I was wondering if a anyone had any insight into this new paper by Bjorn Stevens called Rethinking the lower bound on aerosol forcing. The basic goal seems to be to try and more tightly constrain the forcing due to anthropogenic aerosols. The IPCC AR5 5-95% range was -0.1 to -1.9 Wm-2. Stevens (2015) suggest – via various calculations – that the lower limit should really be -1.0 Wm-2, with an upper limit of around -0.3 Wm-2.
Of course, constraining the range is a good thing, but this result has the “skeptico-sphere” all excited, because it has implication for climate sensitivity. Nic Lewis has a post on Climate Audit and on Climate Etc.. It’s also mentioned on Bishop-Hill and, I presume (although I haven’t looked) on WUWT. As an aside, Stoat has an amusing post on how best to describe Willard Anthony Watts and his blog.
The reason the skeptico-sphere is all a flutter over this, is that if you redo Nic Lewis’s energy balance calculation, the reduced aerosol forcing means you get an ECS range (5-95%) of 1.05 – 2.2K and a best estimate of 1.45K. The TCR range drops to 0.9-1.65K. So, nice and low. Fantastic, if true. However, not only does this seem really implausibly low, it also means that Nic Lewis’ method is now diverging from the IPCC range (1.5 – 4.5K for ECS). In such a scenario, someone presumably has to be wrong (unless reality happens to just lie in the overlap region). Who is it? Well, I guess we don’t know, but we could hazards some guesses. For example:
- Paleo-climate is largely inconsistent with an ECS that is lower than 1.5K. It’s probably difficult to see how we could have moved out of a snowball Earth or between glacial and inter-glacials if the ECS was as low as 1.45K.
- The greenhouse effect itself is inconsistent with such a low ECS, unless – for some reason – the ECS has a very strong temperature dependence.
- The net feedback response (water vapour, lapse rate, clouds) is thought to be around 2 Wm-2K-1. An ECS as low – or lower then – 1.45K would suggest a feedback response of around 0.6Wm-2K-1, much lower then we would expect. I also have a feeling that there is something logically inconsistent about an ECS range that encompasses the possibility of no feedbacks, but maybe not.
Now, I don’t know the answer and am not claiming that such a low ECS must be wrong: it just seems clear that an awful lot of our current understanding must be wrong in order for it to be this low.
There is also an interesting irony about this paper. One of the arguments made in the paper is that the CMIP5 climate models typically underestimate the warming between 1920 and 1950. One way to resolve this would be if these models were over-estimating the aerosol forcing during this period (more negative than it actually is). However, the CMIP models have an ECS range from 2.1K to 4.6K. Therefore it seems a little inconsistent to use the result in Stevens (2015) to argue for an ECS with a range from 1.05K to 2.2K when the result in the paper is partly based on models with an ECS range from 2.1K to 4.6K.
Anyway, those are just my thoughts and the whole aerosol thing is quite a complex topic about which I know little. Hence, I wondered if any of my much more knowledgable readers might have some other insights.
...and Then There's Physics 
ATTP
My understanding is that palaeoclimate behaviour is inconsistent with an ECS below ~2K. Since anthropogenic aerosols have scaled with industrialisation, it seems likely that Stevens et al. has underestimated the anthropogenic aerosol negative forcing over the C20th.
Paging Karsten…
BBD,
When I read my post again after posting it, I thought the same.
Indeed, but I was trying to be subtle about it 🙂
I came here hoping you would summarize the 77 page manuscript.
Bjorn Stevens is a great scientist. I know him from the time I worked on clouds. Since he moved from LA to Hamburg one of the big names in Germany. It is probably futile to hope that mitigation sceptics stop claiming that real scientists would not publish results that are inconvenient for the IPCC.
For me this sounds like good news. It makes my recent results fit better. Thus I guess have to read these 77 pages.
Victor,
Excellent, then you can explain it to me.
The effective TCR (temperature change ratio) of CO2 is what it is, on track for about a 2C transient increase for doubling of CO2. The argument is over whether the other man-made GHGs are canceling the effects of man-made aerosol cooling. You can act like they cancel or treat that as irrelevant — as it all depends on whether the BAU conditions continue that provide the mix of GHGs and aerosols that apparently have given us the consistent upward trend in forcing that we are observing.
The second line of argument is that you demand that whenever Nic Lewis estimates a sensitivity for CO2, that he also provide a doubling sensitivity for methane, N2O, and all the other non-CO2 GHGs. He also needs to provide error bars for every one of these estimates. But first ask him why he doesn’t do this.
I don’t because I assume BAU conditions will continue and thus use the effective sensitivity.
ATTP,
” One of the arguments made in the paper is that the CMIP5 climate models typically underestimate the warming between 1920 and 1950.”
That point i do not really understand, i would speculate that BC-Forcing is incorrect (See Joseph R. McConnell et al. 2007)
“During the peak 5-year period from 1906 to1910, forcing at the D4 ice-core site from BC insnow was 1.02 W m–2, a fivefold increase frompreindustrial conditions, with ~0.76 W m–2attributed to industrial pollution BC (Fig. 3A).”
Also see here: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/d4-2007carbon.txt
So, RCP would we have a Global-Forcing arround 0.04W/m^2 for the time of very much BC in Greenland, that seems to me inplausible, because Global Forcing of BC is to much stabile over the full period of accumulation.
In Context with Greenland Summertemperature: http://www.motherjones.com/files/GreenlandSummerTemps_1.jpg
I tent to be al little skeptic about the claim that weaker increasing temperture for this period must to be a result of to strong negative Aerosol-Forcing, more to a to weak ? BC-Forcing in Snow/Ice-Pack.
But this is speculate from my side, i really dont now regional BC-Forcing of RCPs-Historicals.
ATTP,
” One of the arguments made in the paper is that the CMIP5 climate models typically underestimate the warming between 1920 and 1950.”
In M. Mann’s recent paper and his post on Real Climate about PDO/AMO having a major impact on GMST he has both PDO and AMO rising in phase in 1920, peaking at 1940 and still positive until after 1950. According to Mann’s paper, which is adopting a proposition that has been around for many years but now come to his convenience to explain the pause, one no longer is required to have nearly the model sensitivity to explain the 1925-1950 rise or the 1975-2000 rise. Here is Mann’s post: http://www.realclimate.org/index.php/archives/2015/02/climate-oscillations-and-the-global-warming-faux-pause/
Ron,
The Stevens paper does try to address this
which, I think, is suggesting that if it were internal variability, there should be more of a spread in the model trends.
Ron Graf:
“one no longer is required to have nearly the model sensitivity to explain the 1925-1950 rise or the 1975-2000 rise. ”
That is not even close to what Mann’s Real Climate post says.
The models were not programmed to consider PDO/AMO or any low frequency signal. The CMIP5 improved over CMIP3 by encouraging most if not all to have a random 5-12-year ENSO (high frequency) oscillation of much lower magnitude than what Mann and others suggest for PDO/AMO, which is a 55-62-year oscillation.
Ron Graf:
“The CMIP5 improved over CMIP3 by encouraging most if not all to have a random 5-12-year ENSO (high frequency) oscillation of much lower magnitude…”
Umm, ENSO-like events are emergent properties of better models like NASA GISS Model E or HadCM. And have been for a very long time. That’s a fact.
Reference your claim, please.
ATTP, Are you aware of any attempts to use the recorded GMST and look for energy closure against increases in ARGO measurements? Since aerosols are not dramatically varying year-year except for volcanoes, and GHG is not jumping up and down year over year, and ice and land albedos can be seen and accounted for. That leaves clouds, eruptions and ocean uptake as the only high frequency known variables. One would think that satellite observation of solar emission, clouds and ARGO ocean measurements could possibly tell a story of which is in control of abrupt GMST changes and to what degree. If none of the above correlate then it points to a hidden force. My answer in that case would be to look at temperature spatial homogeneity. Since the less the energy dissipates the more efficiently it can be re-radiated. If change in ocean currents affect the tropical-polar temperature gradient there does not have to be missing energy to explain changes in the energy budget. This would explain the ice ages if they could be linked with fundamental variances in thermohaline conveyor. Of course, M-cycle obliquity is likely a balance tipping trigger. The idea that ECS varies with temperature seems not only born out looking at 500ka charts, it makes common sense. The closer you take a system to its maximum potential the more it will resist (less sensitive) to further forcing. The paleo record shows a clear temp ceiling.
Not sure I should comment after a pub session, but let’s give it a go anyways (since I’m not gonna be online tomorrow).
First off, I only skimmed trough this highly technical paper. However, I had the pleasure attending two of Björn’s Talks in the last 18 months. While I wasn’t too impressed the first time, I was quite surprised to see him going even further during the local Seminar the second time. What baffled me the most was his disregard of Black Carbon (BC) aerosols in the 1910-1940 period. Figure 3b in [McConnell et al. 2007] clearly shows that BC forcing must not be omitted as it imposes a considerable forcing (albedo feedback) to Arctic sea ice during said period, leading to Arctic warming just as observed. Björn brushes it off in two sentences as if a forcing of +3W/m2 wouldn’t matter. Odd … to say the least. Relying on cooling sulphate aerosols alone does not provide an answer for the early 20th century temperature change (besides internal ENSO variability and recovery from strong volcanic activity). No clue why he didn’t discuss the BC issue in more detail. It’s not too far fetched to assume that CMIP5 models tend to underestimate the positive BC-albedo forcing.
Speaking of volcanic recovery, I can’t believe that he seriously thinks that the fact that the period 1920-1950 was a “period with relatively little volcanism” doesn’t have repercussions for global surface temperature. As shown in many papers, you should expect a positive temperature trend even in the absence of any external forcing as Earths energy budget tries to rebalance after strong volcanic activity, reinforced by the interplay with enhanced solar activity and BC forcing in our “real” case. Evidence which undermines the premise of his paper.
The remaining point of interest is the “expected” hemispheric albedo asymmetry which he cannot find in the CERES data. Way above my head at the moment, so I’ve gotta figure what he has actually done and whether or not ENSO variability is sufficiently considered. Hard to believe that it is the game changer his purports it to be (the very reason why he made it such a single author statement paper). [Wilcox et al 2013] still stands and I can’t see any reason why we should rethink anything with regard to aerosol forcing. Not sure how he could reconcile the interhemispheric temperature trend without a rather strong aerosol forcing.
Last but not least, it might be worth noting that I wasn’t the only one in the room who wasn’t too impressed. For the first time I really feel the need for a peppered rebuttal. Rebutting a highly technical and lengthy paper isn’t sth anyone does along his tightly constraint research lines though. But let’s see what can be done 😉
This is the title of Bjorn Stevens’ talk at the upcoming seminar at Ringberg:
Bjorn Stevens (MPI-M, DE): Some (not yet entirely convincing) reasons why 2.0 < ECS < 3.5
From:
Click to access Agenda_Ringberg_2015_20_3.pdf
“This is the title of Bjorn Stevens’ talk”
Oh, gosh, that will put curry’s and McI’s knickers in a twist … “but Lewis!”
Bjorn Steven’s sensitivity estimate is not an outlier- some few studies in the last two decades have offered lower estimates.
What is cautionary is that there is thus far little sign of sequential studies converging on a single value.
Graf said:
No real need to use the CMIP-class of models if the desire is to model ENSO. Adding the factor directly, via a proxy measure such as SOI, works very effectively:
Incidentally, the behavior of ENSO will likely soon be sufficiently decoded to enable better predictions..
http://contextearth.com/2014/11/18/paper-on-sloshing-model-for-enso/
Various studies have pointed to forcing factors such as QBO, TSI, and the Chandler Wobble as the primary drivers to the ENSO pseudo-oscillation, and all it takes is to compose these into a wave equation as Clarke et al suggest in their landmark 2007 paper.
Karsten,
Thank, pretty good for a post pub session comment 🙂
It sounds like you’re suggesting partly that what Stevens is defining as the aerosol forcing isn’t quite what others might regard as the aerosol forcing, and partly that he’s dismissing alternative explanations for the 1920 – 1950 warming. I guess the only confusion might be why the models don’t properly represent that post volcanic warming, or do they possibly so not get the change in volcanic forcing quite right for that period?
Russell
What is cautionary here is that low estimates of S are incompatible with palaeoclimate behaviour.
Karsten
Thanks for your response – much appreciated. I didn’t quite dare mention Wilcox et al. – I prefer to page you and STFU – but that was in my mind for early-mid C20th dominance of aerosol forcing*s*. Very helpful that both you and Christian bring the focus to bear on BC positive forcing. But bloody hell this is complicated. Not surprised you went to the pub 🙂
Russell
I should also have said that this is not the case. There is wide support for a best estimate of about 3K for S_ff / ECS. Outliers are defined by their distance from the widely-accepted best estimate.
@KarSteN
“What baffled me the most was his disregard of Black Carbon (BC) aerosols in the 1910-1940 period. Figure 3b in [McConnell et al. 2007] clearly shows that BC forcing must not be omitted as it imposes a considerable forcing (albedo feedback) to Arctic sea ice during said period, leading to Arctic warming just as observed.”
As you can see there is very little shortwave energy north of 60N latitude. Moreover because sun shines mostly in the summer and not much in the winter the time when BC on sea ice has the greatest effect is when the extent is the least. As well, it melts from both top down and bottom up where BC has no effect on bottom up melt rate. One last confounding factor is that Arctic sea ice retards ocean heat loss by both insulating the water surface against sensible heat loss and preventing evaporative (latent) heat loss altogether so BC causing faster sea ice melting actually increases the rate the planet cools.
Where BC has the larger warming effect is between 40N and 60N latitude over land. This is much closer to the major sources so the BC accumulation is much greater and total shortwave for albedo change to act upon is also much greater. What happens is that in spring when snowcover begins to melt BC floats to the top getting darker and darker as the melt progresses causing the transition from high albedo snow to low albedo dirt to happen much sooner.
How many here think ECS remains constant through glacial/interglacial cycles?
I certainly don’t. Transition from glacial to interglacial period happens very rapidly. ECS is very high at the tipping point. Thus empirical determination of large ECS during a glacial to interglacial transition does not indicate ECS is as high long after the rapid melt has finished. Non sequitur.
David
Before you continue to tell Karsten that he doesn’t know what he’s talking about, he does. Domain expertise and all that. Just a gentle hint.
@ David
I think and in my thougths, Greenland is just a Proxie for large Areas of NH. The main source of BC at this period should be European. Feel free to read T.H.Painter (2013)
“. Inferred annual surface radiative forcings increased stepwise to 13–17 W⋅m−2 between 1850 and 1880, and to 9–22 W⋅m−2 in the early 1900s, with snowmelt season (April/May/June) forcings reaching greater than 35 W⋅m−2 by the early 1900s. ”
And:
“Simulations of glacier mass balances with radiative forcing-equivalent changes in atmospheric temperatures result in conservative estimates of accumulating negative mass balances of magnitude −15 m water equivalent by 1900 and −30 m water equivalent by 1930, magnitudes and timing consistent with the observed retreat. ”
It is also to notice, that BC is not BC, sounds strange, i know, but BC e. g from Biomas-burning(often called Organic BC) have more then a warming event, because on short timscales it coiuld cause cooling. So the Mainquestion is, how many is from human and how many not. Another point has Karsten spot on, Vulcanic Recovery, which should driven Soutern Hemisphäre increase, while NH was dominated by BC melting with little Lag of Temperature incease.
