Okay, not quite, but bear with me. This post is really just a response to those who seem to be suggesting that half of the warming between 1970 and 2000 could be natural, rather than anthropogenic. See my earlier post or Nic Lewis on Bishop-Hill. I’m going, here, to assume that those who suggest that half the warming in the last few decades of the 20th century could be natural, mean that it was due to some process internal to the climate system (as it can’t have been the Sun and can’t have been volcanoes). It’s this that I would argue doesn’t make sense and that, therefore, in our current situation, there is essentially no such thing as natural warming : it is all anthropogenic. I’ll try to explain why – some may disagree, but this could be an interesting discussion nonetheless.
So, here’s my reasoning. What we’ve done through burning fossil fuels over the last 100 – 200 years is to add so much CO2 to our atmosphere that we’ve produced a radiative forcing of about 2 Wm-2. A consequence of this is that it has taken our planet out of energy balance, so that we are receiving more energy than we’re losing. We are therefore gaining energy, some of which will heat the surface and raise the surface temperature. The increase in surface temperature increases the amount of outgoing energy and reduces the energy imbalance, and this rise in temperature will continue until we return to energy equilibrium.
Therefore, the fact that we are warming is entirely a consequence of our actions. If it wasn’t for us burning fossil fuels and increasing the atmospheric CO2 concentrations, we would not be warming (or, at least, not by much). So, that we are warmer today than we were in the past is entirely a consequence of anthropogenic influences and anyone who claims that half of the recent warming could be natural, should go and learn – or brush up on – their basic physics.
Okay, so the above is clearly quite a strong statement and there are some caveats. The Sun can clearly play a role, but it’s relatively small. Volcanoes can too, but they tend to produce cooling. Additionally, natural variability can also play in role in our warming, but what it does is change the rate at which we warm, but can’t really warm in its own right. In other words, this variability means that sometimes we will warm faster than at others. This doesn’t change, however, that the reason that we’re warming is entirely anthropogenic. Given this, however, one could define the long-term trend as the anthropogenic component, and variations about this trend as the influence of natural variations.
So, let’s then consider the possibility that natural variability doubled the rate at which we warmed during the period 1970 – 2000 : i.e., that half of the warming was natural, and not anthropogenic. If you go to the Skeptical Science Trend Calculator you’ll discover that the trend for this period was about 0.16 degrees per decade. If half is natural, the anthropogenic warming trend is then about 0.08 degrees per decade. If you then consider the period 1970 – 2014, the trend is still 0.16 degrees per decade. We’ve, therefore, now had 44 years with a trend of 0.16 degrees per decade, so if the long-term trend is actually 0.08 degrees per decade, we will very soon need to have a multi-decade period (almost 50 years) with no warming.
However, if we continue to increase our emissions, we’ll continue to move the planet further and further out of energy balance. So, those who are arguing that half of the warming between 1970 and 2000 was natural are essentially suggesting that we will have about 50 years of no warming, despite the planet moving further and further from energy balance. I think that’s physically implausible, even impossible. However – and here’s a challenge – if anyone can give a physically plausible explanation for how half the warming between 1970 and 2000 was natural, they’re welcome to try.
I’ve actually been thinking about a post like this all day, but it was a comment from Fred Moolten that motivated me to go ahead and write this. Fred says,
confusion on the part of the authors between the capacity of natural variability to affect the rate of warming from anthropogenic forcing and the role of natural variability as a source of warming in its own right.
I think this is the crucial point. There is a difference between natural variability being able to influence the rate at which we warm (it can) and its ability to warm in its own right (it can’t, or not by much). If people could understand this distinction, I think it would resolve much of the confusion.
...and Then There's Physics 
Okay, I wrote this quite quickly. It’s intended to be intentionally provocative, may not be argued as clearly as I would like, and is probably full of spelling and grammar mistakes. I also have visitors, so may be offline for a while. Bear that in mind 🙂 .
Also, just to be clear, (as Gavin Schmidt pointed out on Twitter) even though the title says “Natural” I’m really referring to “Internal” as in internal to the climate system. Of course natural influences (the Sun for example) can produce warming, but I used “natural” in the title since it is being claimed that half of the warming during 1970 – 2000 could be natural and, my argument, is that it really can’t.
Also, before I disappear, it’s not quite true that internal variability can’t produce any warming. It can on short timescales (decade) but tends to average out over many decades.
