Dr. Gavin Schmidt's Epic Response to Scott Adams

Not just that warming has followed predictions, but that warming has followed the predictions made by Exxon-Mobil and the predictions of BP-Shell (as well as the predictions of climate scientists).

Everyone is in agreement. What a consensus!

The more nuanced quote from Box is

The fact that the polynomial is an
approximation does not necessarily detract
from its usefulness because all models are
approximations. Essentially, all models are
wrong, but some are useful. However, the
approximate nature of the model must always
be borne in mind.”
From the book: Empirical Model-Building and Response Surfaces (1987, p 424), by Box
and Draper.

This doesn't take away from Schmidt's points or Adams' idiocy. It does address the fake objections from climate deniers (including the bozos who repeatedly post here) that the climate models are wrong because they are simply approximations. Everyone knows that; the people who understand things knows that every model is an approximation, and that they are often useful.

You remember how to get home because you have a model in your head that approximates the terrain between where you are and where you want to go..this model certainly doesn't contain all the variables and intricacies of the route but it gets you home.

The Schmidt, he rocks.

Gavin Shreds
(Good name for a band, btw.)

@ ~ 3
Indeed:
On mismatches between models and observations
http://www.realclimate.org/index.php/archives/2013/09/on-mismatches-bet…

“our earth is a globe
whose surface we probe
no map can replace her
but just try to trace her”
– Steve Waterman, The World of Maps

System Of A TakeDown.

Pt. 7: the earth has warmed as predicted you pillock. 23/n

'Pillock' is a fine word, but IIRC, not really in the American English lexicon? I seem to recall getting the odd blank look.

Or is it?

** I know Gavin is a Brit.

Yeah I'm not familiar with that word in US English, and it comes from earlier British English (for "penis")

and it comes from earlier British English (for “penis”)

That fits with the usage. Generally speaking, women call men pillocks and men call men pillocks, but men don't call women pillocks.

Gavin:

The most important point he makes is implied in point 1:

ALL the models show an increase in temperature with increase in CO2 BECAUSE the models "Force" it to. None of the models INTRINSICALLY predict increase in temperature with increase in CO2 concentration; all ASSUME the behavior and Force it.

We can create a model of a chemical reaction say 2H2 + O2 --> 2H2O (including any transition reactions, etc.).

The model will intrinsically predict an increase in temperature of the mixture. No one needs to ASSUME the temperature will go up and add energy to the mixture to realize the ASSUMPTION. This is because we UNDERSTAND this reaction and the model turns out to be predictive and authoritative.

This is not true for climate models. They are very useful for "What if" scenarios, like "what if CO2 DID cause T to rise". And there may be some evidence that it does, but the model CANNOT verify that.

None of the models INTRINSICALLY predict increase in temperature with increase in CO2 concentration; all ASSUME the behavior and Force it.

No. They don't assume the temperature rise. "Force" means thermal force, i.e. increased CO2 increases the watts/square metre sent to the ground. The models try to determine how much the temperature rises from that heating in order to bring outgoing watts/square metre up to the new incoming watts/square metre. Like turning up the flame on a stove - you increase the stove's thermal force. The only issue is how much your pot on the stove will warm up from this increased thermal force.

There is absolutely no doubt that we have turned up the radiant heat coming down to the surface. The only issue is how much the temperature will increase in response.

" “Force” means thermal force, i.e. increased CO2 increases the watts/square metre sent to the ground."

Understood. But why can the model not intrinsically calculate that forcing? In theory if you add the CO2, then radiative (and convective and conductive) exchanges shift, and heat becomes trapped, and ultimately the temperature will rise in the lower atmosphere.

Instead a correlation is used which guarantees that outcome. That is my point. The model does not predict temperature rise, it enforces it. It may predict the amount of temperature rise in various places based on the initial assumed forcing.

None of the models INTRINSICALLY predict increase in temperature with increase in CO2 concentration; all ASSUME the behavior and Force it.

No, model sensitivity to dF (eg CO2 forcing increase) is not parameterised. It is an emergent property of the model physics. You have this entirely back to front.

" “Force” means thermal force, i.e. increased CO2 increases the watts/square metre sent to the ground." (Chris O'Neil)

Understood. But why can the model not intrinsically calculate that forcing? In theory if you add the CO2, then radiative (and convective and conductive) exchanges shift, and heat becomes trapped, and ultimately the temperature will rise in the lower atmosphere.

Instead a correlation is used which guarantees that outcome. That is my point. The model does not predict temperature rise, it enforces it. It may predict the amount of temperature rise in various places based on the initial assumed forcing.

BBD- IF that is true, it increases my confidence in the models. My understanding is that there is a bypass in the fundamental physics for a number of reasons (complexity, computational power, etc.) and a relationship between CO2 concentration increase and some form of temperature/energy increase is enforced. I would then assume the model starts from that and calculates how the injected energy is redistributed.

From Wiki: (https://en.wikipedia.org/wi...

"Radiative forcing can be used to estimate a subsequent change in equilibrium surface temperature (ΔTs) arising from that forcing via the equation: dT=lambda dF" (translated images to equations)

Then

"For instance, the simplified first-order approximation expression for carbon dioxide is: "

They are not modeling it. All they SHOULD need to do is allow the CO2 to increase, and the physics should take care of the rest, ultimately warming the surface.

Instead, the increase the CO2 then use the simplified equation to warm the surface. Why skip all the intervening thermal interchange steps? This indicates that the modelers (if Wikipedia is correct, and ...) presume a correlation and enforce it.

The Wikipedia link for comment #16 is:

https://en.wikipedia.org/wiki/Radiative_forcing#Forcing_due_to_atmosphe…

presume a correlation and enforce it.

