Nic Lewis
James Hansen’s latest paper “Global warming in the pipeline” (Hansen et al. (2023)) has already been heavily criticized in a lengthy comment by Michael Mann, author of the original IPCC ‘hockey stick’. However Mann does not deal with Hansen’s surprisingly high (4.8°C) new estimate of equilibrium climate sensitivity (ECS)[1]. This ECS estimate is 60% above Hansen’s longstanding[2] previous estimate of 3°C. It is Hansen’s new, very high ECS estimate drives, in conjunction with various questionable subsidiary assumptions, his paper’s dire predictions of high global warming and its more extreme concluding policy recommendations, such as ‘solar radiation management’ geoengineering.
Hansen’s new 4.8°C ECS estimate is well above the best estimate of 3°C reached in the IPCC’s latest scientific assessment report (AR6), lies outside the AR6 likely (66%) range of 2.5–4°C and is almost at the top of the AR6 90% uncertainty range of 2–5°C.[3]
Both Hansen’s new ECS estimate and his earlier estimate are based primarily on information about paleoclimate changes, particularly the extensively studied transition from the last glacial maximum (LGM) some 20,000 years ago to the preindustrial Holocene. But is his new estimate (or indeed his earlier estimate) justified by the evidence?
Hansen’s primary LGM to Holocene based ECS estimation.
For his LGM-based ECS estimate, Hansen assumes a 7.0°C rise in global mean surface temperature (GMST) between the LGM and preindustrial Holocene. This value is 56% above the 4.5°C rise that Hansen used previously2. Hansen cites three studies in support of his 7.0°C LGM cooling estimate (which comes from the second of these): Tierney et al. (2020), Osman et al. (2021) and Seltzer et al. (2021).
I published in 2021 an article that was heavily critical of the Osman et al. data-assimilation (reanalysis) based temperature reconstruction. Their reconstruction uses only ocean sea surface temperature (SST) proxies and is based on a single climate model that simulates an unusually cold LGM state[4] and, strongly influenced by the model simulations, produced a 7°C estimate of LGM cooling.[5] The proxy-only based reconstruction in the submitted version[6] of Osman et al. appeared more reasonable, and as shown in my article implied LGM to preindustrial GMST change of about 4.5°C.[7]
The Tierney et al. estimate of LGM cooling (6.1°C)[8] is based on a much larger set of SST proxies, which includes all those employed by Osman et al. used, but similarly uses no land temperature proxies. Tierney et al. uses the same single-model data-assimilation temperature reconstruction method as does Osman et al.[9] Therefore, my criticisms of Osman et al.’s reanalysis-derived LGM cooling estimate very largely apply also to Tierney et al.’s estimate.
The Seltzer et al. 5.8 ± 0.6 °C LGM cooling estimate is for land only and is limited to 45°S–35°N, so does not represent GMST cooling. The authors use a groundwater-based proxy type and a complex model to convert proxy values to surface temperatures. I have concerns about some aspects of their methods.[10] Moreover, their 5.8°C land cooling estimate is based on the error-weighted average of only 15 groundwater records, which show widely varying cooling[11] and may not be adequately representative of 45°S–35°N land areas. Seltzer et al. completely ignore the uncertainty associated with these issues. Their estimate is inconsistent with most proxy-derived estimates of mean ocean cooling over 45°S–35°N, which casts further doubt on its reliability.
I regard the recent Annan et al. (2022) LGM temperature reconstruction as producing a more reliable estimate of GMST cooling than the Tierney et al. (2020) and Osman et al. (2021) studies that Hansen et al. relies upon. The Annan et al. reconstruction uses a similar data-assimilation method to those studies, but with several key differences. Unlike them it uses a simulations from large set of acceptably dissimilar climate models, rather than a single model. Importantly, unlike those two studies, Annan et al. scale the model simulated temperature changes so that the initial guess model cooling estimates used are approximately centered on the data, to minimize model-generated bias. Moreover, Annan et al. use land temperature proxies as well as a larger set of ocean SST proxies to adjust the initial guess. They use the same SST proxy dataset as Tierney et al., but extend its coverage with data from a widely used earlier SST dataset, which in particular reduces Tierney et al.’s huge gaps in coverage of the Pacific ocean.
As a result of the much better proxy coverage, the use of multiple models and the debiasing step, the 4.5°C estimate of GMST cooling at the LGM that the Annan et al. reconstruction produces should be much more realistic than the Tierney et al. (2020) and Osman et al. (2021) estimates that Hansen uses. Indeed, Annan et al. criticize Tierney et al.’s approach, using very cold simulations from a single model, pointing out that it will produce a cool reconstruction regardless of whether the data points to a milder LGM climate.
By coincidence[12], Annan et al.’s 4.5°C GMST LGM cooling estimate is the same value as I adopted for the LGM derived climate sensitivity estimation in Lewis (2023)[13]. That study reworked Sherwood et al. (2020), a very influential World Climate Research Programme linked review of climate sensitivity evidence, which had assessed the LGM to be 5°C cooler than preindustrial.
Hansen’s ECS estimate is increased not only by adoption of an unrealistically large LGM cooling value, but also by very low estimates[14] for the various changes in forcing between the LGM and the preindustrial Holocene[15]. Hansen’s central estimate for the total Holocene to LGM forcing difference is −5.75 W/m2, much smaller than the −8.63 W/m2 assessed by Sherwood et al.(2020) and even further below the −8.93 W/m2 best estimate adopted in Lewis (2023). The LGM section of Table 1 in the Appendix gives details of all the data-variable estimates used to form the Sherwood et al. (2020), Lewis (2023) and Hansen et al. (2023) LGM–preindustrial Holocene based ECS estimates.
The combination of the large GMST change and small forcing change that Hansen adopts for the LGM results in a central ECS estimate of 4.8°C. By comparison, the Lewis (2023) LGM-based ECS estimate was 2.2°C, somewhat less than the corresponding ECS estimate from Sherwood et al. of 2.8°C.[16] Both these estimates are well below the lower bound of the 3.6 – 6.0 °C ECS 95% uncertainty range for ECS that Hansen estimates.