I think it is Gavin Schmidt, commenter “Gavin”, who is schooling Judith Curry on this topic on Curry’s blog:
http://judithcurry.com/2014/08/21/cause-of-hiatus-found-deep-in-the-atlantic-ocean/#comment-620210
Curry meekly asserted:
The suspense is if she ever deigns to pick up a pencil and actually performs a calculation!
What I write here should not be interpreted as a proposal for what really has happened, but you cannot conclude by logic or basic physics alone that there cannot be periods of natural warming of considerable length like 30 years.
It’s logically fully possible that natural variability in large scale ocean circulation leads to such a pattern of ocean surface temperatures that reduces the Earth albedo enough to lead to warming. It may be that such state of low albedo cannot persist for long enough, but that’s a statement that must be justified by a rather detailed and reliable understanding of the Earth system.
Pekka
But presumably this would show up as a reduction in OHC at depth in some basins as OHC in the upper ocean layer increases as energy leaves the ocean and warms the atmosphere?
But IIRC, we see the opposite.
Actually Pekka, this is even more puzzling than I thought:
Are you arguing that reduced SSTs and the concomitant reduction in low marine cloud and so albedo leads to warming?
Reduced SSTs = warming?
Pekka,
Yes, I agree that there are potential scenarios where internal variability could produce actual warming or cooling (in fact, there’s a paper that I may blog about in few days that discusses this). In general, however, these are just ideas that don’t – as far as I’m aware – have any actual supporting evidence. I’d be quite pleased, though, if those who proposed that a significant fraction of the recent warming was natural could actually at least come up with a plausible scenario, rather than simply asserting that some fraction is natural.
ATTP
It seems to me that reduced SSTs sufficient to reduce low marine cloud cover and so albedo would be compensated for by increased TSI. Not much would happen.
BBD,
I probably agree, but at least Pekka is attempting to find a physical mechanism that could explain how internal variability might drive longer term warming. It’s better than simply asserting that it could.
On the other hand, simply suggesting that something could happen, doesn’t mean that is likely. I think that there are two issues with finding an alternative physically motivated possibility. One is that if only half the warming in the period fro 1970 – 2000 were anthropogenic, that would imply that virtually no feedbacks were operating. This seems a little implausible. Additionally, if the other unrelated mechanism actually does something like change our albedo, how do we know that it is unrelated to the CO2, rather than simply a feedback response. I’m not sure how one would distinguish between the two possibilities.
ATTP,
Another way of formulating, what I wanted to say with my previous comment is that I see your post as presenting a claim that you must prove rather than state that it’s true until someone else proves the opposite.
By the proof I mean that you should provide strong and understandable evidence to show that there are no credible mechanisms that might lead to contradiction of your claim.
My example was just the most obvious counterexample, and credible enough until proven moot, there may be other counterexamples all of which should be shown to be of little significance.
To what degree each side bears the burden of proof is seldom trivial. My view presented above is based on the form of your claim. Formulating a similar claim differently could reduce the burden of proof that I would allocate to you.
Pekka,
I think my post had two points. One was that if we have produced an energy imbalance through anthropogenic forcings, then until we retain equilibrium all warming is effectively anthropogenic, however it is achieved. Of course, it might be faster at some times than at others, but that doesn’t change that the reason we’re warming is because of anthropogenic influences.
So, in a sense, even if you can show that internal variability could produce warming in its own right, if we still haven’t retained equilibrium, it’s not obvious that it makes any difference. With respect to the period 1970 – 2000, we were essentially warming because of our influence.
The other part of my post was really just to illustrate that if you want to argue that half the warming from 1970 – 2000 was natural rather than anthropogenic (even if the natural contribution is simply to accelerate the warming) that would imply a lengthy period of no warming in the future, if you want the long-term average to be about 0.08 degrees per decade.
> By the proof I mean that you should provide strong and understandable evidence to show that there are no credible mechanisms that might lead to contradiction of your claim.
One does not simply prove a negative existential, Pekka.
Besides, the proof asked leads us beyond empirical science.
The CO2 we have added warms the climate, provably. Anyone trying to argue that something is interfering with that process needs to provide proof. This is a trivial assertion, true, but it’s also inescapable. The alternative to this approach is a scientific and policy landscape pockmarked with the holes left by constantly shifting goalposts.
