Arguments
Recent Comments
Prev 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 Next
Comments 6801 to 6850:
-
Tom Dayton at 01:36 AM on 5 July 2020Models are unreliable
It is important to understand that GCMs are only a small subset of "climate models," and therefore the evidence that "climate models" provide is far broader and deeper than the evidence that GCMs provide. I highly recommend Naomi Oreskes's book Why Should We Trust Science?, for the broad background on those topics beyond climate science, though she does use some examples from climate science.
-
Tom Dayton at 01:06 AM on 5 July 2020Models are unreliable
Steve Easterbrook has written multiple blog posts describing how computerized climate models are designed, built, tested, maintained, and used. I eagerly await his "forthcoming" book, but in the meantime I suggest everyone interested in that topic peruse his blog posts. For example, there is is his post When is a Model Not a Model?
-
John Hartz at 00:30 AM on 5 July 2020Models are unreliable
Recommended supplemental reading directly related to the current discussion initiated by Climate Demon...
Explainer: How the rise and fall of CO2 levels influenced the ice ages by Zeke Hausfather, Carbon Brief, July 2, 2020
From the article...
In this explainer, Carbon Brief explores how the last ice age provides strong evidence of the role CO2 plays as a “control knob” for the Earth’s climate. It also acts as a cautionary tale of how the climate can experience large changes from relatively small outside “forcings”.
-
Eclectic at 21:40 PM on 4 July 2020Models are unreliable
ClimateDemon @1213 , the bigger context is the paleo evidence ( you can start reading at (SkS) Climate Myths 12 and 13 , and expand out from there.
The modern empirical evidence ~ a temperature rise of 1 - 1.2 degreesC since industrialization 1850-ish, all with a 1.4x rise in air CO2 . . . and your own back-of-envelope logarithmic calc extrapolates that to around 2.0 - 2.4 as TCS and hence ECS around 30-40% higher again. IOW, an ECS of around (roughly) 2.5 -3.5 C. [Which is way higher than the deluded Lord Moncton "calculates".] And which also fits with the paleo estimates.
That all connects well with the "CO2 control knob" (remember to adjust for solar brightening/dimming over time). Find the right thread, if you wish to comment.
-
MA Rodger at 21:24 PM on 4 July 2020Models are unreliable
It is an interesting thought that somebody who uncritically references both a GWPF publication (ie Briefing Paper No 24) that attempts to trivialise the usefulness of climate models (as @1193) and the 2019 Dutch denialist petition to the UN that attempts to reverse the global consensus on AGW (as @1194) would somehow obtain a deep enough understanding of the limitations of GCMs to form a useful judgement on ECS from a rather basic course on the subject, especially given that such a judgement could be gained more simply by other means.
The CLINTEL petiton (CLINTEL is basically an attempt to create a Dutch version of GWPF, the latter having been quite successful in masquerading as an educational charity and finding fertile ground within influential parts of right-wing UK politics) and the GWPF publication both contain the same bold assertion which is fundamental to their denialist argument that GCMs cannot be relied upon.
"The world has warmed at less than half the originally-predicted rate, and at less than half the rate to be expected on the basis of net anthropogenic forcing and radiative imbalance. It tells us that we are far from understanding climate change." CLINTEL petition.
"There is growing evidence that climate models are running too hot and that climatesensitivity to carbon dioxide is at the lower end of the range provided by the IPCC." GWPF Briefing Paper No24.
I would suggest the commenter first considers whether it is correct and proper to present such argument rather than attempting to "get under the hood and see how the models work for myself and to evaluate the predictive sensitivity of these models."
Operations Research (Operational Research my side of the pond) is only narrowly about the mathematics so I am intrigued that somebody with an "extensive background in operations research" (as per described @1162) would consider 'getting under the hood' as the first response to having "read criticism of the validity of the climate temperature models referenced by the IPCC."
-
scaddenp at 20:12 PM on 4 July 2020Models are unreliable
"Candidly a reason for your disappointment evades me." Well the right wing dog whistles and then repeating the GWPF nonsense with claims you should have been able to refute unaided given your IPCC reading had you looked at it critically.
I repeat that it is great idea to understand the models, but only if you are going into without the biases of trying to find something which would aid your disbelief and with no clear idea as to what might change your mind.If your preference for Curry is because she expresses similar political belief to yourself and not her publishing record in climate models, then I dont think we have much to discuss, and certainly not on this thread.
-
ClimateDemon at 19:34 PM on 4 July 2020Models are unreliable
Eclectic @1174
Please explain what you mean by the bigger context, and paleological evidence. Also, please explain how your CO2 "control knob" is supposed to work.
Moderator Response:[TD] Among a huge number of other resources, there is the wonderful and easily understandable 2009 AGU talk by Richard Alley, The Biggest Control Knob: Carbon Dioxide in Earth's Climate History. Steve Easterbrook wrote a good summary, but you really should watch Alley's one hour video. Then read Lacis et al. (2010), Atmospheric CO2: Principal control knob governing Earth's temperature. Alley gave (yet another!) excellent talk six years later, this time just half an hour and to the NAS, 4.6 Billion Years of Earth’s Climate History: The Role of CO2. Among several relevant posts here at SkS is How Do We Know More CO2 Is Causing Warming? Please post your comments in an appropriate thread.
-
ClimateDemon at 17:40 PM on 4 July 2020Models are unreliable
1176 Deplore_This
You seem to be hitting on the same frustrations I am in regard to getting straight information about the climate models and how they are used. It turns out that you can do a free download of many of the codes used in implementing the climate models, and with the make utilities of most Unix systems (including Linux), actually compile and run them. Don't hold your breath, however, in understanding the "nuts and bolts" of the programs or even how to set up and submit a job on those systems. The only people who get that kind of help are the techie types recently hired by a government contractor specifically to do such number-crunching.
Anyway, I will answer your questions as best I can, realizing that I may not know much more about the AGW community than you do. First, I believe that the development and testing of today’s climate models is generally legitimate and done to meet the needs of climate and environmental researchers. Of course, these models were not done single-handedly, but with a team consisting of individuals with several different areas of expertise. Over the decades, they have worked out quite well, and I believe that the statements made by the SkS staff at the top of the page are generally correct.