The radiative physics is not presumed. You can get from this to the PETM hyperthermal event without a CGM in sight.

Indeed. The deniers have no idea what happens so presume what's going on and go from there. Finding out what is happening is beyond them, and changing their minds isn't their thing.

They have an ideology and they force it onto everyone else.

"Instead, the increase the CO2 then use the simplified equation to warm the surface. "

that's what svante arrhenius did with pen and paper. You can do it yourself with an SCM, and do it on your phone.

The GCMs used are far more complicated, but they don't presume a CO2 sensitivity, they just run the simulation of what the radiative balance would be for given CO2 production routes.

And they've all been pretty much on the money on the climatological trends.

The 1980s IPCC estimated about 3.4C per doubling, and we're probably actually there now, depending on how quickly the climate responds to forcings (if could be late 2.x, probably 2.8+ if there's almost no lag, it could be late 3.x, maybe over 3.6 if the lags are 50 years or more).

Thanks, BBD. This looks mechanistically accurate (looking at it briefly). But this is a simplified model (i.e., three isothermal layers, etc.), not a full GCM. Why not incorporate this into GCMs? I am sure there are valid reasons (computational power, complexity to incorporate on a continuum model, etc.).

Why not incorporate this into GCMs?

Not sure what you mean. The atmospheric physics in GCMs is not simplistic.

A reality check on model physics comes from palaeoclimate behaviour, which suggests that ECS to 2 x CO2 is about 3C. The emergent sensitivities of models converge on the same value.

BBD- Forget the simplistic comment. I was referring to teh fact that GCMs are continuum models and do not need to be broken into a small number of isothermal layers (rather the vertical discretization is probably hundreds or thousands of layers).

I am only asking why do what I described in comment #16 when they could do something more like what is described in this paper (except using the full vertical discretization)?

Wow- at least Wikipedia indicates (see comment #16) that they use a simple correlation between CO2 concentration and surface temperature.

BBD- sorry, no edit function here: "this paper" I referred to in comment #23 is the paper you linked "Infrared Radiation and Planetary Temperature".

It there is a problem with model physics, then why do they have emergent sensitivities which agree with palaeoclimate behaviour?

BBD- that is not an answer. The answers vary greatly from model to model, all tend to go up, but by hugely varying amounts.

Maybe the physics is incorporated as it should be. I do not know. I am trying to understand how the models are put together. The Wiki article seems to indicate they use very simplified expressions for forcing. Why not just set the radiation free and let the [pseudo] equilibrium condition dictate the final state?

Here is the paper the Wiki article references. I am not sure this is the current approach or not: http://88.167.97.19/albums/files/TMTisFree/Documents/Climate/New_estima…

BBD- that is not an answer.

Well spotted. It is a question.

An answer would be good...

"I was referring to teh fact that GCMs are continuum models"

What on earth are you talking about here? They're still finite methods models, not analytical solutions. So clearly you can't mean what you appear to mean.

"I am only asking why do what I described in comment #16"

They don't. They say you CAN do it. But that doesn't mean any GCM does.

"Wow- at least Wikipedia indicates"

No they don't. The WP article says you can, you personally, if you want to, do it that way, but it isn't describing how anyone actually does it.

You can go for a walk by hopping on one leg and work out your balance as well as burn more calories.

But that doesn't mean you HAVE gone walking out today hopping on one leg, even though you have just read someone saying you can do it.

You can go and get your own GCM from GISS:

https://www.giss.nasa.gov/tools/modelE/

And stop reading WP articles and deliberately getting yourself confused so you can pretend that GCMs are all badly done so you don't have to do anything.

"BBD- that is not an answer. "

That was not an answer.

"Maybe the physics is incorporated as it should be. I do not know. "

Then you should read the words of the WP as they were written, not as you'd like to interpret them.

Or you could go and actually TRY looking at the models, any of them, to see what they do do, rather than what you'd like to read them having done.

You know, actually take on board and act as if your claim "I do not know" were actually a valid claim as opposed to a dodge for being wrong.

WOW- "You can go and get your own GCM from GISS:

https://www.giss.nasa.gov/tools/modelE/"

Thanks, this is the best reference I have found so far.

BBD, "It there is a problem with model physics, then why do they have emergent sensitivities which agree with palaeoclimate behaviour?"

You mean why does temperature go up (within the range of rates predicted)? That is what I am investigating.

You mean why does temperature go up (within the range of rates predicted)? That is what I am investigating.

If there is a problem with model physics, then why do they have emergent sensitivities which agree with palaeoclimate behaviour?

Who said there was a problem with modern physics? I am looking at numerical schemes and the nature of specific forcing functions.

You're using words that clearly are meant to mean something to us, but they don't.

Go look at the code. Function names will indicate what they're meant to do and most of the code will reference the papers that described the physics going on.

Once you've learned some of what the words are meant to mean, use the correct ones or explain your personal lexicon when you introduce them.

Numerical schemes journal refer to things like finite differences, finite volume, or spectral message. This is what I'm finding for some of these models.

As to forcing function this is what I was alluding to in common number 16.

Who knows what you're alluding to, John. Until you know what you "allude" to and know what words you're supposed to use to "allude" to it, then stop "alluding" and start "saying", you're just blowing air.

Throwing around "spectral message" is just adding more smoke you're trying to blow up people's asses.

