenzy by barbaric islamist terrorist acts in Paris. The perpetrators came from a newly built mosque in Brussels, financed by the arch-petrostate royal tyranny in Saudiarabia… Pure coincidence? I don’t think so).
Karsten VJ: “Piotr: your own and some others here in fact are the ones using trumpist demagogery”
Put your money where your mouth is KVJ – prove your claim about me by quoting my words that Trump would agree with. The way I quoted your words:
“ The IPCC have for long been using the climate models to create the completely unfounded opinion, ”
Trump attacks the climate-science too, and other anti-science trolls like “Escobar” praise you on yours. You are what the people who share you views are. As they say – if you walk like a Trump and quack like a Trump …
Karsten, I for one am surprised to see that kind of arrogant scorn issuing from you, who have otherwise demonstrated a firm grasp on reality. I don’t necessarily agree completely with Ms. Anderson, but there’s definitely an element of “perfect is the enemy of incremental progress” in your comment. You’ve shown an understanding of our political system, so you understand the USA is not Norway. Assuming all your subjective judgements have an objective foundation, what collective action do you recommend American climate realists take, besides hunker in our bunkers and wait for the end? Keeping in mind the truism “politics is the art of the possible”, that is.
to Karsten V. Johansen
Good comment. Hits a number of key points. Ignore the critical cynical naysayers.
Anyone suggesting global heating can be stopped by unfounded unproven net zero theories (opinions & beliefs) and the proposed ‘actions’ globally by 2050 is overtly saying:- “global heating is no big deal” – if it is that easy and so quick to stop.
Beliefs like this are much closer to schizophrenia delusions than a science based material reality.
Good paper ref. It is obvious and undeniable what is happening today is nothing like what happened in the past (causes and outcomes) and is orders of magnitude faster.
As well as totally out of control with a body of climate science unable to explain what is happening and what is coming with any degree of intelligent physics based logic or certainty. People are looking for guidance and solutions from the wrong quarter, the IPCC formulated prognoses being one serious failure. Likely the worst most misguided of all.
E: Beliefs like this are much closer to schizophrenia delusions than a science based material reality.
Good paper ref. It is obvious and undeniable what is happening today is nothing like what happened in the past (causes and outcomes) and is orders of magnitude faster.
As well as totally out of control with a body of climate science unable to explain what is happening and what is coming with any degree of intelligent physics based logic or certainty. People are looking for guidance and solutions from the wrong quarter, the IPCC formulated prognoses being one serious failure. Likely the worst most misguided of all.
BPL: You keep making these accusations without providing any argument to back them up. For God’s sake, crack a book. Science is your friend.
Whether or not science is our friend, ignorance and naive credulity are our enemies.
Re. “Our climate models of course may all be very sophisticated mathematically etc., but they clearly have this serious weakness: because our “experiment” lacks parallels in the geological history, we really can’t calibrate the model results with anything known.”
This is a problem in many areas of physics, for example geophysics and astrophysics and for that matter in research into most any real world phenomenon.That people think those twinkly things in the sky at night are mainly balls of fusing hydrogen at huge distances is based on those same sorts of models.
A final point is that even in experimental sciences where true experimental control is possible I have yet to see an experiment that PROVABLY controls for ALL possible extraneous variables.
Yes. Climate models are but computationally tractable abstractions. To control for all possible extraneous variables, they would need to be the size of the globe, have infinite spatial and temporal resolution, and leave us simultaneously hypo- and hyper-thermic, dehydrated and drowning. Indeed, we need a spare universe to experiment with, to provably control every variable. But won’t someone think of the children 8^|?
Who knows what happened to marine albedo with coccoliths gorging in a warmly carbonated sea?
A surfeit of oxygen … fizzy oceans? /snark off
“happened” or “happens/will happen”? If the latter – obviously it increases albedo, but the extent would depend and the length, area of the ocean, and latitude (sun’s angle). Then again more coccolithophora => more precipitation of CaCO3 => more acidic water around them => surface ocean less likely to take up surplus human CO2.
Such papers convince me even more about the recent claim of the (ex ?) Lancet editor saying that more than 50% of published papers may be untrue/wrong. I suspect even more in climate science.
M: Such papers convince me even more about the recent claim of the (ex ?) Lancet editor saying that more than 50% of published papers may be untrue/wrong. I suspect even more in climate science.
BPL: On what basis? The mere fact that you want it to be true?