However, I believe there is something important concerning these models that the AGW community in general is not telling us. I would like to tell you more, but would rather not do so in this forum. If you are interested please send a message to the (temporary) email address x7evz2yg@protonmail.com and I will send you a return message from the more “permanent” email account I would like to use. -
Eclectic at 17:27 PM on 4 July 2020Models are unreliable
D_P @1210 , alas you are too non-specfic in your reference.
If you meant "The climate models ... don't even do a good job" ~ then that is stating the obvious.
-
Deplore_This at 17:14 PM on 4 July 2020Models are unreliable
@ Eclectic
You obviously don't realize that you've just proven the point that I made in my post at 1207.
-
Eclectic at 17:04 PM on 4 July 2020Models are unreliable
Philippe C , I may have to back-pedal on my skepticism about your Questionable Lady hypothesis. There does indeed seem to be a Curry worship of almost Sub-Continental dimension. Perhaps the good Doctor has a Mrs Hyde facet to her personality?
Deplore_This , your truculence & tone-policing are a red flag. So much so, that your "search for a GCM course" seems merely a pretext for your postings.
Yet if you do have a genuine concern about the value of climate models, then please express those concerns in your own words. Without doing a "cut and paste" from the typically vague and non-substantive rhetoric which is the standard output of Dr Curry.
You seem not to be aware that the GCM's are not the basis of climate science nor are they the basis of expectations of continued global warming & the consequential major problems. The basic physics / paleo climate evidence / and the past 150 years of empirical evidence of climate response to rising atmospheric CO2 . . . all combine to give adequate grounds for policymakers to take urgent action to reduce CO2 emissions.
Climate models can sometimes be used as a test bed for certain sub-components of climate or energy fluxes. And they can (famously) produce a large range of interesting projections. But their pragmatic usefulness for projections, is low for the present & near future.
And that should be very obvious to you, when you take note of the wide range of Equilibrium Climate Sensitivity which is generated by the typical models. In other words, Deplore_This , you will largely be wasting your time if you pursue "a course in GCM's" . You really really do need to study the basic science of climate.
-
Deplore_This at 16:09 PM on 4 July 2020Models are unreliable
@scaddenp 1206
Thank you for your response. Candidly a reason for your disappointment evades me. As I stated in my post 1195 to you I’m trying to evaluate the validity of the GCMs referenced by the IPCC against the criticism of scientists like those posted in 1193 and 1194. All I find from the climate science community are responses like those above who merely state your sources aren’t credible, read this and you’ll understand what we do and if you don’t agree with us you’re a flat earther.
I’m not looking to create a GCM but to understand what they are, their structure, their fidelity and the assumptions that go into the GCMs used by the IPCC. To state it simply I am questioning the validity of the IPCC’s consensus opinion and am trying to find a way to evaluate it myself. I thought that I would take it to the next level and look at the underlying models themselves. I’m not on a career track in the climate science profession I’m merely looking to satisfy my personal curiosity. I thought I would take a university course that climate scientists use to learn the development and use of GCMs and posted here for recommendations. No one here has recommended one yet so I think my only recourse is to contact Penn State and see if course material is available from their last course on GCM.
BTW I’m in the US retired from the wireless equipment manufacturing business. I visited NZ 20 years ago for a broadband wireless system we supplied. The landscape is remarkable; the emerald green of Ireland painted over the rock of Gibraltar and I found the people friendly (that is once I realized that wearing the shirt of the national rugby team of Scotland was a big mistake).
Thanks again for your response.
-
Deplore_This at 15:00 PM on 4 July 2020Models are unreliable
@ Eclectic, @Bob Lowlaw, @Philippe Chantreau, The moderator
Your sophomoric comments memorialize your lack of credibility and reflect poorly on all of the proponents of this website and to some extent to the entire climate science profession. Your adolescent giddiness that you can slander me and the moderator will strike my response that challenges your opinion demonstrates that in your little sandbox here you are not practicing science. If Judith Curry was your Professor I’m sure she’d be embarrassed at your unprofessional and juvenile behavior.
From my perspective your behavior here demonstrates that she is right “We've lost a generation of climate dynamicists. These are the people who develop theories and dig into data on the system and really try to find out how the system works. We've ceded all that to climate models, and the climate models are nowhere near good enough. The climate models were designed to test sensitivity to CO2. They don't even do a very good job at that…we've lost a generation of climate dynamists, and that's what worries me greatly.”
web.archive.org/web/20170105183617/www.eenews.net/stories/1060047798And in the end, you’ve all failed to answer my question so what is your reason for being here.
Good day.
-
scaddenp at 14:57 PM on 4 July 2020Models are unreliable
Deplore_me. Hmm, some disappointing stuff there - it is very disappointing when the best predictor of person's beliefs on a purely scientific question is which side of the US cultural wars they on - but if you are prepared to invest in courses to get answers, then that is great and makes me hopeful. While I am tempted to respond to your answers, I doubt that would either productive or on topic, so sticking to topic.
Assuming you get a model by some means and figure out the workings, it would be interesting to know how you would use it. In particular, what kinds of answers could you imagine your investigations producing that would change your mind. It would be good to be thinking about this and getting the necessary domain knowledge so that you are not misled. Many "skeptics" go after straw-men - trying to take apart claims that modellers and scientists never made. (eg modellers claim no skill in decadal level of prediction). EdGCM would be a good starting point.
Oh and I am in NZ, working in more or less the equivalent of the USGS though our science structures are very different to US.
-
Eclectic at 13:32 PM on 4 July 2020Models are unreliable
Bob Loblaw @1204 ,
The "search" for a course on DIY GCM's is not just certainly odd ~ it is positively hilarious.
But maybe technology is moving faster than I thought. And I had better check Amazon for stocks of those long-promised pocket-size quantum supercomputers (powered by cold fusion, I hope). Doubtless these miniaturized marvels would be quite expensive at first ~ but perhaps early adopters will be issued with a bonus App for a GCM or two.
Our moderator seemed to think that the good Deplore_This was doing some "baiting" ( aka "trolling" ? ). Never in a million years would I have thought such a thing . . . but it might explain the underlying motivation of this recent "encounter" at SkS, and it would explain the confused rambling denialism that he/she is throwing up. And explain the DK-like complacency.