FWIW, stepping back, see basics at RealClimate:

- Do models have global warming built in? (Short answer: No.)
http://www.realclimate.org/index.php/archives/2008/11/faq-on-climate-mo…

- What is a forcing then?
- What do you mean when you say a model has “skill”?
http://www.realclimate.org/index.php/archives/2009/01/faq-on-climate-mo…

3. Model Spead
CMIP5
http://www.realclimate.org/index.php/archives/2016/05/comparing-models-…

Wow, he probably meant to say "spectral methods", as finite differences and finite volumes are two other classes of numerical methods, along with spectral methods.

Quit giving the guy so much flack; numerical methods are a completely fundamental part to any computational method. They're the engine that you use to solve the time-evolution of a simulation.

"Finally, climate change impacts are happening now: Greenland's losing mass, heat waves are worse, rainfall more intense, Arctic ice is…"
If "[Doomsday Global Warming] impacts are happening now", and "Greenland's losing mass", when will we be able to grow barley in Greenland again?
"A sensational find at the bottom of an ancient rubbish heap in Greenland suggests that Vikings grew barley on the island 1,000 years ago.
The Greenland climate was a bit warmer than it is today, and the southernmost tip of the great island was luscious and green and no doubt tempted Eric the Red and his followers."
http://sciencenordic.com/vikings-grew-barley-greenland

Thanks, Windchaser, I meant spectral methods, but was on a smartphone using dictation.

It is appearing that the models are not explicitly predisposed to warm. This is good news. I will continue reading. I found this from a climate skeptic (Dr. Robert G Brown), and even he confirms this (though critically on other points); though he feels they are architechted in in such a way that they will warm with CO2 increase, and possibly incorrectly:

"Fine, so now we’re down to a single attractor, and it has to both be stable when nothing changes and change, linearly, when underlying driving parameters change. This requires linearizing all of the forcings and trivially coupling all of the feedbacks and then searching hard — as pointed out in the talk, very hard indeed! — for some forlorn and non-robust combination of the forcing parameters, some balance of CO2 forcing, aerosol anti-forcing, water vapor feedback, and luck that balances this teetering pen of a system on a metaphorical point and tracks a training set climate for at least some small but carefully selected reference period, naturally, the single period where the balance they discover actually works and one where the climate is actively warming. Since they know that CO2 is the cause, the parameter sets they search around are all centered on “CO2 is the cause” (fixed) plus tweaking the feedbacks until this sort of works.

Now they crank up CO2, and because CO2 is the cause of more warming, they have successfully built a linearized, single attractor system that does not easily admit nonlinear jumps or appearances and disappearances of attractors so that the attractor itself must move monotonically to warmer when CO2 is increasing. They run the model and — gasp! — increasing CO2 makes the whole system warmer!"

link:

[Link to science denier site removed as per blog policy]

Thanks, Obstreperous Applesauce, your links were helpful.

JohnQPublic just posted a link to Anthony Watt's website.
Oh dear. And you were doing so well.

JQP #36:

Who said there was a problem with modern physics? I am looking at numerical schemes and the nature of specific forcing functions.

?

I wrote:

If there is a problem with model physics, then why do they have emergent sensitivities which agree with palaeoclimate behaviour?

You need to think more carefully about this validation of GCMs. You keep skipping over it, which suggests that it is an inconvenient truth.

* * *

No more links to denier sites, please. If you want to discuss science, use scientific sources as references.

"Wow, he probably meant to say “spectral methods”"

Maybe, but you have to work it out for him, don't you.

"Quit giving the guy so much flack"

No. Remember he said he'd studied this for 50 years. He should know what the hell he's talking about and not confuse words. Because if he doesn't like what you interpret what he says into something from a hominid with the claimed experience, he'll whine and whinge and moan about how you're dissing him.

So, no. He's a grown up now, claims to be in his 70s, so he can damn well learn the words and act like an adult who is responsible for their own actions and can take criticism.

"It is appearing that the models are not explicitly predisposed to warm."

It is appearing that you are a denier, as suspected and explicitly predisposed to believe any crap from denier blogrolls and ignore any actual reality handed to you.

Care to tell us which module in the GISS model code predisposes it to warming? You've been given it and "said" it was informative.

Surely you didn't come to this conclusion DESPITE that evidence of an ACTUAL model whilst never having looked at it?

"so that the attractor itself must move monotonically to warmer when CO2 is increasing"

Bullshit bafflegab.

JQP

(Quoting Brown:)

They run the model and — gasp! — increasing CO2 makes the whole system warmer!”

Remember that this arises not from models but from basic physics. Brown - who is not a climate modeller and is confused - is simply ignoring the basics. You really should read the Pierrehumbert essay I linked upthread properly.

We *know* CO2 is an efficacious climate forcing. If it wasn't, then events like the PETM could never have happened.

Watts... I suspected as much. JPQ, he has his fingerprints all over you. You have been led astray.

Let's step back a little further from even the basics and begin to ponder the world in terms of practical metaliteracy. It is admirable that you want to suss this out for yourself. But the people who are out there telling you that anybody can figure this all out from the comfort of their armchair with a little "common sense" are full of baloney.

What we know about the climate comes from the combined efforts of thousands of bright, hardcore, rigorously educated, serious scientists in specialty fields working very hard for over a century. Climate science is like rocket science or brain surgery and arguably more difficult. Even if you are already a trained scientist in another field, trying to take a short cut by burrowing in from the top down will almost certainly leave you lost and confused.

There is a consensus. Consensus matters:
http://scienceblogs.com/insolence/2010/03/24/hostility-towards-a-scient…

And please, let's not call deniers 'skeptics'.
https://en.m.wikipedia.org/wiki/Agnotology

My suggestion would be to reconsider your approach.

Mark M, growing barley on Greenland has already been done in recent years, but it is of very little use for the local economy. Too expensive and a largely uninterested product for the local community. That's the main problem for much of the local agriculture. That Vikings did it is related to their usual diet and inability to get any produce from elsewhere.

