As I saw somewhere "If you can't explain the pause, you can't explain the cause".

[THE HOCKEY SCHTICK - thank you Google.]

Shut up? If people stopped making silly statements, like claiming scientists don't take changes in effective radiating area into account, or claiming that CO2 is such a small part of the atmosphere, then I would gladly shut up. But you just don't stop, do you? I imagine there might be people here who know better and I often wonder why they don't put people like you down. But I guess playing whack-a-mole against your own side gets them down after a while. Or maybe they just consider you to be useful foot soldiers in that you will spread such nonsense widely and confuse the uninitiated - and confusion is as good as it need get when you are trying to sow FUD.

I'm very sad with this thread. And not with Raff this time.

I'm sad because the group as a whole seems to have lapsed back to "yeh this GHE, phooey, trace gas" argument that typified it a few years ago. Every time someone says that here, the credibility of scientific scepticism takes a bodyblow. Again. What is saddening is that we've collectively put it to bed several times, but some of you seem so attached to the mythos, that it comes back again like a dose of shingles.

CO2 is only a 'trace' but it contributes 20-30% of the GHE. This is a measurement, not a model. You can do the experiment yourself if you have a mind. As soon as you says "ok, that might be true but what if..." then you're veering into the ga-ga territory that our critics love - the area of loonidom.

Can't you see that it's the crackpot nature of a large part of climate scepticism that is holding back mainstream science from retreating to a position of realism? Some of them would rather be utterly wrong than admit defeat to the lunatics. They like it when we act stupid, because it allows them to demonise us as a whole - including the section of scepticism that actually as a freaking point.

Tidy up your act, or this thing will roll on for years. (or maybe you want that?)

Radical. The 'proof' that because CO2 levels are rising but temperatures are not has always been intensely embarrassing to me when I hear it trotted out. Nobody except warmist fools have ever argued the relationship is lockstep linear. There is a phenomenon in feedbacks called hysteresis, where an effect with a linear relationship with a forcing can actually go backwards during the time of maximum or minimum forcing. It could be that the CO2 temperature relationship is linear with hysteresis. I'm not arguing that it is, but to argue that 15 years where they don't tally proves nothing either way. All it proves is the relationship, if there is one, is far more complex than some fools believe.

On the point of continuing scientific questioning. If we haven't covered an area before, then it is legitimate to present differing opinions. But people ... we have been over the GHE, the Stefan-Boltzamnn laws, IR emission spectra, DLR... over and over again. When people bring it up AGAIN, then it no longer becomes scientific questioning, but just laziness to read what has gone before.

and never, TBYJ, yet come to a satisfactory answer, at least as far as RR and I are concerned.

And therein lies the problem. You can't argue someone out of an opinion they weren't argued into.
There is no evidence that will convince some people, because they are not convinced by evidence.
If that is you and RR, then you fall into the camp of ideologically-driven doubter, AKA denier.

the group as a whole seems to have lapsed back to ... argument[s] that typified it a few years ago.

A few years? This has been going on for more than a decade. My assumption is that people get into climate when they are hit by a FUD spread by the ignoranti and their handlers. If they are clever they realise they are being fooled, but the ones who don't realise and get hooked spend the next few years re-spreading FUD until they either tire of it or realise how stupid it is. But by that time their FUD has spread to a new generation of ignoranti ready to carry on their work. There are also people here who have still not seen the light after years of spreading FUD, but they are probably motivated not by science but by ideology, which puts them beyond reach.

And we still have the likes of McI churning over the old ground of MBH98. Hardly credible in his case really.

Provide me, please, if you can, with the irrefutable evidence that CO2 has any material bearing on global temperature.

I will when you provide me evidence that gravity is holding you to the surface of the earth.

The point is that you desire a level of evidence for the connection between CO2 and temperature that not only do we not have at the moment, but is probably unattainable under ANY circumstances. You are asking for a level of proof that cannot ever to provided, and your thesis is that we should reject the idea of any connection until that time.

Which is patently nonsense.

RR, do you not for one moment consider that where there is evidence that convinces others but not you, that perhaps you are simply not understanding it? I'm not discounting the possibility hat perhaps you see something others don't but I very rarely am so sure of my ground that I assume I am the sole repository of sense when it comes to things.