In my opinion, there is no Way to say BC is not so important
@ BBD
Its not a coincidence, that Karsten and me come to BC, because we talked about this Topic a few Years ago. And i would not say that Stevens is false, but have some doubts about his claims. I cant see, that the less increase in Models for Period 1920-1950 must be a result of overeastimated cooling effects of Aerosols. For me it looks like a to weak BC-Forcing over this period. This also explain what happend after 1940 when Globals beginn to cool. In Joseph R. McConnell et al. 2007, you can see, that then BC rapidly decrease and Sulfur massive increase.
77 pages? I wasn’t expecting that after reading an abstract which seemed to describe a fairly simplistic inverse modelling exercise. Feels a bit of a mismatch to comment solely on the abstract and what others have written now, but er… here goes…
Karsten’s covered pretty much all the main themes about which I was curious. Based on the abstract I just don’t understand why anyone would view this as ground breaking, or something which could be taken to invalidate all previous estimates.
One part of the abstract jumped out: ‘ a forcing more negative than −1.0 W m−2 is implausible, as it implies that none of the approximately 0.3 K temperature rise between 1850 and 1950 can be attributed to northern-hemispheric forcing.’
Perhaps there’s more to it, but this suggests to me he’s saying a -1 W/m2 present-day global average aerosol forcing would indicate a northern-hemisphere total net forcing of 0 W/m2 between 1850 and 1950. If we take the AR5 forcing history, which uses a present-day -0.9 W/m2 aerosol forcing, the global average total net forcing between 1850 and 1950 is about 0.6 W/m2, which includes global average aerosol forcing of about -0.2 W/m2. If we assume all aerosol forcing in this period was NH and net forcing from all other factors was hemisphere-neutral that still indicates NH total net forcing over 1850-1950 of 0.4 W/m2, which is a good distance from zero.
By my calculations, proportionally you’d need to get to -1.8W/m2 for present day forcing before 1850-1950 NH total net forcing became zero. Must be missing something?
On a more general point, though plausibly related, I was confused by this line: ‘This model, which contains terms representing both aerosol-radiation and aerosol-cloud interactions well represents the known time history of aerosol radiative forcing…’ Presumably this just means he assumes a particular temporal structure for aerosol forcing and just varies magnitudes proportionally within that structure. I didn’t think it was considered that the true temporal structure was actually known to any real extent.
@ dhogaza, As I said, Mann used the AMO/PDO to explain the pause. But logic would require what is down now must have been up (1975-2000) and down (1950-1975), etc… You can’t deny this just because Mann ignored it. He did show us the graph.
dhogaza says to Ron Graf: “Umm, ENSO-like events are emergent properties of better models like NASA GISS Model E or HadCM. And have been for a very long time. That’s a fact. Reference your claim, please.”
I will concede whatever it is you are contesting about the model’s technological evolution, and which are better models. My point was that NONE of them account for PDO/AMO or ANY other low frequency oscillation. The models you point out do simulate ENSO but the “emergence” is mainly controlled by the random start condition from a pre-industrial mode. Taylor et al 2012, pg 494 col 2 here: http://envsci.rutgers.edu/~toine379/extremeprecip/papers/taylor_et_al_2012.pdf
@ KarSten: “As shown in many papers, you should expect a positive temperature trend even in the absence of any external forcing as Earths energy budget tries to rebalance after strong volcanic activity,…”
It depends how responsive one feels the GMST is to delta in ERF. If you say balance is quick after volcanoes then it should be the same for CO2, and thus it’s not waiting in a bank to emerge as many I think wrongly postulate.
I noticed that my main point that the 500ka paleo record shows a temperature ceiling, implying a high resistance termination, is yet unchallenged. Here is a 450ka chart: http://blog.heartland.org/wp-content/uploads/2013/03/gw1_htm_m59f1e64d.png
BTW, the chart plots CO2 to proxy temperature record. Notice the correlation, yet nobody seems to be claiming that CO2 was the cause of the ice ages any more. Then if CO2 lags temperature…hmm maybe it’s because of an increased habitability zone, and maybe the life-cycle (trees) controls atmospheric CO2 on a geologic scale?
Here’s another 450ka with two proxies and arctic ice volume: http://www.astro.virginia.edu/class/oconnell/astr1210/im/temp-changes-450Ka.png
Ron,
Why is that surprising. If your main forcings are ice-albedo and CO2 being released as we warm, then some kind of ceiling is not that surprising. The ice-albedo effect is limited by the amount of ice available and the CO2 is limited by Henry’s Law. The main difference today is that we’re simply digging up and burning fossil fuels and so there is no natural limit. How much we warm will broadly depend on how much we burn.
PaulS,
Thanks for the comment. I must admit that I’m rather confused by this whole issue. I shall have to give it some more thought.
Ron Graf
What ATTP said.
Here’s a 65Ma temperature reconstruction:
Attentive readers will note that global average temperature during the Paleocene and Eocene was very considerably higher than during the Plio-Pleistocene. There is no ‘temperature ceiling’ implicit in the Pleistocene glacial cycles of the last ~900ka. Climate responds to changes in forcings. The PETM (see above at Paleocene-Eocene boundary) is a splendid example of a towering hyperthermal driven by a substantial release of GHGs into the atmosphere. Proof positive that GHG forcing is highly efficacious.
Ron Graf
CO2 (and CH4) are feedbacks to orbital (Milankovitch) forcing. They amplify and globalise climate change – warmer during deglaciation and cooler during the slide back into glacial conditions. They are a part of the overall physical mechanism, feedbacks, not forcings.
Christian
Thanks for the response. This has clarified something that I had not previously known about C20th climate behaviour. Ellie Highwood’s blog is also illuminating.
Karsten: “What baffled me the most was his disregard of Black Carbon (BC) aerosols in the 1910-1940 period. [..] Björn brushes it off in two sentences as if a forcing of +3W/m2 wouldn’t matter.”
Hi Karsten, thank you. Would you mind expanding on the above – what was the gist of the brush-off? Cheers.
David Springer, it would be a mistake to assume that BC’s effect is limited to its effect on sea ice. From 1800 to 1950, the Peppered Moth (Biston betularia) was essentially replaced by the Carbonaria form in those regions of Europe where it had evolved. That shows clearly that BC had significantly darkened vegetation across that region, reducing albedo. This is an effect that occurs in mid latitudes, and probably strongest in late summer to early autumn (when leaves have had the longest exposure to BC). Across the range were it occurred, snows would also have been darkened by BC. I can agree that the actual forcing from BC will be very hard to determine, but dismissing it on the apparent assumption that its primary effect is that in the darkening of sea ice is clearly inadequate.
Ron Graf
“yet nobody seems to be claiming that CO2 was the cause of the ice ages any more. ”
Did someone really do that?
BBD: “CO2 (and CH4) are feedbacks to orbital (Milankovitch) forcing. They amplify and globalise climate change – warmer during deglaciation and cooler during the slide back into glacial conditions. They are a part of the overall physical mechanism, feedbacks, not forcings.”
Feedbacks are forcings. The net is effective forcings. But I understand what you mean; in the ice-age context you believe M-cycle is the driver and GHG is an amplifier both hot and cold. This hypothesis if supported by study would be settled science; It fits what’s desired. Berkeley’s Dr. Richard Muller spent several years trying to confirm it. He even discovered a fourth M-cycle that he thought could be to key. But the numbers did not add up. To this day there is no overall consensus, no 97% or even 60% (in my reading), on the mechanism completely explaining the glaciation cycle.
The first problem in the logic of the amplification hypothesis is that if it is true CO2 would be expected to continue the spiral as long as it still had warming power. The proxy record indicates that levels of CO2 did not get up to present levels. It’s true that CO2’s effect diminishes logarithmically with its delta rise. But if today’s levels can impart warming, then we should have seen it in the last 1000ka. Warmer oceans lose capacity to store CO2. So that exacerbates, not mitigates, atmospheric increase in CO2.
A second problem is that there is just not enough delta forcing in m-cycles. What they mainly do is change the distribution of solar radiation (insolation). Yes, ice albedo, especially below 70 degrees latitude is going to change the energy budget significantly. But if this was the only mechanism we would see they glacial cycle right in phase with m-cycles. This brings us to the third problem.
Not only are m-cycles out of phase with glaciation, there are abrupt transitions from glacial to interglacial and back. M-cycles are gradual. So not only can m-cycles not be the driver, CO2 can’t either because it lags, particularly in abrupt changes. It’s a follower.
In an otherwise a chaotic signal there is a correlation with M-cycle obliquity but only every second or third 43ka cycle. But the glaical cycle followed the 43ka pattern prior to 1000ka BP. So there is something there.
Whether you find flaw with my thoughts regarding thermohaline and ice-age I think it fits the change in temperature profile pointed out in the 65 million-yr proxy record. Plate tectonics change the path and magnitude of ocean currents. I would be interested to see an ocean GCM of Pangea era Earth. If the single super-continent configuration freed circulation rather than restricted it that would explain warming then under my theory.
Ron Graf:
The solubility of CO2 in water is approximately linear. Ergo, increases in atmospheric concentration will be linear with increasing GMST, a relationship clearly seen in the ice core data. In contrast, CO2 forcing increases with the logarithm of CO2 concentration. Therefore an initial increase in temperature would quickly result in a new equilibrium of CO2 and temperature, where quickly is understood in geological terms. What we would not expect – indeed would be flabberghasted to see – is the temperature spiralling out of control from any initial perturbation.
When you get even basics this wrong, why would I have confidence in anything else you have to say?
@ Ron Graff,
“Not only are m-cycles out of phase with glaciation, there are abrupt transitions from glacial to interglacial and back. M-cycles are gradual. So not only can m-cycles not be the driver, CO2 can’t either because it lags, particularly in abrupt changes. It’s a follower.”
Interesting points, thanks. It’s not really an area I’ve looked into much, but your post set me thinking NOAA seem to back your point up, they say:
>>>” Another interesting fact shown in Figure 3 is that temperature variations in Antarctica are in phase with solar radiation changes in the high northern latitudes. Solar radiation changes in the high southern latitudes near Antarctica are actually out-of-phase with temperature changes, such that the coldest period during the most recent ice age occurred at about the time the region was experiencing a peak in local sunshine. This means that the growth of ice sheets in the Northern Hemisphere has an important influence on climate worldwide. ”
Their Fig3:
Why are is the Arctic ice cap affecting global temperatures? Ruminating on it… if we consider an initial state of an ice-free Arctic, then:
i) there is a +ve feedback from loss of albedo – BUT there isn’t much sunlight there during most of the year, and
ii) there is a -ve feedback as the sea there is then able to radiate directly to space (and evaporate to atmosphere). So warmer waters from the Atlantic circulation can now lose heat energy more effectively.
If the effect of ii) is greater that the effect of i) the planet cools (significantly I would think)
iii) Then as the planet cools, ice fills the Arctic, and the arctic ocean is now “insulated”. The sea cannot lose heat via radiation or evaporation.
iv) The Atlantic can now no longer lose heat by shifting it to the Arctic. Planet’s temperature rises.
Just my thoughts, but it would explain why it’s only the 5th solar cycle that flicks us between glacial states, during the rest of the time the planet is cooling or heating via heat loss/gain at the N-pole.
ATTP wrote: “Nic Lewis’ method is now diverging from the IPCC range (1.5 – 4.5K for ECS)”
So what. Nic Lewis’ method (aka Otto (2013)) forced the IPCC to drop their likely range for ECS from 2.0-4.5 K (AR4) to 1.5-4.5 K (AR5). If further publications make it necessary, AR6 could go even lower. The field is evolving. Skeptical blogs assert that projections of future warming have dropped with each IPCC report, but I haven’t verified this claim.
ATTP wrote: “The greenhouse effect itself is inconsistent with such a low ECS, unless – for some reason – the ECS has a very strong temperature dependence.”
Who in their right mind believes that ECS is constant and linear over the 33 K range from 255 K to current temperature?
ATTP wrote: “Paleo-climate is largely inconsistent with an ECS that is lower than 1.5K. It’s probably difficult to see how we could have moved out of a snowball Earth or between glacial and inter-glacials if the ECS was as low as 1.45K.”
It is tough enough to estimate forcing change and temperature change over the periods used by Otto and by Lewis (which have written records and instrumental data). Proxy data from the LGM?
Frank,
Because if you have mutiple methods for estimating the same thing and one of them is very different to the others, it’s important to try and understand why.
I don’t know if it is strictly linear, but I don’t think that there is strong evidence for it being highly non-linear. Remember, the 33K change does not include changes in albedo, so is really only representing the fast feedbacks. I don’t think that the water vapour or lapse rate response is sufficiently non-linear, for example.
So what? I didn’t say it was easy, but firstly there are estimates of ECS from paleo studies. Furthermore, my point was more that if our climate has as low a sensitivity as some are suggesting, then it would have been more difficult to have moved out of some of our past climates.
Morning aTTP,
“Furthermore, my point was more that if our climate has as low a sensitivity as some are suggesting, then it would have been more difficult to have moved out of some of our past climates.”
Well, wouldn’t my new pet theory (:-D) about Arctic ice do just that? Imagine an ice-free Arctic in winter. Zero solar in but tens of W/m^2 over 14 billion square m of open ocean out.
David,
And how do you get an ice free Arctic? Magic?
ATTP wrote: “I also have a feeling that there is something logically inconsistent about an ECS range that encompasses the possibility of no feedbacks, but maybe not.”
Skeptics claim that positive feedback is logically inconsistent with a stable climate, while you have the feeling that negative feedback is logically inconsistent. Both positions reflect prejudice, not logic. If the earth were a black body, it would emit 3.3 W/m2 (Planck feedback) more radiation to space for every degK the surface warmed. (Since this is a loss to the planet, it is often expressed as -3.3 W/m2/K.) Rising absolute humidity blocks about 2 W/m2/K of this outward flux – a positive feedback. Since rising absolute humidity also changes the lapse rate, the upper atmosphere warms more than the surface, increasing OLR by almost 1 W/m2/K – a negative feedback (conventionally -1 W/m2/K). It is trivial to imagine ways that cloud feedback could be positive or negative. Since both negative and positive feedbacks make physical sense, the sum of the non-Planck feedbacks can logically be positive, negative or near zero. The only thing we can be sure of is that the sum of the non-Planck feedbacks can’t get too close to +3.3 W/m2/K and produce a runaway greenhouse effect.