Hansen supports his LGM-based ECS estimate with one based on the difference in GMST between the LGM and the previous, Eemian, interglacial period. His estimate is therefore inflated by his assumption that the LGM was very cool. Moreover, compared to the LGM there is even greater uncertainty in Eemian GMST, ice-sheet forcing, and other non-CO2 forcing. IPCC AR6 mentions all these drawbacks and additionally points outs that accounting for varying orbital forcing is challenging for this period. Sherwood et al. (2020) did not attempt to estimate climate sensitivity from the Eemian to LGM or any other pre-LGM climate transition because the data available are far more limited than for the much more extensively studied LGM. I likewise did not do so in Lewis (2023), nor do I attempt such an estimate here.
Hansen’s analysis of the PETM event and its implications.
Hansen also considers the Paleocene-Eocene Thermal Maximum (PETM) warming event some 56 million years ago, adopting a best estimate for the warming involved of 5.6°C and assuming, as did Sherwood et al. (2020) and Lewis (2023), that greenhouse gases alone produced the increase in forcing that caused the warming.
Rather than estimating ECS using an estimate of the PETM forcing change, Hansen calculates what the PETM CO2 level would have had to be to cause warming of 5.6°C, based on his ECS estimate of 4.8°C, assuming a pre-PETM CO2 level of 910 ppm and that non-CO2 greenhouse gases contributed 25% as much forcing as CO2 did. Hansen thereby calculates a PETM CO2 level of 1630 ppm. In fact, the correct figure seems to be approximately1565 ppm; Hansen appears to have gone wrong somewhere in his calculations.
Although Hansen’s 910 ppm pre-PETM CO2 concentration value is closely in line with other estimates, the circa 1600 ppm value for the PETM CO2 concentration implied by his 4.8°C ECS and his other assumptions is much lower than the estimate of 2400 ppm, with a ±1 standard deviation range of 1700–3100 ppm, that Sherwood et al. (2020) reached after assessing the available evidence. It is also near the bottom of the 1400–3150 ppm uncertainty range given in AR6.
Moreover, Sherwood et al. assessed the best estimate GMST rise at the PETM to be slightly lower than did Hansen, at 5.0°C, and the non-CO2 greenhouse gas forcing to be higher, at 40% of CO2 forcing. All these differences contribute to Sherwood et al.’s PETM-based ECS estimate being, at 2.5°C, barely half Hansen’s assumed 4.8°C. Moreover, Lewis (2023), using identical data-variable assumptions as Sherwood et al. (2020) but the AR6 formula for CO2 forcing, which is more accurate at high concentrations than the simple formula Sherwood et al. used, obtains an even lower PETM-based ECS estimate of 2.2°C.
The PETM section of Table 1 in the Appendix gives details of all the data-variable estimates used to form the Sherwood et al. (2020)and Lewis (2023) PETM based ECS estimates, and the Hansen et al. (2023) estimate of CO2 concentration at the PETM. Figure 1 shows what the central estimate of the total change in forcing involved was, as a multiple of the forcing from a doubling of preindustrial CO2 concentration, for all three studies’ LGM and PETM estimates.
Although there are much greater uncertainties involved when estimating ECS from the PETM event than for the LGM – preindustrial Holocene transition, the available PETM evidence is closely consistent with the lower, 2.2°C and 2.8°C, ECS estimates derived from the LGM data-values used respectively by Lewis (2023) and Sherwood et al. (2020), but not with Hansen’s very high 4.8°C estimate of ECS.
It is also clear that Hansen’s claim that today’s human-made greenhouse gas forcing is, at 4.6 W/m2, at least comparable to the PETM forcing (which his assumptions imply was 4.67 W/m2) is strongly at variance with the evidence as assessed by Sherwood et al.[17] That evidence implies a best estimate of PETM forcing of 1.98× that for a doubling of preindustrial CO2 concentration[18] (versus 1.17× on Hansen’s assumptions), double or more the latest (2022) AR6-basis estimate, in Forster et al. (2023), of 0.88× for greenhouse gas forcing (1.00× when including that from ozone, a short lived greenhouse gas).
Figure 1.The forcing change between the LGM and preindustrial Holocene, and between before and during the PETM, implicit in each study’s assumptions. The forcing changes are expressed as a multiple of that from a doubling of preindustrial CO2 concentration. The associated ECS estimate equals in each case the corresponding assumed GMST change divided by the forcing change shown, so a higher forcing change implies a lower estimated ECS value.
Conclusions
I do not consider that Hansen’s climate sensitivity estimation properly assesses and fairly reflects all the available relevant evidence. Unfortunately, unlike Sherwood et al.(2020), IPCC AR6 and Lewis (2023), Hansen et. al. (2023) estimates ECS using only paleoclimate proxy-derived evidence, which generally varies considerably according to the proxies involved and to the methods used to interpret them. This opens the door for biased (cherry picked) assessments. For instance, Hansen et. al. do not even mention any studies (e.g. Annan and Hargreaves (2013) and (2022)) that find a much lower LGM – preindustrial warming than their chosen value.
Although I respect Hansen’s ability and considerable scientific contributions, in my view papers he leads are increasingly strongly biased towards overheated projections and dire conclusions.[19] The “political recommendations” with great impact on the society in Hansen et al. (2023) cannot be justified because their foundation is very shaky, as shown here for climate sensitivity and, in relation to warming-in-the-pipeline and ocean heating, in Michael Mann’s critique.