Phillipe C @ 1203 ,
your suggestion that the Lady in Question might be the good Dr Curry, is, surely, a tad ungentlemanly? After all, the literary style is somewhat different ~ though I suppose I could be wrong on that (or the style might have had an extensive makeover per Grammarly or similar App).
Still, it will be interesting if there are more developments. I always hope there will be something new to learn, from every "challenge" to mainstream climate science. Admittedly, my hopes have always been dashed ~ but some day there may be a grain of wisdom to be found among the bucketloads of BS.
-
Bob Loblaw at 11:28 AM on 4 July 2020Models are unreliable
Yes, the "search" for a class on "Make your own GCM" is certainly odd.
I'll bet if I did a search through university catalogues for courses on "How to program a Word Processor", I would not find much at all. To use that as evidence that word processing software is not useful - hey, I"m a word processing skeptic! - would not be an effective argument.
I could then switch to listing people that have found bugs in word processing programs as evidence that "word processing is not settled", or that "you can't trust word processors".
Yet somehow, each day people use word processing softare to create all sorts of useful texts. (They seem to create some awful ones, too, but that is another story...)
-
Philippe Chantreau at 09:11 AM on 4 July 2020Models are unreliable
My opinion is that the lady that protest too much might be Curry.
From the WIKI page on GCMs: "Versions designed for decade to century time scale climate applications were originally created by Syukuro Manabe and Kirk Bryan at the Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, New Jersey.[1]"
Further:"In 1956, Norman Phillips developed a mathematical model that could realistically depict monthly and seasonal patterns in the troposphere. It became the first successful climate model.[2][3] Following Phillips's work, several groups began working to create GCMs.[4] The first to combine both oceanic and atmospheric processes was developed in the late 1960s at the NOAA Geophysical Fluid Dynamics Laboratory.[1]"
It is obvious that Fluid Dynamics are at the foundation of all the current coupled atmosphere-ocean GCMs. I find that the dissatisfied search for a specific university course on such models is perhaps disingeneous. They are an area of research, very much at the edge of knowledge. People who participate in them have already obtained graduate degrees in fluid dynamics, applied mathematics and a variety of other fields. I doubt that there are university courses on specific protein folding methods, short of outlining the basic principles and current state og knowledge. However, those who want to orient themselves in that field will easily come across the areas of knwoledge they should master first. Then they can try to go hack it at the cutting edge.
Curry does a favorite trick of hers by exploiting the fact that GCMs are not very good at delivering regional results, something well known in the modeling community, to suggest that they have no usefulness. In any case, the claim that fluid dynamics expertise is absent in the modeling community has no merit.
-
Bob Loblaw at 06:55 AM on 4 July 2020Models are unreliable
Deplore_This:
You have now reached the point where moderators are starting to cut stuff.
You posted a long story from E&E. You are hitting all the main climate denier sites. Well done. You are selecting to quote places that confirm your bias.
https://www.desmogblog.com/energy-and-environment
FYI, I started learning about this stuff in the 1970s. I read a lot of the primary literature long before there was an IPCC. I can tell when someone is trying to fool me.
-
Eclectic at 06:36 AM on 4 July 2020Models are unreliable
Deplore_This , yes everyone with reasonable climate knowledge has heard of Dr Judith Curry ( and I myself visit her blog several times a month . . . it's a sort of upmarket version of WUWT blog ). Dr Curry's commentary is an excellent object lesson for those who wish to exercise their critical thinking! She is one of the very very few climate-contrarian scientists (a dying breed, it appears).
Now, I notice your rapid-fire uploading of long posts at 1:23 AM and 1:24 AM and 1:25 AM. Clearly these were pre-selected & prepared to go, and were not really a response to Scaddenp.
And as you say: "... I've read criticism of the validity of ..." And there is the nub of your problem, Deplore_This.
The internal evidence of your many posts, is that you have not bothered to learn the fundamental science of climate yet. Once you have done so, then you will be able to (A) make an informed decision whether or not to attempt the various complexities of climate modeling (with or without access to a supercomputer)
. . . and (B) see right through the ludicrous nonsense of "the 500" scientists you mentioned
. . . and (C) see right through Dr Curry's vague obfuscatory sophistry.
It is a red-flag sign, that you have allowed yourself to be taken in by the simply unscientific propaganda exhibited by "the 500". But Dr Curry's propaganda is a different matter ~ she uses a more subtle approach (analogous to what the hypnotherapists call "the Indirect method" ). If you yourself are strongly motivated to believe her - which indeed you are - then she seems to make sense. That is, she seems to make sense until you educate yourself past the "veneer" level of climate science. And then, using skepticism and critical thinking, you will see the fatal flaws in her presentations.
# My apologies for sounding patronizing ~ but you really do need to learn the climate science first. Don't be an Ivar Giaever, who succumbed to Motivated Reasoning, and reckoned that half a day or so on the internet sufficed for him to lecture the climate experts on their multitude of errors. ( Yes, there are many humorous events to be found in the sphere of climate science ! )
Moderator Response:[TD] I deleted Deplore_This's lengthy cut and paste about Curry, because only a tiny fraction of it was directly relevant to the Models topic of this thread. Despite the baiting that Deplore_This is doing, please let's try to stick to the thread topic. Thanks.
-
Deplore_This at 04:15 AM on 4 July 2020Models are unreliable
@Bob Lowlaw 1199
Quit with your sanctimonious crap. It certainly doesn’t reflect well on your scientific reputation. I came here stating that I’m a skeptic and wanted a recommendation for university course on GCM, not to believe one person over another.
Judith Curry was the Chair of the School of Earth and Atmospheric Sciences at a well-respected technical university and was obviously imminently qualified to get the job. I’m not going to post people’s names on the Internet to satisfy your curiosity.
I looked at the Spencer Weart link and I’m already beyond that level. I have read the IPCC reports.
If you were going to scientifically challenge Judith Curry’s opinions that I referenced you would point to published scientific scrutiny and not just make juvenile comments. The more emotional you become the more you add to her credibility in my eyes.
Regards.
-
MA Rodger at 03:58 AM on 4 July 2020Hansen's 1988 prediction was wrong
Nylo @62,
It is good to see we make progress, but it is not giant strides.
