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Comments 7301 to 7350:
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Bob Loblaw at 01:14 AM on 11 July 2020Models are unreliable
ClimateDemon @1270:
You mean where Lacis et al use the phrase "If the global atmospheric temperatures were to fall as low as TS=TE..."
Clearly, you have no idea what Lacis et al are saying when they use the symbols TS and TE, even though they explain it in the second paragraph of the paper: "...mean surface temperature (TS = 288 K) and the global mean effective temperature (TE = 255 K)...
That they describe a three-dimensional system by using mean values does not indicate they used a zero-dimensional model.
Frankly, you have absolutely no idea what you are talking about.
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ClimateDemon at 00:09 AM on 11 July 2020Models are unreliable
MA Rodger @1268
All right, so scrap the entire 1265 posting. I never was very good at guessing games anyway. If you go to the paragraph that starts near the top of the third column on page 357, however, you will see that the authors of the Lacis et. al. (2010) paper do in fact use that zero dimensional model with a single temperature earth to make some prediction on the sustainable amount of atmospheric water vapor in the example they were showing. Their ModelE runs were for something else.
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Bob Loblaw at 22:50 PM on 10 July 2020Models are unreliable
ClimateDemon:
Since you seen keen on the concept, why don't you explain, in complete and unambigous terms, just exactly what you think you mean by "global thermal equlibrium".
Unless you have a working definition of that phrase, you're just playing games, not doing science.
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MA Rodger at 21:03 PM on 10 July 2020Models are unreliable
ClimateDemon @1265,
Bar moderator intervention, you are of course at liberty to parade your ignorance here.What do you not understand about "GISS 2° × 2.5° AR5 version of ModelE"? Presumably all of it. (You might find this CarbonBrief article on GCMs useful in raising your understanding of GCMs to a less embarassing level.) And why would the values presented in the paper's Fig 2 throw any light on the complexity of the model used to generate them when, as the Fig 2 clearly states, they present "Global Annual Mean" data? Without there being more than one "globe", such a graph will only have "a single-value global temperature for each time point".
As for your little speech about "inital conditions", perhaps you can give an example of which of these "inital conditions" could be "tweeked" to alter the fundamental finding of Lacis et (2010). (Remember this simple experiment is removing some 30Wm^-2 of greenhouse effect. Such a climate forcing, even without feedbacks, is enough to drop global average temperatures by far more that the last ice age achieved.)
ClimateDemon @1266,
I assume your cunningly crafted question is intended to show that a model of an Earth-like planet's climate in which "the temperature is everywhere uniform" would not capture the topological complexity of such a planet. As Lacis et al did not use such a model, your question is entirely misplaced. -
Eclectic at 20:09 PM on 10 July 2020Models are unreliable
ClimateDemon @1266 , your question must necessarily include a pre-condition ~ How long can this planet maintain equilibrium?
You propose an interesting hypothetical planet. To have a uniform surface temperature, that would require it be evenly surrounded by a sphere of identical suns numbering 40 (better, 100 or more). Unfortunately, the planet's central location would not be gravitically stable, and the planet would drift into one of the suns. So the planet's evenly-distributed temperature would persist until shortly before impact.
The unpleasant scenario would have to include the 40 (or 100) suns gravitically attracting each other, and converging to the original central location including the planet (unless the planet had moved some distance ~ owing to the chaotic & nonlinear wing-flapping of an especially powerful gravitic butterfly).
The Clausius-Clapeyron Equation indicates that the planet's beautiful lakes rivers & oceans would rapidly enter a state of very low relative humidity . . . until reaching the plasma state [a state not describe by the C-C Equation, if I understand your earlier comments].
(Moderators may care to remove this slightly Off-Topic post. )
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ClimateDemon at 18:15 PM on 10 July 2020Models are unreliable
I would like to post this fun question to all of you AGW folks and anyone else interested in participating. And who knows? It may just resolve some confusion about the concept of thermal equilibrium.
Suppose we have a planet similar to Earth, except that the temperature is everywhere uniform. But like Earth, much of the surface is covered with water and the terrain outside of the water has varying elevations. At the lower elevations the air is generally moist and there are lots of lakes and rivers, and at the higher elevations, the air is much dryer and the climate is much more desert-like.
Question: Is this planet in global thermal equilibrium?
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ClimateDemon at 17:21 PM on 10 July 2020Models are unreliable
MA Rodger @1259
In Lacis et. al. (2010) the authors state:
A clear demonstration is needed to show that water vapor and clouds do indeed behave as fast feedback processes and that their atmospheric distributions are regulated by the sustained radiative forcing due to the noncondensing GHGs. To this end, we performed a simple climate experiment with the GISS 2° × 2.5° AR5 version of ModelE, using the Q-flux ocean with a mixed-layer depth of 250 m, zeroing out all the noncondensing GHGs and aerosols.
Now, the authors did not provide the input data they used, but they did say they performed a simple demonstration. Of course, I don’t know their definition of “simple”, but I believe it most likely would include a uniform temperature and zero fluid velocity and pressure gradients. Also, examining Figure 2, I see that one of the results of their ModelE runs is a single-value global temperature for each time point, which we already know is unrealistic. Although I am not familiar with ModelE, I do know a few things about GCMs in general, including the fact that the results of any such number crunching is highly dependent upon the initial conditions, many of which are unknown. This is what makes these models “tweakable” for purposes of hindcasting, but even that process is far from perfect. Although the ModelE demonstrations may well have produced valid results for the particular set of initial conditions chosen, they should not be regarded as “typical” output from the model.