Nicholas Lewis 6 November 2023
Appendix
Table 1. Paleoclimate evidence data-variable best-estimate valuesa used to estimate S and ECS
| Description | Symbol | Sherwood et al 2020 | Lewis 2023 | Hansen et al 2023[20] | Comment re Hansen |
| ERF from doubled CO2 (W/m2) | F2×CO2 | 4.00 | 3.93 | 4.00 | |
| LGM | |||||
| Change in GMST (°C) | ΔT | −5.0 | −4.5 | −7.0 | |
| Changes in forcing, as ERF (W/m2) | |||||
| CO2 | −2.28 | −2.24 | See GHG | ||
| Methane (CH4) | −0.57 | −0.57 | See GHG | ||
| Nitrous oxide (N2O) | −0.28 | −0.28 | See GHG | ||
| Total greenhouse gas (GHG) | −3.13 | −3.09 | −2.25 | ||
| Land ice and sea level | −3.20 | −3.72 | |||
| Vegetation | −1.10 | −1.10 | |||
| Dust (aerosol) | −1.00 | −1.00 | 0 | Excluded | |
| Forcing excluding that from GHG | ΔFexCO2 | −5.30 | −5.82 | −3.5 | |
| Change in total forcing | ΔF | −8.43 | − 8.92 | -5.75 | |
| Dependence of feedback on ΔT (W/m2/°C2) | α | 0.10 | 0.10 | 0 | |
| Resulting estimate of ECS (°C) | ECS | 2.79 | 2.24 | 4.87 | |
| PETM | |||||
| Change in GMST (°C) | ΔT | 5.0 | 5.0 | 5.6 | |
| Fractional change in CO2 concentration | ΔCO2 | 1.667 | 1.667 | 0.72 | Implied |
| CO2 ERF relative to with log(concentration) | fCO2nonLog | Ignored | 1.117 | 1.19 | See note b |
| CH4 forcing as a fraction of that from CO2 | fCH4 | 0.40 | 0.40 | 0.25 | |
| Change in total forcing | ΔF | 7.93 | 8.70 | 5.75 | |
| Estimate of ECS (°C) | ECS | 2.52 | 2.26 | 4.8 | Assumed |
Notes:
a Data-values for Sherwood et al.(2020) and Lewis (2023) are medians that have been extracted from Table 3 of Lewis (2023), the notes to which are incorporated here by reference. See those papers for details of the sources used to derive their respective data-variable estimates.
b Using the Hansen et al. (2023) Table 1 formula for CO2 forcing
[1] ECS is defined as the global mean surface warming for a doubled CO2 concentration after so-called fast-feedbacks have been fully activated and the ocean has reached equilibrium (which it approaches within a thousand or so years). Earth system sensitivity (ESS), which also includes very slow feedbacks such as those from changes in ice sheets, represents global warming arising over much longer timescales. ESS is relevant when studying paleoclimate changes, but not when projecting changes over the next few centuries.
[2] E.g., in Hansen et al (2013) Climate sensitivity, sea level and atmospheric carbon dioxide. Phil Trans Roy Soc A. https://doi.org/10.1098/rsta.2012.0294
[3] Some of the latest generation (CMIP6) global climate models do have ECS values above 5°C, but they are generally regarded by climate scientists as being too sensitive.
[4] Actually two slightly different versions, iCESM1.2 and iCESM1.3, of the same underlying CESM1 GCM.
[5] Supporting my critique of their reanalysis, I showed that its co-located estimates were uncorrelated with values from the cave speleothem proxies it used. Moreover, unlike proxy-based reconstructions (e.g., Caufman et al. (2020)), which show early Holocene GMST 5,000–9,000 years ago being circa 0.5°C higher than late preindustrial (1750) GMST, their reanalysis showed that period as being significant cooler than late preindustrial GMST.
[6] The final, published version of Osman et al. was slightly different, with no mention of the change in the peer review files, and cooled marginally more near and at the LGM.
[7] Using a more recent model generation than the older ones Osman et al. used to derive the ratio used to convert their ex-polar sea surface temperature (SST) proxy-based estimates to GMST.
[8] No explanation is available of why, disconcertingly, this differs from the 5.9°C in their submitted manuscript.
[9] The Osman et al. cooling estimate may be greater because they use only a subset of Tierney et al.’s proxies, and have no proxy coverage at all in the central Pacific ocean.
[10] While Seltzer et al. validated their model on modern proxy data, it may not be valid for conditions at the LGM, when factors such as vegetation cover, rainfall patterns, and seasonal temperature and precipitation cycles were different. An additional concern is that Seltzer use two alternative methods to select LGM samples, which give noticeably different LGM cooling estimates (5.8°C and 4.8°C). They prefer the method giving the higher estimate, however it will tend to pick out particularly cold temperatures from datasets, and so may overestimate LGM cooling. Interestingly, the average of the Annan et al. LGM reconstruction’s cooling estimates for grid cells co-located with the 15 proxies that Seltzer et al. use is close to the 4.8°C estimate that Seltzer et al. obtain using their second method.
[11] Thus, excluding two particularly cool, low assessed uncertainty proxy estimates would reduce the estimate by 0.4°C.
[12] Lewis (2023) was submitted earlier than was Annan et al (2022).
[13] Lewis, N., 2023. Objectively combining climate sensitivity evidence. Climate Dynamics, 60(9), pp.3139-3165.
[14] Hansen’s estimate of the greenhouse gas forcing change, relative to that from a doubling of CO2 concentration, is 27% lower than the value assessed by Sherwood et al. and also adopted in Lewis (2023). Moreover, Hansen ignores the significant dust aerosol forcing change assessed by Sherwood et al., likewise also adopted in Lewis (2023).
[15] In the formula for estimating ECS, the change in forcing (ΔF) forms the denominator: ECS = F2×CO2 × ΔT/ΔF, where ΔT is the GMST change in equilibrium and F2×CO2 is the forcing from a doubling of atmospheric CO2 concentration. All forcing changes given in this article are for effective radiative forcing (ERF), the principal forcing metric used in AR6.
[16] Sherwood et al. (2020) and Lewis (2023) focused on a climate sensitivity measure, S, an easier to estimate approximation to ECS that is normally derived for global climate models instead of ECS. They accordingly converted their underlying paleoclimate ECS estimates into estimates of S.
[17] Hansen’s claim here that today’s human-made GHG forcing is 4.6 W/m2 is moreover inconsistent with the statement earlier in his paper that it is 4.13 W/m2 for 2022 (1.03× his value for a doubling of CO2 concentration, close to the AR6-basis ratio), and growing by 0.5 W/m2 per decade.
[18] Based on the AR6 formula for CO2 forcing
[19] Moreover, I’m not sure that Hansen is fully up with recent developments in climate science. For instance, when discussing different measures of radiative forcing, a topic on which Hansen wrote a seminal paper in 2005, he wrongly claims that (unlike for the formulae in his equation (3)) AR6 uses the biased-low Fo measure for its long-lived (non-ozone) greenhouse gas effective radiative forcing (ERF) estimates, and on that basis adjusts the AR6 forcing values. The 2013 (AR5) IPCC assessment report did use Fo, but AR6 uses a measure that, like Hansen’s preferred Fs, excludes the effect of surface temperature change.