Not that these facts will change your beliefs, but maybe a few others here will do some research and see that your reference to growing barley is a good example of a talking point based on ignorance. Stated with much confidence, just like Trump spwes his nonsense with confidence.

Wow:

Maybe, but you have to work it out for him, don’t you.

Well, given that he said finite differences and finite volumes, I figured it was pretty straightforward: "spectral message" was mispelled or dictated improperly. This is just a thing that happens, and it doesn't signify that a person doesn't know the concepts. It's usually just their phone being weird.

It's just like "hey, what fits with finite differences and finite volumes, starts with 'spectral' and sounds like 'message'? Oh, right, spectral methods".

I'm just saying, let's maybe tone down the combativeness, eh? Pretty please?

JohnQ:

"Since they know that CO2 is the cause, the parameter sets they search around are all centered on “CO2 is the cause” (fixed) plus tweaking the feedbacks until this sort of works."

Sounds like he thinks these parameters are just tuned to fit the output, like this is more of a statistics-based model than a physics-based one.

A lot of folks on 'skeptical' sites confuse these. E.g., comparing financial models with climate models. But the physics underlying radiative models aren't really tunable. The physics is what the physics is. And the results, showing warming, follows primarily from that physics.

And like I said, you had to interpret it for you.

For someone who'd claimed to be interested in this for years, this is not a tenable mistake to make.

And it's later turned out that he doesn't know or care what he;s talking about, he's another faker trying to get JAQing off and making asinine denier claims out on the internet under the pretense of being an interested party with no dog in the show. Which was a lie.

You know what's dumb about the "Oh, you tuned the values to get the sensitivity to the desired value"? Mad Christ Monckton has a "model" which "proves" climate ECS is about 1C per doubling CO2e. He does this by putting a maximum on feedback parameters, and the value he put in to his model was such as to make sure it had that value for climate sensitivity. It was an input to his model.

Yet deniers think that's what the real climate scientists are doing. When its just what they have to resort to doing in their cluelessness.

And project onto the professionals.

Windchasers

Sounds like he thinks these parameters are just tuned to fit the output, like this is more of a statistics-based model than a physics-based one.

A lot of folks on ‘skeptical’ sites confuse these. E.g., comparing financial models with climate models. But the physics underlying radiative models aren’t really tunable. The physics is what the physics is. And the results, showing warming, follows primarily from that physics.

That was my impression too, but also that JQP is greatly over-stating the importance of models to the scientific understanding of CC. It is, after all, a standard contrarian rhetoric.

If he comes back, I will talk to him a bit more about this.

@ Wow

Where have you come across JQP before? The handle does ring a bell, but I can't place him.

There's one as a denier on slashdot and appears in Graun comments sections BSing denier rubbish, but it's not like Joe Random User here had to be the same denier moron.

@Marco, March 11, 2017.
Do you have a link to support your 'fact'?
Remember, Vikings grew it for centuries, not one season.
Thanks in advance.
As for my 'beliefs', what a bizarre comment.
I gave you a scientific link, It is not about 'belief'.

As for my ‘beliefs’, what a bizarre comment.
I gave you a scientific link, It is not about ‘belief’.

Oh yes it is. Stop pretending you aren't a contrarian. Nobody's fooled :-)

As for Viking agricultural myths:

Over the last decade, however, new excavations across the North Atlantic have forced archaeologists to revise some of these long-held views. An international research collective called the North Atlantic Biocultural Organisation (NABO) has accumulated precise new data on ancient settlement patterns, diet, and landscape. The findings suggest that the Greenland Norse focused less on livestock and more on trade, especially in walrus ivory, and that for food they relied more on the sea than on their pastures. There's no doubt that climate stressed the colony, but the emerging narrative is not of an agricultural society short on food, but a hunting society short on labor and susceptible to catastrophes at sea and social unrest.

Source

Perhaps the role of marginal cereal cultivation is being over-stated.

Do you have any support for your fact? Because every link I have says that Greenland wasn't lush, it was a hellhole and lasted only a few years, needing support all the time because it couldn't support itself.

You gave a blog link, not a scientific one. They're just geeks who like nordic culture, being northerners themselves.

Your claim is similar to the whinge about how Romans used to grow grapes in the UK in the past, but

a) it was a religious requirement
b) there was no other way to clean the water for drinking
c) there were no threshers wine stores in those days
d) it was REALLY shitty wine, but because of a, b and c, there was no competition
e) it's being made COMMERCIALLY further north than it ever was in the roman times

So, yeah, I'd like to see the papers sourced (if indeed any were) for their claim it was warmer in Greenland (note, they don't call it lush, YOU added that non-fact opinion in there).

Mark M, the link does not show they grew barley for centuries, nor does the actual scientific paper (challenge to you: find the paper). You literally made that up. There is some evidence barley was grown most likely solely for personal use. Some Greenland farmers have done the same in the last 10+ years (only some media reprts on that). But what's the use? Barley simply isn't an important produce anymore. Potatoes is much more important.

There is some evidence barley was grown most likely solely for personal use.

To make beer :-)

Ok. Looks like I stirred the sh*t a bit. Thanks Windchaser for maintaining a level head.

I linked Dr. Brown, because I came across it in a Google search, and it verified (as I said even from a skeptic) that the model are NOT preloaded to warm. I am not necessarily taking his argument about weather being chaotic and and thus not being amenable to over-simplification and linearization as gospel, but it is an interesting point. And climate science is based on physics, by the way.

For the second time, I dictated spectral methods and missed that it interpreted it as "spectral messages" when I did a quick review as I was stepping out of the car and sending.