While you do rush past many aspects of this matter that do require consideration and perhaps have dropped a few beads off the abacus before reaching your assessment that the Hansen et al Scenario A results "seem to be off by approximately 44%", I perhaps would flag up the point that climatologists do use complex climate models for a reason.
On the CH4, I don't find the -200ppb value you arrive at for the 2010-20 difference between Scenario A and 'actual'. And I'm not aure that is a useful measure even if it were correct.
The Scenario A increase from1400ppb at 0.6%, 1% then 1.5% yields roughly the 1500ppb and 1650ppb 1970-80 seen in Lacis et al Table 1. Running forward, that gives 2984ppb for 2019, and an increase over the decade from 2009 of 413ppb. The measured CH4 levels (from ESRL) are 1794ppb and 1867ppb, a 2009-19 rise of 73ppb. Thus 'Actual' - Scenario A = 340ppb. But do also note that the 'actual' CH4 increase 1988-2019 is also similarly less that the Scenario A projection for the two preceeding decades.
And while you might imagine we could put that CO2 assessment to bed as the concentrations projected by Scenario A and 'actual' are entirely similar, the assessment of the resulting forcing from such a CO2 increase has been revised in the years since 1988. As per Fig b1, the 1988 assessment was a non-feedback equilibrium temperature increase for 2xCO2 of +1.2ºC. Yet today that is put at +1.0ºC, a significant difference in the underlying forcing.
To complete this analysis will require an item by item assessment. 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'm not surprised to see that is roughly what is shown in Fig 4 of the Advanced OP above. So, without considering negative forcings, we should expect Scenario A to be showing a lot more warming than 'actual'.
If you wish, we could work through this assessment. But that does lead to the need to calculate the resulting warming. Climatologists turn to their models at that point. Maybe we can dodge that with a short cut. Yet reaching that objective is, on our past performance, not a quick exercise to see through to a conclusion.
-
Bob Loblaw at 03:05 AM on 4 July 2020Models are unreliable
Deplore_This:
Who tells you she is "credible"? On what basis are they credible?
You have chosen who you are going to believe. That is not the sign of a skeptic. You have bought into the shite they are selling to you. There are lots of places on the internet that will point out the crap you have read that is confirming your bias.
Go read the Spencer Weart link I posted earlier.
Have you read the IPCC reports, or do you just read the comments about the IPCC that you get from your "credible" sources?
I agree with Tom Dayton. You are not here to learn anything.
-
Deplore_This at 02:44 AM on 4 July 2020Models are unreliable
@Bob Lowlaw 1197
As I stated Judith Curry was the Chair of the School of Earth and Atmospheric Sciences at my alma mater. I don’t know her personally but I know people who do and they tell me she is credible. As a courtesy I reviewed your links and I don’t see anything that refutes that opinion. It appears to me that Judith Curry is a scientist who disputes some of the “group think” and is shunned and unfunded. If the climate science community can not engage in open debate then it is not practicing science. As a climate skeptic I am accused of not believing science but without open debate it is not science.
Bob, I believe Judith Curry before I believe you. So my dilemma remains and I’m not sure what to do next. Thank you for your response.
-
Bob Loblaw at 02:16 AM on 4 July 2020Models are unreliable
Deplore_This:
Judith Curry is not, I repeat, not, a reliable source of information. She peddles "uncertainty", and much of what she says is simply wrong. Start here:
https://skepticalscience.com/skeptic_Judith_Curry.htm
and continue here:
https://www.desmogblog.com/judith-curry
In addition, pretty much anything published by the GPWF is full of crap:
https://www.desmogblog.com/global-warming-policy-foundation
Same for the Climate Intelligence Foundation:
https://www.desmogblog.com/climate-intelligence-foundation-clintel
You need to find better sources of information. You're paying attention to people that are selling shite to you.
-
Deplore_This at 01:41 AM on 4 July 2020Models are unreliable
@Bob Lowlaw 192
Thank you for your response. As I stated in my first post 1162 and my post at 1195 I am an anthropogenic climate change skeptic because I’ve read criticism of the validity of the climate temperature models referenced by the IPCC like those posted in 1193 and 1194. I am aware that there are multiple climate models and classes of climate models. According to the syllabus the Penn State course I referenced included multiple climate system components including atmosphere, ocean, land, cryosphere, biosphere, role of parameterizations and model coupling.
http://www.met.psu.edu/intranet/course-syllabi-repository/2020-spring-syllabi/meteo-523Without repeating my post at 1195 I’ll just state here that I remain open to any suggestions. Thank you again for your response.
-
Deplore_This at 01:25 AM on 4 July 2020Models are unreliable
@scaddenp
As I stated in my first post 1162 I am an anthropogenic climate change skeptic because I’ve read criticism of the validity of the climate temperature models referenced by the IPCC like those posted in 1193 and 1194. The corrupt media and the bureaucrats at the EPA say it’s settled science but I see no record of balanced climate research or any open debate. It appears that scientists who raise doubts of the validity are shunned and unfunded.
So my dilemma is how do I know what and who to believe. It is my nature not to blindly believe anything, especially what the government tells me. I thought a solution would be to take a university course in climate modelling so that I could hands on use and understand the development of GCMs and form my own opinion. If this was the 16th century and I’d probably get a telescope to test Galileo’s claim of heliocentrism. I am surprised to find that there aren’t such courses which leads to an even more startling revelation that the majority of the “97% of climate experts agree humans are causing global warming” have never been taught or used a GCM themselves and base their opinion on the opinion of others. To me that looks more like group think than science. And they call us climate skeptics “flat earthers”.
So my dilemma remains and I’m not sure what to do next. I may contact Penn State and see if course material is available from their last course on GCM. I’m not going down the paleological path because there are other issues there and because the IPCC’s opinion that is used for public policy is based on GCM predictions. I remain open to any suggestions. Thank you again for your help.
-
Deplore_This at 01:24 AM on 4 July 2020Models are unreliable
@scaddenp 1187
Here is another example of scientists who disagree with the IPCC’s conclusion on GCMs where more than 500 scientists and professionals in climate and related fields sent a “European Climate Declaration” to the Secretary-General of the United Nations asking for a “long-overdue, high-level, open debate on climate change” and were denyed.