[20] Hansen estimates ECS from changes in greenhouse gases (GHG) between the LGM and the mid-Holocene. The GMST estimate he uses is the same for that period as for the immediately preindustrial period (circa 1750). However, changes in non-GHG forcing agents are more uncertain for the mid-Holocene than for the preindustrial period (which most forcing change estimates relate to). In particular, aerosols and land surface albedo could have been significantly affected by deforestation starting well before the preindustrial period, a possibility mentioned in Hansen’s paper. This makes ECS estimates based on LGM to mid-Holocene changes more uncertain than those based on LGM to preindustrial changes.
Hansen had, perhaps still has, a habit of varying his message according to audience — alarmist pronouncements for Congress in 1988, or the present public but more modest claims in the scientific print. This is a sign of activism overcoming reasonable sense.
Call him “Sneaky” Hansen. News story – Solar and Wind Power booming in USA. It gets worse….a kill switch must be on all new US vehicles in 2026…..make those vehicles cost more and add more gubment control. We are in a war on all fronts!
What do you expect for a guy that has been arrested for his activism.
“but more modest claims in the scientific print”
The claims being criticised here were made in a scientific paper.
His upfront rants are bordering on utter lunacy… his print doesn’t quite reach that level .
Understand !?
So much ‘scientific cr@p written in ‘scientific’ papers. So what is your point?
This looks like a desperate drive by posting since you haven’t come back and explained your statement in more details and in replies to others thus your feeble attempt to fog up this thread died quickly.
Epic fail.
Look at this Nick:
In Hansen and Lebedeff Geophys. Res. Letters. Vol 15, n. 4, pp 323-326. We find the conclusion “… the 1987 global temperature relative to the 1951-1980 climatology is a warming of between 2 and 3 standard deviations. If a warming of 3 standard deviations is reached it will represent a trend significant at the 99% confidence level. However, a causal connection of the warming with the greenhouse effect requires examination of the expected climate system response to a slowly evolving climate forcing, a subject beyond the scope of this paper.” Six months later, in his testimony before congress Hansen stated “… the global warming is now sufficiently large that we can ascribe with a high (99%) degree of confidence a cause and effect relationship to the greenhouse effect.” Obviously the science is being represented differently to different audiences.
Hi Nick, you are stictly on target with your comment. How did it happen that this BS was reviewed?? best Frank
A political animal driving the current Biden administation’s need for net zero dictates.
I have always believed that Hansen was the spokesperson for bad science.
James H. is from Iowa. I’ve wondered if coal trains from Wyoming didn’t rumble past his house and keep him awake at night, thus stimulating his anti-coal feelings.
Most likely he never had any contact with those untermenschen coal miners. So he won’t have to feel bad about destroying their industry.
I think the author is being overly generous to Hansen. His paper is not based on poor science, it is based on alarmism – Hansen is desperately trying to reassert his previous status by making more and more alarmist ‘shock-jock’ style pronouncements.
and based on proxies and models?
I could appreciate if an astronomer provided proof that a gigantic asteroid will hit the Earth in the near future. That, I would believe. Such a proof is probably fool proof.
Well I have proxies from the Chixculub impact and models that prove, beyond doubt, that an asteroid might hit Earth in the next 20 to 2 million years. It’s imminent, I tells ya!
I’d say 100% of these authors completely ignore real measurement uncertainty associated with using proxies:
T (K) = C (K / unit) * P (unit),
then:
U(T) = U(C) + U(P) or
U(T) = sqrt[ U(C)^2 + U(P)^2 ]
Whatever the conversion constants are, I’m willing to bet the real U(C) are a lot larger than 0.1K. I’ve never seen any numeric estimates of these, they just hand-wave about “uncertain”.
That this forcing changes with time indicates that it isn’t a fundamental constant; a better description might be “fudge factor”./
Sigh. Lukewarmist nonsense criticizing off-the-rails Warmunist hyperdrive nonsense.
What exactly is “Lukewarmist nonsense” in the main post? If true it would be easy to determine because all used data and sources were published. Please help to bolster your claim…
I think it’s fairly obvious from the article that the author isn’t even trying to challenge Hansen’s overly alarmist claims, his extreme take on data using the upper band of probability (in some cases higher than almost every other source) or the validity of his source material. The only concern the author appears to have (which he cites Mann of all people in apparent agreement) is that the claims are higher than other papers. Either the author is doing an extremely cursory job or he is in broad agreement with the basic tenets of this approach, hence the mention of ‘lukewarmist’.
Thanks Richard. However, I asked Bruce…
I know, but it was such a big open goal that I simply couldn’t resist giving the ball a boot.
“…the author isn’t even trying to challenge Hansen’s overly alarmist claims…”
True, but it’s nice to see them fighting- proving that the climate ain’t “settled”.
And the – “Hansen also considers the Paleocene-Eocene Thermal Maximum (PETM) warming event some 56 million years ago, adopting a best estimate for the warming involved of 5.6°C and assuming, as did Sherwood et al. (2020) and Lewis (2023), that greenhouse gases alone produced the increase in forcing that caused the warming.”
Also might one of the processes have been, When a continent breaks apart, as Greenland and Northwest Europe did 55 million years ago, it is sometimes accompanied by a massive outburst of volcanic activity due to a ‘hot spot’ in the mantle that lies beneath the 55 mile thick outer skin of the earth. When the North Atlantic broke open, it produced 1-2 million cubic miles (5-10 million cubic kilometres) of molten rock which extended across 300,000 square miles (one million square kilometres). – See more at: http://www.cam.ac.uk/research/news/under-the-sea#sthash.LLR1IIV5.dpuf
Molten rock can vary between 700 and 1,200 degrees C (1,300 to 2,200 F). So 8,000,000 Km^3 of 1,000 C rock in one of the most important ocean circulation areas or back-radiation of CO2? Which might have the most affect?
And what other lava flows were going on at the PETM? How many candles should be on the Mt. Denali/McKinley birthday cake this year?