Therefore, my claim that the CO2 “control knob” has not been proven still stands. -
Jasper at 15:47 PM on 10 July 2020It's only a few degrees
Thank you for your help. English is not my native tongue so please forgive me if I make any language mistakes.
I am a chemistry teacher in the Netherlands and I teach 14 till 18 year old students. On a regular basis I encounter young sceptics that are difficult to win over with the normal arguments because they live in a social environment where everybody thinks climate change is not a problem. You can think of them as the Dutch republicans (to put it in an American perspective).
A few months ago a student said to me that an increase in 3, or 5 degrees C will not mean much because in winter in can be below 0 C and in summer it can be 40 C. It was a new argument for me. I thought about the average temperatures in the ice age, but that is for a 14 year old too abstract.
I teach in an agricultural area and the arguments about droughts (The Netherlands was famous for its rains, but recent summers meant long hot dry spells, which means something to these farmer kids...) and the fact that because of temperature change crops might not be able to grow anymore or (more importantly) will give a lower yield might also mean something to them.
Hopefully with this I will be able to start some students of mine on the track of re-evaluating their believes in climate change.
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scaddenp at 09:18 AM on 10 July 2020Models are unreliable
BaerbelW, I rather think that Climatedemon is like our old friend cosmowarrior/coolearth et al. He/she struggles to comprehend information that is at odds with prior beliefs so would struggle in the course.
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Bob Loblaw at 06:51 AM on 10 July 2020Models are unreliable
Yes, Baerbel, ClimateDemon is a good example of denial because he's such a bad example. Even in his most recent post:
- "...most of which I have never heard about..."
...but he still knows
- "In most of the peer-reviewed literature on climate change, existence of the control knob is simply assumed ..."
...and he concludes
- "...all of those references you sent me are rendered meaningless."
So, he isn't aware of of much of what we pointed to, but knows that the entire field of climatology assumes things that they don't, and dismisses an entire field of science as "meaningless" even though he isn't aware of what it contains. Rinse, Repeat.
It doesn't matter what is presented to him - without reading it, he knows it is all wrong.
The Morton's Demon is strong in ClimateDemon.
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JohnSeers at 06:46 AM on 10 July 2020Models are unreliable
Climate Demon @1258
You have gone from "the control knob is easily debunked" to "absolutely essential" (for AGW) to "never been proven" to "simply assumed" to some waffle about zero-dimensional models to some mumbo-jumbo about Claudius Clapeyron to there is "no valid proof".
You finish with a flourish. Everything is "rendered meaningless".
It's a bit of a cop-out on your part, isn't it? Just make a list of random assertions, assert it is all meaningless and pat yourself on the back.
Sorry, you have to put more effort into it than that. -
BaerbelW at 21:24 PM on 9 July 2020Models are unreliable
ClimateDemon @1257
Well, judging from your comments here, you'd provide ample examples for the students in our MOOC of how science denial can look like! Your contributions in the forum might therefore end up as actual case studies for them of what they'll encounter in real life! And who knows, you might still learn something - at least if you are prepared to really engage with the material and watch the expert interviews included in the course.
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Postkey at 19:56 PM on 9 July 2020Models are unreliable
" Without the radiative forcing supplied by CO2 and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state."
Moderator Response:(BW) re-formatted the link
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MA Rodger at 19:19 PM on 9 July 2020Models are unreliable
ClimateDemon @1258,
It appears you require your feed of information served up to you in the most readily consumable form.
Lacis et al 2010 use a model. You say that model is "a zero-dimensional model which assumes a single-temperature earth."
The model used was GISS ModelE. This model is a full-blown GCM. What you say about GISS ModelE is complete and utter nonsense.
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ClimateDemon at 18:23 PM on 9 July 2020Models are unreliable
Well, I must thank you all for sending me such an impressive stack of references covering various aspects of arguing for AGW, most of which I have never heard about, and I will agree that as scientists, we must consider all available evidence on any issue before coming to a conclusion. I must also point out, however, that a chain is only as strong as its weakest link, and with AGW, the CO2 “control knob” is absolutely essential, yet it has never been proven. Without such a control knob, H2O vapor becomes the controlling as well as the strongest GHG, and in this case human contributions to temperature changes would be insignificant.
In most of the peer-reviewed literature on climate change, existence of the control knob is simply assumed without references or supporting arguments. If references are given, I find they don’t explain the justification for the control knob either. The only paper I have found that even pretends to address this issue is the Lacis et. al. 2010 paper that I cited in a few earlier postings, although I have heard that other authors have made similar arguments. The problem, however, is that they make two false assumptions in setting up their model. First, they use a zero-dimensional model which assumes a single-temperature earth whereas temperatures on the real earth can vary by 50-60 degrees C over the surface. Second, they apply the Clausius Clapeyron equation to obtain the water vapor concentration. This equation assumes constant thermal equilibrium when in fact the earth is never in thermal equilibrium. Thus, there is no valid proof of the CO2 control knob effect.