Climate models project that about 2 W/m2 more radiation will escape to space (-2 W/m2) through clear skies for every degK of surface warming. This is in reasonable agreement with the 2.25 W/m2/degK increase in LWR from clear skies observed from space during the 3.5 K increase in GMST that occurs every year. Manage et al: http://www.pnas.org/content/110/19/7568.full
The sum of Planck feedback and all other feedbacks is called the climate feedback parameter (in (W/m2)/degK) and its reciprocal (technically the additive inverse of its reciprocal) is ECS (in degK/(W/m2)). Ignoring cloud and slower ice-albedo feedback, we are at -2 to -2.25 W/m2, which is an ECS (for 2XCO2) of 1.65-1.80 K. This is in the center of the range reported for energy balance models like those used by Lewis and others – modestly higher than Lewis’s latest calculation and modestly lower than Otto (2013), but well within their confidence intervals. So we might conclude that energy balance models are predicting that the remaining net feedback (cloud feedback + slower ice albedo feedback) is negligible compared with water vapor + lapse rate. An ECS for 2XCO2 of 3.7 K is equivalent to a climate feedback parameter of -1 W/m2/K, so climate models are predicting that cloud feedback + ice albedo feedback is about +1 W/m2/K.
The inconsistency between energy balance models and climate models mostly revolves around whether climate models get cloud feedback right. The difference between medium and high sensitivity climate models also arises from cloud feedback. The behavior of clouds depends on their parameterization, not fundamental physics. The IPCC acknowledges that cloud feedbacks are the largest source of uncertainty. Observations from space show that cloud feedback in LWR is negligible during the annual cycle. The changes in the SWR channel are harder to interpret, due to the difference in ocean and cloud coverage between the two hemispheres. However, observations from space clearly show that climate models fail to reproduce the changes in OLR and reflected SWR that are observed from space during the annual cycle. Even worse, different models show problems in different channels.
The lower half of Nic’s latest pdf (ECS 1.0-1.5 K) makes me uncomfortable, but the upper half doesn’t appear to conflict with anything we know with reasonable certainty. Which explains why it made it into AR5. A better question is whether we should continue to believe in climate models with high climate sensitivities. Otto (2013) reported ECS of 1.2-3.9 K (5-95% ci) with a best estimate of 2.0. The central estimate for LC14 was lower, but the upper end of the confidence interval wasn’t any lower. Lewis’ latest (non-peer reviewed) confidence interval is 1.05-2.2 K (5-95% ci). The exciting news for skeptics shouldn’t be the central estimate for ECS of 1.45 K, but what might happen to the upper end of confidence intervals for TCR and ECS if Steven’s work is widely accepted.
@aTTP,
Not magic. I presume you didn’t read my post? Or did I not make it clear enough? It’s melted by warm Atlantic currents.
Phase 1) When the Arctic is frozen over, the ocean below is prevented from radiating to space. Warm currents from the Equatorial Atlantic can’t lose heat via radiation to space at the Arctic, so energy builds up. And builds up. And builds up. Eventually there’s enough heat in the system to start melting the ice again, leading to…
Phase 2) Only when the ice cap has lost sufficient area can the process shift to the opposite phase. As the Atlantic can now lose heat via the now Ice free (or mostly ice free) Arctic the energy in the system starts to fall. And fall. And fall. The Arctic is also evaporating water vapour, but there’s limited solar. So cold temperatures + moisture –> snow, snow, snow, snow, snow, and the ice builds up, and we move back to phase 1.
The M-cycles may be the final “push” that melts that last bit of Arctic ice sending the system between phases. That explains why it’s only the peak cycles that do so. The change in their own energy is (as you pointed out the other day) not sufficient on it’s own.
The bad news is (if the theory is correct) we are doomed to an ice age – so we’d better start pumping out some CO2 :-D.
Frank,
Well, that’s obviously wrong.
This isn’t what I said. I was wondering if it is logically consistent for feedbacks to exactly cancel. It might not be logically inconsistent, but does seem physically implausible. It would probably mean that internal variability should be incredibly small, and we know this is not true.
David,
You’re just waving your arms wildly. I can’t really respond to flailing.
Frank,
“A better question is whether we should continue to believe in climate models with high climate sensitivities.”
This is not a question of faith, it is more a point of less certainly about this Values, LC14 can also not exclude high climate sensitivities, because there is to much uncertainy. On the other Hand, every methode is in large part very limited For those like L&C Otto et al is it also true.
Examples:
Adjust to Stevens (2015) = lower ECS/TCR
Adjust to Cowtan and Way (2013) = higher ECS/TCR
Adjust to D.A Ridley et al (2014) = higher ECS/TCR
Adjust to Durack et al (2014)= higher ECS
So what? In fact, we dont know a best value of ECS/TCR for L&C//Otto-Methode. We not can exclude high climate sensitivities, also low ones.
PS:
And it meaning nothing, that CIMP5 in Forecast shows a to large increase, that must not mean, that sensivitiy is to high (but could).
See also Schmidt et al. 2014
“Climate models projected stronger warming over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El Niño evolution, may explain most of the discrepancy.”
In that way, i would be a bit more carefully to be sure about the reasons
” Paleo-climate is largely inconsistent with an ECS that is lower than 1.5K. It’s probably difficult to see how we could have moved out of a snowball Earth or between glacial and inter-glacials if the ECS was as low as 1.45K. “|
If Paleo climate is climate over quite extended periods of time [ the study of changes in climate taken on the scale of the entire history of Earth.] small responses can move mountains
Christian, in the light of the headline of this blogpost the Schmidt et al. claim gaíns indeed some more importance. There are: 1. aerosols, which forcing could be reduced about 30-50%. 2. volcano: we don’t see a remarkable change in this forcing during the last 15 years. 3. solar inputs: according to AR5 forcings this is only about 3% of aerosol- forcing in this time, more or less negligible.
And IF the aeosol-forcing is indeed reduced than you have to lower TCR/ECS to replicate the observed temperatures. There seems to be no other way?
angech,
You’re essentially arguing for both low and high sensitivity. How our climate responds to radiative perturbations is essentially what climate sensitivity is. You can’t argue that it’s low and that the response can also be high. That’s largely inconsistent.
Frank,
That could be true, but one of the arguments that Mann is making is that the discrepancy can be due to internal variability and hence that you don’t necessarily need to reduce the climate sensitivity to explain the discrepancy. Additionally, as Karsten is pointing out, the Stevens study seems to have ignored some factors that others would regard as contributing to the aerosol effect.
ATTP: Mann indeed showed internal variablity , in his “key-figure” http://images.huffingtonpost.com/2015-02-12-Sci15FigHuffPost-thumb.png there are up’s ( i.e. post 1920) and downs( pre 1970). AFAIK such “decadal fluctuations” are not considered in any CMIP5 model, so it seems to me that the last word is not spoken in this case.
Stevens ignored factors: Also in this case the dialogue is pre-matured I think. The main point of Kasten AFAICS is the “BC” and when one looks at the 1920-1950 time span as Stevens did and calculates the relative forcing-change of BC and aerosols in this time based on the AR5-forcings: there is only 10% BC vs. aerosols. I don’t know if this is a game changer. Anyway, I think that also Stevens was aware of this point, so let’s see what he says in this context.
Frank,
“There are: 1. aerosols, which forcing could be reduced about 30-50%”
If.. Yes
“we don’t see a remarkable change in this forcing during the last 15 years. ”
That is what u saying, if D.A Ridley et al (2014) right, then:
” Incorporating these estimates into a simple climate model, we determine the global volcanic aerosol forcing since 2000 to be −0.19 ± 0.09 Wm−2″
And…
” 3. solar inputs: according to AR5 forcings this is only about 3% of aerosol- forcing in this time, more or less negligible.”
Mhm, that looking to me inconsistent, because how do you know, that discrepancy is a result of 1 process, could also be multiple processes and then, small bias in solar Forcing could is also a part of explanation
And..
“And IF the aeosol-forcing is indeed reduced than you have to lower TCR/ECS to replicate the observed temperatures. ”
That is a game we should not play, it is also IF and with certain, we dont know, could also be, Stevens is wrong, or D.A Ridley et al (2014) is wrong. So, for both of them, havent read rebuttal for now.
And i repeat myself:
In that way, i would be a bit more carefully to be sure about the reasons
ATTP,
“That could be true, but one of the arguments that Mann is making is that the discrepancy can be due to internal variability and hence that you don’t necessarily need to reduce the climate sensitivity to explain the discrepancy. ”
Yes, this statement by you is consist with Gerald A. Meehl et al. (2014)
“If the recent methodology of initialized decadal climate prediction could have been applied in the mid-1990s using the Coupled Model Intercomparison Project Phase 5 multi-models, both the negative phase of the IPO in the early 2000s as well as the hiatus could have been simulated, with the multi-model average performing better than most of the individual models.”
And thats it, there is no certain about what clearly cause the discrepancy, as shown in Meehl et al. (2014) also could be a resultat of natural variablitiy which is not in phase with models. Its to early to conclude models are to sensitive.
Chistian, I think you miss the point. The discussion is not about the “discrepancy” in post 2k-Temps. Stevens investigated the aerosol-forcing and looks at much older time spans. So the need to reduce ECS/TCR ( IF he’s right) arises also for 1920-1950 and the whole record since 1850 which was not the point of Ridley (2014).
Frank,
See comments here from Karsten or me to this topic. It can be solved wihout touching ECS/TCR and its unclear to me why (if he does, i have not a full version of Stevens) he think BC dosent matter, there so much Papers about the clear strong impacts on NH.
PS:
Also is to say, many of discrepancy in 1920-1950 could also be a result of natural variability (e.g PDO and ENSO), but in my opinion, because NH warming was strong and BC-emission too, it should be both.
But thats not my part to explain, if something is really wrong with Stevens Paper, a other Paper will make that clear.
Yes, the fact that the outgassing feedback is only moderate (i.e. doesn’t spiral out of control) allows us to find the endpoints. As is usual, you never see the first-order physics evaluation for the steady-state global warming carried out. It is straightforward to estimate where the moderate feedback will stabilize:
http://theoilconundrum.blogspot.com/2013/03/climate-sensitivity-and-33c-discrepancy.html
It’s essentially solving a quadratic equation. That will be enough to scare the skeptics away 🙂
Ron Graf
Have a look at Shakun et al. (2012).
The physical mechanism of deglaciation is (roughly):
– NH summer insolation increases from ~21.5ka especially at high latitudes
– By ~19ka, mid/high latitude NH temperature increase causes sufficient melt from NH ice sheets for freshwater flux to inhibit NADW formation and halt AMOC (THC fact sheet: http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html see fig. 2).
– NH now *cools* as equatorial >>> poleward heat transport stops
– With the NH ‘heat sink’ turned off, the SH *warms*, as it must
– Deep water warming in SH ocean causes release of carbon to atmosphere. This positive feedback globalises and amplifies the warming
– NH melt resumes, fully engaging strongly positive ice albedo feedback
– Deglaciation accelerates until largely complete by ~11.5ka. Holocene interglacial begins
* * *
Spatial and seasonal reorganisation of TSI is enough to trigger a train of positive feedbacks sufficient to terminate a glacial. See Shakun et al.
Deglaciation after the Mid-Pleistocene Transition (MPT) occurs at times of high obliquity and multiples of the 41ka obliquity cycle. Deglaciation is not ‘out of phase’ with M-cycles (I presume you mean Milankovitch cycles). The transition from the ’41ka world’ to the ‘100ka world’ at the MPT is a whole topic in itself which we don’t need to go into here.
Relatively speaking, it takes a long time to grow an ice sheet and very little for it to break up and collapse. Hence the abrupt glacial terminations and gradual (not abrupt, as you say) slides back into full glacial phases that characterise major climate changes since the MPT.
I’ve already said that nobody is arguing this. CO2 and CH4 are feedbacks to orbital forcing. See Shakun et al.
Maybe providing an answer to my question upthread, someone’s posted a copy of Stevens 2015 online, and the sentences Karsten referred to might be :
oneuniverse,
Well, that sounds to me, play down effects of BC. But BC is to important and to complex, also see here: http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50171/full
For me, it is a weak argument to say it is more plausible the estimate in AR5 comes from effects of different time periods or Models.
Sorry ATTP I know the topic is aerosols. I got my knuckles whapped on CA for this… “Lord Ron, riding in every direction”.
To answer (“did somebody really believe that CO2 caused the ice ages?”) I would say the presence or absence of CO2 causing the ice ages was a major theory from 1896 since it was first postulated by Arrhenius to about 1987 when ice cores resolution revealed its lag to temp. https://books.google.com/books?id=7waExgo5OP8C&lpg=PT42&ots=rkfiXg-n1Q&dq=arrhenius%20ice%20age%20theory%20confirmed&pg=PT42#v=onepage&q=arrhenius%20ice%20age%20theory%20confirmed&f=false Middle of second paragraph.
BBD, the ice age fluctuation of CO2 was from about 150-300ppm, a delta of 2X, regardless if the CO2 came from the increased carbon (life) cycle or from the sea. Since CO2’s warming effect should be the same for each doubling I would agree that whatever effect we see presently should have been felt more when the Earth was nearer the center of it’s temperature elasticity. (And this contradicts ATTP’s statement that led me on this tangent. I think paleo sensitivity should certainly not be the same.) I followed your thoughts and others on ice-age. Feedbacks by definition are not initiators and in the case of CO2 and polar ice they add inertia against abrupt change. I agree CO2’s saturation is diminished by temp rise as everyone opening a warm soda has experienced. M-cycles are gradual and weak. There correlation to the cycle is sporadic. This indicates to me that M-cycles are not drivers but are occasional triggers.
When I first learned that ENSO affected GMST I wondered how could this be since the heat is all remaining within the dome of the atmosphere. Then I learned that a short-circuiting of the thermohaline conveyor off Labrador correlated to the Younger Dryas, a temporary reversal of temp., a 2-3ka stutter in our coming out the last ice age. It hit me that the oceans role in heat dispersal could be that major driver, the huge natural variable. Since ocean temp is always inverted; heat stratified on top, the engine for it’s central current is polar ice melt. Anything that increases melt increases current and heat dispersion from tropical surface to poles. The more dispersion the less efficiently the total heat can be dissipated by radiation from the TOA. The same as CO2, if the outgoing radiative efficiency is dropped the Earth must warm, which increases melt. And this is why the interglacial comes almost a straight ride up from glaciation maximums. The fuel is ice melt. My hypothesis is that the conveyor, now terminating between Iceland and Greenland, is in an excited state that only occurs in interglacials periods. The conveyor’s 90% normal (ice age state) termination point is, I think, off Labrador.
ATTP, I’m a chemist, not a physicist, is my thought on radiative efficiency of dissipated heat versus concentrated valid?
Ron,
I’m not quite sure that I get what you’re asking. One issue with any kind of internal heating mechanism is that the atmosphere has a very low heat capacity. Therefore if you heat the surface and atmosphere through some kind of ocean cycle, it should lose this excess energy very quickly (days/weeks/months). However, what I think actually happens is that these internal processes lead to feedback responses such as enhanced water vapour, changes in cloud the introduce a radiative perturbation and allows these internal processes to produce warming, or cooling. However, since it’s being driven internally in a system with a finite amount of energy, it will have to reverse and can only really drive warming/cooling for years or maybe decades. It can’t really contribute to very long-term warming/cooling.
The one exception might be something like the Dansgaard-Oeschger events in which a change in a major ocean current is thought to have lead to a rapid retreat of the NH ice sheets and a period of very rapid NH warming. Again, however, this reverses and repeats.