Over tens of millions of years, Mt. McKinley has been uplifted by tectonic pressure (collision of the Pacific plate with the North American plate) while at the same time, erosion has stripped away the mostly sedimentary material above and around it. (Portions of slightly older sea floor rock (flysch) are found near the 20,320′ true, or south summit, and they completely cap the 19,470′ north summit of Mt. McKinley.) The crystallization age of the Mt. McKinley granites is around 56 million years ago, giving it plenty of time to be uplifted and eroded to it’s present lofty condition.
https://www.nps.gov/dena/upload/Brief%20Geology%20of%20Mt.pdf
How many KM^3 in the Alaska Range?
It’s in those pesky assumptions about how GHGs “drive” climate.
YOU find it “pesky”. BUT: What if right??
After over 50 years of unproven claims, failed predictions, debunked papers, and increasingly shrill and more alarmist rhetoric from the climate enthusiasts there is still not a shred of evidence that they are right. All the evidence is against them so they are resorting to unscientific political machinations to achieve their aims. This does not give any indication that it is “right” in any way, just a pesky irritation that should have disappeared long before now.
Anybody with a slightly technical bent can use UChicago Modtran at climatemodels.uchicago.edu which is a much more tested climate model than Hansen’s curve-fit and spreadsheet.
Get the program on your browser screen. Leave 70km ”down” and to start with, the default “locality” is fine but later you will want to see the effect of clouds (Earth has 65% cloud cover).
Change the “offset” which is the surface temperature to something minor like .01 degrees so that the relative humidity box pops up. Use 400 ppm CO2 in the first box.
Check the RH box so that water vapor in the atmosphere changes with surface temp. as you change the “offset” in future runs. This will reasonably correct for the “water vapor feedback”.
Every time you change a box, the program reruns. Now that you have the boxes the way you want them for a base case, SAVE this to background (will be your base case).
Now CHANGE CO2 to 800 ppm from the original 400 ppm. Output will give you a new graph, watts per sq. M. etc. There will be fewer upward watts at the 70 km level, meaning more “Watts of warming” at ground level due to the CO2 you added to the calculation. Take note of the watts difference.
Now, your objective is to enter new “OFFSET” temperatures until the surface temperature is warm enough that the radiation to outer space through the atmospheric window balances the CO2 effect.
Leave the 800 ppm. Change offset to 1 degree. Note the change in watts. Mentally interpolate or extrapolate what your next guess for “OFFSET” should be instead of 1 degree offset, that will result in zero watts difference from your base case. Two or three guesses and you will have [New minus Background] watts zero or close to it. This is where the higher surface temperature emits the same amount of heat upwards as the CO2 in the atmosphere affects the surface.
Depending on what locality and cloud cover, and after enough runs, you will get numbers from about .7 to 1.7 degrees offset. Which is your ECS for the planetary conditions you assumed. And is long term and allowing for water vapor “amplification” and Planck feedback through the atmospheric window……
Also you need to remember that the planet actually emits 240 watts IR to outer space, not the 300 or so that Modtran gives you for its “cloudless tropical locality” that is its initial setting. When selecting “locality” that initial setting obviously doesn’t include any cloud cover reflection of solar SW back to outer space…which is actually a factor that can’t be ignored unless you are in a cloudless tropical locality, of course.
Net result will be an ECS a bit over 1 degree per CO2 doubling. So Crisis or Hype ?
MODTRAN has no hope of being useful to predicting what will happen with climate. The OLR from a tropical ocean at 303K can have a monthly average as low as 180W/m^2. Try to get MODTRAN to produce that OLR over a 303K surface.
If the tropical ocean was just a tiny proportion of Earth’s surface, MODTRAN may be able to offer insight. But tropical ocean is a significant portion of the global surface area.
The notion that Earth’s energy balance is controlled by a delicate radiative balance is just silly. There are far more powerful processes at work. Right now the white stuff coming into Alaska is being driven by wind at 250hPa reaching 106KILOWATTS/m^2. Sort of makes a few watts minuscule in the scheme of things. And that snow on the ground will reflect more than half of any sunlight that gets to it.
No climate model predicted that new snowfall records would be set year after year.
303 K surface with emissivity if .95 is going to emit roughly 450 watts/M^2. So where does the LW energy between the 450 emitted by the surface and the 180 emitted by TOA in your scenario ? Or are you mixed up by Steradians in some Planck’s function from an astrophysics textbook ?
There is no long wave radiation emitted to space from most tropical ocean surface. The OLR emitted comes from around 220C in the atmosphere.
You can get actual data here:
https://neo.gsfc.nasa.gov/view.php?datasetId=CERES_LWFLUX_M
or here
http://climexp.knmi.nl/data/iumd_olr_105-110E_3-8N_n.png
I have attached a copy for the ocean regoion north of Borneo. Monthly averages get as low as 187W/m^2 in this plot. If you lookout at 1X1 degree grid you will find monthly values over tropical ocean in the low 180sW/m^2
Like I posed above – try to get MODTRAN to produce that value: In fact, try to get MODTRAN to produce the long term average over tropical ocean north of Borneo of around 220W/m^2.
MODTRAN is not a useful tool for understanding Earth’s energy balance.
The situation can be summed up in 5 words:
There is no climate crisis.
The problem is that so many people believe there is a crisis….that it is now accepted as given and anyone who disagrees is vilified…so one is better off saying “yes CO2 causes some warming…I can even show you how much…and it’s well below crisis level.”
Story tip
“””Shell is suing Greenpeace for $2.1 million after activists from the environmental group occupied one of its vessels to protest against its North Sea oil drilling plans.
The oil major claimed that it had incurred significant costs after six Greenpeace activists boarded a ship carrying a floating production, storage and offloading vessel in January as it was en route to a shipyard in Norway. The activists occupied the vessel, which is ultimately intended for use at the Penguins field in the UK North Sea, for 13 days.
Shell said the protest had been extremely dangerous. It offered to drop the court action if Greenpeace paid it $1.4 million and agreed never to attempt to board or obstruct any Shell equipment at sea or in port ever again””” – The Times
https://www.thetimes.co.uk/article/shell-sues-greenpeace-for-2-1-million-over-north-sea-oil-protest-l0zzfvdh8
Can’t read the link without subscribing. But, that ship had no security? What right does a ship owner have to keep uninvited people off? Isn’t this comparable to a “home invasion” for which you could use gun fire? After all, you’d have no way of knowing that the “invaders” don’t mean you harm.