“There is no climate emergency…Climate science should be less political, while climate policies should be more scientific. Scientists should openly address the uncertainties and exaggerations in their predictions of global warming, while politicians should dispassionately count the real benefits as well as the imagined costs of adaptation to global warming, and the real costs as well as the imagined benefits of mitigation.”
“Natural as well as anthropogenic factors cause warming. The geological archive reveals that Earth’s climate has varied as long as the planet has existed, with natural cold and warm phases. The Little Ice Age ended as recently as 1850. Therefore, it is no surprise that we now are experiencing a period of warming.”
“Warming is far slower than predicted. The world has warmed at less than half the originally-predicted rate, and at less than half the rate to be expected on the basis of net anthropogenic forcing and radiative imbalance. It tells us that we are far from understanding climate change.”
“Climate policy relies on inadequate models. Climate models have many shortcomings and are not remotely plausible as policy tools. Moreover, they most likely exaggerate the effect of greenhouse gases such as CO2. In addition, they ignore the fact that enriching the atmosphere with CO2 is beneficial.”
“There is no statistical evidence that global warming is intensifying hurricanes, floods, droughts and suchlike natural disasters, or making them more frequent.” “However, CO2-mitigation measures are as damaging as they are costly. For instance, wind turbines kill birds and bats, and palm-oil plantations destroy the biodiversity of the rainforests.”
“We invite you to organize with us a constructive high-level meeting between world-class scientists on both sides of the climate debate early in 2020. The meeting will give effect to the sound and ancient principle no less of sound science than of natural justice that both sides should be fully and fairly heard. Audiatur et altera pars!”
https://clintel.nl/brief-clintel-aan-vn-baas-guterres/
-
Deplore_This at 01:23 AM on 4 July 2020Models are unreliable
@scaddenp 1187
Thank you for your response. To answer your question here this is an example of scientists who disagree with the IPCC’s conclusion on GCMs:
“GCMs are important tools for understanding the climate system. However, there are broad concerns about their reliability:
- GCM predictions of the impact of increasing carbon dioxide on climate cannot be rigorously evaluated on timescales of the order of a century.
- There has been insufficient exploration of GCM uncertainties.
- There are an extremely large number of unconstrained choices in terms of selecting model parameters and parameterisations.
- There has been a lack of formal model verification and validation, which is the norm for engineering and regulatory science.
- GCMs are evaluated against the same observations used for model tuning.
- There are concerns about a fundamental lack of predictability in a complex nonlinear system.
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. The IPCC climate model projections focus on the response of the climate to different scenarios
of emissions. The 21st century climate model projections do not include:- a range of scenarios for volcanic eruptions (the models assume that the volcanic activity will be comparable to the 20th century, which had much lower volcanic activity than the 19th century
- a possible scenario of solar cooling, analogous to the solar minimum being predicted by Russian scientists
- the possibility that climate sensitivity is a factor of two lower than that simulated by most climate models
- realistic simulations of the phasing and amplitude of decadal- to century-scale natural internal variability
The climate modelling community has been focused on the response of the climate to increased human caused emissions, and the policy community accepts (either explicitly or implicitly) the results of the 21st century GCM simulations as actual predictions. Hence we don’t have a good understanding of the relative climate impacts of the above or their potential impacts on the evolution of the 21st century climate.”
-— 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 -
Bob Loblaw at 23:35 PM on 3 July 2020Models are unreliable
Deplore_This:
I am still unsure as to exactly what you expect to accomplish with respect to climate models. So far, it looks like you have a pre-conception that something must be wrong, and you are on a search for details to support that position. I think you may experience a bad case of confirmation bias, if your postings here are an indication.
As has been pointed out, climate General Circulation Models (GCMs) are only a small part of climate science. I suggest that you read Spencer Weart's "The Discovery of Global Warming" to learn more about climate science in general.
https://history.aip.org/climate/index.htm
In addition, you seem to be under the impression that GCMs represent a "single" climate model. They do not. A GCM is a collection of many types of climate-related models that are knit together to provide a comprehensive view of climate - much as the science of climatology has many, many areas of specialization that need to be knit togther to form a full picture. Areas that represent distinct sub-classes of "climate" models include (but are not limited to):
- radiation transfer. Much detailed work was done in the 1960s, when the military wanted to make sure that their IR-seeking missiles would hit the intended targets. (HInt: their "target" was not "climate")
- atmospheric dynamics (motions). Especially important for weather forecasting. The general field is "Geophysical Fluid Dynamics" (GFD) and atmospheric motion is only one area of application. The same science is used to model air flow on airplane wings, or fluids in pipes or in-ground oil reservoirs, etc. Each application has its own specific issues, so modelling approaches differ - but there is a lot in common.
- ocean dynamics. Another application of GFD, Oceans have some different issues from atmospheric motions, though.
- Surface energy balance issues. Receipt of radiation, partitioning into evapotranspiration, thermal fluxes (to atmosphere, to soil or water). Effects of surface type, vegetation, etc. Often referred to as "microclimate". (This was my area of specialization when I worked in the discipline.)
- soil heat transfer.
- cloud physics.
- and so on.
And once the climatologists develop their theories, there is the task of finding efficient algorithms to transform the science (usually in some mathematical form) into computer solutions. Generally covered as "Numerical Methods" in the computing science world. Systems of partial differential equations that cah be solved either through finite difference, finite element, or spectral methods. These methods are not unique to "climate science".
No single university course is going to cover the full level of details of every aspect of climate models - or climatology in general. Different groups that develop GCMs make different decisions on which components of which "climate" sub-models will be incorporated, and how they want to code numerical solutions.
These difference approaches lead to different results in detail, but the broad picture is the same: CO2 from fossl fuels plays an important role in current temperature trends.
-
Nylo at 21:17 PM on 3 July 2020Hansen's 1988 prediction was wrong
MA Rodger @61 I think that what you say is good. The description by Hansen of what the evolution of methane is in his scenario A must contain an errata. Lacis claimed a 150ppbv increase in 1970-1980 instead of 1.5ppbv per year which would hardly achieve 15ppbv.