Unfortunately, since we cannot establish the existence of a CO2 control knob, all of those references you sent me are rendered meaningless.Moderator Response:[DB] Continuing to make things up is unhelpful. Sloganeering snipped.
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ClimateDemon at 11:54 AM on 9 July 2020Models are unreliable
BaerbelW @1254
I have seen some of the videos and other materials used in this course, and I highly doubt that you and the other faculty/staff members would want me in it.
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Philippe Chantreau at 03:27 AM on 9 July 2020Models are unreliable
I'm trying to make sense of Climate Demon post at 1252 and it's difficult.
This "they used their models to conclude there is global warming" is rather strange. The real situation is: the models suggest that global temperatures would rise under an increase in non-precipitable GHG scenario, accompanied by other phenomena like some decrease in stratospheric temp and changes in tropopause height, etc. Independently of models, multiple observations (tropospheric temps, sea surface temps, stratospheric temps, sea level, species movement upward and poleward, Arctic sea ice loss, etc) show without a doubt that there is global warming. These observations are what leads to the conclusion that there is global warming, not the models. They are, however, consistent with the expectations obtained from models when increased forcing from non-precipitable GHG are introduced. All this is in the original post.
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wilddouglascounty at 23:31 PM on 8 July 2020Saharan dust cloud was most intense in decades, and more, though milder, are coming
There were several things that were notable from my vantage point in Kansas:
1) The dust cloud was also accompanied by a very humid tropical air mass, making it almost intolerably uncomfortable to be outside because of the accompanying humidity. In fact I wasn't sure for a while whether the haziness was due to the dust or the extreme humidity. I suppose it was a combination of both. So I don't know which part of the situation contributed the most to the situation: the dust or the humidity. I guess it doesn't really matter as both can make breathing more difficult.
2) What made it unmistakebly certain that it was the dust was, well, the dust. It laid down a very fine layer that coated everything, very noticeably on cars. I've seen it happen in dry years when March winds can bring dust in from the western parts of the state, but to come all the way over from the Sahara is pretty impressive.
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scaddenp at 12:39 PM on 8 July 2020Climate sensitivity is low
leehoe - do you understand the difference between Equilibrium Climate Sensitivity (often just climate sensitivity) and Transient Climate sensitivity? The box on pg 1110 of the IPCC WG1 has some explanation.
Discussions around estimates of climate sensitivity from the instrument record here especially the Marvel et al paper. And also here for earlier work by Otto, Curry, Lewis
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Eclectic at 11:30 AM on 8 July 2020Climate sensitivity is low
Leehoe @383 ,
please, the word is Sensitivity. Remember the humorous old saying :-
"Typo me once, error me twice".
Yes, the past 6 decades have been a moderately good time for doing a back-of-envelope calculation of sensitivity, because of the fairly flat level of insolation ( around 1360 w/m2 ). And with only a rather small change in non-CO2 / non-H2O greenhouse gas levels.
Unfortunately, the last part of of your post was so abrupt, that your meaning is ambiguous. Please expand your wording, to give a clear indication of your meaning. Readers may be confused on your intention regarding ECS versus TCS. And it is entirely unclear whether you were alluding to the industrial aerosols and volcanic aerosols during this 6 decade period.
Please clarify !
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JohnSeers at 10:37 AM on 8 July 2020Models are unreliable
Climate Demon @ 1252
For you to say you have asked a question and "nothing more, nothing less" is disingenuous. Comments like "the control knob is easy to debunk" say a whole lot more.
Others more knowledgeable than me have attempted to signpost you to more enlightening information but you think you are too informed to be bothered with that.
I will give a partial answer to your no more, no less question. The question iteself shows you are not really clued up enough. Climate models do not provide proof humans are causing global warming. Climate models are a consequence of the scientists testing their theories against the data and evidence. They prove nothing in themselves. They are confirmation of what we think we know and help us feel we are on the right track. If we trust them enough we can use them for projections. Our trust grows over time as they are developed and used. (And as our computers get faster!)
Models are one piece of evidence (not proof) of the consilience of evidences that add up to proof of AGW. That is evidence from many sources and lines of enquiry all point in the direction of AGW.
So, how much more specific can you be? A suggestion is you look through the references supplied (I recommend the Richard Alley lectures and his course) and then, (as you can simply debunk them Ha Ha), form a very specific question and work through it with the refutations you will get. You might learn something if you do it diligently.
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leehoe at 09:15 AM on 8 July 2020Climate sensitivity is low
Interesting math, but it doesn't appear to be consistent with NASA, Berkeley, Hadley, World Meteriorlogic Organization, and Cowtan and Way global temperature datasets--every international real-time and long-term dataset for Global Temperature.
Please bear with me as I focus on real data generated by hard working climate scientists over the past 6+ decades.
Mauna Loa Observatory (MLO) began recording CO2 in Mar1958 and continues to be the longest real-time record of atmospheric CO2.
The average temperature change of the above internationally highly acclaimed datasets for global temperature (Mar1958 through May2020), is 0.85 C {1.00, 0.92, 0.78, 0.72, 0.83} respectively.
CO2, per MLO, rose from 315.71 to 417.07.
If climate sensetivity for CO2 was 2 C (.85 C / ln[417.07/315.71] x ln(2 or a double) = 2 C), CO2 alone would explain 100% of all climate change!
1) The Sensetivity of all GHG combined > 2 C is not supported by real-time climate for the past 6+ decades.