Time to follow in the footsteps and charge them with attempted piracy on the high seas? Russia doesn’t appear to have had any repeat incidents.
I should think that international laws would consider boarding a ship like that is a kind of piracy.
Nope, you’d be very wrong. The international law of the sea allows protesters to board and occupy a vessel as long as they don’t damage or remove property belonging to the vessel or master. There have been several cases brought to try to limit or stop protesters from boarding ships as this would constitute a security threat in the light of incidents over the last 20 years or so; all have been unsuccessful. It’s been left to individual countries to sort out if a vessel, with protesters aboard, subsequently enters territorial waters and approaches a port of that country. Usually the protesters get a suspended sentence and the ship owners get damages for loss of trade, etc. It’s been a problem for nearly 40 years and will still remain so as long as the protesters are indulged as naughty children and not treated as potential terrorists.
I think the loss of trade is the only answer if the “protesters” don’t do any actual damage to the vessel.
But in the early 1970s I was twice boarded by pirates in Indonesian waters and it wasn’t a pleasant experience, although all the ship lost was some crew posessions. Worse, one of the other vessels in the trade had a junior officer killed by pirates. Eventually we kept them off by running the fire pumps 24/7 and if any unidentified boat approached it was filled with water.
But certainly charge the “protesters” with loss of trade.
Well, clearly then, international law is no dam good. I don’t own a boat but if I did and anyone attempted to get on it who wasn’t in danger, they wouldn’t get on it because I wouldn’t let them. They could sue me. I don’t get it. Why is international law so stupid?
This isn’t international law as such. This is the ‘International Law of the Sea’ which has been built up over several hundred years or so by competing naval powers and merchant shipping to protect their own interests and increase their own maritime trade often at other nations expense. It only takes effect outside of territorial waters and you can occasionally find a precedent for almost anything if you look hard enough – the term ‘sea lawyer’ was not considered a compliment. Every so often attempts are made to change, amend or straighten out conflicting or messy legal problems in it but, more often than not, they are unsuccessful.
OK, but what’s the logic that says it’s OK to allow anyone to get on board who has no business being there? Maybe it made sense way back for a good reason but I can’t understand why it would make sense now. As you said earlier, the Russians don’t have this problem. Whoever tries to board probably gets eliminated so they can’t sue. 🙂
No it’s better than that – the Russians just arrested and charged them. They got released after a while but in order to sue they’d have to do it through a Russian court…
I know a little about it but not enough to give you the why’s and the wherefore’s unfortunately.
One of the first things one is supposed to do when presenting your idea is to provide a “survey of the literature”. Thus, I thought this was interesting:
For instance, Hansen et. al. do not even mention any studies (e.g. Annan and Hargreaves (2013) and (2022)) that find a much lower LGM – preindustrial warming than their chosen value.
Which is why climate “science” is more like religion, philosophy, psychology, sociology because they can’t prove anything. I doubt chemists ever debate anything because they can prove it in a lab.
What are “ocean sea surface temperature (SST) proxies”? An example?
Whatever they decide they are and fit the narrative.
All of the climate modeling work published by Hansen’s group is fraudulent, by definition, because of the underlying assumptions used, before the first line of code is even written. There is no ‘equilibrium average climate’ that can be perturbed by an increase in ‘greenhouse gases’. The concepts of radiative forcing, feedbacks and climate sensitivity to CO2 are pseudoscientific nonsense. The correct value for the ‘climate sensitivity’ is ‘too small to measure’.
In 1976, Hansen’s group copied the fraudulent one dimensional radiative convective (1-D RC) 1967 model developed by Manabe and Wetherald and added 10 more ‘minor species’ [Wang, Hansen et al, 1976]. Then in 1981 they added a slab ocean model, the CO2 doubling ritual and the calculation of the global temperature record using a contrived set of ‘radiative forcings’ to the 1-D RC model [Hansen et al, 1981]. There are 6 basic scientific errors in M&W, 1967 and nine in Hansen, 1981.
The fundamental error is that an LWIR radiative forcing by greenhouse gases does not produce a change in temperature. It produces a change in the rate of cooling by long wave IR emission in the troposphere. The total tropospheric cooling rate at low to mid latitudes is in the -2 to -2.5 °C range. A doubling of the CO2 concentration from 300 to 600 ppm produces a decrease in this cooling rate or a slight tropospheric warming of up to +0.08 C°. This small change cannot accumulate in the troposphere because of the normal diurnal and seasonal variation in the surface temperature. The ‘time marching’ procedure used by M&W and copied by Hansen is invalid. The horse does not even get out of the starting gate. The change in temperature does not accumulate in the first step or in any of the subsequent ‘marching’ steps in the model year needed to reach a fictional steady state.
The small increase in downward LWIR flux produced by a ‘CO2 doubling’ cannot penetrate below the ocean surface. It is fully coupled to the much larger and more variable wind driven evaporation. Any temperature rise is too small to measure in the normal variation of the latent heat flux.
There can be no ‘CO2 signal’ in the global mean temperature record. The main warming signal is produced by the coupling of the ocean oscillations, notably the Atlantic Multidecadal Oscillation (AMO) to the weather station record. The more recent warming also includes urban heat island effects, changes to the rural/urban station mix and downright data ‘fidlin’ disguised as ‘homogenization’.
Later, as computer technology improved, coupled atmosphere-ocean GCMs were used to simulate the global mean climate record using a contrived set of radiative forcings. The 1-D RC algorithms were hidden inside the unit cells of the GCMs. The models are still ‘tuned’ to match the ‘global mean temperature record’. In the Third IPCC Climate Assessment Report (TAR) [IPCC, 2001], the number of ‘forcing agents’ used in the climate models had increased to 15. In addition, starting with the TAR, the radiative forcings were separated into ‘anthropogenic’ and ‘natural’ forcings. This was used as a political tool to control the energy supply by claiming an anthropogenic cause for ‘extreme weather events’. Most of the initial work was performed at the UK Hadley Climate Center [Stott et al, 2000, Tett et al, 2000]. This is the foundation for ‘Net Zero’.
For more details see the following articles posted on my website.