Ron Graf
The abrupt drainage of proglacial Lake Agassiz pumped enough fresh water into the high latitude N Atlantic to inhibit NADW formation and turn off the AMOC. The resulting abrupt NH cooling gave us the YD.
This is the same mechanism of meltwater-forced AMOC interruption discussed earlier but here delayed past the peak Laurentide melt.
Some definitional confusion:
Positive feedbacks amplify forcings. Negative feedbacks diminish the climatic effects of forcings.
Why do you claim that CO2 and ice albedo (both positive feedbacks) “add inertia against abrupt change”?
How?
Sorry – I meant to add:
Fast feedback sensitivity seems to be much the same in hot and cold climate states. The fully-equilibriated Earth System Sensitivity (ESS) appears to be lower in warm climate states as the cryosphere is absent or greatly diminished and positive ice albedo feedback is entirely or largely absent as a factor in long-term (slow feedback / ESS) response to changed forcings.
I should probably have added that Dansgaard-Oeschger events only operate during glacials when the ice sheets are large.
“to about 1987 when ice cores resolution revealed its lag to temp”
Errr….no. When the first antarctic ice core CO2 data was presented, there was no clear evidence of a lag. There was simply too much unknown about dating the air in the ice cores at that time.
That evidence came much later (papers in the early 21st century), well after the lag had been already *proposed* in a paper by Lorius et al (http://www.atmos.washington.edu/2003Q4/211/articles_required/Lorius90_ice-core.pdf), although there may well be earlier suggestions of the same process. It may not be directly obvious, but in the paper the effect of greenhouse gases (and ice-sheet reductions) is mentioned as an amplification of the orbital forcing, which automatically means it comes *after* the orbital forcing starts the process.
In essence there was no clear evidence for Arrhenius’ hypothesis for the role of greenhouse gases (CO2 in particular) in the glacial cycles until the ice core data was available, i.e., 1987.
Ron, building on BBDs point, the normally used definition of sensitivity, ECS, explicitly excludes the effects of ice sheet albedo.
So, other than the effect of ice sheet albedo, why do you believe ECS would be higher during an ice age?
vtg,
Indeed, and this is a point that many seem to not get. The paleo estimates of ECS treat ice-albedo effect as a forcing, not a feedback. Hence they are estimating the fast-feedback equilibrium climate sensitivity and not the earth system sensitivity, which would be higher.
And building on Marco’s post (verily I stand on the shoulders of giants today), the history of the Milankovitch theory is described by Spencer Weart here:
http://www.aip.org/history/climate/cycles.htm
VTG; ATTP; Ron G
Sorry, I can see that I did not define ECS / S_ff and ESS very clearly. Thanks for the tidying-up, VTG and ATTP.
Ron – there’s a good discussion of this here.
Christian: “And thats it, there is no certain about what clearly cause the discrepancy, as shown in Meehl et al. (2014) also could be a resultat of natural variablitiy which is not in phase with models.”
As I pointed out with a link reference up thread, the CMIP5 has ENSO in random phase. Any ensemble should have near zero net phase.
Ron,
Well, yes, which is why one can’t really argue that the models (plural) didn’t predict the “pause”. Ensembles will typically do a poor job of representing such variability.
ATTP,
A better way to state my question is in the thought experiment. In the two scenarios below does one have a lower GMST,(i.e. outgoing radiative efficiency,) or is it the same?
1) A non-rotating Earth having all the solar heat concentrated on one side like Mercury and the back side was near zero K.
2) An Earth rotating on a 45 deg axis, with much more even distribution of heat.
Ron,
I think the simple answer is yes; this can be easily demonstrated by imagining an earth where, rather than the whole surface is at 300 ish K, half is at 600 and half at zero. The latter will radiate 8 fold more heat, despite having the same average temperature.
I guess reality might be different for small changes, as the same forces causing redistribution of temperature might also cause a redistribution of emissivity eg through cloudiness with the opposite effect.
But hey, I’m just an engineer, what do I know?
Ron,
Well, if they receive exactly the same amount of energy per second, then they both need to radiate exactly the same amount of energy per second back into space. One way to determine a planet’s temperature is to determine the average amount of energy it radiates per square metre per second and to equate this to the temperature of a blackbody that would radiate the same amount of energy per square metre per second. These two planets would have the same average temperature, if determined this way.
However, the distribution of temperatures on these two planets would be very different.
In fact, I’ve had a lengthy discussion (argument?) about this on BH. If you look at the temperature of the Moon it is highly variable, swinging from almost 400K to as low as 100K. If you average the temperature itself, it has an average of 206K at the equator, and clearly lower than this at other latitudes. However, if you determine the average blackbody temperature (from the energy it has to radiate back into space) it is 270K, because the hot regions dominate the energy output.
ATTP,
Thanks. Yes, I looked at the black body plank emission for double the energy and it of course is requires a much less increase in temp. Thus, if one takes the new average one lowers the GMST. Therefore anything that moves to homogenize spatial temperature or dissipate heat to the poles decreases radiative efficiency and increases GMST. This is why I was asking about studies to find heat closure in the ocean. It may very well be that a change in ocean current changes GMST non-elastically. You don’t need to pay it back.
Ron,
Okay, yes, I think I see what you mean now. It’s certainly true that we could be in energy balance with a very different temperature distribution.
I’m not sure I quite get this. If we were at a constant temperature, then it would be the BB temperature. On the other hand, we could have a big difference in temperature between the equator and the poles (as on the Moon) but then the equatorial temperature would be higher than the average BB temperature, and the poles would be much colder than the average BB temperature.
The bottom line is that we can be in ice age an meeting our energy balance simply due to poor ocean circulation, or air circulation. The small increase in temp in the tropics would ice over the poles even without help from ice albedo. The M-cycles then by creating warm enough summers to get a significant melt going then kick-start current at some point to an excited state improving dissipation and warming the entire globe.
Ron,
I think you have to be a little careful, because if we do start increasing ice coverage then the albedo will change and that will change the energy balance.
I absolutely agree that ice albedo is a positive feedback accelerating change both ways.
Are you also agreeing that ocean circulation is also a positive feedback, not just a resistance?
If so, ocean currents could largely explain the non-oscillating temp plot throughout the paleo record, including the MWP and LIA.
Hi Christian,
I assume Stevens does have a substantial (possibly incorrect) argument to support the quoted sentences, but he doesn’t seeem to present one in the paper. Perhaps it might be worth dropping him a line.
W.r.t. McConnell ea. 2007 and estimated BC Arctic forcing:
The Humboldt ice-core from the north of Greenland (one of the cores considered in
Bauer et al. 2013) has a very different BC profile compared to the southern Greenland D4 & D5 cores used in McConnell ea. 2007 (and the Act2 core also examined in Bauer ea. 2013). (Confusingly, Bauer ea write that McConnell ea use the Act2 and Humboldt ice cores, whereas the supporting information for McConnell ea. indicates that they used D4 and D5).
I’d like to see the BC profiles from other Arctic ice cores before deciding how much confidence to place in McConnell et al.’s extrapolation of D4’s estimated forcing across the Arctic. (I’d be grateful for any pointers to data – a brief search has not found much eg. in the list at NCDC).
Ron,
Technically, I don’t think that ocean circulation would be regarded as a feedback as it doesn’t (we think) respond to changes in temperature. However, changes in ocean circulation can certainly drive other changes in our climate – Dansgaard-Oeschger events being an example.
What do you mean by non-oscillating?
I don’t think it is plausible to explain paleo variations as purely due to ocean circulations. The Milankovitch cycles show a global temperature variation of 5oC. This can’t simply be due to ocean circulation. The best known explanation is that about half of this is due to ice-albedo changes and half due to variations in atmopheric CO2. Overall, this produces a change in forcing of about 6.5Wm-2. If you divide 5oC by 6.5Wm-2, you get about 0.75oC/(Wm-2), which if you then multiply by 3.7Wm-2 gives just under 3oC per doubling of CO2.
ATTP,
I meant the ocean circulation to be a feedback of polar melt rates. Poor choice of terms. I agree its not a feedback.
In fact, my point is deviations in ocean currents are powerful enough to be a driver. And, they are not only reversible oscillations that are banking or unbanking heat. Any loss in radiative efficiency caused by increased dissipation of tropical heat to the poles is lost output that needs to be rectified with increase in GMST just like GHG caused loss of radiative efficiency.
If this is so this is another important variable and could be the missing explanation for MWP and LIA, which both occurred in such recent pre-industrial times they cannot be explained by CO2 or polar albedo changes. Do you concur?
Ron,
Okay, yes, I think this would be a factor.
Okay, yes, if you were to cool the equator at the expense of the poles, there would – I think – be some additional warming so as to produce energy balance.
Hmmm, not so sure. The MWP was probably not synchronous or global. The LIA could well be partly enhanced volcanism.
To be clear, though, it is quite possible that some form of internally driven variability played a role and will play a role in the future. However, I don’t really think that this implies some kind of significant implication with regards to externally forced warming. If our climate is very sensitive to perturbations, then that should be true whether those perturbations are internal or external.
ATTP wrote: “Because if you have mutiple methods for estimating the same thing and one of them is very different to the others, it’s important to try and understand why.”
If you have two rigorous methods for determining the same thing, the correct answer should lie at the intersection of the pdfs for each method or in Bayesian approach to combining the pdfs. This “intersection” approach was used to narrow the range for the mass of the Higgs boson, for example. The intersection of the pdf for paleoclimate and energy balance models isn’t very different from the pdf for energy balance models alone (so I ignore paleoclimate). Climate model output contains an unknown amount of parameter uncertainty. There is no legitimate way of putting a confidence interval around the output from the IPCC’s “ensemble of opportunity”, which doesn’t systematically explore parameter space. When combining pdfs for energy balance models with climate model output, the IPCC has created a union (not an intersection) which covers both. That union only widened 5-95% ci for Otto (2013) from 4 K to 4.5 K at the upper end. In theory, the correct answer should lie within the pdf for energy balance models and intersection can be used to exclude climate models parameterized so as to produce results incompatible with energy balance models. IF (a big IF) one accepts Stevens’ range for aerosol forcing and the less iffy methodology of Otto et al (co-authored by many prominent non-skeptics), the upper end of the confidence interval from Nic’s latest calculation now excludes most current climate models. In other words, it may be time to re-tune the models so that they agree with observations. (The current tuning process is ad hoc, not rigorous, so there is no reason to assume that other parameter sets can’t perform at least equally well at reproducing today’s climate.) Before doing so, however, one needs to consider that the uncertainty for energy balance models includes both statistical uncertainty in the input (forcing change and temperature change) and systematic error with the basic approach (Shindell, for example). And one paper from Stevens does not represent a consensus.
ATTP wrote: “I was wondering if it is logically consistent for feedbacks to exactly cancel. It might not be logically inconsistent, but does seem physically implausible. It would probably mean that internal variability should be incredibly small, and we know this is not true”.
How close to “exactly canceling” would make a feedbacks “implausible”? Taken in isolation, a small fraction of Nic’s 5-95% ci for ECS (1.05-2.2 K) around 1.2 K might appear mplausible at first glance, but net non-Planck feedback needs to lie somewhere below 3.2 W/m2/K. Water vapor + lapse rate feedback puts us around 1 W/m2/K. If cloud feedback is strongly negative, a net feedback near zero is logically possible (though not likely).
ATTP wrote: “I don’t know if [ECS] is strictly linear [over 33 K], but I don’t think that there is strong evidence for it being highly non-linear. Remember, the 33K change does not include changes in albedo, so is really only representing the fast feedbacks. I don’t think that the water vapour or lapse rate response is sufficiently non-linear, for example.”
ECS includes changes in cloud and ice-albedo feedbacks, so changes in albedo are included when you use a 33 K change to estimate ECS. The C-C equation for water vapor saturation is non-linear, rising from a 6% change per degK to about 20% per degK. FWIW, Lacis et al published a modeling study (“the CO2 control knob”) on what would happen if all CO2 (but not other WMGHGs) were removed from the atmosphere. Surface temperature dropped to -22 degC (more than 33 K with some GHGs remaining). Sea ice covered 50% of the ocean, on the verge of a snowball earth. Maybe we can treat the feedback from a 1-2% change in GMST as being linear, but a 10% colder planet would be radically different from today’s. (I personally believe in the GHE, but hate all of the assumptions that need to be made when calculating a GHE of 33 K.)
There seem to be 2 Franks commenting here, so I’ll use my new WordPress name franktoo. The Frank replying to Christian about 2:00 pm was not me. Fortunately the other Frank didn’t say anything I object to. I wrote at about 10:00 am and 11:00 am.
ATTP
In warm climate states, the equator to pole thermal gradient is reduced sufficiently to move deep water formation from high to lower latitudes. The ocean becomes less well mixed (stratification) and increasingly anoxic at depth, triggering ocean anoxic events (OAEs), which are an eco-bummer (see Permian Extinction for worst-case scenario).
frank,
Except we don’t have two rigorous methods.
ECS does not include ice-albedo feedbacks. That’s why it’s unlikely to be strongly non-linear and to depend strongly on climate state. ESS probably does as that includes the ice-albedo feedback, but ECS does not.
Ron,
How significant do you believe your mechanism might be?
Bearing in mind that the total change in GMST from interglacial to glacial maximum is about 5K.
Or, to put it another way, “he who refuses to do arithmetic is doomed to talk nonsense”
http://scienceblogs.com/stoat/2011/10/25/he-who-refuses-to-do-arithmeti/
Some sums would be nice. Please*
See also
http://scienceofdoom.com/2012/01/30/blah-blah-blah-vs-equations/
My fag packet says the order of magnitude we’re looking at is 0.1K. Happy to be proved wrong.
BBD,
Yes, that’s a good point. I was hoping you might comment as my knowledge of the specifics of this is quite poor.
vtg,
Indeed, I would expect the effect to be quite small, but some sums would be nice.
ATTP,
I think you understand my argument: oceans are not just an internal resistance to climate change due to their vast heat capacity. I am postulating the oceans currents, the conveyor in particular, are affecting external forcing; they are a player in the lineup just like GHG, clouds, ice albedo and aerosols. To the extent they increase temperature homogenization on the planet that effect is non-elastic. It is not internal banking or local shifting.
So I am not sure how to understand your response: :Okay, yes, if you were to cool the equator at the expense of the poles, there would – I think – be some additional warming so as to produce energy balance.”
If this means yes to my hypothesis. Have you seen this anywhere else?
Ron, what is your hypothesis?
In numbers, not words.
How much do you hypothesise temperature distribution changes the earth’s energy balance?
VTG: “he who refuses to do arithmetic is doomed to talk nonsense”
Thanks for your input on supporting the validity of the theory. As an engineer you know that is usually the easy part. But it needs to be first. Any equations or work on your 0.1K would be welcome.
Ron,
Yes, I do realise that, but there is a fundamental issue. Many of the other factors are genuinely external. Changes in solar flux, volcanic or anthropogenic releases of CO2, anthropogenic and volcanic aerosols. I appreciate that some aren’t quite external (CO2 released through warming during Milanovicth cycles) but the effect is to produce an external forcing. So, yes, I can see that you’re arguing that if some major ocean current were to change it could change the temperature distribution and produce an effective warming/cooling, but what causes the ocean current to change.