I have commented several times at Climate etc that arguing about the relative historical shares of AGW and natural variability is essentially irrelevant, what’s relevant is the strength of future AGW. Concentrating on that circumvents many unnecessary disputes.
Estimating the climate sensitivity does not require accurate knowledge of natural variability, although good knowledge would certainly help.
“Concentrating on (the strength of future AGW) circumvents many unnecessary disputes.”
Rather, circumventing discussion of that, or discussing it it with the objective of discounting it, is the purpose of the unnecessary disputes. Climate Etc. wouldn’t exist otherwise.
I once estimated that I rank as a top 5 commenter at C.E. in terms of volume (definitely not popularity 🙂
I was always hoping that it would turn into a real academic forum, and that somehow I could help sway the discussion towards science instead of the train wreck of dreck that it mostly is.
This is my take on the why of CE :
In college the polar extremes in professors ranged from the hands-off to the hands-on types. The ultimate hands-off professor I had was Walter Heller, who was famous as an economic advisor to Pres Kennedy. For his econ course, they basically wheeled him into an auditorium and he would ramble for awhile and that would be that — in one ear and out the other. He was the keeper of knowledge, but it ended at that.
In contrast, EVERY physics professor I took a course from had the ability to whip out a simplifying derivation of some phenomenon and leave me with real problem solving knowledge. This is hands-on teaching at its finest.
So it has taken me awhile but I am now convinced that Curry is the Walter Heller of climate science. She has never provided any real hands-on transfer of knowledge on her blog, yet I keep waiting for something substantial to transpire. And as Steve Bloom is implying (I think) she doesn’t actually want to engage, as that would starve THE UNCERTAINTY MONSTER that she is trying to keep feeding. The ultimate objective is to position herself as the authority and lord over the “wicked climate problem” of uncertainty, and build up a devoted cult, the so-called denizens of C.E, around that house of cards.
As to why I keep on commenting at Climate Etc — it’s like witnessing a slow-motion train wreck up close, but knowing I can jump off any time I want.
I hope that helps to elaborate on the earlier comment I made on this thread.
Best response on Twitter: So we’ve never come out of an ice-age?
Steve,
That’s exactly the reason for my comments, and also the justification that I have clearly stated or implied in the comments. Entering discussion about the relative importance of natural variability favors those who promote skeptical views, when the truth is that the absolute strength of AGW is known better than the strength of natural variability.
Richard,
Proving that they haven’t read the post, or understood it – both being equally likely.
Pekka,
Yes, that’s pretty much my view.
ATTP,
The point of Richard is closely related to what I have written. In case of arguments of the type you present in the post it doesn’t mean much that the argument may be correct, when understood correctly. What matters is, how the arguments are understood in reality. In reality your argument is too easy to ridiculize by references to ice age, warming from LIA, or warming that ended in 1940s. It doesn’t help that you can show, how those examples do not really apply as they do matter to all those, who might learn something from your argument.
Those who agree already fully with you on climate change are likely to accept your presentation (but perhaps not even all of them). What do you gain by that?
Pekka,
Really? Most of what you’ve written seemed quite sensible.
Presumably what you mean is that the title of the post is easy to ridicule given what you’ve said. Unless I explained myself poorly in the post and in the first few comments, I made it clear that I was referring to internal variability – rather than natural – and that I was really only referring to the latter decades of the 20th century. The title was really chosen because there are many saying “half the warming from 1970 – 2000 was natural” – so it was intended as a response to that.
To be honest, I no longer really care about those who will choose to ridicule something without reading it. Says more about them than about me. I don’t really think they’d learn anything even if the title was 100% correct and as clear as I could have possibly made it.
“So we’ve never come out of an ice-age?”
Technically quite true, colloquially not. Should we manage to temporarily terminate the ice sheets, I suppose it will make for an interesting debate for the chronostratigraphers as to whether we’re still in one or not.
Just to add, Pekka, someone who would make a remark like that is spending their time talking about climate the way most people talk about weather. IOW they’re not interested in understanding it as an integrated whole, choosing instead to cling to a comforting ignorance. But while they’re not worth spending time on, lurkers are.
ATTP,
What you care about must depend on what you wish to achieve by posting in a blog. My intuitive expectation is that you wish to influence what (some) people are thinking, and more specifically people who do not fully agree with you already. If that’s your goal, you should be interested in the reactions that the posts cause. You cannot expect that many people read the post carefully. Most read the title and skim the post. The initial impression based on the title influences the interpretation of what’s read in skimming through the post.