I proved here a few years ago by looking at a simple night-time DLR graph that the GHE from CO2 was 20-30% of the entire effect. This is not fancy-pants models, speculation, or opinion. This was a simple measurement followed by squared paper and a pencil approach that nobody disputed at the time.

Here is the graph: DLR.

Work out the area under the curve (by printing on squared paper and counting squares if you want to keep it simple)
Work out the area under the section of the window entitled CO2.
Divide one by the other.
Answer: 25% or so.

This technique has the simple advantage of not worrying about concentrations and traces and being unconvinced about the effect etc. It's s simple look at a measured night-time spectrum and working out the proportion of longwave radiation which comes from CO2 molecules.

In what way does this not prove to you in a simple unequivocal way about the approximate magnitude of the effect of CO2 with regards to the entire GHE?

Raff

Given that most palaeo "reconstructions" use Mann's methods and even rely on some of the same data, it is surely still relevant to try to understand the bad science involved in all of Mann's papers. In any case, I think it is a long time since Climate Audit focused on MBH98. In case you had not noticed, most of the recent Climate Audit posts have been concerned with demolishing PAGES2K - a recent piece of work, which seems to depend heavily on the Gergis paper that had to be withfdrawn because of the incompetence with which it was prepared and which has not been republished. And who spotted the errors on which it was based?

But here you are, still spreading your brand of FUD. You have displayed your ignorance of economics and of the political situation in the Ukraine, and you have tried a typical alarmist smear against the GWPF, presumably out of some sense of misguided zeal and determination to show that the only reasonable way forward is to be alarmist about the tuture behaviour of a climatic system that is not at all well understood nor measured. Please carry on Fudding. It is relatively amusing to see you flounder against facts.

Radical,

The fact that you don't understand terms like DLR and be able to read a graph is the sort of thing I am talking about. This is a very simple graph, of a very well-understood phenomenon. There's very little to confuse there.

It's absolutely fine to not understand something, not everybody needs to understand science. But you have to realise that by failing to acquire an understanding of basic physics, you disqualify yourself from criticising the theories that do exist. You see that, surely? A grumbling sense of unease that you are not convinced by an argument is not the same as a scientific critique, you can see that?

Unlike Martin, I don't welcome the same uninformed questions over and over again. Perhaps someone with a teaching temperament doesn't mind going over the same old ground time and again, but this isn't a physics class... this is a showcase of the best of critical thinking in the climate world. And it's embarrassing to have to show the world just how shaky the ground is if the best we can offer is the ubiquitous "trace gas" battle cry.

There are well-founded problems in climate science. There are problems with data homogeny, proxies, poor modelling techniques, badly understood stochastic systems, crooked scientists who will say anything for a grant. And yes, Martin, a big problem is one of communication - because it's hard to explain, science communicators have adopted a 'just trust us' attitude which is deeply unhealthy. There are loads of legitimate scientific problems with the consensus. The greenhouse effect is not one of them, and the longer we go over and over and over it, the stupider we look and the longer this goes on.

RR, google it, it's not rocket science engineering.

Downward Longwave Radiation

> This is a very simple graph, of a very well-understood phenomenon.
> There's very little to confuse there.

As an engineer I want to know....

1) How much does the H2O portion extend off the left of the X axis? (I can't quickly find figures).
2) What was the cloud cover?
3) How much wind was there?
4) What was the elevation
5) What was the ambient temperature?

6) How much does the graph change if you change variables 2 - 5 above?

Without some context this is a bit like showing CO2 absorbs energy at certain frequencies in a test tube.

Radical,

I'm sorry you feel patronised (perhaps we've stumbled on some psychological basis for GHE doubt?) but science is a bit fascist on this point - you only get to criticise something if you understand it. It's a spur to self improvement. The graph is labelled just fine, but for one last time I'll explain (again) what it shows.

People often like to shout about CO2 and how 'trace' it is, and how it can't possibly be having an effect on anything much at all, hoping I think that people don't really know how much of an effect it has, which reduces the argument to a matter of opinion. But we can measure how much energy is re-emitted back by CO2 molecules quite easily, and the experiment has been done numerous times.

You take a spectrum analyser and point it at a dark cloudless sky.