Also, how big would the change have to be? As I understand it, the difference between the Earth’s average BB temperature and the average of the temperature is quite small. Hence changing the distribution of the temperature is likely to be a small effect. Also, most of the insolation is at the equator, so there’s only so much that an ocean current could do to change the latitudonal temperature gradient.
Except, I don’t think your hypothesis has a driver or physical mechanism. Simply pointing out that a major change to ocean circulation could produce some effective warming or cooling is not really sufficient. You do need some idea of how this could happen, not simply a suggestion that it could happen.
Unless, I’m misunderstanding this, the average temperature based on measurements is just under 14oC. The average BB temperature is more like 15oC. That would seem to suggest that there’s only around 1oC to play with – well unless we make the temperature distribution much more extreme, like the Moon.
ATTP, VTG,
I grant that it is already understood that the conveyor is a least in part due to polar ice melt. Other factors include saline caused density gradient and Coriolis effect as well as ocean bottom topography. If the YD period 14.5-12ka BP was caused soley by a shift in the conveyor that the mechanism I would say by Occam’s Razor would be the heat dissipation lost by restricting the warmth from the Arctic.
Ron,
Seriously. If you have a theory it is up to you to put numbers to it, not ask me for them. If you haven’t done that, you do not have a theory, so give up the many words you’re expending on it. If you do have numbers, post them.
ATTP,
numerically, if the earth starts at 300K, the change in radiating temperature caused by a temperature difference of 10K across hemispheres whilst maintaining same arithmetic mean temperature would be
(0.5*(295^4+305^4))^.25, slightly over 0.1K
Too late to work out latex for the algebraic answer.
ie a 10K change in temperature distribution has an effect equivalent to 0.1K
Thanks for the nice discussion. I take it VTG does not want to be co-author credited on this. 🙂
Ron G
The YD wasn’t a global and synchronous cooling event. It was most strongly expressed in the NH and centred on the N Atlantic basin. There is antiphase between NH and SH temperatures during the YD, suggesting that the inhibited AMOC cooled the NH and warmed the SH, as it must.
Numbers please Ron
Ron Graf, If you want to seriously discuss your ideas, get yourself a user login from the Azimuth Project Forum http://forum.azimuthproject.org. Currently, we are working on modeling ENSO and on estimating GHG concentrations. Lot more efficient than participating in a blog comment section.
Temp K Black body Radiant Emittance: W/m-2
295 429.5
300 459.3
305 490.7
((490.7+429)*.5-(459.3) = 0.80 W/m-2 for 10K overall mixing of temp around the globe
OK, its not a whole lot. You can talk about aerosols again.
@ATTP:
Well, Bjorn defines it as follows:
How this goes together with a potentially [strong Black Carbon forcing as of McConnell et al. 2007] is something the referees should have asked (which I’m sure they did, but didn’t insist on including). I certainly have a different definition, although one might not even need the BC forcing to reconcile the 1920 – 1950 warming.
That would be my suspicion too. What we see throughout all model evaluation exercises is a tendency of the GCMs to warm the ocean surface too fast and way too uniform. That for me indicates that there’s either a pending issue with ocean heat fluxes, or it is to do with the observed circulation changes that aren’t properly reproduced in the models (which in turn may cause a preponderance of El Nino/La Nina). The same problem will then apply in case of volcanic eruptions. Too strong a fast response, but too weak a slow response (aka recovery due to pseudo-forcing). For the post 1920’s, that may well have led to a warming of system which we didn’t see in the GCMs with the same magnitude (some might have issues with proper initialisation of the oceans). Applying a two-box EBM which allows for fast and slow recovery from volcanic eruptions produces a considerable positive pseudo-forcing right between 1920 -1950 (NH forcing):
Overlaid with some reconstructions and GISS, the EBM is doing a fine job all the way back to the 16th century:
This led me to say that I think Bjorn brushes the volcano issue off way too easily:
Not only didn’t increase the aerosol forcing rapidly (in fact, when BC snow forcing is considered – which I didn’t in my EBM – the aerosol forcing in the Northern Hemisphere might well have been slightly positive), but also increased GHG forcing and solar. But the biggest share is the post-volcanic pseudo-forcing. So why should the NH not warm faster than SH? The NH did in fact warmed mainly in the Arctic and parts of the North America. I don’t follow his argument at all. I am not claiming that my EBM provides ground truth, but I tend to think that it is much much closer to reality then Bjorn simplified assumptions.
I still haven’t got around fighting my way trough the clear-sky ocean asymmetry problem which is perhaps the more interesting point anyways … in that he might actually have a point at all 😉
@BBD: In fact we need the pub session every Friday … that’s how bad it is! 😀
@Paul S: Had to laugh about your intro. Same thought I had, but in my case based on the content he presented in the two seminars I attended. I am tempted to say: much sophistication about nothing.
@oneuniverse: I hope this comment provides a more elaborated explanation of what I was getting at. Regarding Susanne’s paper (Bauer et al. 2013), her Fig. 9e (black line) seems to look pretty similar to McConnell’s data. The other results are model simulations.
@Frank: I can tell you that Bjorn work isn’t accepted by anyone other than himself. He might have gotten it through peer review, but the flaws are too obvious for the actual experts to see to remain extremely skeptical. And I go as far as to predict that this paper is gonna be heavily attacked. It’s virtually certain that it’s not gonna be widely accepted, let alone it already has. You know how science works, don’t you?
And no, my main point is volcanic recovery, which he doesn’t even mention. I am also not sure whether he is sufficiently aware of this issue to be honest as it hasn’t gained the traction it should have gained in the community given the immense repercussions. Including BC may not change his conclusions sufficiently indeed. It’s an important player though.
@Christian: Thanks for helping out 😉
Thanks Ron.
Arithmetic rocks!
ATTP wrote: “ECS does not include ice-albedo feedbacks. That’s why it’s unlikely to be strongly non-linear and to depend strongly on climate state. ESS probably does as that includes the ice-albedo feedback, but ECS does not.”
ESS, but not ECS, includes very slow feedbacks such as centennial to millennial changes in ice sheets and changes in vegetation, which are somewhat faster. The desertification of the Sahara 6000 years ago might be a good example of the latter. Changes in ice sheets and vegetation are also associated with hysteresis – the time required for change is different in forward and reverse directions. (http://www.realclimate.org/index.php/archives/2008/04/target-co2/) Climate sensitivity determined by paleoclimate methods is technically a measure ESS, not ECS
However, there are what I call (perhaps mistakenly) “ice-albedo” feedbacks that occur RAPIDLY. When winter snow cover disappears several week earlier in the spring and re-appears several weeks later in the fall, there is a large change in surface albedo at those times. The same thing occurs when polar sea ice melts earlier and refreezes later because of AGW. These relatively fast ice-albedo feedbacks occur in the output of climate models and are relevant to energy balance models. When the annual cycle is observed from space, about 6 W/m2 more reflected SWR is observed over clear skies – i.e. higher surface albedo – during winter in the NH than during winter in the SH, because the SH has little land with seasonal snow cover. So there is a fourth fast feedback in addition to WV, LR and clouds associated with the loss of seasonal snow and ice – which I referred to as ice-albedo feedback above. If there is a better term, please let me know.
Taylor expansion tells us that small changes in differentiable functions can be approximated by a linear function, but this relationship will break down when higher order terms become important. We can’t know where breakdown occurs for the complex relationship between forcing and temperature.
Potential for non-linearity abounds: As noted above, the response of absolute humidity to temperature is non-linear. Planck feedback varies with the fourth power of T. The albedo and thermal diffusivity of oceans make a step-function change around 271 degK. The greenhouse effect on Mars, Earth and Venus is 5, 33 and 500 K when measured in temperature; but 10, 150 and 16,000 W/m2 measured in terms of the difference between surface and TOA flux.
For the Lacis control knob paper (eliminating all CO2), the forcing is about 25 W/m2 according to Modtran (equivalent to about 7 halvings of CO2). A temperature fall of 37 degK over 25 years produces an ECS/TCR of 5.5 K. Unfortunately. 7 halvings actually leaves about 2 ppm of CO2. Complete elimination of CO2 can’t be described in terms of halving. Removing all GHGs from the atmosphere is a 34 W/m2 forcing (equivalent to 9 halvings), and a 33 K GHE gives a ECS of 3.7 K. This discrepancy can be explained by recognizing that Lacis reports albedo increasing to 40% in 5-10 years, while a 33 K GHE assumes albedo doesn’t change. So you are right that albedo change contributes to non-linearity, but the albedo change is relatively fast in the cooling direction.
I personally hate the whole idea of a 33 K GHE, because skeptics waste so much time with complaining about it. If the earth were a blackbody with a constant albedo and with constant illumination, removing all WMGHGs from the atmosphere would lower the temperature by 33 K. The real earth behaves differently: albedo changes, humidity changes, day and night exist, a snowball Earth is possible without GHGs. 33 K comes from a model that has little to do with the real planet. Say the GHE is 150 W/m2 (less OLR at the TOA than the surface) and you’ll get fewer arguments.
franktoo,
Not, it is not. Paleo estimates of the ESS (there is a Hansen paper that discusses this) are about twice as large as paleo estimates of the ECS.
I think this is nonsense. The idea that the typical “sceptic” is simply annoyed by what they see as an overly simply model is absurd. I get the feeling you’re trying to pretend that their arguments are somehow really sophisticated and that people like me simply don’t realise that. If that was true, why don’t they actually present these more complex arguments, rather than simply disputing what others are saying.
Furthermore, the 33K is the difference between the effective BB temperature of the surface (which emits an average of 389Wm-2) and the effective temperature of the planet (which emits an average of 240Wm-2). So to say it has nothing to do with the real world is simply incorrect.
Franktoo,
This is I’m afraid, simply factually incorrect.
As I best understand this, the way it works is that “slow feedbacks”: ice sheets and vegetation albedo forcing plus known forcings such as CO2 concentration are imposed as a boundary condition. A model (GCM or simple) can then be tuned to best fit the conditions of the LGM. The parameters from the tuning can, in turn, be used to estimate ECS.
It is, of course, more complicated than this; I can’t find a simple description anywhere but see for example AR5 section 5.3.3.2:
Hansen and Sato for a good discussion of ECS vs ESS and methodology from paleoclimate:
Click to access 20120508_ClimateSensitivity.pdf
Slide 10 here gives some actual numbers for the forcings applied in the calculation:
Click to access Schmittner-sensitivity.pdf
It is also possible to estimate ESS from the same data but with different boundary conditions (ie keeping the ice sheet albedo as a feedback)
Karsten: “Regarding Susanne’s paper (Bauer et al. 2013), her Fig. 9e (black line) seems to look pretty similar to McConnell’s data. The other results are model simulations.”
Thank you for your comments. Re: Bauer, yes I did point out the similarity of Fig. 9e in my previous comment. However, as mentioned, Fig. 9a (black line) , the measured BC flux for the Humboldt ice core (not model simulation) is dissimilar to McConnell’s – Fig. 9a has a significantly more uniform profile.
(Sorry, I said earlier that Humboldt was dissimilar to D4, D5 and Act2, but I didn’t actually say that D4, D5 and Act2 had similar profiles, I should’ve done.)
Reading the paper has confirmed what I thought was probably happening. Stevens uses a different forcing temporal structure than that shown in AR5, based solely on an SO2 emissions history, with the assumption that this can be used as a proxy for all aerosols. That means about half of all historical aerosol forcing occurs between 1850 and 1950 in his model, whereas the figure is about 25% in the AR5 time series. It would completely change his results if he used the AR5 temporal structure, as I outlined in my previous comment.
Oneuniverse’s quote from the paper shows Stevens attempting to argue why the AR5 temporal structure is wrong, but his argument begs the question. He says the AR5 series is implausible according to his model, but that takes into account only SO2 emissions whereas the AR5 series takes into account varying histories of multiple aerosol species. Justification for the AR5 RF time series (though not including cloud interactions) is clearly laid out in Figure 8.8 of Chapter 8 – it shows BC and sulfate largely cancelling between 1850 and 1950, after which sulfate accelerates and other species like organic aerosols and nitrate also contribute to the negative side from about 1950.
Figure 8.8 also shows uncertainties for each of the species. Taking into account these uncertainties you could construct any number of varying histories for total aerosol forcing, more so when you factor in changing spatial structures and cloud interactions. Stevens’ history is plausible, but so is the AR5 history and many alternatives, and each would produce different results using his method. It’s quite easy to get a constrained result if you don’t consider key uncertainties.
I think this sentence from the paper provides a proper framing for reading it: ‘One advantage of the simple approach adopted here is that, even if one does not accept my arguments, they help identify what would be required for an aerosol forcing to be considerably more negative than about −1.0Wm−2.’
PaulS,
Essentially: if everything assumed in the paper turns out to be correct/reasonable, then aerosol forcing is unlikely to be more negative than -1.0W/m^2? Otherwise, it could be considerably more negative than -1.0W/m^2.
On volcanic recovery as an explanation for early historical warming, there are some handy simulations in CMIP5 which can be used for guidance.
The standard CMIP5 historical runs are generally initialised by a generic pre-industrial spin-up. This is problematic because the period immediately preceding the 1850 start date is actually very unusual in terms of large volcanic events.
The handy simulations are historical (1850-present) runs which have been initialised by a full forced simulation of the previous millennium (named ‘past1000’). I’ve been able to cross-check simulations from the same underlying model using each initialisation method (across three models: CCSM4, GISS-E2-R and MPI-ESM-P) and found the past1000-initialised runs typically produce about 0.15K more warming between 1850 and 1950.
@Paul S: Thanks for digging deeper. Regarding the volcanic recovery, Figure 1 in [Gregory et al. 2013] gives it away in an impressive fashion. Assuming that sea level rise is a good proxy for ocean warming, there’s no way around long spin-ups, or to correct for it as proposed in the paper. Your comparison of “past1000” vs “standard” simulations puts a reasonable number on the associated GMST change. Bottom line: Omitting the first half of the 19th century inevitably leads to an underestimated 1920-1950 warming, just as diagnosed in CMIP5. I keep wondering why so many colleagues fail to acknowledge this issue. Also, CMIP5 should have been stricter in that regard. As I’ve said earlier, I am pretty sure Bjorn wasn’t even aware of it, or at least he doesn’t think it matters in any significant way. I’m personally convinced that it matters a lot.
Ron Graf, Now you went and done it — advertised my skills elsewhere on the interwebs.
Shorter version: Stay away from WHT cuz .of #WHUT he sez.
Many of the GHGs and aerosols are co-linear with CO2 and each other so that it becomes difficult to find a non-degenerate multiple regression solution if one tries to include them all. Much better to treat CO2 as a leading indicator and then get an effective factor out of the regression results. Pragmatism rulz.
@Paul S (and ATTP of course): In case you haven’t seen it yet, there is a very early draft of an upcoming paper by Trude Storelvmo available at the [Ringberg Webpage]. In fact way too early to have a serious discussion, but the chosen methodology to estimate TCR strikes me as pretty smart (spoiler: TCR goes up). The most interesting thing though, they obtain a temperature response due to aerosols alone which is in the range of -0.3K between 1964-2010. That’s exactly the same magnitude that [Wilcox et al. 2013] found in their model based attribution study. If Trude’s paper gets published, it would be a fairly strong observationally based confirmation of what I’ve been considering the most sophisticated attempt to pin down the aerosol impact to date (the Wilcox paper).