It’s typical (as I see it) that posts that get the strongest applauds from some regulars are least likely to influence those who are basically receptive for new arguments while still somewhat skeptical.
@Wotts
As you know, if someone doesn’t understand you, you should first wonder whether you have explained yourself sufficiently clearly.
Your title is as clear as it is wrong.
Steve,
I don’t mean that the person who wrote that tweet could have been influenced, what I tried to say is that offering tweeters such opportunities is likely to weaken the possibilities of making positive contributions.
A blogger cannot discuss important issues without a clear position. It’s, however, possible to influence the reception of the arguments without giving up the position.
Pekka,
In my case, I think it changes from day to day 🙂
I don’t think that’s quite true, even if it once was. I’m certainly not trying to change the views of those whose views seem quite fixed. I don’t think I’ve ever really intended to influence people, more simply write my views on a blog. If anything, I’ve learned a lot doing this, so don’t see myself as someone who is educating others. More as someone who understands this topic quite well, can write blog posts about this topic, and in which the comments can sometimes be more informative than the original post (although that’s mainly the other commenters than me).
Sure, I am interested. In this case, I was aware that the title would attract the kind of comments that Richard has illustrated. Maybe I should have chosen a different one, but I didn’t. I do comment below the line a lot and am typically more than happy to engage with those who comment and to explain things and even to accept when someone makes a good argument against what I’ve written.
I don’t see my posts as the last word on the matter. Sometimes they’re just a way to get a discussion going. In this case, it’s clear that – literally speaking – my title is wrong, but anyone reading the post and the comments may actually learn something. Then again, maybe not 🙂
That’s the problem with using journalise! Everyone knows that the title of the post is a rather provocative tab but when there are hard-bitten nitpickers around and those determined to find fault, vast edifices of contrariness can be built by focussing contrived indignation onto single sentences or phrases. Think of the glorious hammering that certain climate scientists were subjected to on the basis of two or three phrases in private email correspondence.
The ill use of snappy titles as a way of publicising ones’ work (not suggesting ATTP’s example is one of “ill use” btw!) can be otherwise problematic. One annoying example is the paper of Ioannidis in PLoS Medicine some years ago titled “Why Most Published Research Findings are False”. This is obviously not true and Ioannidis was referring to a very limited set of statistical analyses in certain types of medical research – his interpretations were also otherwise dubious.
However the title of Ioannidis paper (cited over 2000 times already) is catnip to those who find it convenient to attempt to beat up on scientists and trash science they happen not to like (a popular sport nowadays – often accompanied by hand-wringing and crocodile tears!), and one quite often sees the assertion (something like “well, most science has been shown to be wrong anyway…”) on message boards as a result of the very popular title of Ioannidis paper…
Pekka,
Possibly, or it illustrates that those doing the tweeting are more interested in ridiculing than engaging in any serious discussions. I’ve seen nothing to convince that that isn’t essentially the case.
Richard,
Of course. Something maybe you should bear in mind?
Indeed it is, as the first line of the post points out. I’m guessing you didn’t read it, or – if you did – didn’t understand it?
To be honest, if you’re just going to point out that the title of the post is wrong (as it obviously is) you can stop now, as it’s rather irritating (which is – I assume – your intent, as it appears to always have been).
In a sense, this title was chosen partly to see what the response would be. I assumed that some would crow about it being wrong and take great delight in pointing that out (and hence illustrating that they hadn’t bothered to read the post or engage with the basic argument). Am I surprised by who’ve done so? I’ll leave that for the readers to decide.
Richard,
Oh, by the way, if you don’t understand the argument, I am happy to explain it again. Just ask, and I’ll give it another go.
ATTP,
A provocative title works, when it gets people to read the post well enough to understand it.
A provocative title does not work when it results in a major part of readers to misunderstand the actual message.
Both of the above comments are about the influence of the title on the reception of that particular post. The titles affect also, how people consider the whole site, and this is what I had mainly in mind. This influence is to very significant part affected by the comments elsewhere in the blogosphere. There are people, who wish to spread the message that this site is highly alarmist, one-sided, and not worth of taking seriously by anyone even a little skeptical of main stream climate science or strong climate policies. That’s not true, but my impression is that you formulate your writings often in a way that helps the task of those people.
