What's the question then, Mr D?

Mr D, the trouble you go to over the idea of consensus is amusing. You really do belong on the dork side at WUWT.

As a wild guess, I imagine there has never been an opinion poll to test whether people believe that trees are green. Or that ice floats. Or that things fall downward. Does that make these things untrue? It is blindingly obvious that if the rate of increase in CO2 concentrations is half the rate of anthropogenic emissions then the cause of the increases is anthropogenic (sorry Martin, it is). No opinion poll is needed.

"CO2 started increasing before man started increasing his emissions..."

I watched Salby again to see where that statement came from. His evidence seems to be that according to Law Dome ice cores, emissions were rising before the instrumental record began the 1957. But our emissions did not start in 1957; the industrial revolution was in the 18thC. The Law Dome record is interesting, showing an almost perfect hockey stick for CO2.

CO2 levels have been relatively stable for hundreds of thousands of years, as some of your fellows here will happily claim. Salby says differtly, but his account is not believable. He plots a curve that shows an exponential rise in the inaccuracy of ice core measurments and claims that 10k years ago the cores are out but a factor of two (in other words 100ppmv in the core was actually 200ppmv in the atmosphere) and 100k years ago they are out by a factor of fifteen (100ppmv was actually 1500ppmv (he says 1000)). He doesn't go any further back for obvious reasons. His graph is exponential remember so at 200k years, levels must be much more than 1000ppmv. And back to 300ka, 400ka etc - the levels must have been huge. Do you really believe that?

And then there is his cross correlation of observed CO2 rises to temperature over the instrumental period. He shows a graph with a peak at a 10 month lag - CO2 lagging temperature and suggests this is significant. But it seems to me that what he is correlating is the wiggles in the graphs, not the slope of the rising CO2. We know that CO2 peaks at the end of spring which is around 10 months after the previous mid-summer, so the correlation is clearly just between the annual northern hemisphere growth cycle and the summer/winter temperature cycle, nothing more. Big deal!

I'm not able to nail any other fallacies in his presentation as it is too complicated. He pulls equations out of the air and I have no idea of their relevance or correctness. (Neither do you you I would guess.) But if even I can spot simple things that seem wrong or insignificant, the chances are that there are more.

So I'd repeat the basic facts that few will reject (ie there's a consensus):

- the rise in atmospheric CO2 has an anthropogenic source

- CO2 is a greenhouse gas

- increasing concentrations of CO2 cause an energy imbalance resulting in energy accumulation.

Martin A,
Yes, that's fairly close to my take on it. It is not necessarily the case that levels were xyz amount higher or lower back in the mists of time, just that the peaks and troughs are smoothed out by mixing/diffusion. You wouldn't expect to see the extreme short-term excursions.

Of course, the same principle applies to many other measurements in the real world.

Well it is quite possible that I misunderstood :-) My comprehension skills seem to be failing me here, for example when you said:

"He's not saying the CO2 fluctuations get bigger as you go back. What he is saying is that you have to multiply the ice record figures by bigger and bigger scaling factors as you go back."

these two sentences seem contradictory. Like saying "he's not saying x, he's saying y", but to me, y is the same as x.

Of your description of a spike being attenuated by diffusion, without any knowledge of the diffusion properties of deep ice cores how can you or I say whether or not this is plausible? Is Salby an expert in the chemistry of ice cores? There are many very clever people who study cores as their day job, surely some qualified and competent people among them, and it seems strange that they would have overlooked this. Maybe Salby knows more about their subject than they do. That doesn't seem likely. Compare this apparent out-of-domain super-sense with his treatment of the correlation between temperature and CO2 over short periods (the 10 month lag) as something significant to his arguments. This seems laughable even to me and I think indicates that he is dabbling in areas of which he has no expertise - he is out of his depth and doesn't realise it.

If there really were such spikes in CO2 then you need a mechanism for producing those spikes. If you are saying it was temperature, then what caused the temperature to spike?