I will be frank and disclose that I am coming from the skeptic side (and I was not hiding that previsously and do not find it an untenable position), but actually am very open minded. I certainly hope that ANY of you that claim to be climate scientists are also skeptics. I understand radiation physics from the perspective of thermal modeling, experiment, and being involved in scientific thermal imaging (and understand the role of gases such as water and CO2 in the atmosphere in radiative absorption). I have knowledge of chemistry and physics, and have worked as an engineer for many years, and spent many of those years involved in structural and thermal modeling as well as CFD plus some hybrids (i.e., multi-physics). For the record this includes finite difference methods, finite volume methods, and finite element methods.

I am interested in the CGMs because I find them fascinating; I am curious if they stand up to the task of deciding world policy on (even coupled with paleo-climatological observations)- this might be my skeptics position; I am generally curious about the numerical techniques and physics in them. As computer power increases, and it still is increasing, we might be able one day to run an unsteady fully-3D atmospheric model (maybe a while before we can do that for 100 years, but maybe long enough to gain some insight), but I suspect we are far from that computer power yet. I do not feel the modelers are intending to commit fraud, and probably have put together some very interesting and powerful models that are at least very capable of performing useful and interesting studies (there may be some exceptions such as climategate, but I have not studied that in any depth).

This is not a religion. I already have one of those, and do not need another. Science should be less heated; though politics can get pretty heated (as can religion).

I understand that many of you truly believe that world is on a collision course, and I do not doubt there is a general sincerity to it. I actually see Donald trump's presidency as an opportunity for real dialog. The "Believe what we say or else" attitude has no choice but to back down, and everyone will perhaps have a chance to discuss more frankly and calmly. If the current AGW proponents are correct, it could be a big problem, but it is as it is.

Some of The questions are:
1. Is the earth/atmosphere ocean heating? I think there is evidence for this.
2. Is man responsible for it, and by how much? I think you feel you have the answer for that. (yes and 100%).
3. If 2 is true, what would the consequences be for mankind? I think this is even more open than 2.
4. If 2 is true, what can we and/or should we do about it? This is political question. This also depends on the certainty of 2 and even 1.
5. If 2 is true is it good, bad, or something else? This depends on 3 and the certainty of 3,2,1.

I do not expect that I alone will be able to answer all those questions for myself. That is why for now I am mainly looking into the models. This is an area I have some comfort and interest. I am willing to read about the other areas. Unfortunately I have a day job and a family, so like some of you I can only spend so much time doing any of this.

I intend to maintain an open mind going forward. Peace.

That is why for now I am mainly looking into the models. This is an area I have some comfort and interest.

A standard not-really-sceptic meme is that climate models are the source of scientific understanding of climate change. This is not true.

You will be familiar with James Hansen, who, unlike Dr Brown, does have relevant domain expertise. What does Hansen think about models?

Here's an excerpt from an interview in which Hansen says treat the models with scepticism:

TH: A lot of these metrics that we develop come from computer models. How should people treat the kind of info that comes from computer climate models?

Hansen: I think you would have to treat it with a great deal of skepticism. Because if computer models were in fact the principal basis for our concern, then you have to admit that there are still substantial uncertainties as to whether we have all the physics in there, and how accurate we have it. But, in fact, that's not the principal basis for our concern. It's the Earth's history-how the Earth responded in the past to changes in boundary conditions, such as atmospheric composition. Climate models are helpful in interpreting that data, but they're not the primary source of our understanding.

TH: Do you think that gets misinterpreted in the media?

Hansen: Oh, yeah, that's intentional. The contrarians, the deniers who prefer to continue business as usual, easily recognize that the computer models are our weak point. So they jump all over them and they try to make the people, the public, believe that that's the source of our knowledge. But, in fact, it's supplementary. It's not the basic source of knowledge. We know, for example, from looking at the Earth's history, that the last time the planet was two degrees Celsius warmer, sea level was 25 meters higher.

And we have a lot of different examples in the Earth's history of how climate has changed as the atmospheric composition has changed. So it's misleading to claim that the climate models are the primary basis of understanding.

It's very important to recognise the difference between the distorted views espoused by contrarians and the actual state of scientific knowledge about climate.

Fair enough, but how do you project out 100 years for policy decisions without models? I get the impression that the models are very critical to organizations such as the IPCC.

Yeah, right. Cool story bro. Who did you think would buy that?

At the very best for you, you've got a problem that you've made up yourself. Most likely you're just BSing.

Wow- clearly a skeptic!

Yes, as are just about all scientists. We're skeptics. Deniers, however, aren't, they believe any old crap as long as it's Anything But Carbon. And they'll pretend "honest queries" so as to resurrect the old zombie denier arguments before, when it fails to get anyone unable to answer them, turning into full denier mode.

Fair enough, but how do you project out 100 years for policy decisions without models? I get the impression that the models are very critical to organizations such as the IPCC.

Because model sensitivity is close to palaeo-derived sensitivity there is fairly high confidence that the models will have predictive skill on the global scale and the centennial scale.

The uncertainty is more about regional effects on shorter timescales and it is not a comforting kind of uncertainty.

So to answer your question, the IPCC (and others) are right to place fairly high confidence in 100-year projections of GAT response to various emissions pathways.

The basis for a policy response to scientific projections of warming is sound and indeed only fake sceptics actively seek to cast doubt on it.

"Fair enough, but how do you project out 100 years for policy decisions without models? "

By using reality to guide the expected outcomes of your actions. You know, like every single thing you ever plan doing. "I need to eat later this week, so I shall go shopping and get some food". You plan for the future using what you know of reality, not by running a computer model of your biochemistry.