Pekka,
Indeed, you’re right. Sometimes it works, sometimes it doesn’t. Once it’s done, it’s done, though.
Possibly, but I’m yet to be convinced that there is a way that I could formulate it that wouldn’t end up being used in that way (well, unless I was suddenly to start claiming that AGW is a sham, that’s it’s all the Sun, UHI, the Hockey Stick’s been debunked, …..). I think the debate is too polarised. Accept mainstream science = alarmist in some people’s mind.
To be fair to you though, I do sometimes (often) write things when I’m particularly frustrated by some of what I’ve seen or read. It’s therefore hard not to let the frustration show and therefore to not write something that could then be used against me. I try to compensate for this, but don’t always (never?) succeed. I could always choose to wait until my frustration has subsided, but then I might not bother writing anything. I’m not doing this because I think the general dialogue is fine and that the general picture being presented to the public is a good representation of our understanding of the science. If I did, I’d be doing something else.
Rachel,
🙂
@Wotts
Your title is wrong, and your opening sentence says “not quite” which I guess you will defend as an understatement.
Your argument only works if there is no other external forcing, and if the system starts in steady state. Neither assumption is true.
Richard,
My argument was never meant to be complete.
I really wouldn’t waste my time trying.
True (kind of, see below), but acknowledged.
No, not if we’re out of a steady state because of our influence. That was essentially the point. If anthropogenic forcings have moved us out of equilibrium, then essentially any warming can be regarded as anthropogenic – I would argue that this could even apply to warming from the Sun, because until we retain equilibrium we can’t really cool (i.e., a system that is gaining energy can’t really get colder). Of course, natural effects can influence the rate at which we warm, but that doesn’t change that the reason we’re warming is because of a change in anthropogenic forcings.
Are you actually seriously interested in this, or just trying to nitpick? I would normally assume the latter, but am happy to be convinced otherwise.
“So, that we are warmer today than we were in the past is entirely a consequence of anthropogenic influences and anyone who claims that half of the recent warming could be natural, should go and learn – or brush up on – their basic physics.”
I think I have to learn my basic physics. Where is the basic physics that claim that most of the recent warming is manmade?
Pekka has a point. The operators-in-bad-faith cannot hope to win any scientific argument so instead they distort and misrepresent, often through childishly transparent nit-picking. Moderation can reduce the damage done, of course.
nobodyknows
Are you serious?
Here’s a pretty picture that explains it in simplified but sufficient detail.
GAT (surface) annual means are shown at the top (green). The three lower curves are coherently-scaled forcings. Well-mixed GHGs (blue) and solar (yellow; bottom) bracket the total net forcing (red).
Do, please, go and read around the topic before posting anything else or people might think you are trolling.
Why am I being moderated again?
BBD,
For agreeing with Pekka? 🙂 No, I think we have the word trolling in the moderation filter.
nobodyknows,
Simple answer. We’ve warmed by almost 1 degree since the late 1800s. There is no evidence to suggest that we were significantly out of energy balance at that time. Without our influence, an increase in temperature of 1 degree should have lead to very rapid cooling back to mid-to-late 1800s temperatures. We’re clearly not doing that, we’re still warming. The reason we’re doing so is because of the continual increase in anthropogenic forcings. Got it now?
ATTP
Ah. I did wonder. I’ll attempt to remember that in future. Thanks 😉
To be fair, you and Pekka do have a point, but sometimes I just feel like giving the nit-pickers the win they so desire, or – at least – an apparent win 😉 .
ATTP
If I had an argument in which my position was so weak that I was forced to resort to childish nit-picking I’d be embarrassed. I wouldn’t consider that I had won any kind of victory 😉
> offering tweeters such opportunities is likely to weaken the possibilities of making positive contributions.
What kind of “likely” is that, Pekka?
Any blog post, comment, tweet or even word written by someone who’s been targeted in a game of climate blog thrones provides such opportunity.
Also note that this comes right after AT realized our Beloved Bishop is more an interpreter of interpretations than anything else.
The task now, for our Serengeti show to continue, is to show that AT is no better.
You obviously (?) don’t understand how to play THE UNCERTAINTY MONSTER.
Applying Judith Curry’s philosophy, the title of this post would have changed to:
There’s no such thing as natural warming! (?)
Note the placing of the (?)
Does she know what she is doing or what? (?)