2) CO2 is not the only GHG and GHG is not the only thing causing climate change.
Moderator Response:[TD] It appears that you did not read the Advanced tabbed pane of this post. Please do.
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BaerbelW at 05:59 AM on 8 July 2020Models are unreliable
ClimateDemon - here is a challenge for you: register for our MOOC "Denial101x - Making sense of climate science denial" and work through the six weeks worth of lectures. You'll get a good understanding of the basics of climate science - including about models - and how/why these basics get regularly distorted. Once done, come back to the comment threads here with any clarifying questions you might still have. But frankly, there shouldn't really be (m)any as what you keep asking here has been answered more than enough already - it's up to you to put in the effort to learn and understand.
Here is the link to the MOOC: https://sks.to/denial101x
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MA Rodger at 05:18 AM on 8 July 2020Models are unreliable
ClimateDemon @1252,
Are you familiar with the United Nations Intergovernmental Panel on Climate Change? I ask because your comment @1252 only makes sense if you are not familiar with this organisation and its work. I would draw your attention to IPCC AR5 WG1 which reviews the science showing both that "there is global warming" and that "humans are causing it." I would draw your attention to Chapter 10 'Detection and Attribution of Climate Change:from Global to Regional' and, as you have show interest specifically in the role of CO2 in the global warming, also Chapter 5 'Information from Paleoclimate
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ClimateDemon at 04:48 AM on 8 July 2020Models are unreliable
John Seers @1251
I only asked how the current climate models show that humans are causing global warming — nothing more, nothing less. How much more "specific" am I supposed to be? It is these "sources" that are vague and not answering my question. Frankly, I am very much disturbed by the fact that the climate science "experts" are using every scare tactic available to get nations to drastically cut CO2 emissions at a great economic sacrifice, yet none can give a straight answer as to how they used their models to conclude there is global warming and that humans are causing it. Making your studies clear and traceable is an important part of doing good science, and it is not happening in the AGW community.
Moderator Response:[TD] At the top of the home page there is a big image labeled "Newcomers, start here." In the resulting "Welcome to Skeptical Science" page, look for the section "Good starting points for newbies." Click the links in that section.
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JohnSeers at 23:54 PM on 7 July 2020Models are unreliable
"What makes you think I haven't looked at those sources ..."
If you had looked at them properly and with an open mind then you would have formed more specific and meaningful questions. That is why I think you have not looked at them.
The "control knob is easily debunked" is not a statement that is easy to engage with.
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RedBaron at 19:07 PM on 6 July 2020Hansen's 1988 prediction was wrong
@ Nylo
You said, " to my knowledge no effort has been made to reduce CH4 emissions. Lots of talking but zero measures. There is no reason to believe that we are emitting less methane than in the 80s, despite it is increasing at about half the rate that Lacis said that it was increasing in the 80s (8ppbv/year instead of 15ppbv/year)."
This is not true at all. There have been significant changes in agricultural practises that have partially restore methane absorption and metabolism by methanotrophs in the soil over vast acreages.
Namely the widespread use of no-til combined with multispecies cover crops.
“No-Till” Farming Is a Growing Practice
And also there is significant acreage that has been converted from set stock acreage to holistic managed acreage, even though there is huge active resistance campaigns to prevent this. That reduces atmospheric methane even more.
I have written about that here before, but was asked to consolidate that information and use it like a reference. So I wrote about it here:
What reaction can you do to remove methane?
There is actually more though. Several major gas pipeline leaks have been documented and repaired too. Those apparently were a major source of the increased methane. Some say the major source.
preindustrial CH4 indicates greater anthropogenic fossil CH4 emissions.
There are multiple reasons and the issue is at least as complex as the CO2 cycle. So while there is certainly a huge degree of uncertainty, claiming there is nothing being done is just wrong.
A lot is being done, we are just not entirely sure how efficacious it is yet.
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Nylo at 16:11 PM on 6 July 2020Hansen's 1988 prediction was wrong
MA Rodger @63
You are right again, the errata by Hansen could be writting 1.4ppbv instead of 1.4ppmv. Given the very low number I though he had missed the per year part, but he actually probably meant total concentration and just gave it in parts per million instead of per billion and that would lead to your numbers. So while for every other gas he is talking about the progression of the concentration change (the delta), here he was talking about the progression of the concentration itself.
Isn't it fantastic that, despite ZERO efforts to reduce our methane emissions and despite the alleged existance of a methane bomb in the arctic that is releasing more and more methane each day, the actual increase in the atmosphere in the last decade is 5 times smaller than predicted? And this is after accelerating, because the previous decade saw almost no increase at all.
You write:
A quick back-of-fag-packet calculation suggests to me that adding all the forcings from the different GHGs shows the 1988-2019 projections of Scenario A to be 200% of 'actual'.
I think that what you have just written there means that Hansen expected the forcings from Methane and CFCs together to be bigger than the forcing of CO2 in that scenario. Because if they are smaller but not zero today, and CO2 is like scenario A, but we are getting half the warming that he expected, then the missing part of CH4+CFCs must be not-having an impact as big as the current CO2+CH4+CFCs. Interestingly though, the focus to avoid a climate catastrophe due to warming has always been the CO2 emissions, never the other 2. The reasons for the CFCs reduction have always been the ozone hole, and to my knowledge no effort has been made to reduce CH4 emissions. Lots of talking but zero measures. There is no reason to believe that we are emitting less methane than in the 80s, despite it is increasing at about half the rate that Lacis said that it was increasing in the 80s (8ppbv/year instead of 15ppbv/year). The reduction must come fundamentally from natural sources, or else, it is disappearing now faster from the atmosphere than it was then.