Max, as I try to explain even to the regulars here, people make fundamental errors in reasoning because they aren’t clear and precise in language, and in understanding how science works.
The problem with the “wrong” papers in the Lancet context is that they reported experimental results which could not be reproduced by other researchers. Something like “drug A reduced blood pressure 40% compared to the control group taking drug B”.
Obviously, in climate science, you don’t get to do that kind of stuff. Which brings us to what we mean by “wrong”. To address that, we have to clearly state what the question is for which we got a “wrong” answer.
My short version of the critique of the reaction to this paper is that it may be “right” that [climate sensitivity] was correct for the time period studied A, but “wrong” for the current time period B. Well, meh.
Climate science papers are often like this, in that data analysis or modeling tells us something, but by themselves, they don’t provide some very definitive or significant conclusion that can be directly applied.
Point being, that doesn’t make them “wrong” like the medical papers, so your comparison is incorrect.
Another example of ‘my theme’
Z says:
My short version of the critique of the reaction to this paper is that it may be “right” that [climate sensitivity] was correct for the time period studied A, but “wrong” for the current time period B. Well, meh.
Climate science papers are often like this, in that data analysis or modeling tells us something, but by themselves, they don’t provide some very definitive or significant conclusion that can be directly applied.
………………..
Meh indeed. Gavin’s article response needs to be peer reviewed otherwise we’re being asked to equate steak with sausages while assuming the sausage must be of higher quality by default.
Escobar” “Gavin’s article response needs to be peer reviewed otherwise we’re being asked to equate steak with sausages “
Then PROVE YOUR CLAIM that Gavin’s commentary on the paper “equates stake with sausages”. Don’t be shy – show your thinking that led you to these insinuations of dishonesty and manipulation on the part of Gavin. Put your money where your mouth is.
P.S. And don’t cry how the unfriendly people here ask you to prove your insinuations toward others. If you can’t stand the heat, don’t start fires.
Max: Such papers convince me even more about the recent claim of the (ex ?) Lancet editor saying that more than 50% of published papers may be untrue/wrong. I suspect even more in climate science.
Let’s stipulate there is a “replication crisis” in biomedical and human behavioral sciences. Without going into just how distinct the physical, biological, and behavioral sciences are, the incentives for professional researchers in each of the latter two domains are rather different in the physical sciences, and especially the earth sciences, which include a historical dimension. So are the rules and methods of empirical investigation and intersubjective verification. AFAICT, we are talking about the superior epistemic authority of physical science, arising from the larger culture it’s embedded in. Scientists are made of the “crooked timber of humanity”, after all: it’s just that the transnational, transgenerational, cumulative, collective enterprise of science is the only cultural adaptation our species has evolved for explaining reality* and predicting the future, that’s more successful than divination with entrails. Here is where scientific metaliteracy becomes especially valuable to genuine skeptics. People to whom science is an alien sub-culture may read about publishing fraud in clinical medicine or psychology, and assume it’s the same across all the sciences. They don’t understand that no one actually wants anthropogenic climate change to be real, our fault or an existential threat to global civilization as well as biodiversity; or that the most tempting incentives for scientists to cheat are offered by carbon capitalists. And that those incentives notwithstanding, all who go into climate science hoping to get rich will soon be discredited by their specialist peers around the world.
Are biomedical and behavioral scientists appearing on talk shows to correct Max’s erroneous presumption? IDK, I don’t watch ’em. I do think it’s important for climate scientists to publicly defend their findings against high-profile pseudoskeptics, while alluding to the cultural differences between physical and social sciences, and the comparative lack of incentive to publish sloppy or deceptive work. Lastly, is it worth pointing out that if climate scientists are mistaken or lying, and there is no anthropogenic global warming, the PNW heat dome of 2021 wouldn’t have killed at least 914 people, while I huddled in my heat-pump-cooled house and hoped my power stayed on? (It did, FWIW, but it might be time for me to invest in some capacious battery storage, and maybe solar PV on my roof. They might save my life. Thanks, science!)
* “That which, when you stop believing in it, doesn’t go away.” -PK Dick
Max: “ more than 50% of published papers may be untrue/wrong. I suspect even more in climate science.
and you are basing it on your …. thorough knowledge of or all areas of climate sciences, right?
Otherwise, Max’s opinions in, garbage out.
Now go away or we shall taunt you a second time!