—
When Walter Heller taught, he would give an economics lecture only once every two weeks; the rest of the lectures were given by TA’s. The first day a TA taught, he wrote a long equation on the chalkboard. He then promptly erased it and said that was the last equation we would ever see.
You can see the approach. Stay hands-off and let the goons do the work for you. And then wipe your hands clean of the damage you have done.
What about natural warming?
” However – and here’s a challenge – if anyone can give a physically plausible explanation for how half the warming between 1970 and 2000 was natural, they’re welcome to try.”
More likely it is near enough all of it if one accepts the Earth system response to solar variations as ‘natural’ and here is a physically plausible explanation:
http://www.newclimatemodel.com/new-climate-model/
More GHGs might have a miniscule effect on global atmospheric circulation but near nothing compared to solar and ocean variability.
Whatever the cause of variability the system is kept in thermal balance by changes in atmospheric circulation though of course there will be an imbalance at any given moment as thermal inertia leads to variations about the mean.
The mean being set by atmospheric mass, the strength of the gravitational field and top of atmosphere insolation.
Variations about the mean being caused by changes in the proportion of top of atmosphere insolation that gets into the oceans i.e. variations in global albedo / cloudiness and no doubt GHGs play a role in that – just too small to measure.
You wanted an ‘interesting’ conversation, did you not? 🙂
Stephen,
Hmmm, yes lets clarify your position with regards to the greenhouse effect. Are you of the “mass of the atmosphere” school, or the “influence of radiatively active gases” school.
I think Stephen may be confusing “interesting” with “rational”.
Stephen Wilde is featured in the field guide to the [Mod : Redacted].
http://tinyurl.com/ClimateClowns
Both, because one can accommodate radiative characteristics within the mass based scenario but I don’t think anyone else has proposed that.
Mass sets the baseline temperature but radiative gases influence the proportion of solar energy passing through that exits to space from the atmosphere as compared to the proportion that exits to space from the surface.
The more radiative gases one has the more energy escapes from within the atmosphere and the less from the surface.
No radiative gases and it all exits from the surface.
If radiative gases could be 100% efficient then all radiation to space would be from within the atmosphere and none directly from the surface.
Either way, energy out always matches enerrgy in subject to variations about the mean caused by internal system variability.
The effect of radiative gases is to change atmospheric circulation and not change the system energy content.
Such GHG induced changes in atmospheric circulation would constitute climate change but changes in climate due to solar and ocean variability are magnitudes greater.
If we say that the climate zones shifted 1000 miles latitudinally from MWP to LIA and from LIA to date then I guess that our emissions might have contributed about 1 mile.
Stephen,
Parts of what you say makes sense, but overall it doesn’t and your comment Both, because one can accommodate radiative characteristics within the mass based scenario but I don’t think anyone else has proposed that is concerning as it seems to suggest that you’re verging on the mass of the atmosphere school of greenhouse effect and as much as I’m interested in interesting discussions, I’m not really interested in ones that aren’t actually physically plausible.
So GHGs are opaque to outgoing (reflected) SW radiation? Wow. Never knew that.
“So GHGs are opaque to outgoing (reflected) SW radiation? ”
GHGs would both reflect SW and radiate to space longwave energy received from the surface by radiation and conduction.
“I’m not really interested in ones that aren’t actually physically plausible.”
No problem, I didn’t expect you to agree.
Mind you, I’d be interested in discussing why you think that my description is not physically plausible.
I’d hate to be wasting my time if I’m really getting some basic physics wrong.:)
Stephen,
I don’t really have the energy at the moment, but your statement Mass sets the baseline temperature seems fundamentally wrong.
Ok, lots of people have problems with accepting that atmospheric mass subjected to gravity determines density at the surface and density at the surface determines the proportion of solar energy passing through that can be involved in conduction.
Then the greater the proportion involved in conduction the higher the surface temperature must rise above the S-B expectation.
But it’s your blog and if you don’t want to go there then I respect your wishes.
So does this. Downright crazy in fact. GHGs do not ‘reflect’ SW.
How do the glacial cycles work, Stephen? Are you claiming they’re due to insolation changes? And how do you explain the Eocene hyperthermals?
Also, I read your page but didn’t see any sign of a model. Can you point to it, or to any start at the physical calculation needed to construct one? I’m especially interested in a demonstration as to how the climate can be significantly sensitive to insolation but not GHGs.
Stephen,
Yes, I think I would really rather not go there. I’ve spent far too much of my time talking with those who think there is some new and novel explanation for the greenhouse effect.