Or do you?

I actually see Donald trump’s presidency as an opportunity for real dialog.

Seriously? Are you always this delusional?

It gets better...

I actually see Donald trump’s presidency as an opportunity for real dialog. The “Believe what we say or else” attitude has no choice but to back down, and everyone will perhaps have a chance to discuss more frankly and calmly.

Somehow JQP has mistaken the authoritarian, vindictive bellowing from the White House for something other than "believe what we say or else". Quite a feat of misapprehension, that.

Amazingly, he goes even further and ascribes the authoritarian, threatening rhetoric to scientists who are simply explaining the scientific evidence to decision makers. This is alt-reality, monkeys-out-of-unicorns'-bottoms stuff indeed.

JQP @~ 68 (Engineer... Quell surprise, just enough knowledge to be dangerous and puffed.)

I understand that many of you truly believe that world is on a collision course, and I do not doubt there is a general sincerity to it. I actually see Donald trump’s presidency as an opportunity for real dialog. The “Believe what we say or else” attitude has no choice but to back down, and everyone will perhaps have a chance to discuss more frankly and calmly. If the current AGW proponents are correct, it could be a big problem, but it is as it is.

Donald Trump is a dangerous mess with no fix in sight. If you can't see that... Yikes!

"The 'Believe what we say or else' attitude..."

This is a childish mischaracterization. If you've ever heard scientists try to debate creationists, you get pretty quickly how and why they get irked. It's the same situation with denialists of just about any stripe.

Furthermore it's just blind petulance from people who can't accept a basic principle of learning. Until you are at the point where you yourself have actual expertice in a complex subject like this, you necessarily have to rely on the expertice of your professional peer reviewed, well published teacher in the relevant field. Get that? You have to trust that they know what they're talking about. It's amazing how many deniers think that they are instant Galileos because they read a blog that tells them so.

Being an overweening amateur with Dunning-Kruger syndrome, will simply not help you to advance. Nor will it earn you much respect among the professionals. Exactly how much this applies to you would be hard for me to say, but it certainly applies to the base of the community you embrace.

I do not expect that I alone will be able to answer all those questions for myself. That is why for now I am mainly looking into the models.

Good. But I suggest that you start at the beginning with introductory climate science textbooks and move on from there. If you're as smart as you think you are, you'll be into the good stuff in a relatively short time. Or is it that you think you're just too cool for school?

@~78 above.

Damn. Oh, for a preview.

Forgot the quotes in the penultimate paragraph.

Didn't close the bold for climate science

>No, model sensitivity to dF (eg CO2 forcing increase) is not parameterised. It is an emergent property of the model physics.

Then how is RealClimate able to use a climate model tuned to yield a 3C response? See their post about Keystone XL.

My suspicion is that if Scott Adams said he believed the scientists on global warming(which he actually does but you know what I mean), then you would be calling his work funny.

"Then how is RealClimate able to use a climate model tuned to yield a 3C response?"

They don't.

"My suspicion is that if Scott Adams said he believed the scientists on global warming"

He doesn't, so you have no data to make any claim on.

You do have data indicating you are incorrect, since Greg's opinion appears to be it was good and funny but has rode it out too long and has to retread the same old stuff. Much like the Simpsons from about S9/S10.

My suspicion is that if you were able to find out this alternative reality showed you were wrong you'd merely go on and bitch about something else, never once changing your opinion, merely finding the next morsel of bullshit to make you feel like you were vindicated.

On models and related questions vis-a-vis CO2 and other greenhouse gas effects on the environment:

The point of much of this research is to find out how a change in CO2 concentration changes the heat balance of the planet. It is not the case that the relationship between CO2 and, say, surface warming is a presumed correlation. The "correlation" (relationship) between the two is the question being asked, not a presumption in the model, most of the time.

The baseline is simple physics. A simple nitrogen atmosphere (zero other gasses of any kind) on a planet with no ocean (which you would need to have no gasses!) would involve a very rapid and very knowable, easily calculated, relationship with the sun, and adding a fixed amount of CO2 to that atmosphere would produce an easily calculated number. On such a planet, for example, it would be very cold at "pre-industrial" levels, and doubling the amount of CO2 would probably raise the average temp at two meters by about 1.2C. However, if you add water vapor, some other gasses, and thus clouds, and oceans, etc. and run a pile of highly advanced models using everything we know, you get two interesting results.

1) The models run up to, say, 1980, predicting the future, give a range of future temperatures that the actual temperatures that happened subsequently fall nicely within. A few years ago, the actual temperature for the coldest running interpreted data sets neared the allowable lower margin (but did not pass it) and now we are nearing the higher end of the allowable range (having the effect of STFU the deniers who were so titilated by the earlier trend). In other words, the first result is that the models, not using a presumed correlation came up with a result that predicted 40 years of time pretty accurately; and

2) Looking over the longer term, where C02 makes it all the way to 500ppm, and then we look even farther ahead to see all the effects, these models give estimates for future warming that range from about 2 to perhaps 7 degrees C. The lower end (around 2) are impossible because the empirical observations have already obviated them. The higher numbers are low probability but most models allow it. The best guess is close to 3.5.

A great resource allowing both a good explanation of various models as well as a comparison of the "these models don't work" denial machine results vs. actual scientists results is found in the book I review here:

http://scienceblogs.com/gregladen/2015/03/11/climatology-versus-pseudos…

MikeN

Then how is RealClimate able to use a climate model tuned to yield a 3C response? See their post about Keystone XL.

Link please.

"See their post about Keystone XL."

Lame, even for you. If you actually have one in mind, that you've read, state which it is. They have numerous posts with discussions and comments about Keystone XL.