ATTP, Don’t let Fitzy and Carrick get to you. Crazy that Carrick estimates a ECS of 2.5C versus I think it may be 3C, yet they are the ones that do the contrarian freak-out.
VeryTallGuy and ATTP: Thank you for taking the time to point out my mistake: The climate sensitivity calculated from the temperature change and forcing change from the LGM to the Holocene is called ECS. However, the difference between ECS and ESS (Earth System Climate Sensitivity) is supposed to take into account slower changes in ice sheets and vegetation. There certainly were large changes in ice sheets and vegetation between the LGM and Holocene that aren’t present in the output of climate models or the input to energy balance models. As best I can tell, we should expect a difference between the climate sensitivity calculated from climate models or energy balance models and the climate sensitivity calculated from the difference between the LGM and the Holocene. We appear to call both ECS.
Hansen makes the point that the LGM and the Holocene represent two points of equilibrium and therefore define ECS. I can’t argue with that, but policymakers have little reason to pay attention to changes that take millennia to reach equilibrium. ESS is even more distant. We are stewards of a billion year old planet, but that planet has seen bigger changes than we will be able to cause with fossil fuels. So I prefer to think in terms of climate sensitivity that is relevant to the next century. (AGW will be faster than most earlier changes, and I’m not eager to see my generation equated with the K-T extinction. If that happens, the term anthropocene WILL be appropriate.)
Climate models try to span two [near?] equilibrium states, but they aren’t capable of simulating all slow feedbacks, so we shouldn’t expect them to agree with paleoclimate studies. Energy balance models certainly don’t span two equilibrium states – they compensate (partially?) for this problem by correcting for ocean heat uptake. Since both depend mostly on fast feedbacks – WV, LR, cloud, and the fast component of ice-albedo (changes in seasonal ice and snow) – they should produce the same answer.
WHT,
Yes, that’s what I don’t get. Half of what they say seems perfectly reasonable. The other half is just prattish. I guess pointing that out doesn’t help, though 🙂
franktoo,
Well, it won’t take millenia. The reason it took a relatively long time to go from a glacial to an interglacial is that the changes were slow. We will likely double CO2 and produce a change in forcing of 3.7Wm-2, faster than at any time in human history. It will still centuries to fully equilibrate, but we’ll get pretty close within decades. The figure below pretty much illustrates it. Charney sensitivity on a timescale of decades to centuries. ESS on multi-millenial timescales
Relentless, ongoing sea level rise as the WAIS and bits of the EAIS go, along with the fast glaciers on the GrIS. Unstoppable, endless coastal attrition. Half the major cities in the world gone. All port infrastructure. Salination of vast tracts of low-lying agricultural land etc. Food shortages. Those long-awaited millions of climate refugees. Re-settlement disputes. Border disputes. International tension. Food shortages. Welcome to the 22nd century, based on a couple of degrees warming over the present.
SLR to continue for several more centuries.
ATTP wrote: “The idea that the typical “sceptic” is simply annoyed by what they see as an overly simply model is absurd. I get the feeling you’re trying to pretend that their arguments are somehow really sophisticated and that people like me simply don’t realise that.”
I try to understand what is right and wrong about both skeptic and consensus arguments and discover the easiest way to correct mistakes. It is pretty hard to be sure the consensus is wrong – until they stop telling Schneider’s “whole truth with all the caveats” and start the “scary stories”.
Climate science doctrine says that a blackbody with constant illumination and albedo is a good model for an earth without GHGs, but its only virtue is ease of calculation. You define the GHE as the 33 degK difference between this model and the real earth. Others justifiably don’t like your choice of model, creating unnecessary controversy and confusion – especially when more sophisticated versions of your model are computationally problematic and don’t give an answer of 33 degK. The GHE is tough enough to correctly explain without unnecessary problems. We’ve even got poorly informed (or malicious) physics professors confusing the subject.
Climate science doctrine that GHGs trap heat in the atmosphere is for the simple-minded. GHGs also radiatively cool.
The idea that DLR warms the surface runs into difficulties with the 2LoT that many skeptics can’t resolve. (Individual molecules may be fast and slow, but they aren’t hot or cold. So energy transfer between individual molecules is not governed by the 2LoT. Heat transfer is the NET flux between groups of molecules large enough to have a well-defined temperature and it obeys the 2LoT.)
The atmosphere functions in some ways like an insulating blanket. Unfortunately, most people think blankets keep you warm by preventing heat loss by convection and possibly conduction, not by radiating infrared. When they don’t understand the GHE, they don’t understand blankets (which are more complicated).
Only rarely is the proper physics discussed – the Schwarzschild eqn. Surprise, that equation predicts that a GHE will exist only where temperature drops with increasing altitude! (This is why increasing GHGs cools the stratosphere. Blocking upward flux from below is for the simple-minded. Flux from below is blocked in both the troposphere and stratosphere. The former warms and the latter cools.)
If you are simply preaching to the choir, you may as well treat AGW as a religion or politics and remove physics from the name of your blog. In those fields, you can denigrate the beliefs and motivations of others without having to consider the merits of their arguments.
ATTP added: “Furthermore, the 33K is the difference between the effective BB temperature of the surface (which emits an average of 389Wm-2) and the effective [BB] temperature of the planet (which emits an average of 240Wm-2). So to say it has nothing to do with the real world is simply incorrect.”
That 149 W/m2 difference between the TOA flux and the surface flux is exactly what I prefer to call the GHE – without inventing some mythical world that is 33 K colder. Remember, “effective BB temperature” is a measure of radiative flux, not temperature. When you talk in terms of BB equivalent temperature, you are using my preferred explanation, not yours. (See the AMS’s definitions of brightness temperature and then BB equivalent temperature: http://glossary.ametsoc.org/wiki/Brightness_temperature)
franktoo,
The problem is that a lot of what you describe are simply fallacies or anologies.
Yes, but they’re essentially equivalent.
I’m sorry, but I find it hard to believe that the real problem is simply that some don’t like or don’t understand some of the ways in which this is sometimes explained. From what I’ve seen, that is simply a convenient way of objecting to something while trying to maintain some credibility. If we changed everything we did to try and do what we thought would be suitable for sceptics, they’d simply find something new to criticise.
franktoo,
Well, no, I’m using my explanation and I’m using what others mean when they refer to the 33K difference.
Notice that one is not allowed to hold the view that AGW is potentially dangerous. That, you see, is ‘alarmist’ and forbidden:
This is all about denial.
And there ends any point in further interaction.
Tall’s 4th Law of Thermodynamics: “The frequency of a blog commentator quoting any of the preceding 4 laws is inversely proportional to their understanding of it”
Still, I learned a little bit by reading AR5 on use of the LGM for calculating ECS, so it wasn’t all wasted.
No, F2. What you do is start to discuss the physics, but then give up and offer your analysis on what “policymakers” ought to pay attention to. That is not science, it is politics.
Or consider this observation. The leading light of the skeptics is Carrick and according to another skeptical leading light, Fitzpatrick, Carrick says that the ECS is 2.5C. Is Carrick wrong? That number seems awfully close to the mean value of 3C that has been in place since the Charney report published in 1979.
Or are these two not the skeptical go-to guys? Who exactly are the brains behind the skeptics? I really don’t know. Whenever I find something interesting that they are doing with regards to math or physics, I peel away the veneer and all I see is a political agenda, or for better or worse, a contrarian mean-streak.
ATTP wrote: “I’m sorry, but I find it hard to believe that the real problem is simply that some don’t like or don’t understand some of the ways in which this is sometimes explained. From what I’ve seen, that is simply a convenient way of objecting to something while trying to maintain some credibility.”
I think there is a spectrum: some are malicious, some are blinded by prejudice, some are technically hopeless, some are reasonable or informative. Behind every person who comments are several dozen lurkers (your real audience?). In the US, one can go to Fox New to get the conservative spin or to MSNBC for the liberal viewpoint. Getting out of our comfort zones and being exposed to new idea can be good for all of us.
ATTP also wrote: “Yes, but they essentially equivalent.” with “they” being explanations for the GHE in terms of flux vs temperature difference.
Not really. Surface outward flux is obvious and it does come from surface temperature. At first glance, information about the TOA outward flux appears to require knowledge of a blackbody equivalent temperature and a poor model. However, the TOA outward flux is simply the post-albedo inward TOA flux. It doesn’t need to be converted to a temperature via a good or bad model. Every model for earth without GHGs must emit an average of 240 W/m2 of OLR.
The moon is a good model for earth without GHGs because it receives the same incoming SWR and a bad model because it has a different albedo. However, I know it emits (1-a)*342 W/m2 on the average. I don’t need to worry about the 200 degK difference between day and night.
franktoo,
Well, yes, that may be true, but it’s also true that the average surface flux is the same as a BB with a temperature of 288K. I think we’re just arguing about details. There are different ways to present information that is equivalent and much of the climate debate would probably improve if people recognised this more often.
franktoo said:
One of the elements that is routinely missing from the naive skeptical argument is any understanding of spectral characteristics of radiation and of course statistical mechanics. Having done all my thesis work in various forms spectroscopy, I can easily detect when someone is posing.
I suggest that you start from scratch.
” Whenever I find something interesting that they are doing with regards to math or physics, I peel away the veneer and all I see is a political agenda, or for better or worse, a contrarian mean-streak.”
you over estimate your powers of perception and further the agenda dont change the math.
carrick has 153 publications some on rather fundamental physics. That’s not an appeal to authority, just a heads up that you aint got the chops to handle a one v one fight with him.
so you better stick to the ad homs. I can help you there, ad homs are all about the style.
Despite argument from assertion to the contrary by Steven, there is no policy-relevant difference between ~2.5C and ~3C. So why even bother talking about Carrick?
> carrick has 153 publications some on rather fundamental physics.
I have yet to see SteveF spelling Carrick’s complete name and to link to his CV.
It’s better to take it from the horse’s mouth:
How Carrick probes the blog’s “faction” (H/T the Auditor) while shifting the burden of proof on me shows the importance of truth in his ClimateBall life.
That Carrick comments at Lucia’s (a libertarian “faction”) and Jeff’s (a tea party “faction”) also shows the importance of being the middle on science or policy for him.
Willard,
I was also trying to work out when I spoke of policy. I guess I criticise Matt Ridley and the GWPF, but am not sure why they immediately suggests not playing down the middle. Of course, anyone with any sense would recognise the the distribution of sciencieness is very skewed and so you have to be careful of how you define the middle.
Yea Mosh, the cracker Carrick thought I was a high school student. He has impressive perceptional powers 🙂
As far as physics is concerned, I can clean his clock. He’s a one-trick pony.
ATTP: Fodder for your next OP! 🙂
Now almost two years old, John Cook’s 97 per cent consensus paper on anthropogenic global warming has been a runaway success. Downloaded more than 300,000 times, voted the best 2013 paper in Environmental Research Letters, frequently cited by peers and politicians from around the world, the paper seems to be the definitive proof that the science of climate change is settled. It isn’t.
Global warming consensus claim doesn’t stand up, Op-ed by Richard Tol, The Australian, Mar 25, 2015
> [A]nyone with any sense would recognise the the distribution of sciencieness is very skewed and so you have to be careful of how you define the middle.
To “define” the middle explains the lukewarm brand, AT:
http://en.wikipedia.org/wiki/Overton_window
This ClimateBall episode reinforces your point about “crowing about how they can see truths that others are unable to see, and suggesting that somehow they’re above all this kind of identity politics.” How SteveF (you know he was SteveF, didn’t you?) and Carrick dismiss your blog smells more like identity politics to me than truth-seeking. In fairness, lots of commenters here play in the same playground, just like everywhere.
***
Speaking of which, another gem:
Sameolsameol, as would say Joshua, whom Judy silenced, to much chagrin of Don Don and Big Dave, except perhaps from Brandon’s defense of the Twitter’s decision.
Tol and his ilk had best take heed…
Climate change is a moral challenge threatening the rights of the world’s poorest people and those who deny it are not using God’s gift of knowledge, says presiding bishop Katharine Jefferts Schori
Climate denial is immoral, says head of US Episcopal church by Suzanne Goldenberg, The Guardian, Mar 24, 2015
@KarSteN (March 23, 2015 at 11:34 pm)
Thanks for the link to the Storelvmo paper. I like the idea of using the GEBA surface flux measurements. Their paper could be improved, however, by including the effects of BC. Ignoring black carbon will, I think, have caused them to over-estimate TCR:
The GEBA DSRS measurements will have registered BC’s direct effect, of atmospheric SW absorption, as a surface dimming (at least for downwelling SW – absorption of surface-reflected SW will not have registered), but the paper doesn’t appear to account for the fact that the atmosphere will have heated as a result of the absorption. BC’s snow/ice albedo effect is also not accounted for. Both of these omissions will, as I understand it, result in TCR being over-estimated.
Speaking of CV, here’s Ron Graf, who commented a bit earlier on this thread:
http://rankexploits.com/musings/2015/new-thread/#comment-135820
SteveF continues his search for truth, and Carrick declares having found the thread entertaining. Moshpit will suggest ways to improve upon their styleless ad homs in 3, 2, 1.
JH,
I can’t seem to access that article and I’m not sure I can face another consensus thread here. I’m starting to suspect that there a couple of secret GWPF manuals; one titled “How to whine like a 7-year old when criticised” and the other “Persistence: how to keep repeating nonsense, so that eventually people will give up and stop telling you you’re wrong”.
Willard,
Yes, as you probably realised, my point wasn’t that this site doesn’t play the same kind of games as elsewhere, but someone criticising it without acknowledging their own biases is rather irritating.
Willard,
Yes, what’s with the whole “LOL” thing and why is posting my CV so amusing. Maybe I’m missing something, but it seems like a perfectly normal CV.
> Yes, what’s with the whole “LOL” thing and why is posting my CV so amusing.
Some consider doxing amusing, AT:
http://en.m.wikipedia.org/wiki/Doxing
***
> Maybe I’m missing something, but it seems like a perfectly normal CV.
Here’s SteveF:
http://rankexploits.com/musings/2015/new-thread/#comment-135821
So we have: green bashing, ad hom, and both.
The truth is out there for the contrarian vigilance.
ATTP: Here’s the url for Tol’s slop-ed referenced above.
http://www.theaustralian.com.au/opinion/global-warming-consensus-claim-doesnt-stand-up/story-e6frg6zo-1227276959248
Willard,
Jeepers, the man’s a mind reader, and not a very good one. I was employed by the South African National Antarctic Programme (SANAP) as a physicist, and SANAP happened to fall within the remit of a government department which happened to be called the Department for Environmental Affairs and Tourism. I’ve no idea why and it had no influence on what we did, which was to film aurora, record radio waves, measure ozone and UV (okay, Matt Ridley will be horrified), and have fun in the snow and ice 🙂
JH,
Nooooo, don’t make me look! (Edit : Actually, it’s still going to a site that requires payment to view the article. I’m afraid I have better things to do with my money than pay to read Tol’s dross.)