The Double Fantasy of Net Zero
The ‘Equilibrium’ Climate Modeling Fraud
Time Dependent Climate Energy Transfer: The Forgotten Legacy of Joseph Fourier
A Review of the 1967 Paper by Manabe and Wetherald
A Review of the 1981 Paper by Hansen et al
Further details on climate energy transfer can be found in the book Finding Simplicity in a Complex World – The Role of the Diurnal Temperature Cycle in Climate Energy Transfer and Climate Change (RorschPublication.com).
It is time to stop playing with mathematical equations and climate models in the equilibrium climate fantasy land and address the real, time dependent, climate energy transfer physics.
Question: If you calculate ECS based only on the change in estimated temperature and green house gas concentrations over a period of 8,000 – 12,000 years does that mean you’ve ignored all other potential natural causes of the temperature change? I don’t see any mention of TSI, ocean currents, volcanic activity, etc. that might have contributed to a few degrees of warming over several millennia. I there were such factors wouldn’t that reduce the estimate of ECS due to GHG changes? I respect Nick Lewis’s independence and objectivity, but found no mention of this question in his paper.
Oops, my bad, I see that the table includes an estimate of “forcing excluding that from GHG” which could be described as natural forcing changes I suppose.
“natural forcing”- just more hypotheticals, like GHG forcing
To me, it seems absurd that climate “scientists” use the word “forcing”.
Yes, I have never warmed to the word either.
It places equilibrium assumptions on a non-equilibrium system.
Equilibrium considerations are useful for placing absolute limits in many circumstances, but often not so much in localised real world scenarios. You often don’t get to average them out in a simple manner.
Also, “forcing” sounds violent, abusive, domineering, etc. Inappropriate word to use in science. Anthropomorphic.
One used to find estimates a factor 10 off in early astronomical stuff. But now climastrology is catching up. 4.5 degrees is about ten times the much more realistic an likely 0.5 degrees.
In Mann’s comment, he starts with “Let me preface my commentary by saying that I have nothing but the greatest respect for James Hansen.”
then he clobbers Hansen 🙂
I find Mann’s first claim to be of interest: “So our best estimates today are that surface warming stops when carbon emissions stop, i.e.that there is no additional surface warming in the pipeline when emissions reach zero.” The reason is that many climatistas here in Wokeachusetts claim that the warming will be in the pipeline for centuries. I doubt that Mann can prove it anymore than he can prove that CO2 is the temperature control knob for the planet- but I can use it against the local climate nut jobs. 🙂
If man-made carbon dioxide emissions ever reach zero, it will make not the slightest jot of difference to the overall level of carbon dioxide in the atmosphere. Not one jot, absolutely nothing whatsoever. The emissiins reduction because of the idiotic Covid lockdowns were the climate enthusiasts best hope for showing man’s contribution to the levels of atmospheric carbon dioxide and the result was zero, no change; despite close scrutiny of the data there was absolutely no change ever detected in the level of carbon dioxide.
Sorry my fat fingers – emissions obviously.
I think the level was still going up trivially at the same rate as before- so there was no deceleration of the rise- thus, the lockdowns had no impact.
The author reports:
Hansen also considers the Paleocene-Eocene Thermal Maximum (PETM) warming event some 56 million years ago, adopting a best estimate for the warming involved of 5.6°C and assuming, as did Sherwood et al. (2020) and Lewis (2023), that greenhouse gases alone produced the increase in forcing that caused the warming.
Comment: So, CO2 really is the climate control knob (tweaked 25% by methane et al -see below paragraph)? Am I misreading numerous papers published during the past five (5) years disputing that conclusion?
The author also reports:
Rather than estimating ECS using an estimate of the PETM forcing change, Hansen calculates what the PETM CO2 level would have had to be to cause warming of 5.6°C, based on his ECS estimate of 4.8°C, assuming a pre-PETM CO2 level of 910 ppm and that non-CO2 greenhouse gases contributed 25% as much forcing as CO2 did.
Hansen thereby calculates a PETM CO2 level of 1630 ppm. In fact, the correct figure seems to be approximately1565 ppm; Hansen appears to have gone wrong somewhere in his calculations.
Comment: In the scheme of things (how much do we need to cut fossil fuel emissions, as what Alarmists insist that we do to save the planet) does a 35-ppm difference even warrant a comment, much less a criticism?
Conclusion:
Nic’s review, together with Hansen’s alarmism, notches up my bull feathers detection monitor reading a few more points indicating that “CO2 science” reporting is mostly bull feathers, and if the CO2 Coalition does not endorse it, don’t waste time reading it. Isn’t 30 years and hundreds of Papers beating this issue to death enough? Time to move on: N2N, natural gas to nuclear,
Does anyone know what this is about?
Reversed asymmetric warming of sub-diurnal temperature over land during recent decades
https://www.nature.com/articles/s41467-023-43007-6
Using BEST and CRU, so is bound to be something to do with Urban Warming and how the “adjustments™”, infilling and data fabrication are being used.
Nothing coming out of those not-data sets, is real.
Urban Heat Island Effect?
I think they are proposing that they noticed a pattern of higher night-time temperatures which has recently reversed, possibly as a result of reduced cloud cover. It’s a bit obscure and jargon-laden for me to understand much of it, I’m afraid.
The man started modeling Venuses atmosphere via radiative transfer algorithms built by the military and found the ultimate gravy train…
He probably has been the most instrumental in sowing blatantly false predictions, and derailing any progress to finding the right couple of million lines of code to make a climate model work.
His image in the future will be one of examples to students about what is not the correct way to reach a scientific conclusion.
Trofim Lysenko, James Hansen, Michael Mann, Phil Jones, Andrew Wakefield. You could just keep adding names to the list.
Most folks have a personal ‘coefficient’. Some are invariably punctual, some reliably half an hour or more late all the time. IPCC temperature forecasts needed a 0.3 coefficient multiplier to bring them closer to subsequent actual measurement.
Dr Jim’s near-hysterical apocalyptic climate presentation to the US Senate in 1988 (he genuinely believed it at the time), prompted a journalist to ask what changes we would see in NYC in 20yrs, he opined that the Westside highway would be underwater! The highway at the time was about 10 feet above the water. After 20yrs, the highway as still about 10 ft above the water (less about an inch of SL rise). In early 2000s, Jim said he meant in 40yrs at which time it will still be about 10 ft above water!