To which are you referring?

@BBD, #64: I dont pretend.
I prefer 'deplorable', as 'contrarian' can be included, with bonus name calling for those inclined to use them.
Nice link you provided.
I like this:
"Temperature
Winter temperatures dropped below the long-term average by more than a degree halfway through the 5-century occupation, according to oxygen isotope data in cores taken from the Greenland Ice Sheet."
Is there nothing rising carbon (sic) can't do?
PS. Check my link in response to Wow #65 for an update from your 2016 link, dated March 2017.

@Wow, #65: Despite "every link" you have, you fail to provide one.
RE: "blog link ... to geeks ..." ...
"Henriksen, an archaeobotanist at the National Museum's Environmental Archaeology and Archaeometry section (NNU) in Copenhagen ..."
Not sure Henriksen would thank you for so easily dismissing his hard work.
News flash: Geeks ahoy in science!
And, like potatoes, pointing at unicorns amongst the grapes: fail.
So here is another link, and, fwiw, the article treats the Medieval Warm Period as the fact that it is:
"Accordingly, the Vikings were not just dumb, they also had dumb luck: They discovered Greenland during a time known as the Medieval Warm Period, which lasted from about 900 to 1300.
Sea ice decreased during those centuries, so sailing from Scandinavia to Greenland became less hazardous.
Longer growing seasons made it feasible to graze cattle, sheep and goats in the meadows along sheltered fjords on Greenland’s southwest coast."
http://www.smithsonianmag.com/history/why-greenland-vikings-vanished-18…
Who wants to be the first to call the Smithsonian a name?

@Marco, #66:
The link says vikings settled 1000 ya and abandoned 140 (approx).
Perhaps they only grew it for 1 year.
"(challenge to you: find the paper)."
As you failed to provide a link to the paper to prove me wrong, I would be 97% confident you haven't read it.
But, Marco, you have failed to provide a link showing that the experiment has been reproduced as you claimed.
Perhaps you made that up.
Look over here, a unicorn hiding amongst the potatoes.

Unexpectedly, you are wrong. I did read the paper and therefore know you made stuff up. I cannot show you any scientific papers on current-day barley growing, because people usually don't write scientific papers about a few Greenland farmers trying out stuff.

Anyway, one example (but in a bad piece of historical journalism) is here
http://www.economist.com/node/7852916

I know of field trials of barley in Greenland going on, but they focus on commercial production, so are much more likely to fail.

Someone should come up with a parody version of Dilbert, called Dilbit.

"@BBD, #64: I dont pretend."

Oh, so you're a moron in real life, then.

"“(challenge to you: find the paper).”
As you failed to provide a link to the paper to prove me wrong"

As you failed to do so, you have not met your burden of proof and your claims are contrary to what we know, there's no need for us to prove you wrong, you have failed to prove you right.

"@Wow, #65: Despite “every link” you have, you fail to provide one."

And you have given a link that doesn't say what you claim, and what you claim is wrong.

Give a link proving you aren't wrong, retardo.

Andy, it should be called "Dickbit".

Summary: m55 has made several claims, mistaken climate and weather , and failed to supply any evidence at all for what he says, but mocks people for not reading support that doesn't exist.

Just another ignorant asshat in the vein of rickA and the mikes

"Who wants to be the first to call the Smithsonian a name?"

What sort of name? I call them wrong on this. But that may be more due to simplifying it for children and the uneducated, without worrying about malicious retards deliberately misreading what they say and quote mining the shit out of it.

"the Medieval Warm Period as the fact that it is"

What wasn't a fact, and one your retarded denier mates made up, was that there was a global MWP and that it was warmer then than it is now.

Care to show where in that link it says the MWP was globally warmer than it is today?

Moreover, the impression you want to give is that the MWP is being pretended as never to have existed. Got any evidence of this, or was what you said there more industrial-grade stupidity from you that means nothing, because nobody is saying there never was an MWP?

Maro, according to the Smithsonian link, Greenlanders were dependent on imports from mainland to survive and paid for it by ivory hunting:

For all their intrepidness, though, the Norse were far from self-sufficient, and imported grains, iron, wine and other essentials. Ivory was their currency. “Norse society in Greenland couldn’t survive without trade with Europe,” says Arneborg, “and that’s from day one.”

Are you going to be calling the smithsonian names now? Especially since they're claiming this quote from you is incorrect:

The Greenland climate was a bit warmer than it is today, and the southernmost tip of the great island was luscious and green and no doubt tempted Eric the Red and his followers.”
http://sciencenordic.com/vikings-grew-barley-greenland

So you gave a link and called it a done deal, gave another link and showed the earlier one was either misrepresented by you or wrong.

Who are you going to call names now, dumbo?

Mark M

“Temperature
Winter temperatures dropped below the long-term average by more than a degree halfway through the 5-century occupation, according to oxygen isotope data in cores taken from the Greenland Ice Sheet.”
Is there nothing rising carbon (sic) can’t do?

So it got colder from about 1ky BCE. Exactly as expected based on reduced NH summer insolation - it's been falling since orbital dynamics ended the last glacial 11.5ky ago at *peak* NH summer insolation.

Then, post-1850, comes the Industrial Revolution and aCO2 starts to increase, triggering a slow background warming that really took off post-1970 when emissions did.

Next, the 'MWP' that wasn't. You - like so many contrarians - have an imaginary global, synchronous warming event as warm as or warmer than the present. It never happened. There were discontinous, regional warming events spread over several centuries, but global average temperature did not match, let alone exceede late C20th values.