I finally got through to the Australian article by Tol and you are not missing anything ATTP. For anyone who has been down that road before the view is unchanged. Accusations of bad science, possible fraud, sloppy methods and anything else you may have ever heard disparaging the paper. The only value it has is to colelct all that rubbish in one place.
“As far as physics is concerned, I can clean his clock. He’s a one-trick pony.”
doubtful web. over confidence is un becoming. Seen you argue. It isnt particularly good.
Just saying. You still could learn.
However, as a practice exercise why dont you give us a review of his Astrophysics article or one of his Physic Review pieces. Start with the stuff before 1990 so you are not tempted to discuss climate.
Go ahead, show us what you got.
Steven,
You’ve made me go and look at his pubication record. Some interesting stuff there, but maybe we could avoid some kind of physics-off. Not quite sure how we’d judge it anyway.
Yawn.
Webby wrote: “One of the elements that is routinely missing from the naive skeptical argument is any understanding of spectral characteristics of radiation and of course statistical mechanics. Having done all my thesis work in various forms spectroscopy, I can easily detect when someone is posing. I suggest that you start from scratch.”
My comment was about the relative merits of describing the GHE as a 33 degK difference in temperature or as the difference between surface and TOA OLR. As best I can tell, spectral distribution and statistical mechanics aren’t needed. Spectral distribution is a trivial issue when discriminating between reflected SWR and LWR while determining albedo and crucial for calculating OLR at the TOA from some model of the atmosphere. Making TOA OLR equal to post-albedo SWR, with a small correction (about 0.5 W/m2) for heat uptake by the earth, avoids the need for radiative transfer calculations. (The model of the the atmosphere used in radiative transfer calculations have been “tuned” to agree with observations from space.)
Having done my thesis work outside spectroscopy doesn’t prevent me from recognizing the difference between rational science, argumentum ad hominem, and argumentum ab auctoritate. Let’s stick to rational science and avoid adding argumentum ad nauseam to this list. I’m sure you or I could go through my comments on this thread and find numerous real problems to criticize (beginning with loquacity!). However, I’m most interested in hearing about whether 33 K contributes to our understanding of climate sensitivity (a claim made by our host) or explaining the GHE to various audiences.
> Having done my thesis work outside spectroscopy doesn’t prevent me from recognizing the difference between rational science, argumentum ad hominem, and argumentum ab auctoritate.
Being a ninja, I can recognize an appeal to one’s own authority, a false dichotomy between ad arguments and “rational science,” and the invalid assumption that such appeals are irrational.
So Mosh, why did Carrick sign up for a login on the Azimuth Project forum sometime last year, and he hasn’t done squat to engage in the discussion? I don’t think he has posted once to the forum, yet his full name is right there in the membership records.
You know why? Cuz he’s a sniper. He is going to take his shots from 1000 yards away.
And Mosh, you can also look at what I have got. I have a couple of named spectroscopy algorithms implemented on the Argonne National Labs X-ray server. Very practical physics stuff (and named after me of course, which isn’t that difficult to figure out). If that is enough of a taunt to get him to actually engage in a real discussion, that would be great. I am not holding my breath though.
@oneuniverse:
Good point actually! While I can’t spontaneously say what the BC effect on surface dimming is (aerosol loading is more than an order of magnitude lower for BC compared to sulphates), the BC warming of the upper atmosphere could indeed have led to some surface warming due to rapid adjustments. However, the surface BC effect can still be negative (despite net warming of the whole atmosphere), and this is what is looked at in the paper by virtue of using the surface temperature data. [Ban-Weiss et al. 2011] have more to say about the BC surface forcing (spoiler: it is strongly height dependent).
I guess BC on snow isn’t so much of an issue since the 1960’s anymore, as BC aerosols didn’t make it in the Arctic anymore (due to the strong decline in North America and Europe). It may have an effect on mid-latitudinal snow pack.
Both points are worth being considered, but I wouldn’t expect a significant change of the results. Thanks for sharing your thoughts anyways. Much appreciated!
KarSteN
I have some useless anecdotes on BC. In Minnesota, used to always get sooted snow in years past. Not so much anymore. Only reason I know this is XC skiing over the years where the stuff does a number on your wax, and therefore poor glide.
But in Westchester NY it is much worse, I would gather soot on the inside of my windshield. Never saw that in Minnesota.
As always, concerning anecdotes, YMMV.
Mosher –
Carrick makes some really bad arguments, as does SteveF. So as someone who can’t judge the scientific arguments on their own merits, I have no way to assume that their appeals to self-authority (or others’ appeals to authority on their behalf) are any more persuasive than this dude:
Carrick and SteveF, like Salvatore, understand that the reason why Anders disagrees with them is either because he’s biased or because he’s not up to their level of expertise. Yet Salvatore is free to make the same claim about SteveF, or about Carrick if he felt so moved.
When I see Carrick making such bad arguments, his list of publications becomes meaningless. It becomes and empty appeal to authority.
Pingback: ECS > 2K? | …and Then There's Physics
@WHT, I noticed tonight that you attributed to quote regarding yourself upstring. In fact, I never uttered a word of that quote or anything like it. I am learning to be careful of what and now I realize its important to circle back to watch by wake. My apology if you thought I ignored your offer. I simply felt unqualified at this time. I realize how tensions in climate can lead to distrust. I hope we can both chalk this up to that. No hard feelings.
Ron, You propagated my invitation to join the Azimuth Project on the Blackboard blog , and that quote was the predictable nasty response expected from that group. I figured you recognized it as such.
> I am learning to be careful of what and now I realize its important to circle back to watch by wake.
RonG is learning very fast:
http://rankexploits.com/musings/2015/new-thread/#comment-135825
RonG might need to learn a bit faster.
WHT, Again I am a new person in the discussion and thought I was passing on something useful. I am sure that EVERYONE posting here, regardless of their current personal ECS estimate, is in the top 0.1% of talent on climate science.
This is a great venue to learn because it’s also social. I would be happy to check out the Azimouth Project if I am able to keep investing enough time that I think I might be useful. Nobody is trying to be a spy and, of course, there should never be science worthy of secrecy if there is no proprietary element. I have some views but none are more important to me than the integrity of method. Process does matter. BTW, I consent to have this and my previous comment removed if you consent for the same on your last two on this topic.
-Ron
Ron,
You appear to be ignoring what Willard is trying to illustrate.
Ron
Couldn’t agree more. Now, try and reconcile palaeoclimate behaviour with central estimates of ECS that are below 2C.
Err… no. I’m certainly not. This is just the peanut gallery. A point worth remembering.
Ok, I even get arguments from my compliments here. Tough crowd. I did not spend that much time on Willard as I think we need to graduate from kindergarten. Those that take themselves too seriously are ripe for satire would be the point that I would take away. BTW, I hope the people at Sharp Lab were still as nice when you were there, ATTP, as when I was many many moons ago.
BBD, I have been working on the question of paleo sensitivity and behavior since paleo is a perfect non-biased laboratory on a lot of questions. That I think we can all agree on.
> Those that take themselves too seriously are ripe for satire would be the point that I would take away.
Are you suggesting that kindergarten is too serious, RonG?
I don’t think satire describes very well your lulz about doxing. In fact, the opposite may very well apply. Freedom fighters are usually Very Serious persons.
***
You have not lulzed when the Auditor corrected SteveF’s tentatives to dox Tom Curtis. Here’s what you suggested instead:
http://rankexploits.com/musings/2015/new-thread/#comment-135840
You were you mentioning something about “worthy of secrecy” earlier.
***
In any case, I’d like to join. My email is on my tumblog.
Ron,
Very pleasant, enjoyed it there a lot. Although, I was part of the Bartol Research Institute, not the Physics Department.
Ron
Sure. Let’s try again with the actual question:
Now, try and reconcile palaeoclimate behaviour with central estimates of ECS that are below 2C.
There’s no need to retain RonG much longer, BBD. He already grabbed his coat.
Willard: “What were you saying about being worthy of secrecy?”
One makes a good point, there is a sort of blur between privacy and secrecy. I don’t agree that “doxing” is appropriate if it is simply to invade privacy. And, I apologize for LOL and that my laugh was so interesting that it had to be amplified. I am not for personal ad hom or invasions.
A discussion of whether freedom should tolerate privacy or secrecy though is not fit in a blog post about aerosols. I understand now what Steve Mc was talking about when he said that if you don’t keep a tight lid on moderation that all the strings ending up sounding the same.
==> “BTW, I hope the people at Sharp Lab were still as nice when you were there, ATTP, as when I was many many moons ago.
Is anyone else as impressed with Ron’s credentials as I am?
Ron –
==> “I am not for personal ad hom or invasions.
Then could you explain why you participated in that thread in the way that you did?
Ron –
That “exchange” was full of ad homs – from the keyboard of Steve and Carrick.
Assuming that wasn’t a different Ron Graf at Lucia’s, there seems to be a contradiction between what you’re “for” and what you say you’re “for.”
Ron –
Yeah, shame on willard for “amplifying” your “LOL.”
Oh. Wait.
I guess you only amplified it because you “had” to amplify it, eh? Because it was “so interesting.”
Ron –
==> ” I don’t agree that “doxing” is appropriate if it is simply to invade privacy.”
Perhaps you could explain when “doxing’ is appropriate?
> I understand now what Steve Mc was talking about when he said that if you don’t keep a tight lid on moderation that all the strings ending up sounding the same.
Control over topicality is one of the Auditor’s superpowers, RonG.
There is no need to worry about that thread repeating itself, even if you rediscovered peddling, like BarryW, MikeR, and many others before you.
Which I believe you won’t.
Thank you for playing,
W
Willard, Joshua, and followers, I meant it that you likely are at the top of the climate knowledge pyramid. I would think that at some time you would all grow up to realize that you are not the only ones.
Hmmm? To be fair, my single word description of the online climate debate is “infantile”. On the other hand, I think that much of what Willard and Joshua are doing is attempting to illustrate that, or something broadly consistent with that (although, infantile may be slightly more pejorative than what they often try to illustrate).
Ron, I meant that you are not at the top of said pyramid, likewise myself. I would hope that at some time we can grow up and realise that. Paying due diligence to those who are at the top would be a good way to demonstrate that growth.
Juvenile, I think, is more accurate. Rather similar in nature to a junior high school lunchroom food fight.
Which is all that much more interesting, IMO, because the participants are for the most part, exceptionally intelligent and well-informed adults who, I have no reason to doubt, act in perfectly adult ways in the vast majority of their daily, real-world interactions.
What explains this juxtaposition?
I’d rather say it’s super powers all the way up, AT. It takes more than talent to apologize for lulzing and then requesting that you, among otters, grow up.
I may never be able to sleep now that RonG shattered my illusion that we were alone. Perhaps one day my hope that freedom fighters discover the truth out there will compensate.
Joshua,
Yes, indeed, juvenile is indeed more appropriate. I agree, I don’t quite get it either. There are many who are indeed quite intelligent and informed and yet seem unable to avoid the juvenile taunts. To be clear, I’m not suggesting that I don’t indulge myself, but I would prefer to minimise that if I can.
Ron –
==> ” I would think that at some time you would all grow up to realize that you are not the only ones.”
1. Would you consider that statement as evidence of “grown up” behavior?
2. On what basis have you determined that I don’t “realize” that [we/I] are “not the only ones?”
Anders –
==> “I agree, I don’t quite get it either.”
Well, truth told I do think that I kinda get it. My question about what could cause such a juxtaposition was a rhetorical one (please don’t tell willard!).
Joshua,
You may have to explain it to me then 🙂
Ron –
I’ve asked you a number of questions. Now asking a lot of questions in these discussions, particularly when you line them up one after another as I did, is often rightfully criticized as being suboptimal.
But behind the rhetorical nature of my questioning, suboptimal as that rhetorical quality was, I was making the point that there were (IMO) a series of abundantly obvious logical flaws in your comments – if they were to be viewed from a non-juvenile, good-faith orientation.
It might be interesting to have a good faith exchange regarding those (IMO) flaws, and I would like to read your responses, but my guess is that in the end it would amount to little other than sameolsamol.
So here’s a thought. I think that if you choose to do so, you could still salvage a good-faith exchange with people who are quite intelligent and knowledgeable about the science of climate change. (I couldn’t participate, but by reading such exchanges I might be able to learn sumptin’). Rise to the occasion.
To be fair to Ron, I was genuinely impressed by this
Something very rarely seen in climateball.
Anders –
I chalk it up to identity-protective behaviors (a combination of identity-defense and identity-aggression) that often accompany interactions between people with contrasting views within the context of highly polarized and politicized contexts.
When I see smart, knowledgeable people (who presumably act like adults throughout the vast majority of their daily interaction) act like defensive and aggressive juveniles in such a polarized and politicized context, I think that their identity-protective instincts are rising to the surface. My view is only strengthened when I see, along with those juvenile behaviors, smart and knowledgeable people making very obvious logical flaws in their arguments (so obvious that someone like me who is far less intelligent and well-informed can see them so easily).
The bottom line is that identity-orientated reasoning overwhelms evidence-based reasoning. In other words, what’s on display is motivated reasoning/cultural cognition.
willard –
Yeah, I saw that too. It got me scratchin’ my head, as it made it that much more difficult for me to understand some of Ron’s other “contributions.”
Joshua,
I think you meant VTG.
You said something on the Polemics thread that struck me.
I often see you highlight what seem to be obvious inconsistencies only to then be attacked. Your identity argument makes sense, but it’s also hard to understand how others can’t see this obvious inconsistency. It makes me think that they do, but justify it in some way (they’re right, for example).
This also struck me
I have sometimes wondered if this isn’t exactly the issue. Those who can see their own inconsistencies (or are willing to acknowledge them) just don’t participate and so you’re left with those who either don’t, or who have a way of justifying it.
You need super powerful big boys pants, Joshua
Joshua: “I chalk it up….” All can agree on your points which makes us all scratch our heads.
Just think if Alexander Fleming did not have the humility to show his moldy dishes to his former assistant Merlin Price we would not have Penicillium.
http://www.thefamouspeople.com/profiles/alexander-fleming-151.php
> Your identity argument makes sense, but it’s also hard to understand how others can’t see this obvious inconsistency. It makes me think that they do, but justify it in some way (they’re right, for example).
SteveF justified his doxing by pretexting you entertained some kind of holier-than-you stance, AT. Which is kinda funny since the doxing occured at Judge Judy’s.
Willard,
Yes, I’ve noticed this claim of holier-than-you. Okay, but I’m not sure how highlighting my own CV would somehow make it less likely that I’ll behave in a manner that can be interpreted as holier-than-you.
Anders –
Yes, I meant VTG.
==> ” It makes me think that they do, but justify it in some way (they’re right, for example).”
What’s interesting is that they can see the dynamic in play when it happens with the “other.”
Kahan just has a post up where he talks some of the “they’re right” tendency:
http://www.culturalcognition.net/blog/2015/3/25/you-talking-to-me-are-you-talking-to-me-actually-no-im-not-t.html
==> ” … so you’re left with those who either don’t, or who have a way of justifying it.”