I think I will leave the discussion here.
Best,
Nylo.
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ClimateDemon at 14:13 PM on 6 July 2020Models are unreliable
Tom Dayton @1248
What makes you think I haven't looked at those sources and a whole lot more. If they are so relevant, then howcome they don't even pretend to answer my questions. And no, I am not trolling but it's getting tempting since asking politely isn't working.
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Dawei at 13:37 PM on 6 July 20202020 SkS Weekly Climate Change & Global Warming Digest #27
The hyperlink under Click Here, for "Click here to access the entire article as originally posted on The Guardian website", is not right.
Moderator Response:Proper link inserted. Thanks for bringing this glitch to our attention.
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Bob Loblaw at 10:40 AM on 6 July 2020Models are unreliable
ClimateDemon @ 1247:
Sure. I'll do that as soon as you explain what caused the financial crisis of 2008, and give a detailed explanation of the factors leading up to the Second World War.
What's that? Oh, you mean we're not just playing a game of "ask irrelevant questions?".
I'll take it as a given that you actually have no constructive argument for your previous statements about water vapour.
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Tom Dayton at 08:39 AM on 6 July 2020Models are unreliable
ClimateDemon, I gave you links to Richard Alley's lectures. There are relevant posts here on SkS as well, which you were given links to, in moderator's comments. There is no point in me or anyone else responding to your requests for information when you refuse to read or watch those resources. It is clear you are merely trolling.
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ClimateDemon at 08:25 AM on 6 July 2020Models are unreliable
Bob Loblaw @2445
Very good! Now explain how all of this implies that humans are causing global warming.
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nigelj at 08:16 AM on 6 July 20202020 SkS Weekly Climate Change & Global Warming News Roundup #27
The Guardian article says "I’m not saying facts don’t matter or the scientific method should be watered down or we should communicate without facts. What I am saying is that now the climate science has been proven to be true to the highest degree possible, we have to stop being reasonable and start being emotional."
Yes, but it may depend on the emotions. I get angry with lack of mitigation and denialist rhetoric, but getting angry with denialists and shouting at them or becoming personal can lead to them getting more entrenched in their views. Its a fine balance where the anger needs expression but needs control.
Crying tears about the end of the world gets a predictably negative reaction from the political right. Getting really angry with our leaders is sometimes very justified, but it can quickly escalate out of control to shouting matches and their views becoming more entrenched. Put it this may the anger needs to be very facts based and focused.
Climate scientists could write more accounts including their more personal fears. I think everyone would connect with that.
Yes world views are important. Much of the denialism comes from the political right and its driven by ideological fear of things like taxes etc. You can try to empathise with the political right, and find solutions that minimise the perceived problems of "big government" and couch the problem in terms the political right understand, such of concern for other people as our neighbours rather than using the word inequality. But attempts to do this have not yeilded great results.
Yes its clear climate denialism and weak climate mitigation policies are driven by political tribalism but mitigation is weak even in countries without much political tribalism. Even one party states like China are still building a lot of coal fired power. So other things are at work. Perhaps everyone is complacent and wants to preserve the status quo, especially the leaders in society. But I think much of it comes back to my previous comment:
Humans are hard wired to respond most strongly to very present threats (like covid 19) rather than long term and future orientated threats like climate change.This doesn't mean fear is not a motivator for climate action, but it clearly signals it may not be sufficient, so we need a focus on the benefits of solutions as well. (this creates positive emotions)
www.bbc.com/future/article/20190304-human-evolution-means-we-can-tackle-climate-change
And yes I can see facts are not enough to convince people. But facts are part of it. More needs to be made of the devastatingly high risk lower probability events like hothouse earth and multi metre sea level rise. This is lacking in the IPCC reports and its this politicians look at.
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ClimateDemon at 08:12 AM on 6 July 2020Models are unreliable
Tom Dayton @1224 and 1244
Thanks for your responses, and please understand that I am not trying to tear down the general integrity or accuracy of the current models. I do have serious concerns, however, as to how the climate science community is applying these models to conclude that humans are well on the way to toasting the entire earth with their CO2 emissions. Over the last 5-10 years, however, the only analysis I have been able to find that at least indirectly blames humans for the warming trend during the last two decades of the 20th century is the CO2 control-knob theory as explained on the Lacis et. al. paper. I did find several different authors, including John Cook, but they all said pretty much the same thing.
Now, in your statement 1224, you claimed that this was not the only model and paper that predicts the CO2 control knob and AGW. So, what I need to know is what models and papers are out there that do predict AGW, and specifically who or what the AGW community (including politicians as well as scientist) is referring to when they make swooping claims such as "scientists say that humans are causing global warming".
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Bob Loblaw at 07:02 AM on 6 July 2020Models are unreliable
Although water vapour's role may be better discussed elsewhere, ClimateDemon has made some rather inaacurate claims about climate models. That makes this on topic (I think) for this thread.