Missy,

"Of your description of a spike being attenuated by diffusion, without any knowledge of the diffusion properties of deep ice cores how can you or I say whether or not this is plausible?"

Re-phrasing and re-iterating what Martin A has said, diffusion is diffusion. It is not only plausible, but it is required by the 2nd Law of thermodynamics. The questions are "how much" and "how fast?".

For me, Salby's presentation was certainly lacking in how he arrived at the details of his ice core calculations, but I consider the basis of his assertion as sound. The peaks and troughs of historical data will always be smoothed, and more so the further back you go. Recent data must always be considered with this in mind. I think Marcott (and others) wilfully ignore this aspect.

Some years ago I also presumed that those who made a living in this field had addressed all these issues. These days I am less sure. You can call it physics, or you can call it chemistry. But calling it climate-science does not move it into a higher realm where physicists and chemists gain no admittance.

I've mentioned twice the apparent naivety in his treatment of the correlations in observed CO2/temp and you prefer to totally ignore this in favour of promoting his assumed surfeit of skill relative to his peers. Your faith in Salby is remarkable - but then he is saying what you want to hear.

Now I'm hand waving. Well aren't we all? We are not sufficiently qualified to have an opinion. If you wanted to wait until Salby publishes, then why start the thread?

Diffusion is diffusion? Well it is not without surprises. Consider how graphene membranes can be Helium-tight and yet allow water to pass through. Even if you cannot, I will admit that I don't know enough about diffusion in deep ice cores to comment usefully. Spikes might be attenuated by diffusion and they might not. If they are, then once again, what is your proposed cause for such spikes?

The Sun burped.

You lot still arguing with Missy? I'm going to need an extra decimal place to calculate your average IQs at this rate.

Martin,

Sorry, you miss my point. Missy is not here to be convinced by argument, she's not even here to read your replies to her unending questions. She's here to waste your time, and as a sideshow, to demonstrate how gullible deniers are in being led up the garden path. She's being fed questions and responses by someone very well informed on the consensus position - it wouldn't surprise me if somewhere there is a private blog where your and Dung's responses are being measured, recorded and laughed at by a group of people - perhaps even as another Lew-esque psychology experiment. Expect the paper "The Unending Gullibility of Deniers" soon.

You seem to think she wants us to prove how 'scientifically knowledgeable' we are. She doesn't. She want's to see how long she can spin out a pointless thread for, because there's more than one way to be stupid, and they have noticed we beat them on the science every time.

I don't even think Missy is a 'she' as such. I suspect the name was chosen carefully to elicit certain male responses from the denier demographic. Perhaps if this person was called GrumpyBloke or say BitBucket, that you probably would not be wasting so much time on it. This is perhaps a side experiment. Compare an contrast the length of threads when the nick is male or female.

She's not here to be convinced by your arguments, she's here to demonstrate how foolish deniers are. Please don't prove her correct.

Martin, it is not the cross correlation that is fallacious, but its use. He wants to show that CO2 rises _after_ temperature rises (that it follows the integral of temperature) and his correlation result purports to show just that. If he were just doing an interesting side-exercise in comparing annual plant growth and CO2 cycles, he would have surely have said so instead of giving the impression that the 10 month lag strengthens his theory. He uses that correlation plot more than once I think, which is odd for a graph showing that summer is warmer than winter and plants grow in the spring.

James, you are a cynic. I thought we were having a nice discussion, not an argument. However it would indeed be interesting research project to study how many conflicting ideas some of those here can hold at the same time. I have seen it written that this is a right-wing phenomenon, so it would be interesting to find whether left wing blogs have the same characteristics. The discussion here is not perhaps very useful, as you say, especially as, taken together, people demonstrate that they are happy to rely on arguments supplied by others with which they disagree if it helps the group as a whole score 'points'. Pretty point-less really.

I am not controlled by others as you think, but you are right that there are some colleagues with whom I have discussed our conversation. They actually think I am nutty talking to you. Come September I shall be too busy to play here so you'll be rid of me. You'll no doubt be happier just talking among yourselves.