I would go so far as to say that 100% of all published work is incorrect in some manner or other or will be superseded at some future time by better knowledge. The trolls here seem to think this is a bug for science. Actually it is one of science’s most fundamental characteristics.
Bravo!
Reproducing the results of a controlled experiment, i.e. replication, is the benchmark in science. No argument that controlled experiments are impossible in climate science. The closest thing that we have are the pseudo-controlled experiments of monitoring impulse responses such as solar eclipse events and volcanic disturbances such as Hunga Tunga. Yet, these are even tricky as other factors can’t be controlled, so the HT emissions are conflated with changes in man-made aerosol production. See the shipping lanes model.
Not the stuff that I published based on real laboratory-controlled experiments in the condensed matter realm. The only questions that came up is who came up with the results first. Frequently one can find papers on a research lab finding from Japan and the USA that emerge simultaneously. Climate science can only dream of achieving a similar level of laboratory control to enable reproducibility and thus validation.
Look at that supposed finding of a room=temperature superconductor produced in South Korea from 2 years back. That was quashed within a few weeks by others trying to replicate and offering alternative models of what was happening.
OTOH, someone in climate science offers up an idea and it gets published and filed away, often ignored because there is no way to replicate the model via an experiment.
jgnfld, youre probably right that all papers are flawed. One irritant is the trolls that think that because a paper isn’t 100% perfect, it’s by definition 100% useless. And the trolls that constantly complain things like climate models and IPCC evaluations have imperfections, as if we dont already know.
I have a research background, but am not a climate scientist. For the last year I’ve been writing a compendium of information on climate change from multiple fields. We don’t have to worry about a runaway greenhouse effect, as several have commented. We do have to worry, I argue, about a global societal collapse. From my Executive Summary:
“The probability that there will be a global societal collapse is high because the second and third order effects of climate change, such as crop failures leading to starvation, are not fully appreciated and will lead to intra- and interstate conflict. Compound hazards and cascading effects will also increase the damage to individuals and society, and there are interconnections among risks arising from environmental, economic, technological, geopolitical, and societal factors that will increase the probability of societal collapse. This is a “polycrisis.””
Here is the latest version (which is updated weekly):
https://docs.google.com/document/d/1xHvUneUT-1xx1W72yZTXpqrtNfIqUKB5oooOvwcw1OM/edit?usp=sharing
The paper is not peer reviewed, and is also available on EarthArXiv
A lot of people have looked at this paper, but no one has provided any good counter arguments, at least so far. If you have some, please let me know.
Demetrios Karis: A lot of people have looked at this paper, but no one has provided any good counter arguments, at least so far.
Well, your Executive Summary pretty much tells me what I need to know. I, for one, am quite able to entertain all manner of catastrophic scenarios arriving before the end of this century. We (i.e. all humanity) are indeed faced with a polycrisis. As a senior US citizen with no family and modest means, my choices are pretty much limited to voting Democratic, and hoping not to be visited by personal catastrophe during my remaining natural life. Since I can all too easily imagine the worst, I have no need to read your paper. Good luck to you, sir.
Demetrios,
I think it is always important to state the obvious, to be sure everyone in a discussion is on the same page, but,,, you had to write a whole paper?
Seriously, though, given the complexity of the individual systems (climate, humanity) and the complexity of their coupling, attempting to specify what qualifies as “societal collapse” seems pointless.
I don’t think anyone doubts that if we continue to increase the energy in the climate system, eventually its resulting disruption will create a new “ecosystem”, to which humanity will have to adapt. It will not be fun.
What more do we need to say?
A very superior work. Have read enough of it to know that for certain. Very well done, a credit to you Demetrakis, And very brave, given what you are up against! You’ll find no friends here. Maybe Geoff, Escobar, Sabine, and Karsten if they haven’t already given up or banned. Hopefully they and many others will contact you privately offering encouragement and support. I know I will.
My expectation is the breakdowns with famine and violence w mass deaths become thick and fast before 2040 not post 2050. Population decline begins feeding into consumption declines which stalls ghg growth. Zero confidence any mass movements will arise anywhere. The protests that will happen will be dealt with by mass shootings by draconian policies with increasingly long term prison sentences and them being labelled as ‘terrorists’. As is already happening in the UK and elsewhere (eg Just Stop Oil protest sentences) .
Please reach out here where you will find other sane well adjusted rational evidence based like-minded souls like yourself.
https://metacrisis.org/META-CRISIS/00.+%F0%9F%91%8B+About/Start+Here
Good Luck CJ