Rather than creating a strawman using a simple "single-temperature earth model constrained to thermal equilibrium at all times" (which sounds like ClimateDemon is thinking about zero-dimensional equilibrium models only), let's discuss how precipitation and evaporation work in something like a General Circulation Model (GCM). Such models have full hydrological cycles, and atmospheric dynamics very much like a weather forecasting model. In such a model:
- Evaporation from the surface (land or water) is calculated as a function of surface moisture availabilty, energy availability, atmospheric humidity, and the atmospheric motions that can move vapour away from the surface.
- Moist air is then moved around until it cools enough for clouds to form, and they grow until droplets (or ice particles) are large enough to fall to the surface - precipitation.
- Cooling the air enough to create large amounts of precipitation is usually accomplished by moving the air up, where it cools adiabatically.
Now, the real world does the same thing, and there are typically three primary ways of getting air to rise and cool. This is covered in pretty much any reasonable introductory weather or climate course or book. The precipitation types related to these processes are used to label the precipitation type;
- Frontal precipitation, where warm moist air is pushed upwards by colder (more dense) air. Happens in your typical storms.
- Orographic precipitation, where warm air is forced up over hills or mountains. West coasts, monsoons, etc.
- Convective precipitation, where air is heated enough to rise on its own. Summer afternoon showers and thunderstorms.
GCMS include all three of those processes.
Now, ClimateDemon has said "Yes, H2O vapor will condense if cooled, but not the entire earth instantaneously. ", so we need to consider how long we are talking about. So, what amount of time are we talking about for each of those three processes? What is the time lag?
- In frontal precipitation, these storms form and dissipate over spans of days. Water does not evaporate and linger in the atmosphere for years, decades, or centuries. We can easily see this in the difference between summer and winter. We also see if in things like hurricanes, that start to lose strength mere hours after they move over land and lose their source of water vapour (energy to feed the storm).
- In orographic precipitation, you need an upwind source of water, so this is usually found where mountains or high land is close to large bodies of water. The rain dumped on Vancouver (Canada or US - take your pick) is probably only a few hours away from the ocean.
- In convective precipitation, the clouds form in a few hours after the sun rises (the source of energy for evaporation). The precipitation is predominantly later in the day. It is rare for such events to span continuously over several days, let alone years or centuries. Each day is a new day, with new evaporation.
So, in both climate models (GCMs) and the real world, removal of precipitation from the atmosphere is a very rapid process. Not instantaneous in the life of a fruit fly, but pretty close to instantaneous in terms of geologic time.
Mother Nature is unable to drive atmospheric moisture levels up enough to increase the water vapour greenhouse effect for any length of time beyond a few days, because Mother Nature is so good at removing it through precipitation.
The only way to increase long-term global average humidity is to find some other way to warm the global average atmosphere. A way that has more permanance. Then water vapour can increase, and its greenhouse gas properties will act as a feedback on temperature, but it can't do it on its own.
Water vapour will not drive climate change. The models agree with reality on this one.
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Tom Dayton at 01:12 AM on 6 July 2020Models are unreliable
Among the bazillion courses that cover climate modeling (sinisterly hidden so they can be discovered only by searching the intertubes for climate modeling course class university!) is this free one by David Archer that starts today. Obviously Deplore_This will deny it is relevant to climate modeling, but other folks might be interested: Global Warming II: Create Your Own Models in Python.
This class provides a series of Python programming exercises intended to explore the use of numerical modeling in the Earth system and climate sciences. The scientific background for these models is presented in a companion class, Global Warming I: The Science and Modeling of Climate Change. This class assumes that you are new to Python programming (and this is indeed a great way to learn Python!), but that you will be able to pick up an elementary knowledge of Python syntax from another class or from on-line tutorials.
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Eclectic at 23:28 PM on 5 July 2020Models are unreliable
ClimateDemon ,
your posts here have been rather off-topic for this thread.
Why not return to the comments section of Climate Myth 36 , where in 2016/2017 you were given frequent & extensive explanations on the subject of H2O vapor and non-condensable GHG's role as climate Control Knob.
That would be the place for you to express any new & convincing arguments which you may have managed to produce since then.
Moderator Response:[TD] Uh oh, good memory, Eclectic! Perhaps ClimateDemon is yet another sock puppet of JeffDylan, MartianSky, cosmoswarrior, and so on?
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ClimateDemon at 19:00 PM on 5 July 2020Models are unreliable
Bob Loblaw @ 1229
Well how about that! I, too, have a friend whom I would like you to meet — nonequilibrium. At least I believe you are still strangers since you don’t seem to recognize him at all.
Yes, H2O vapor will condense if cooled, but not the entire earth instantaneously. However, if you use a single-temperature earth model constrained to thermal equilibrium at all times (ie. CO2 control knob model), this is exactly what you are assuming. By not handling these atmospheric problems regarding the atmosphere as the nonequilibrium system that it is, you miss all transient effects and temperature changes seem to happen quite suddenly. Here are a couple of quotes from the SkS Climate Myth 36 page that I believe illustrate my point quite well.
Eclectic @268 Climate Myth 36… Now picture all CO2 suddenly removed from the atmosphere — result: a strong rapid negative feedback. Temperatures plummet, with widespread snow & frost precipitation on land and a fast-spreading layer of ice on the sea [with further sunlight reflection and further spread of sea-ice, to 100% coverage]. Ultimate result: a frozen world (and with minimal H2O in the atmosphere).