Since you bring it up, there's an important point that contrarians never seem to get about the fantasy 'MWP'. There is no evidence for any major forcing change ~950CE - 1350CE. So the various regional climate shifts of the MCA (correct term) were responses to only very slight changes in net radiative forcing.

Now, *if* there actually had been a 'hot MWP' (global and synchronous; as warm as or warmer than the present) it would be very strong evidence that the climate system is really quite sensitive to radiative perturbation. This means that the danger of climate impacts from increasing CO2 forcing is increased.

One should always think things through, don't you agree?

As for the silliness about Vikings, the link I provided at #64 says exactly the same as the Smithsonian article:

The findings suggest that the Greenland Norse focused less on livestock and more on trade, especially in walrus ivory, and that for food they relied more on the sea than on their pastures. There’s no doubt that climate stressed the colony, but the emerging narrative is not of an agricultural society short on food, but a hunting society short on labor and susceptible to catastrophes at sea and social unrest.

Presumably this cockwomblery on you part is intended to peddle the 'hot MWP' meme, but if you do that, you are arguing for high climate sensitivity, which I assure you is not what you want to be doing.

So please sort out the mess of half-truths, fully wrong stuff, and confusion over the basics or you are going to come badly unstuck.

God but this shit gets old.

http://www.realclimate.org/index.php/archives/2011/11/keystone-xl-game-…

Greg Laden, you say low end 2C is impossible, then why did IPCC in its latest report use 1.5C-4.5C, for a slightly higher CO2 concentration than 500?

"you say low end 2C is impossible"

It is. Based on current trends, it's already oever 2C and it's not equilibrium yet.

" then why did IPCC in its latest report use 1.5C-4.5C"

Why is that a problem? Unable to read?

MikeN, how does that realClimate article (from 2011) support your assertion?

Greg Laden, you say low end 2C is impossible, then why did IPCC in its latest report use 1.5C-4.5C, for a slightly higher CO2 concentration than 500?

Because of a couple of papers using EBMs that produced what are now understood to be under-estimates of S. The IPCC had to include the low-ball end of the range because there was *at the time* no reason not to. Nobody would do this now, and I am willing to bet that the lower bound will go back up to 2C again in AR6.

Frankly, even that is too low. The range that is compatible with palaeoclimate is 2.5 - 3.5C centered on a most likely value close to 3C.

This lukewarmer crap never did fit with palaeoclimate so it was always obvious to the non-partisan that it was wrong.

And what dean said at #99. Why are you repeatedly waving that RC article around?

Dean they are unrelated. I was asked to provide a link.

Ah, so you provided a link to something else. But you were asked to provide a link, but no such link was found. You showed a HYPERTEXT LINK.

Try again, moron.

So the claim in #80 about models tuned to 3C is unrelated to the realclimate post? The juxtaposition of the two in #80 is confusing

Sorry, thought you meant the link and the rest of #97. In the post, "and is based on simulations with the U. of Victoria climate/carbon model tuned to yield the mid-range IPCC climate sensitivity. "

Ah, "mike", that is what we call "a big fucking lie" there. You were asked for a link here:

Then how is RealClimate able to use a climate model tuned to yield a 3C response? See their post about Keystone XL.

Link please.

So there's no possible way you can be telling the truth in 105.

Whatever, everyone else understands what was said, so if you want to play pretend word games, have fun.

I think people are misunderstanding what Scott Adams is saying. Gavin can be 100% right, and Scott Adams can 100% agree with what Gavin is saying, but it still keeps Scott's main argument intact- that climate scientists are not very persuasive and arguing weakly.

"Whatever, everyone else understands what was said"

No: if I had known you meant something else I wouldn't have asked. You hadn't posted 105 at the time you made that comment.

“Whatever, everyone else understands what was said”

Clearly wrong.

"main argument intact- that climate scientists are not very persuasive and arguing weakly'"

But this is no way mentioned as his "main argument".

And it is also clearly wrong.

Notice how MikeN is studiously unresponsive to the answer at #100 to his question at #97, opting for a flurry of misdirection instead.

MikeN, if one's ideology depends on rejecting something, no 'proponent' will be able to be persuasive enough to convince that person. To come with an analogous situation, I once spent hours on explaining someone some basic math to show he used the wrong equation in his paper. It did not register, because he would have had to admit the main result in his paper was wrong. He used a similar excuse that my arguments were not persuasive enough, ultimately using the argument from popularity: others were still using the equation, so my arguments had apparently not convinced these people...

BBD. I have no followup. Thanks for the answer.

Dean, Wow had 105 when he responded. I assume you understood what I was saying after #105. Seems like a reasonable misunderstanding all around, but Wow decides to go to calling 105 a lie.

"Dean, Wow had 105 when he responded."

But I never demanded a link, you lying arsehole.

I assume you know you're lying, but just don't like it being pointed out.

I didn't know that all statements at this blog are assumed to be about you. I never said you demanded a link.

#90 Great idea. But i like the name Didcot.

‘Pillock’ is a fine word, but IIRC, not really in the American English lexicon?

Common parlance in the RN.

Great points on climate models and sensitivity, as well as pointing at palaeoclimatology from BBD, Greg etc. I do grasp all this but useful for debating elsewhere so bookmarked.

And yes Gavin rocks on this stuff. Love his comment replies at Real Climate - so instructional.

Well, Scott is angry at Gavin for not accepting the calls of an ignoramus (and when you don't know something, KNOW you don't know something, but pontificate on it anyway, that is the definition of ignoramus, no matter how smart you are elsewhere) and made another dumbass cartoon to hit back.

Because reality doesn't really let him win.

Sure, "he's a comic writer", but he's personally invested in this so it really doesn't work like that. You can't "go comedian" when you're evidently deadly serious about something.