Admitting that you are probably correct and reworking my calculations accordingly, Hansen would have expected a rise of 282ppbv for the period of 2010-2020, and we have experienced only 80ppbv. So we are indeed below Scenario A emissions in terms of methane, by 200ppbv in the last decade, which would lead to around 1/8 of 0.16ºC less (by figure B1, as 200ppbv=0.2ppmv is 1/8 of 1.6ppmv), or 0.02ºC less in this latest 10 years period for which Scenario A forecast half of a degree increase (by latest Real Climate diagram shown above in @55). So based on methane and CO2 alone, we should change that 0.45ºC increase in 2010-2020 to 0.43ºC. The observed increase has been 0.26ºC so the remaining extra 0.17ºC that we have not experienced in the last 10 years must all be due to differences in CFC emissions compared to Scenario A expectations.
For CFCs (F11, F12) the forcing in the 1980s was, according to figure B2, roughly 0.02ºC. As Scenario A expected a 3% increase in emissions per year, doing the calculations the forcing in 2010-2020 for CFCs would be 2.57 times bigger than the forcing in the 80's, or about 0.055ºC. Assuming that, instead, we have experienced none, that would reduce the expected temperature increase in that scenario for this decade if we use actual instead of modelled emissions by 0.055ºC. The +0.43ºC warming that the model would have predicted by replacing methane projections with actual values, goes down to +0.375ºC if we do the same with CFCs. And again, we have witnessed +0.26ºC. Hansen projections seem to be off by approximately 44% (44% more warming in his models than in real world).
Am I ignoring something else perhaps? Feedbacks to radiative forcings? Would those change the 0.075ºC of combined radiative forcings of the differences in methane and CFCs between model and reality, to the needed +0.28ºC difference between Scenario A predictions and observations? That would require a feedback level of more than 3.5 to the forcings.
-
Eclectic at 20:26 PM on 3 July 2020Models are unreliable
ClimateDemon @1190 ,
You have made the mistake of promoting "binary" assertions ~ all-or-nothing, black-or-white. Not "evidenceless" assertions ~ but illogical assertions. Illogical, because not sufficiently evidential i.e. you have chosen to cherry-pick one small area which pleases you, and you have ignored the bigger context that displeases you (and which does not support your assertions). You have therefore failed to think logically.
(1) The globe as a whole is in thermal equilibrium (or very close to it) over duration of time. Obviously the globe is warming gradually, as evidenced by melting ice and rising sea level. Surface temperature varies : and the seasonal and historical evidence is that this variation has tight bounds.
(2) The Clausius-Clapeyron equation describes physical activities ~ at any local terrestrial site, of varying temperature humidity and pressure. Obviously these activities operate within bounds, and so can be said to be in a form of equilibrium dynamically within these limits and durations.
(3) Because of the above, the C-C equation does apply "to the earth and atmosphere system for predicting global effects" ~ which have been observed and measured in recent decades.
( If my memory serves me, you have fruitlessly questioned these concepts, in other threads in past years. )
-
MA Rodger at 20:24 PM on 3 July 2020Hansen's 1988 prediction was wrong
Nylo @58/59/60,
I don't see that I can agree with any of that.
Note the primary source of CH4 levels is NOAA ESRL and these provide global data from 1983 although this record was not established as such until the 1990s. Thus you will note that Hansen et al (1988) references Lacis et al (1981) for its CH4 data. And this reference should give a bit of a warning that something is amiss with the passage from Hansen et al Appendix B that you quote.
Lacis et al describe the rise in CH4 1970-80 as being 150ppb, from 1.5ppm to 1.65ppm.
And there is evidently an error in Appendix B of Hansen et al. We have two alternative errors, one a simple typo (although an error nonetheless) and the other one a careless omission with massively significant implications. (i) Either the error was that the "1.4ppbv" should have read "1.4ppmv" = 1,400ppbv. (ii) Or the value "1.4ppbv" for 1958 which CH4 "increases from" is meant to be the start value of a rate-of-increase rising by a set percentage per year. If this were the case, it should have read "1.4ppbv per year in 1958".
It is evident from Lacis et al that the corrected version is "1.4ppmv". Using percentage increases set out in Hansen et al, the "1.4ppmv" start-point in yields a 1970-80 CH4 level running from 1504ppb to 1670ppb.
The alternative appears a tiny bit ridiculous as, if Hansen et al did work with CH4 based on "1.4ppbv per year in 1958" it would require both a profoundly mistaken reading of Lacis et al and an egregious miscalculation of the forcing resulting from the vastly reduced rise in CH4 levels. That is, CH4 rise would total 20ppb 1980-90 rather than the 270ppb using the "1.4ppm". (Modern estimates/measurements yield 220ppb 1980-90.) If you examine Figb1, an increase of 1.6ppm CH4 yields 0.16ΔTo(ºC) which pro rata would yield from Figb2's 0.0295ΔTo(ºC) a 1980's decadal CH4 rise of 295ppb, a finding which is wholly incompatible with the adoption of a 20ppb decadal increase.
....
Concerning the CH4 'hiatus' of the early 2000s, the deceleration in the atmospheric CH4 rise was spotted by the early 1990s and its cause (a reduction in anthropogenic emissions) was understood before 2010 (although which anthropogenic source wasn't clear), as was the obvious signs if it ending.
-
SirCharles at 19:41 PM on 3 July 2020House Democrats eye 2021 with comprehensive climate action plan
Still not enough. CAT would rate existing US target under the Paris Agreement “Insufficient”, as it is not stringent enough to limit warming to 2°C, let alone 1.5˚C. However, given the decision to withdraw from the Paris Agreement, the rate is “Critically insufficient”!
???? https://climateactiontracker.org/countries/usa/
-
Nylo at 18:16 PM on 3 July 2020Hansen's 1988 prediction was wrong
MA Rodgers @57 please allow me a small correction to what I wrote in @58, as I made a small mistake. Our CO2 emissions are higher than what was expected in Scenario B, but they are not higher than expected in Scenario A, I mixed up things. Our CO2 emissions are exactly equal to the ones expected in Scenario A, which would have provided +2.6ppmv increase per year by 2020 and an average for the last 10 years of 2.44ppmv which is almost exactly the same that has been observed. Therefore:
* The observed CO2 concentration evolution is almost exactly what Scenario A contemplated,
* The observed Methane concentration increase is twice as big as what Scenario A predicted,
* The observed CFCs evolution is way smaller than what Scenario A expected, although not enough to compensate for the doubling of the emissions of CH4.