KR @284 Climate Myth 36Non-condensible gases set the thermal equilibrium, condensible gases (water vapor) can only act as feedback because they respond so quickly to a temperature change, even if their overall effect is quite large .
Do the temperature changes and precipitation actually happen that fast? – Not really. What we are seeing here is an artificial discontinuity in temperature due to the neglect of transient effects in the equilibrium model. It’s somewhat like turning on a new refrigerator and expecting the temperature inside to immediately drop to the operating temperature.
At this point, I would strongly suggest that you and your AGW comrades educate yourselves some more on the fundamental physical laws behind the climate models, and recognize when you are working with equilibrium and nonequilibrium systems. Maybe then you won’t be quite so bamboozled by CO2 control knobs and icebound earths.BTW — I'm actually all grown up now so you can knock off the kid talk!
Moderator Response:[DB] Inflammatory baiting and sloganeering snipped. You need to up your game by citing credible sources to support your claims. Assertions are not sources.
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MA Rodger at 18:08 PM on 5 July 2020Models are unreliable
ClimateDemon @1240,
You cite your comments @1173 & @1190 as providing demonstration that the CO2 'control knob' concept of climate is "false".
I would suggest there is no such provided demnstration.
It takes little effort to examine these comments of yours.
@1173 you compare the role of CO2 and H2O when accounting for the energy balance of the atmosphere and jump to the assertion that "there is nothing to indicate that CO2 has any 'control knob' effect." Appended to that rather incomplete analysis, you cite Lacis et al (2010) as describing "the only model that predicts AGW and the CO2 control knob" but that Lacis et al are wrong because this "only model" simplifies the climate system too much. In particular, you describe this "only model" using the Clausius-Clapeyron equation and with "the earth's temperature is represented by a single scalar value T." Your final assertion sets out "It took several false assumptions to make the control knob argument, so there are very likely problems with it."
@1190 you call for people "who claim that I am making evidenceless assertions" to provide "just one example of such an assertion" that you have made. You append to this call three ground rules which you insist all will agree. (i) A world witout a "uniform" surface temperature is not in "thermal equilibruim". (ii) Use of the Clausius-Clapeyron equation cannot be extended to include the large global temperature variations. (iii) An equation should not be used beyond its limits.
(ClimateDemon, do correct me if I misrepresent the intention of your comments @1173 & @1190.)
I find these comments disturbing in many ways but let me here provide a little more than "just one example" of "evidenceless assertions" by naming that "only model."
That "only model" @1173 can only be the one used by Lacis et al (2010) and that is GISS ModleE which nobody in their right mind could ever describe as being:-
"a highly oversimplified, zero dimensional model in which the earth's temperature is represented by a single scalar value T, and the H2O vapor concentration is determined by the Clausius-Clapeyron equation at temperature T. This means that the entire globe is rigidly held to this one fixed value of temperature and corresponding value of humidity, which we know is false."
Yet that is what I read @1173.
Further, the initial consideration @1173, that CO2 and H2O are treated identically within energy balance equations and that of the two H2O is the more powerful GHG, ignores the obvious point that GISS ModelE models the hydrological cycle (thus setting H2O as a feedback) while the levels of those non-condensing GHGs (of which CO2 is the major component) are simple inputs into the model (thus setting CO2 as the primary GHG forcing agent). And that treatment of CO2 & H2O is the same as that in other GCMs. GISS ModelE is/was never "the only model that predicts AGW and the CO2 control knob."
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ClimateDemon at 14:35 PM on 5 July 2020Models are unreliable
Philippe Chantreau @1222
I am not trying to overturn anything. I just want to see the science done correctly. Also, your comment about me arguing that water vapor can serve as a forcing instead of a feedback shows that you are still thinking in terms of the "control knob" model which I have already shown in 1173 and 1190 to be false.
Moderator Response:[DB] Making things up is unhelpful.
Sloganeering snipped. -
Eclectic at 12:28 PM on 5 July 2020Models are unreliable
Deplore_This ,
Firstly, allow me to thank you for bringing entertainment to this thread.
Secondly, allow me to state the obvious ~ being what all readers here are thinking ( including you yourself! ). It is obvious that part of your activity is you indulging yourself in some trolling (but please be calm, because my words are charitable ~ since the alternative diagnosis would be distinctly more unflattering.)
But I see that you are actually here for two purposes (whether you realize it or not). For like many people who start off as climate-science deniers and visit SkS, your mind is split in two. One part knows that it is in the wrong about the science. And actually would like to learn "climate". The other part angrily rejects that self-acknowledgement, and wishes to challenge (and troll) the mainstream science position. [ Here, I won't now go into your subconscious motivations for rejection of the well-established science ~ but you really do owe it to yourself to do some self-examination. It is sad for anyone to live the "unexamined" life. ]
One part of your mind knows that it really ought to learn about such important science. And because in the long run, the science always wins (and history condemns the foolishness of the Flat-Earthers, Geo-centrists, Anti-Evolutionists, et alia.)
The other part of your mind (call it the Denialist part) wishes to fight on, and cause as many waves as possible. Inevitably, this ends up with you embarrassing yourself publicly ~ but the Denialist part is too angry to care about that, and rather enjoys making futile waves.