BBD said:
“GHGs do not ‘reflect’ SW”
Depends on their optical characteristics and you confused me by saying this:
“So GHGs are opaque to outgoing (reflected) SW radiation? Wow. Never knew that”
Not relevant to my case anyway which is that GHGs increase longwave radiation to space at the expense of longwave radiation from the surface for a zero net effect.
Stephen,
Unless I’m misunderstanding you, this is just so wrong that I really would rather just drop this. I have no great interest in debating the greenhouse again.
“Mind you, I’d be interested in discussing why you think that my description is not physically plausible.”
The ball’s in your court to show that it’s plausible.
Also, I see that you place great reliance on Miskolczi, who at least tried to do some physics but whose work seems to have been thoroughly discredited. Even Woy thinks it’s bogus.
Oh, maybe shouldn’t have posted that last, but the links will be useful for anyone wanting to look into this further.
Steve Bloom,
Ice Ages seem to be primarily due to Milankovitch cycles. Climate swings due to changes in the mix of particles and wavelengths from solar variations are different.
The model is crystallised in the numbered steps set out in the article. It is a conceptual model not a numerical one and has been constructed around actual observations. We do actually observe changes in the sequence set out.
The climate responds to solar variations by changing cloudiness in the way I describe. That effect is magnitudes greater than the effect of GHGs because it alters the proportion of TOA insolation able to get past the atmosphere and into the oceans to drive the climate system.
GHGs do not do that. They rely on an infinitesimal slowing down of the energy flow to space by radiating about half of their absorbed energy back to the surface.
In contrast, more clouds with their reflection to space, prevent energy from getting into the system in the first place. That is a vastly more powerful mechanism.
Stephen,
Sorry, but you don’t seem to understand this particularly well, so can I ask that we drop this now. I’m not really interested in a lengthy exchange about something that appears to simply be a a conceptual model not a numerical one. With all due respect, that seems to just be code for I just made this up.
“The ball’s in your court to show that it’s plausible.”
Agreed, but it is designed around actual observations.
There are many ways that real world observations could change so as to invalidate my conceptual model but none have happened yet.
I accept that the passage of time is required to test it.
Anyway, I’d better stop there in case I irritate our host – unless he confirms that I may continue to respond to queries.
Steve Bloom shares my interest in this very odd property of SW’s model. I see this as a fundamental problem. A watt per metre squared is a watt per metre squared. Energy is energy.
ATTP
Sorry. As per usual, we crossed 🙂
May I reply to BBD at 6.28 pm?
BBD,
I’ve actually been out trying to show you up by doing some actual surfing, and now I’m absolutely exhausted. Avoiding a lengthy discussion on the greenhouse effect would be my preference 🙂
Stephen,
Yes, alright, but I may live to regret this.
Thanks, but I’ll be brief.
The rise in surface temperature above S-B is all a matter of slowing down the flow of solar energy through the system.
The amount of delay involved in radiating back down and then up again is miniscule.
In contrast, increases in global cloudiness alter the proportion of solar energy arriving at the top of the atmosphere which is able to enter the oceans.
That is a complete denial of insolation to the climate system and mimics the effect of a less bright sun or moving the Earth further away ftrom the sun.
I do not see how changes in GHG quantities could compare with that natural mechanism.
I just leave it for you chaps to think about.
I generally find it more rewarding to discuss matters with AGW proponents than with sceptics provided only that the discourse can remain civilised.
> There are many ways that real world observations could change so as to invalidate my conceptual model but none have happened yet.
Such sharp shooting can be a feature but also a bug.
Since predictive skill has been used by Stephen to dismiss the established climate models (and perhaps also some of the theories underpinning them), Stephen must establish that his own favorite model has predictive skill.
This is done by providing the formal apparatus to establish productivity.
The word “formal” has been introduced in the last sentence to underline that Stephen’s “real world observations” looks a lot like the good old empiricist gambit.
ATTP
Goodness me, you don’t need to get wet and cold and risk drowning to show me up 😉
Are you on holiday again? You aren’t that nice Mr Cameron are you? I thought you were a physicist.
Argument from personal incredulity and from ignorance is a twofer logical fallacy, Stephen.
Some background reading:
http://scienceofdoom.com/2011/01/06/does-back-radiation-%E2%80%9Cheat%E2%80%9D-the-ocean-%E2%80%93-part-four/#comment-8640
Note that SoD refers to a theory, not a model.