For all of this, I think that the correct scenario to which we should compare the evolution of temperatures is Scenario A.
-
ClimateDemon at 18:08 PM on 3 July 2020Models are unreliable
I have a challenge for those who claim that I am making evidenceless assertions. Give me just one example of such an assertion. If you can, please do so and I will and I will make appropriate corrections. Otherwise, please don’t make such claims against me.
Also, please keep in mind the fact that there are a few items upon which we must be in agreement, or there is no point in attempting to communicate.(1) The earth and its atmosphere are not in thermal equilibrium. This is well evidenced by the fact that temperature varies widely over the surface. If the globe were in thermal equilibrium, the surface temperature would be uniform.
(2) The Clausius-Clapeyron equation is derived for determining the vapor pressure of a substance that is isolated and in thermal equilibrium with its condensed phase. While this equation may be useful in predicting local precipitation over ranges in which there is little temperature change, it is not applicable to global models or effects over which temperatures can vary by 50-60 degrees C.
(3) We only use mathematical theorems or formulas within the range of their validity. This means we don’t apply the Pythagorean theorem to obtain the longest side of a non-right triangle. Similarly, we don’t use classical equations of motion to predict the motion of a particle traveling at or near the speed of light. Finally, we do not apply the Clausius-Clapeyron equation to the earth and atmosphere system for predicting global effects. -
Nylo at 17:09 PM on 3 July 2020Hansen's 1988 prediction was wrong
I think I understand what is going on here, why the original article claims that the CH4 emissions have been lower than scenario B (and therefore also A) despite they have been twice as big as scenario A. The article was written in 2010, judging by the dates of the first comments. And in 2010 we had witnessed an almost complete stop in the increase of CH4 concentrations that had lasted roughly a decade. I guess it was predicted to continue to stop. It hasn't, so if we are going to continue to compare what Hansen predicted to today's temperatures, we also need to update the emissions scenario that we are closest to. And this is scenario A.
-
Nylo at 16:54 PM on 3 July 2020Hansen's 1988 prediction was wrong
MA Rodger @57 I think you are making a mistake but I cannot blame you. I was taking for granted some of the things claimed in the main article but I have done some calculations and it happens that they were not true!
This is how Hansen describes the evolution of the CH4 increases in Scenario A, the one with the most emissions, I copy literally:
"CH4, based on estimates given by Lacis et Al. [1981], increases from 1.4ppbv in 1958 at a rate of 0.6% yr-1 until 1970, 1% yr-1 in the 1970s, and 1.5% yr-1 thereafter".
By this description, if you do the calculations, the yearly increase by 1970 would be 1.5ppbv, then 1.66ppbv by 1980... etc (continue to multiply by 1.015 each year) until 3.01ppbv per year today, in 2020. This is, I repeat, the evolution of CH4 concentrations in Scenario A. The reality, what the data shows, is that today's CH4 concentrations are increasing by more than 5ppbv per year, every year in the last decade, and some years almost 10ppbv, averaging +8ppbv per year. My data comes from here, if you have different data feel free to share:
https://www.methanelevels.org/
Now, I don't know what is the starting methane concentration that Hansen is using. I highly doubt that he is using the concentration in 1958 because we already knew by 1988 that the progression in the methane levels of the model would have been completely wrong. But no matter what his starting concentration is, he would get a total increase of +70ppbv in the 30 years following 1988. And what we have witnessed is more than twice that ammount. More than twice the methane increase of Scenario A. Therefore not only do we have a worse increase in CO2 than Scenario A, we also have a twice as bad increase of Methane than Scenario A. And they are the main contributors according to Fig b2. The only one that is lower than expected by Hansen is CFCs.
As you say, the effect of the extra 0.5ppm per year of CO2 would be quantified by Hansen as having a 0.027 additional forcing. With a similar calculation, the twice-as-big-as-1980 increase that Hansen expected to have by now in Scenario A (3ppbv/year vs a starting 1.5ppbv/year) would have had a +0.06ºC forcing per decade, and given that the real, measured, increase in concentration has been twice as big as what Hansen expected, we are getting another +0.06 forcing compared to Hansen expectations in our last decade. So we are already at a +0.087ºC/decade forcing compared to Hansen's scenario A, if we add together the extra CO2 and the extra CH4.
Now, Hansen expected a lower forcing from CFCs than from methane, like you have said. This means that if the real forcing of Methane has doubled, then it would not matter even if the CFCs had stopped increasing in 1988, reducing their impact to zero. The effect of Methane alone, would still be larger than what Hansen predicted for the two. And again, we are talking about scenario A, not B!
Emissions of the largest contributor by Hansen's expectations are 26% bigger than scenario A. Emissios of the second largest contributor by Hansen's expectations have been twice as big (+100%) as scenario A. Are we saying that the reduction of CFCs, the third largest contributor, have the power to counter all of that? Even if it had such a power, we would still be at scenario A's expected increase of temperatures, not B's!
I beg you to tell me where is it that I did wrong the calculations. Because I cannot find it.
-
Deplore_This at 12:20 PM on 3 July 2020Models are unreliable
@scaddenp
Thank you for your response. I'll look at the CMIP6 and respond to you. But for now I have a quick question; When you say "us", what organization are you associated with?
Thank you.
-
scaddenp at 12:13 PM on 3 July 2020Models are unreliable
You can find the list of participants in the CMIP6 project here (via the map). CMIP models are what inform IPCC reports.
-
scaddenp at 12:07 PM on 3 July 2020Models are unreliable
Looking at CMIP6, I see about 100 different climate models from 49 modelling groups worldwide. Most of climate science is not building AOGCMs. Vast resources are required just to observe climate. I dont do GCMs but the models I work with and maintain involve people learning on the job not products of university courses. I expect the university to provide us with graduates who have the necessary skill base (physics, coding, numerical analysis) to be able to contribute and learn by getting their hands dirty improving the code or adding new features Models are developed by slow evolution.
On a side note, as far as I can see EPA doesnt do any climate modelling of the AOGCM. I may be mistaken, but it also doesnt strike me as something that would be part of their brief.
Most people dont have access to the kind machinery required to run an AOGCM. You would be better getting the code from an earlier generation of models and starting with running that. You might want to look at the isca framework or an old model E. Tom has also suggested the EDCGM which looks an excellent way to learn how these are put together and get a feel for code. Lots of university resources based on it and fits with your desire to understand the models.