Heh. That’s an interesting angle. It’s kind of a wicked twist: some of those engaged may actually be those who can most clearly see their own inconsistencies and as a result, are most motivated to force fit a justification. In fact, they may have the best skills for identifying the inconsistencies and thus have the best skills for justification.
What if I told you Galileo might have won his trial could have he been able to explain the parallax problem?
What if I told you the Confederacy won the Civil War?
What if Groundskeeper Willie ruled over Scotland?
Counterfactuals are fun.
The holier-than-though claim was kind of the linchpin, IMO.
I think that among the people I’ve seen participating in these discussions, Anders is among the least “holier-than-though.” Not to say that I don’t think that sometimes he engages in identity-protective behaviors, but his near constant refrain of (paraphrasing) “Well, that’s how I see it and I might be wrong and I’d appreciate the input of people more knowledgeable on the topic than I, is, IMO, a key signal of an application of scientific reasoning – of the sort that I find almost completely lacking in the vast, vast majority of blogospheric exchange. It is a direct nod to the importance of giving due credit to uncertainty
In contrast, most of what I see is, “You’re wrong because I know more than you” – as if being write or wrong is a direct function of the degree of someone’s knowledge level, and as if such claims of superior knowledge can ever really be validated except by a complete faith in the logic of appeal to self-authority The lack of respect for uncertainty is the biggest tell of all for an underlying mechanism of confirmation bias.
SteveF’s “holier-than-though” argument was a textbook example, in a textbook of textbook examples.
“What if I told you the Confederacy won the Civil War?”
This is equivalent to: “What if the Holocaust was a big lie?”
Which is equivalent to a denier. We all get the logic.
Half of us disagree.
Not to be holier-than-though here either. We just need to keep talking and less attacking and assuming the worst of people’s intentions, motives and integrity.
I point at this:
And I point at this:
That is all.
Cue to the M word.
OK . We all finally agree.
BTW, Nice to meet you Willard, Joshua. I hope we can talk some science sometime. Like what is the ECS estimate that makes one a borderline denier ;).
To show good faith I will agree there are extremists on the skeptic/denier side that I would have to wonder if they were anywhere motivated by truth seeking. I am in play. What got me into climate was reading about the hockey stick (didn’t even know about climategate) four months ago. The closer I began to look the more troubled I became. I started on Skeptical Science and found them none too skeptical. I noticed a huge difference on CE. Have been expanding since.
Oh, my current ECS estimate is 1.5, but it’s flexible. Politics behind climate is a whole other area and I’m game to talk with you on CE about that as chance permits.
If the models get improved enough to bring in the error bars to +/- .03 for five years and stay on track for ten I would accept that as validation to the model’s TCR. Having a model ensemble prove it from hindcasting would not convince me.
Thank you VTG for the positive comment. Even a small forcing may be important enough to keep in mind, maybe even put in the models if not in already.
Wow!
Holier than though. Write or wrong?
My brain does some really weird shit. Good thing I don’t have to take responsibility for any of it.
“However, the CMIP models have an ECS range from 2.1K to 4.6K. ”
Why use “K” when “C” would do just as well and be slightly more accessible to the public?
That’d be like using R (Rankine) in the United States to say something is going to be 6R warmer.
Why, you’re welcome
The models work by performing heat and mass balance on a grid. That includes radiation, so your effect is inherently included.
If you’ve only been thinking about all this for four months, yet feel you are qualified to judge ecs better than all the experts, you might wish to consider the humility you admire in Alexander Fleming.
@KarSteN
Thanks Karsten. Like you, I expect Storelvmo’s BC-related overestimation of TCR to be on the small side.
Thank you for the pointer to the Ban-Weiss paper – so below 4km altitude, BC is expected to contribute to an increase of the surface temperature. According to Ramanathan ea 2007, peak BC concentrations in the Indian atmospheric brown clouds have been measured at about 2km altitude, and the bulk of the BC is below 3km. If other major plumes around the world have a similar profile, this would affect the majority of GEBA stations used in the study, stations close to sources of BC emission such as those in Europe and Japan, and particularly China, Africa and India (Fig 1a and 1b of Ramanathan & Carmichael 2008, fig 1A of Storelvmo).
To show good faith I will do this.
First, I will use my super powers to throw some extremist squirrels under the bus.
Second, I will point out that van der Sluijs & al (1998) found out that climate sensitivity has been for two decades (since 1979) between 1.5 and 4 C, arbitrarily excluding higher estimates, and void of any clear conception of what “climate sensitivity” really was.
Third, I will observe that RonG only picked one number, and the lowest one to boot, as prescribed in the lukewarm playbook.
Fourth, I will recall out that the actual topic of the blog post is Stevens’ presentation, which concerns the lowest bound of
justified desingenuousnessaerosol forcing.Fifth, I will remind everyone that ClimateBall episodes around CS are usually proxy debates to look sciency, which according to Essex’ op-ed in Breitbart’s is the real deal.
Sixth, I will declare that GRRRRROWTH wins.
Thank you.
Ron G
That’s good because you *still* haven’t explained to us how you square 1.5C with palaeoclimate behaviour which is incompatible with an ECS below 2C and strongly suggestive of a value closer to 3C.
Ron G
Models don’t *predict* short-term natural variability and natural variability is dominant on sub-decadal timescales so what you are asking is impossible. Perhaps after such a short period of study, you don’t understand the topic very well?
Ron Graf:
You implied that you had posted commnents on the Skeptical Science website. What username did you use?
VTG: “If you’ve only been thinking about all this for four months, yet feel you are qualified to judge ecs better than all the experts, you might wish to consider the humility you admire in Alexander Fleming.”
Actually it was a combination of Flemings humility and Pryce’s impertinence to not throw out the moldy dishes while doing his job of cleaning up the lab. He noticed the weird pattern and made a decision to keep them to show to Fleming. Pryce then refused Flemings wishes to share credit. http://www.biusante.parisdescartes.fr/ishm/vesalius/VESx2002x08x02x006x025.pdf
I believe the IPCC has been estimating ECS to be between 1.5 and 4 since their first report (in 1990 right?). Also, Stevens aerosol paper and the implications of PDO/AMO demonstrate the 1990 estimate could have been overly generous on the high end of range. So, I don’t feel that my current opinion is in conflict with ALL the experts, maybe just the ones here.
BBD: “Models don’t *predict* short-term natural variability and natural variability is dominant on sub-decadal timescales so what you are asking is impossible.”
If you can’t think of at least 2 ways that your statement is possibly wrong in two seconds I am wasting time but: 1) Models can predict whatever we program them to. 2) Everything in nature is natural. Variability is dominant is what a non-entomologist says when they see an ant colony in action.
“You implied that you had posted comments (sic) on the Skeptical Science website. What username did you use?” I was mostly a reader. I made one comment that never made it out of moderation. I got a snide email instead.
BBD: ” you *still* haven’t explained to us how you square 1.5C with palaeoclimate behaviour which is incompatible with an ECS below 2C and strongly suggestive of a value closer to 3C”
I feel paleo is the wrong place to look for support of current ECS since there is no guarantee of congruity. Better to use paleo to better understand the “impossible to know” unknown variability issues so that we can do accurate ECS with all the known variables.
Ron,
Try watching Andrew Dessler’s video. I think few experts think that ECS is less than 2K.
Ron G
You have just reconfirmed that you are clueless. Models can no more predict natural variability that we can. Can *you* predict volcanic eruptions? Can *you* predict ENSO? Try thinking before typing. What I said above stands. You need to learn more.
Who cares what you ‘feel’? What matters is whether or not you can back up your assertion that palaeoclimate cannot be used to derive estimates of ECS that are applicable to the present. Please either reference this claim or admit that it is baseless nonsense.
Ron Graf:
What is the uncertainty range of your estimate?
If you do not have one, you are being extraordinarily dogmatic in your estimate.
If you do have one, and 1.5 C is at the lower end of the range, you are deliberately misreporting your estimate in order to quote a low value for ECS.
If you have one, and are quoting the modal value (or the median, or mean value) then you assign very high probabilities to ECS values the IPCC says have a low probability of occurring. That does not mean you are wrong. It does mean that you are in conflict with the IPCC.
Except the anthropogenic forcings, which dominate on multi-decadal timescales.
Tom: “What is the uncertainty range of your estimate?”
I would say roughly 1.3 to 2 tops. Thanks for asking though I am not prepared to list the 100 variables, tangible and intangible, that affect my judgment on that. Every good paper of new thing that seems well plotted and confirmed moves the judgement.
@BBD, I’m sorry I used a bad tone. I am sure you don’t believe that we can’t make progress on the “uncertainty monster.”
Here’s a wild hunch for you all to shoot down: Whereas the solar cycle is now more and more believed to be caused by the magnetic fields of Jupiter and to a lesser degree Saturn, and whereas the Grand Conjunction (Jupiter and Saturn alignment) is a 20 year period, and whereas that every third Grand Conjunction repeats closely in orientation to Earth’s vector every third period, what if the 60-year PDO/AMO is related to the 60-year Grand Conjunction cycle?
Ron,
Well, the top of your range is essentially the bottom of most experts’ range.
Energetically, this seems highly unlikely, but I’d need more than some vague blog comment before I put in any real effort.
The correct response is that Rog Tallbloke has all the answers. But that he is not letting the cat out of the bag just yet due to intellectual property concerns. #WHUT is up with that?
Oh, is this one of Tallbloke’s ideas?
ATTP: “Well, the top of your range is essentially the bottom of most experts’ range.”
Correct. I think the divide is likely more on politics than on science. The concern that brought my attention was the misquoting of science by politics.
“Energetically, this seems highly unlikely, but I’d need more than some vague blog comment before I put in any real effort.”
What would the Bartol Research Institute think? You did not even correct me. It’s the “Great Conjunction,” not Grand. Are you old enough to remember the alarm some were putting out about the “Jupiter Effect.” Here I found a link: http://www.wewillbehere.com/2012/11/1982-planetary-alignment/
The idea was catastrophe by volcanoes and earthquakes being caused by the tidal forces. That was all a red herring but maybe it had something to do with initiating a warming from a PDO/AMO effect? 1940 was the prior and 2000 the later conjunctions. Couldn’t tides affect currents?
I thought of it independently 30 minutes ago due to BBD comment. I swear.
Ron,
It’s getting late.
Yes, but I don’t.
The ratio of the tidal force due to, for example, the Moon and the Sun is
where the r refers to the distance. If you put in the values for the Moon and the Sun, the tidal force due to the Moon is 2.2 times greater than that due to the Sun. If you replace the Sun by Jupiter (assuming I got this right) the tidal force due to the Moon is 150000 times greater than that due to Jupiter. Seems pretty negligible to me.
Thanks for helping me with the math. As VTG and you know that’s one of my weaknesses.
I did a search for Tallbloke and PDO and came up with a hit but it does not place it to the Great Conjunction. He is only talking about the solar cycle, which is what I guess I heard. The Great Conjunction comes up in another one his blogs but not with PDO.
about.https://tallbloke.wordpress.com/tag/climate/
Peak tidal force in N:
Moons: 7.7 e18
Jupiter’s 5.6 e13
Saturn 1.6 e12
I did a little better than you estimate with about a 100,000:1 ratio.
I don’t know how they were predicting earthquake catastrophe but I am going to read and will let you know.
Ron Graf, is that a likely (66% CI), very likely (90% CI), extremely likely (95% CI) or virtually certain (99% CI) range?
Tom: “Ron Graf, is that a likely (66% CI), very likely (90% CI), extremely likely (95% CI) or virtually certain (99% CI) range?”
The politicians ask the IPCC every four years. I’m learning from the pros about getting into a pickle as seen below:
1990 AR1: ‘The unequivocal detection of the enhanced greenhouse effect from observations is not likely for a decade or more. ‘
1995 AR2: “The balance of evidence suggests a discernible human influence on global climate”
2001 AR3: “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.”
2007 AR4: “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations”
2013 AR5: “It is extremely likely that human activities caused more than half of the observed increase in GMST from 1951 to 2010. The best estimate of the human-induced contribution to warming is similar to the observed warming over this period.”
If I was investing on the odds I would say it is 95% certain that the latest IPCC expert analysis best estimate is wrong and 50% certain that their extremely likely assessment is wrong.
Can I suggest a new post on the exciting new Rahmstorf & Mann paper?
****Update on Jupiter Effect on Earth — It seems that the 1974 best-selling book by John Gribbin, Ph.D., and Stephen Plagemann was alarmist trash that, if your old enough you notice about once per decade. And although the book did rely on 1/100,000 of the Moon’s tidal force as it’s thesis, and creating an actual tide of 40 microns, the idea that Jupiter and Saturn could have an effect is not insanity. Jupiter has a magnetic field that is 20,000 times more powerful than Earth’s, rivaled only by the Sun’s. The oceans are a giant electrolytic solution that is in flux, which creates and induced magnetic field (which is being studied now as a way to detect deep ocean floor currents).
The idea that the solar cycle is caused by Jupiter and Saturn’s magnetosphere is a serious proposition. The perturbation effect on the Sun could act as an amplifier or reinforcing harmonic. Even without the Sun’s help a harmonic effect might possibly be induced into the Earth’s magnetic field, perhaps inducing a flow pattern of mantle core flow, which in turn, is inducing the ocean current enough to create a detectable pattern. What you climate physicists could help with is how does the PDO/AMO change GMST? What is the best current theory and for Tom’s sake include some certainty assessment
Or, does anyone have a fresh update on black carbon BC?
Ron,
There’s a problem with Clive Best’s analysis that I’ve tried to explain to him a number of times. He assumes that he can divide the temperature into a forced component and a natural component. This, in itself, is fine. The problem is that he assumes that the only external forcing is CO2, and this is incorrect. There are other anthropogenic forcings (other GHGs, aerosols, BC, land use) and there are natural external forcings (solar, volcanoes). Therefore, his supposed natural variability contains both natural and anthropogenic contributions. The IPCC analysis tried to extract only the natural contribution and so his analysis isn’t actually a fair way to assess what the IPCC did.
Ron
Before disappearing up your backside, why not ask why is everything we know about radiative physics and the atmospheric greenhouse effect wrong?
Before shifting attribution you need to get rid of the GHE. At least be systematic in your crankery.
Ron,
Now we’re firmly into astrology to explain why you know better than the ippc, can I refer you back to my earlier suggestion on humility?
Ron,
I really doubt it. The Solar cycle – as I understand it – is caused by the differential rotation of the Sun. The equator rotates faster than the poles. This causes the magnetic field to wrap around the Sun, eventually undergoing reconnection and reversing. It happens about every 11 years.
This is an earlier (2013) paper by Stevens on aerisols that might be of interest.
Aerosols: Uncertain then, irrelevant now
Bjorn Stevens
Nature 503, 47–48, (07 November 2013) doi:10.1038/503047a
http://www.nature.com/nature/journal/v503/n7474/full/503047a.html
For what it’s worth, here’s a link to Bjorn Stevens’ Ringberg slides in which he argues for a range 2.0 < ECS < 3.5, so not consistent with Nic Lewis's interpretation and within the IPCC range.
Click to access Stevens_Ringberg_Talk.pdf
MarkB,
Thanks, very interesting.
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