What did Jim do as a good consensus scientist? The Grandfather of Crisis Anthropo Global Warming, on the eve of his retirement, invented the jiggering of temperature data to get the T° to jibe with the catastrophist models. In 1998, he was disappointed that the super el Niño did not break the late 1930s – early 1940s global T° highstand. He pushed the 20th century high down over 0.5C and raised present temperatures to rid the record of the early high and the 40yr “Ice Age Cometh” cooling that followed – both of which were inconvenient for the Global Warming theory. It is no accident that NASA’s GISS weather station temps and RSS satellite temps are the highest of global data sets. Like IPCC, Dr Jim is doubling down on a notoriously legacy. History will, or should be brutal.
From National Geographic we have a Hansen statement regarding whether the Earth’s oceans could boil away.
“The key to the argument is a well-documented positive feedback loop. As carbon dioxide warms the planet through the greenhouse effect, more water evaporates from the ocean—which amplifies the warming, because water vapor is a greenhouse gas too. That positive feedback is happening now. Hansen argues that fossil-fuel burning could cause the process to run out of control, vaporizing the entire ocean and sterilizing the planet.”
So I think it’s fair to say Hansen wants ECS to be considerably higher than 4.8C if only he could justify it.
Apropos nothing, it is strange how you can tell an author by reading what they write.
I landed myself in the middle of this article, for no good reason, and quickly thought “Is this written by Nic Lewis?”
Nic, that is intended as a complement, not an insult. I fully intend to take the time to read it all later.
Compliment not complement.
At least he is looking at the historical evidence but has the cart before the horse. If he realised that CO2 follows the warming he would be on to something.
There was no one burning fossil fuels at the start of any of the previous glaciations.
The difference at the start of the current glaciation is that humans are burning fossil fuels. That may allow humans to exist on the ice as it accumulates but it will certainly accumulate.
New snowfall records across the NH this week. Latest today:
They are just calling 30-year weather “climate” now.
I think it pretty safe to assume anything from Hansen … “is based on poor science” or what people in the trade call “fraud” …
In the table showing the respective forcings of individual gasses, nowhere is H20/water vapor listed. Nowhere is it explained why, if there are positive feedbacks, the Earth doesn’t either go into a runaway greenhouse during interglacials, or snowball Earth during glacial maxima. Also, applying the magnitude of temperature change from the Eemian to the LGM and comparing it to the Holocene is wrong: the ice core data show that the warmest interglacials tend to be shorter, while longer interglacials like we’re probably in now tend to be somewhat cooler. That screams orbital forcing as the primary driver of temperatures during ice ages.
Feedback tends to be stabilizing. The question is the degree of stability. The more negative the net feedback parameter λ, the more stable the climate.
λnet is the sum of various feedbacks.
Planck ~ -3.5 Wm-2/K
Lapse Rate ~ -1 Wm-2/K ??
Water Vapor ~ +1 Wm-2/K ??
Cloud radiative effect? ~ 0 Wm-2/K ??
Sum positive and negative feedbacks = net feedback parameter. Normally Lapse rate + Water vapor is listed as a single term, as they tend to offset one another.
This determines the sensitivity i.e. how much other factors erode the direct increase of power to space with warming (Planck).
Some people want a very strong water vapor effect, so that it overwhelms the lapse rate effect. This would create a less stable climate.
We can see below that Hansen lists a substantially less stable climate regime than, say, Sherwood 2020.
λnet = ∆Fnet / ∆T
Hansen:
λ = -5.75 Wm-2 / 4.87 K
λ = -1.2 Wm-2/K
Sherwood:
λ = -8.43 Wm-2 / 2.79K
λ = -3 Wm-2/K
Sherwood lists a more stable climate than Hansen.
Hansen’s is suggestive of an almost unstable regime, but not quite. Runaway warming / cooling would only occur if the system became unstable, i.e. if the net feedback parameter became positive.
My apologies
Hansen:
λ = -5.75 Wm-2 / 7 K
λ = -0.82Wm-2/K
Sherwood:
λ = -8.43 Wm-2 / 5K
λ = -1.7 Wm-2/K
I inadvertently used the wrong ∆T corresponding to change in forcing since LGM.
Well..reposting myself from last week..
Your citation of different paleo-works (including yours!!) coming to different “results” only reinforces McShane and Wyner from back then:
=>(I corrected some typos)
Wow, amazing! Another proxy based article.. How do they keep getting those through peer review?
The editor and reviewers must be asleep for more than 10 years..
Is it really possible that people do not know about the rejoinder by McShane and Wyner?
(it can be found here and ended a discussion involving Mann, Schmitt, Amman and others quite conclusively.. very well worth the read as well as their initial paper and the comments it drew.
https://projecteuclid.org/journals/annals-of-applied-statistics/volume-5/issue-1/Rejoinder–A-statistical-analysis-of-multiple-temperature-proxies/10.1214/10-AOAS398REJ.full )
One of several key points McShane and Wyner made quite impressively, was that any data analysis MUST include uncertainties which might arise from the proxy selection
“””
Consequently, the application of ad hoc methods to screen and exclude data in-
creases model uncertainty in ways that are immeasurable and uncorrectable.
“””
If it was common sense before McShane and Wyner, it is now an official published answer to any proxy reconstruction article and any paper not addressing it is worthless, Hansen or not!
My point being, that all articles above must give the SAME result for the past global temperature, it is just hidden behind sloppy science and incomplete (systematic) error analysis!
RE: I really like the mash-up image of Lenin and Hansen. Good satire speaks for itself. However, I sometimes wonder whether captions aren’t in order to explicitly identify the many AI images you now use to open your posts even though their genesis may seem obvious. I would even like to see a brief explanation of how such images are generated, including the instructions given to the AI computer.
WUWT prides itself on deconstructing inaccurate, misleading and self-serving theories and arguments. Your opponents aren’t just the fear mongering evangelists, but the alternate realities they create. As an important news source opposed to the fantasy world of the green proselytes, WUWT should hold itself to a higher editorial standard for the images it uses. Good, honest photojournalism has not gone out of style even if print newspapers have faded from the picture.
Hansen is wrong. There is no real evidence that CO2 has any effect on our global climate. The AGW hypothesis has been falsified by science. There is plenty of rational to support the conclusion that the climate sensitivity of CO2 is zero.