"But there are scientists who disagree with their conclusions" Want to tell more about these people? I assume you have investigated whether they have the requisite background to make useful criticism and not just reflecting an ideological bias.
-
Deplore_This at 11:55 AM on 3 July 2020Models are unreliable
@Dayton
It's OK if your answer is "no". That isn't a problem. No worries.
-
Deplore_This at 11:38 AM on 3 July 2020Models are unreliable
@Dayton 1184
That’s not very nice or respectful. I thought this was a scientific community. Please just answer my question; do you know of any course that is comparable to Penn State's METRO-523?
Thank you.
-
Tom Dayton at 11:19 AM on 3 July 2020Models are unreliable
Deplore_This: Clearly you are not actually interested in learning anything.
-
Deplore_This at 11:17 AM on 3 July 2020Models are unreliable
@Dayton 1179, 1180, 1181 and 1182
Thank you for your responses. All of the other courses that reference GCM's that I've seen don't give me the opportunity to get under the hood of the models and determine for myself how they work. Your suggested Module 4: Introduction to General Circulation Models How Good are GCM's? is a perfect example. https://www.e-education.psu.edu/earth103/node/1013 So is Tom Osborn's page. There are explanations but there is no way I can hands on understand the nuances of the models and confirm their observations.
My objective is to understand the models themselves. I apologize in advance if this sounds rude but I really don't care what your opinion is concerning whether I have the sufficient prerequisites to take a course in this subject. Quite candidly, you're wasting your time trying to steer me in a different direction. I know where I want to go and I'm smart enough to determine if I meet the prerequisites for a particular course and to negotiate any shortfall with the school. My question is very simple, do you know of any course that is comparable to Penn State's METRO-523?
Thank you again for your help and I apologize if I am being too coarse.
-
Tom Dayton at 11:07 AM on 3 July 2020Models are unreliable
Deplore_This: Tim Osborn has an excellent web page Climate Models for Teaching.
-
Tom Dayton at 09:59 AM on 3 July 2020Models are unreliable
Deplore_This: The very first thing you might do is take Module 4: Introduction to General Circulation Models, from the Earth in the Future series.
-
Tom Dayton at 09:52 AM on 3 July 2020Models are unreliable
Deplore_This: Your own description of your background makes it sound like you are unlikely to benefit much from a specialized course in climate modeling, due to your lack of the prerequisite knowledge. So again I urge you to take some other courses, or if you really are dead set on diving into specifically GCMs (versus other types of models and theories), then get a textbook. Before you even attempt to write code for a GCM, or even look at the code of a GCM, experiment with the easier to use human-computer interface of the EdGCM project, whose underlying GCM is the actual GISS Model II GCM. If you want to look at the code of that underlying GCM, you can get it here.
-
Tom Dayton at 09:45 AM on 3 July 2020Models are unreliable
Deplore_This: You are finding few courses because you are looking too narrowly for courses labeled specifically "Climate Modelling." As scaddenp explained, there are many components of GCMs, and they are used also independently from GCMS. Also, GCMS use theories, models, and computer code from multiple sub-disciplines.
So nearly any course you take in atmospheric science will give you some knowledge about GCMs. If you try to take a course specifically about GCMs, you will need to have that prerequisite knowledge in order to gain the insight you say you want to gain. Just look at the Penn State meteorology course list, for example. In addition to the Modelling the Climate System course you wrote is "no longer offered," are many other courses that include solidly relevant knowledge for climate models. (By the way, universities do not offer all listed courses in every academic period. So that course unlikely is discontinued, because unlikely they would list it at all. It might happen to not be offered right now when you want it.) Just one example is course METEO 520: Geophysical Fluid Dynamics, whose prerequisites are vector calculus and differential equations.
-
Deplore_This at 08:33 AM on 3 July 2020Models are unreliable
@scaddenp 1177
Thank you for your response. I don’t know what an AOGCM computer model looks like under the hood which is why I am looking for a university course on them. I have a minor in math, I took differential equations, I’ve taken Physics in Engineering school, I’ve not only written computer code but in my career I’ve project managed the creation of multi-million dollar IT systems. I wasn’t planning on writing a half million lines of code but I haven’t seen anything yet that would make me believe I would be in over my head working with an AOGCM model. But I haven’t been successful finding a way to actually work with one.
I am somewhat confused by your comment. I would think there would be a plethora of courses on climate modeling otherwise how would all of the climate scientists learn how to construct and evaluate them? We have legions of climate researchers at the EPA, who taught them?
I understand the paleoclimate approach but I am specifically interested in understanding the more sophisticated AOGCMs, specifically their fidelity on climate sensitivity. I’ve gone through the WG1 report and read the results and conclusions. But there are scientists who disagree with their conclusions. To understand the competing arguments I’m trying to educate myself on the models they are using and how they are used. I thought that taking a university course on the subject would be a good approach but not finding one I am stuck. How do the climate researchers at the EPA get the knowledge of which expert and model to believe? What course would they take?
Thank you again for your help.
-
scaddenp at 07:44 AM on 3 July 2020Models are unreliable
Climate models are around 0.5 million line of code created by discipline experts for each of the climate processes. Starting from scratch to write your own is somewhat ambitious. Note that they are not statistically based so I am skeptical that a background in stats or operations research would help you much. The background requirement is numerical solution to systems of partial differential equations. No shortage of courses of these.
I cannot comment on US university or course, but going into serious atmospheric sciences here would be based on undergraduate degree in physics and maths. The numerical solution of systems of partial differential equation is specialist area of mathematics - numerial analysis. Our institute (geology/geophysics) typically has mathematicians, programmers and subject specialists working together on problems of this kind of class.
I still think predicting the base level of future isnt that hard. If surface irradiation increases, then surface gets warmer. The complicated bit is by how much will feedbacks magnify that effect. (Equilibrium Climate Sensitivity) And yes, predictions of future are based are done by AOGCMs. However, there are also paleoclimate constraints on climate sensitivity. Too crude compared to models but good enough to cause serious concern. Again, the WG1 report is good place to find the papers on emperical constraints on climate sensitivitiy.
Prev 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 Next
