Bishop Hill That 800 year lag
Mar 16, 2007 Climate: Surface One of the most striking claims of the Great Global Warming Swindle was that in the historic climate record, the temperature rise preceded the rise in CO2 by approximately 800 years. On the face of it, this is pretty good evidence that temperature is driving CO2 rises rather than the other way round, which is exactly what the heretics claimed in the programme. As far as I can see, its existence is largely undisputed (although I have been pointed to one dissenter).
The orthodox response to this is that CO2 is a feedback mechanism. Something causes CO2 to rise. Because CO2 is a greenhouse gas, it warms the earth, which raises CO2 levels, which warms the earth further and so on. My initial objection to this was that the cycle should feed back exponentially. Apparently the answer to this is that the supply of CO2 is l finite, so when it runs out the feedback loop is broken. But nobody actually knows what causes the rise in CO2 anyway, so we're in the dark as to the details.
From my perspective, this all looks somewhat dodgy. Both methods rely on an initial warming of the earth to produce CO2 (by a mechanism which isn't understood). The heretical case is that that's the end of the story. Warming produces CO2. (I assume they argue that any warming from the CO2 is small because, relative to water vapour, the contribution of CO2 to the greenhouse effect is small). The orthodox case, however, imposes a CO2 feedback on the initial process. This, however, requires another process to prevent the feedback spiralling out of control - one which is inextricably mixed up with whatever started the whole cycle off in the first place.
Which seems, I must say, a tad unconvincing. Certainly not something I'd like to rely on before I took drastic action. The orthodox case seems to fall foul of Occam's razor.
I must say, I feel certain there must be more to it than this, so if anyone can enlighten me, I'm always keen to hear. Why is the the heretical case not considered more plausible? What is the flaw in their case which requires imposition of a feedback loop?
As always, I should point out that I'm an interested amateur rather than a professional scientist, and there is a possibility I've got either camp's arguments (and probably both) completely wrong.
Reader Comments (10)
The 800 year lag tracks the warming and the cooling of the planet- which is almost entirely dependent on the sun. In fact, green house gases are dependent on the sun; to work they trap sunlight. Less sunlight, less of an effect. And the levels of CO2 are so small in the atmosphere, it doesn't have much of an effect anyway.
Then of course, there are clouds...
But you have watched GGWS, it just takes some time to get a feel for it.
Something is lagging T(earth)? But I thought the claim was that there was no such thing as T(earth) and it can go up or down depending on how you define it.
This is one example of why I am sceptical of the denier's claims to be "sceptics". Always, always, ignore the problems that their objections create for their own pet theories. Another example is the readiness to consider and even accept absolutely any theory of warming on the slimmest of evidence, EXCEPT that CO2 is a GHG.
Very much in the mode of the ID crew, who demand that Darwinists explain every step of how a molecule came to be, while they themselves cannot explain any step.
The burden of proof lies fair and square in the court of those who believe in AGW.
And besides, the whole point of science is to ask questions. Questions, questions, questions. AGW proponents should welcome them.
Another thing: I don't think anyone questions that CO2 is a GHG do they? It's just the sceptics think that it's weak and not very abundant.
"There is a big difference between climate scepticism and ID. Evolutionary theory is not being used to try to make massive changes to everyone's way of life, and to impose massive tax increases, subsidies to windfarms and so on. AGW is."
That is the moralistic fallacy. Even if the AGW theory means tax increases that doesn't mean it is wrong. But in fact whether AGW is true and what to do about it are two separate questions.
And in fact the use of the moralistic fallacy is *yet another* point in common with creationists, who have argued that Darwinism means eugenics and that Hitler believed in 'surivival of the fittest' and have you. Which, again, is both untrue and separate to the question of whether Darwinism is correct.
"The burden of proof lies fair and square in the court of those who believe in AGW. "
Certainly. And so far they are meeting it. Warming is occurring and so far the only theory capable of explaining it is AGW. It is also the best supported theory.
Those with alernative theories for warming also need to provide proof and it is noticeable that they don't. Not only that, but they also need to explain where the scientists who support AGW have gone wrong. So far their performance on that front has been abysmal and amounts to a crackpot worldwide conspiracy theory. Such extraordinary claims require extraordinary evidence.
The moralistic fallacy, from what I can see, was coined in response to calls to control the study of "dangerous knowledge". This is obviously something that the AGW proponents are guilty of rather than the sceptics! I made no claim that research into AGW shouldn't be made, only that the burden of proof was on its proponents.
AGW may well be the best supported theory, but of course this is the logical fallacy of the argumentum ad numeram. It's also a very long way from proof and, as we agree, the burden of proof is on the orthodox, not on the sceptics. You say that the sceptics need to provide alternatives. This is the fallacy of shifting the burden of proof. They don't.
So to return to the point of the post, with the burden of proof on the orthodox, there needs to be proof that the purported mechanisms do in fact exist, in order to explain the 800 year lag.
"AGW may well be the best supported theory, but of course this is the logical fallacy of the argumentum ad numeram."
No, I said nothing about numbers of scientists. I said it is better supported (by evidence).
"You say that the sceptics need to provide alternatives."
And so they do. The phenomenon (warming) is there to be explained. So far as I can see it is currently impossible to explain it without reference to AGW, which (along with the other climate variables) does explain it. Perhaps that may change with further understanding but right now this looks like the best theory.
The other problem for the 'sceptics' - and I guess for all of us or at least future generations - is that CO2 is a GHG and there is an unprecedented amount of it in the atmosphere right now. And so they would need to explain why that wouldn't result in warming and why adding yet more of it is safe.
"Proof" doesn't enter into it - science doesn't deal in 'proof' - and is yet another creationist cry I'm afraid.
I beg your pardon, I misunderstood you.
I was using "burden of proof" in the logical sense rather than trying to put any spurious scientific sense on it. I mean that the proponents have to be able to demonstrate their case with a high degree of confidence. (I can use that expression if you prefer, but it will make my replies rather long-winded). They need to have theoretically sound model which can be tested empirically against the climate record. It is not for the sceptics to make a case at all, if they don't want to. They are free to take pot-shots at the AGW case, and if any of their attacks are telling, then it will bring down the AGW theory in its current form. That's just science.
Coming back to the point of the post, the 800 year lag is a problem for their theory, and it prevents anyone having confidence in their model. Saying "you ain't got nothing better" doesn't change that.
Going back to your original question of why the feedback loop does not spiral out of control, it is possible that the additional amount of warming produced by warming-released CO2 is less than the original amount of warming, and that the subsequent release of CO2 produces a still smaller warming, and so on - a series of geometrically-regressive increases.
In other words, it's a bit like Zeno's paradox in the real world - Achilles quickly catches up with the tortoise. (Or testudoid kebabs, for the Pratchett fans.)
Is there anything we know of in Physics that would suggest why such a mechanism was possible? Presumably in a laboratory, more CO2 gives more absorbtion.
I was under the impression tha Creationists have a theory that explains every step. There being only one step. The fact that the theory is unprovable is irrelevant.