Only if the effect were global and persistent. If such a mechanism actually existed, there could have been no Cenozoic hyperthermals and no deglaciation under orbital forcing. The strong negative feedback from low marine cloud formation and concomitant albedo change would have prevented both types of event from happening. It didn’t, so we can safely infer that no such effect operates and that you are mistaken.
BBD,
You mean it’s easy to show up the Boogie Board Diva?
I was going to say that you’ve just guessed who I was, but I can’t bring myself to pretend to be Cameron, even in jest.
“Stephen must establish that his own favorite model has predictive skill.”
Just watch the real world and compare it to my conceptual model over time.
[Mod : Sorry, but lets just drop this. I’ll have a look at your ideas and the SoD post to which Willard links, but I’d be very surprised if that changed anything. If it does, I’ll happily carry on with this discussion.]
Stephen,
Sorry, that not really how science works. You can’t propose something without any kind of justification (other than some kind concepts) and then say “wait and see”. Plus, if SoD has shown your idea to be in error, I’m pretty happy to go along. SoD understands this stuff extremely well and if you really want to understand the greenhouse effect, I’d read his blog thoroughly.
SW
Please address the gaping hole in your argument and stop waving your hands around.
“Sorry, that not really how science works. You can’t propose something without any kind of justification ”
The justification is that it fits observations to date.
The test will be whether it fits observations into the future. That’s the bit that is currently going awry for the models.
So far, so good.
Me and Stephen share this interest:
> My field is words and concepts rather than equations but I’m quite sure it could be done by someone suitably experienced.
http://scienceofdoom.com/2011/01/06/does-back-radiation-%E2%80%9Cheat%E2%80%9D-the-ocean-%E2%80%93-part-four/#comment-8731
Conceptual model thus seems to mean equation-free.
ATTP
Bloody UKISS. I knew I’d never live that down the instant I read it 🙂
No, there are limits and that’s right up there with Morris Dancing and incest.
“If such a mechanism actually existed, there could have been no Cenozoic hyperthermals and no deglaciation under orbital forcing. The strong negative feedback from low marine cloud formation and concomitant albedo change would have prevented both types of event from happening. ”
Why so?
A mechanism that produces the MWP, LIA and current warm period need not be powerful enough to offset such events.
> Just watch the real world and compare it to my conceptual model over time.
How exactly can we compare a conceptual model with the real world, Stephen?
And then there’s naive physics:
http://en.m.wikipedia.org/wiki/Na%C3%AFve_physics
Stephen,
I’ll respond to this, but am not keen to continue
No, it doesn’t because all you have is some handwavy concepts. It only fits the observations in the sense that you assert that your hand wavy concepts fit the observations. You don’t have any numbers or any kind of numerical model. Without those, your claim that it fits the observations is largely nonexistent. If climate scientists didn’t use GCMs, their ideas would fit the observations too. It’s that they’re actually trying to use complex models to try and understand the climate system that gives people like yourself the opportunity to say “see, their extremely complex model that is based in physics doesn’t quite fit the observations, therefore my hand wavy, conceptual model is better.”
“How exactly can we compare a conceptual model with the real world, Stephen?”
Easy.
If real world climate changes occur differently to the sequence set out in my model.
Since I created the first version in 2010 or thereabouts the real world has been complying nicely.
Stephen,
4 years, you’re havin a larf, right? Aren’t you?
[Mod : Okay, I think we should call this quits. It’s unlikely to end well.]
I think those who read the thread Willard points to will realize that discussions with Stephen will end up nowhere.
>If real world climate changes occur differently to the sequence set out in my model.
A trivial thing to say considering that all the theorical concepts in that statement are not defined by a way of equations.
Even day traders would not buy such a model, and God knows their attunement to sharply shot portfolio strategies, as evidenced by their collective unsuccesses.
Ah, a negative feedback that is strong when the forcing change is weak and which attenuates as the forcing increases…
Cobblers.
@ Marco
Yes.
[Mod : Okay, I think we should call this quits. It’s unlikely to end well.]
I expressed willingness to stop on request.
My post should have been allowed and then followed by your request and I would have ceased contributing.
Stephen,
Okay, fine, my apologies. Can we call it quits now?
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Gavin responds. http://www.realclimate.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/#sthash.U36924UB.dpuf