It has to be dark, so you won't measure direct solar radiation (which would drown out the smaller signal from the hot gases in the sky). It should be cloudless, because some of the effects may be from vapour clouds which are even better at bouncing IR back. We're looking to see what a normal, fairly dry warm night atmosphere is doing, not the sun, not the clouds.

Now a 'black body' at a certain temperature emits photons at different wavelengths in a pretty continuous curve, called a Planck curve. There are plenty of pages about Planck curves, so I won't go into massive detail, just say that what a Plank curve describes is how the energy emitted by the 'black body' is spread across different wavelengths of photons emitted. It is generally higher at the low energy photons, and lower at the high-energy photons, and for a perfect black body is a smooth downward sloping curve at most temperatures.

The air in the atmosphere is not a black body, because it is made up of only a relatively small number of different molecules. So the air is only able to emit in certain 'bands' sometimes called 'windows'. These bands correspond to the emission/absorption properties of the molecules. So instead of a smooth Planck curve, you get one which has lots of 'drop-outs' in the parts of the curve where no molecule exists which can emit in those ranges.

So when you point your spectrum analyser at the sky and take some readings, you come up with a graph of DOWNWARD (because it's coming down out of the sky) LONGWAVE (because we're only looking at the longer wavelengths emitted by atmospheric gases) RADIATION (because, well, it's radiation and not convected heat). Or the DLR.

So the graph you end up with - of the DLR - shows you not only that radiation is coming down out of a clear sky that must be coming from the molecules in the air - it also shows you - due to the bands - which molecules emitted them.

So if you go back and look at the graph again - you can see the shape of the graph is a sort of smooth downward Planck curve, with drop outs. Wavelength is along the bottom, from left to right from longwave (low energy) photons to shorter wave (high energy) photons. And on the vertical scale, we have Radiance - which (to simplify) means 'energy per square metre' - or simply energy.

So you can see immediately from the graph that the H2O window is fairly wide - contributing to the DLR across almost the entire range. CO2 contributes at the left hand peak, and other gases as you go along. Apart from the Ozone mini-peak in the middle, the long flat section in the middle is called the "IR Window" or sometimes the "atmospheric window" - this is the part of the IR spectrum which pretty much gets through to space unhindered. There are no (or few) molecules able to absorb in this window). The reason we see it as flat is not because it's not being emitted from the ground (which IS a pretty good black-body because it has a varied atomic composition) but because none of get gets back-radiated by the air.

So even at first glace you can see how much effect CO2 has. If you consider the 'area under the graph' as a metric which demonstrates 'the sum of energy across the wavelengths coming back from molecules in the air' then you can print this graph on squared paper and count the number of squares under the line to get a feel for the total amount. If you then count squares under just the narrow CO2 section (say from wavenumbers 600 to 750) you have an idea of the contribution from CO2.

Put one over the other, you get a guesstimate for the contribution CO2 makes to the entire greenhouse effect. And it comes out to between 20% and 30% of the entire effect. It doesn't matter if the relative concentrations of CO2 are small, 'trace' or negligible. Even at these small levels it contributes a large percentage of the effect. This is why even a small rise in these concentrations can have a large effect.

Let's do another back-of-fag-packet calculation. The warming effect of the atmosphere raises it form the 255K that solar insolation would make it .. to about 285K. About 30K difference.

So if 25% of that effect is from CO2, then that means CO2 contributes 7.5K warming.

So if we, through uncontrolled emission of CO2, manage to raise CO2 levels by say 33% (say from a pre-industrial 300ppm to a business-as-usual 400ppm) that means it's not impossible we might get a proportionate rise of 33% x 7.5K = 2.5K.

Let's say I got my visual square counting wrong, and it's only 20% contribution from CO2. That means we might get a rise of (20% x 30K) x 33% = 2K.

Scary? Not really. This is the UNCONTENTIOUS part of climate science. Ask Lindzen.

It's all about the feedbacks, that's what stops this inexorable rise. That's where scientific scepticism lies. It's all about clouds, and the hydrological cycle.

Not this nonsense about the greenhouse effect.

There is nothing so far (apart from the various approximations and manhandling that experts would point out in my explanation) to contradict such a possibility. The fact that CO2 is 'trace' does not detract from it.