Ah, we humans are an interesting lot
. . . often Deplorable, yet always Interesting.
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Deplore_This at 10:10 AM on 5 July 2020Models are unreliable
@Bob Lowlaw 1237
You aren't intelligent enough to understand what I know.
Moderator Response:[DB] Please note that posting comments here at SkS is a privilege, not a right. This privilege can and will be rescinded if the posting individual continues to treat adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Moderating this site is a tiresome chore, particularly when commentators repeatedly submit offensive personal attacks, off-topic posts or intentionally misleading comments and graphics or simply make things up. We really appreciate people's cooperation in abiding by the Comments Policy, which is largely responsible for the quality of this site.
Finally, please understand that moderation policies are not open for discussion. If you find yourself incapable of abiding by these common set of rules that everyone else observes, then a change of venues is in the offing.Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter, as no further warnings shall be given.
Egregious personal attack removed. -
Bob Loblaw at 10:02 AM on 5 July 2020Models are unreliable
Deplore_This:
It is not enough to read the IPCC or any other material. You also have to understand it. I have seen nothing in your postings here to suggest that you understand anything at all about climatology or climate models.
I have see nothing to suggest that you have understood any of the material that you have been pointed to here, or that you understand any of the materail that you have cut and pasted from denial blogs and sources.
You parrot stuff you don't understand. You accept everything that suits your pre-conceived bias. You reject everything that disagrees with that bias.
DNFTT.
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Deplore_This at 08:53 AM on 5 July 2020Models are unreliable
@Tom Dayton 1234
Climate sensitivity is absolutely critical to accurately scientifically predict ACC as are the natural causes of CC. Regulatory policy decisions are based on those predictions. But that is a discussion for another article in SkS.
Moderator Response:[DB] Off-topic snipped.
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Deplore_This at 08:41 AM on 5 July 2020Models are unreliable
@Tom Dayton 1232
BTW I've already been through the climate sensitivity part of SkS.
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Tom Dayton at 08:36 AM on 5 July 2020Models are unreliable
Deplore_This: Also, you seem to be overweighting the practical importance of the exact value of sensitivity. If you're in a car 200 feet from a rock wall, heading directly toward that wall, it doesn't really matter much if your speed is 50 or 60 miles per hour; the consequences are bad enough in either case that you should be applying the brakes right now. For climate change there is the additional urgency that the problem gets worse as time goes on, so even if sensitivity is on the low end, that merely delays the same bad consequences by an inconsequentially few years. Yet another time urgency comes from the fact that the primary causes (in particular greenhouse gas emissions) and feedbacks (e.g., lower albedo from loss of ice) are impossible to reverse on time scales that will be useful. Ice loss, for example, effectively is permanent on human timescales. Another problem with delaying action is that warming accelerates due to feedbacks, sort of like interest accruing on a loan. The longer you wait to pay, the more money you need to pay.
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Deplore_This at 08:36 AM on 5 July 2020Models are unreliable
@Tom Dayton 1232
You’re speculating. You may not be able to “evaluate that claim without someone else’s opinion” but that doesn’t mean someone more capable isn’t able to. And for climate research to be science it must promote hypothesis that can be empirically tested. If scientists are not allowed to challenge the common body of opinion like those I posted in 1193 and 1194 then it is not science, it’s group think.
You don’t need to respond here. I am going to post this philosophical argument under the correct category of SkS. I’ll post a link here.
Moderator Response:[DB] Inflammatory snipped.
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Tom Dayton at 08:04 AM on 5 July 2020Models are unreliable
Deplore_This: It is impossible for you, or anyone else, to evaluate that statement "without relying on someone else's opinion." Because science is a collaborative enterprise. Even, and 100% of, the scientists who create GCMs rely on other people's opinions--critically so. Certainly you can reduce your reliance on someone else's opinion, by learning about climate science. Computer simulated GCMs are only a tiny portion of that climate science. And trying to learn climate science by directly trying to learn computer simulated GCMs is an utterly doomed approach. Several people have given you multiple resources for learning enough climate science for you to start to be able to rely less on other people's opinions. You could stop rejecting those suggestions out of hand.
With regard to the particular claim you mentioned, you could start with the "How sensitive is our climate?" post here on SkS. Read the Basic tabbed pane first, then the Intermediate, then the Advanced. To dig in a bit more, go to RealClimate and type "sensitivity" into the Search box at the top right, then peruse the resulting posts. If you want to jump to cutting edge research on that topic, see the recent RealClimate post about the CMIP6 models.
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Deplore_This at 07:47 AM on 5 July 2020Models are unreliable
@Tom Dayton 1230
Alright, I’ll simplify this. How to I evaluate the following claim without relying on someone else’s opinion? (I’ve already read the IPCC reports).
“There is growing evidence that climate models are running too hot and that climate sensitivity to carbon dioxide is at the lower end of the range provided by the IPCC. Nevertheless, these lower values of climate sensitivity are not accounted for in IPCC climate model projections of temperature at the end of the 21st century or in estimates of the impact on temperatures of reducing carbon dioxide emissions.”
-— Judith Curry, the former Chair of the School of Earth and Atmospheric Sciences at my alma mater
https://www.thegwpf.org/content/uploads/2017/02/Curry-2017.pdf
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