What happened to global warming then?

[bikepete]

The gist I'm getting is that the methodology/formula used by Mann would produce the 'hockey stick effect'(whatever that is) no matter what data it was applied to. This, as far as I can tell, seems to be acknowledged by everyone.

I'm not sure this is the case. The 'randomised data' referred to was indeed 'noise' but with characteristics which mimic real climate data... see e.g.

http://deepclimate.org/2010/11/16/replication-and-due-diligence-wegman-style/

Obviously the author knows which side of the debate he's on :-) but it's a pretty detailed critique of these claims. Read it all and the comments...

"Finally, I’ll return to the central claim of Wegman et al – that McIntyre and McKitrick had shown that Michael Mann’s “short-centred” principal component analysis would mine “hockey sticks”, even from low-order, low-correlation “red noise” proxies . But both the source code and the hard-wired “hockey stick” figures clearly confirm what physicist David Ritson pointed out more than four years ago, namely that McIntyre and McKitrick’s “compelling” result was in fact based on a highly questionable procedure that generated null proxies with very high auto-correlation and persistence."

In other words, the 'random noise' was in fact not random, but actually (deliberately?) generated in a fashion which resulted in a 'hockey stick' shape when analysed the way Mann analysed real data.

 

[Crackle]

Ahem! Dendrology? Google Briffa, Jones, Mann. Just pick the tree rings of choice.

It was the Antiques Roadshow!

 

[MacB]

I'm not sure this is the case. The 'randomised data' referred to was indeed 'noise' but with characteristics which mimic real climate data... see e.g.

http://deepclimate.org/2010/11/16/replication-and-due-diligence-wegman-style/

Obviously the author knows which side of the debate he's on :-) but it's a pretty detailed critique of these claims. Read it all and the comments...

"Finally, I’ll return to the central claim of Wegman et al – that McIntyre and McKitrick had shown that Michael Mann’s “short-centred” principal component analysis would mine “hockey sticks”, even from low-order, low-correlation “red noise” proxies . But both the source code and the hard-wired “hockey stick” figures clearly confirm what physicist David Ritson pointed out more than four years ago, namely that McIntyre and McKitrick’s “compelling” result was in fact based on a highly questionable procedure that generated null proxies with very high auto-correlation and persistence."

In other words, the 'random noise' was in fact not random, but actually (deliberately?) generated in a fashion which resulted in a 'hockey stick' shape when analysed the way Mann analysed real data.

Interesting I'll await authorative responses to this, I can say neither yea or nay...dress something up in high level maths and you could tell me anything

 

[jonesy]

MacB, mangaman, I think you've missed the key point of this debate, which is the accusation of lying and cheating. That is not the same as having a flawed methodology, and I'd hope you would both recognise the fundamental distinction. I fear you have both been bamboozled by arguments about statistics, and have failed to notice that whenever VamP has been pressed on the specific charge of lying he has not substantiated it, indeed articles he has cited in support have actually contradicted the claim of dishonesty. This isn't a point of pedantry, it really isn't approrpriate to accuse someone of lying without very good cause and I hope you would both place the bar rather higher in your own work.

 

[MacB]

MacB, mangaman, I think you've missed the key point of this debate, which is the accusation of lying and cheating. That is not the same as having a flawed methodology, and I'd hope you would both recognise the fundamental distinction. I fear you have both been bamboozled by arguments about statistics, and have failed to notice that whenever VamP has been pressed on the specific charge of lying he has not substantiated it, indeed articles he has cited in support have actually contradicted the claim of dishonesty. This isn't a point of pedantry, it really isn't approrpriate to accuse someone of lying without very good cause and I hope you would both place the bar rather higher in your own work.

Actually I think we both get that distinction very clearly and I did take the time to read up on a few of those articles. Failing to damn some one is not the same as proclaiming them totally innocent, and that seems to be the extent of the support.

Though science of this nature should be far more honest, and less corrupt, than economics and high finance, I can still see similarities in the structure of the debate. With the latter I know enough to be able to recognise when someone is a damned liar and a cheat, and there are plenty of them...regardless of what's provable in court or what the stock party/MSM line is.

So what I'm getting is VamP is claiming enough knowledge to be able to recognise a liar and cheat on the facts/maths/science. Whereas yourself, User482, and to a lesser extent FM, are following the party line. But you're failing to, or not able to, address the specific mathematical points raised.

 

[User482]

Got to say I'm scoring this one heavily to VamP right now.

Obviously I know bugger all about the subject and can't follow the maths anyway

The gist I'm getting is that the methodology/formula used by Mann would produce the 'hockey stick effect'(whatever that is) no matter what data it was applied to. This, as far as I can tell, seems to be acknowledged by everyone. Also acknowledged seems to be the idea that the conclusions weren't awry(broadly correct seems to be the vogue term) it was just the method.

So, did Mann, as VamP believes, realise that this flaw existed and chop/excise/jiggle to make it go away? Or was it a genuine error that doesn't amount to a heap of beans? Was he so target orientated that he subconciously took these steps or were they in mind all along?

It's a mystery but from a neutral viewpoint I'm seeing facts(or at least things proclaimed as fact) on one side countered by subjective rhetoric, and avoidance of addressing the facts, on the other.

Just my ever helpful 2p worth

Do you really think so? Let's look at the evidence:

1. Mann's data and statistical methodology gives a hockey stick, with confidence that the result is statistically significant at >95%.
2. Mann's data and McIntyre & McKitrick's statistical methodology gives a hockey stick, also statistically significant at >95%.
3. Around a dozen other reconstructions, using various data sets and methodologies give a hockey stick.
4. Mann's data, with 70% of it missing, using McIntyre & McKitrick's statistical methodology does not give a hockey stick (or a hockey stick with two blades).

So for VamP to be correct, you'd have to believe that Mann somehow came up with a statistical methodology that always gives what subsequently turned out to be the correct answer, no matter what data is used. What are the chances of a) Mann's methodology always giving the same graph shape regardless of data and b) the graph shape being the same as that given by a dozen other models? It simply isn't remotely realistic. It also ignores the publicly available information shown that Mann's model was tested using a Monte Carlo simulation (i.e. using random data).

I'm actually pretty surprised that VamP is making a claim that was refuted so long ago.

 

[dellzeqq]

well, much as I love all this jolly hockey sticks stuff, may i respectfully point out that our subeterranean reserves of water are being depleted? And, while that might be serious in Kent it's 'hit the global panic button' time above the Ogallala Aquifer.

If Brandane really wants to know what happened to global warming, he should look at the price of his veg. And reckon on paying more next year.

 

[Danny]

I'm actually pretty surprised that VamP is making a claim that was refuted so long ago.

And having taken a back seat on this thread up until now, I think it is still unclear where VamP is coming from.

He claims he is not a "denier" but adopts the classic denier tactic of challenging the validity of the hockey stick model - and by implication much of the science which underpins our understanding of global warming.

If he is really the expert he claims he could simply have explained to the OP that the overwhelming body of scientific evidence shows that global warming is taking place and remains the most serious threat facing the planet.

 

[Red Light]

well, much as I love all this jolly hockey sticks stuff, may i respectfully point out that our subeterranean reserves of water are being depleted? And, while that might be serious in Kent it's 'hit the global panic button' time above the Ogallala Aquifer.

If Brandane really wants to know what happened to global warming, he should look at the price of his veg. And reckon on paying more next year.

The problem with water in the UK as an expert on the topic told me is not that we are short of water but the water is in the wrong places. I suspect that the problem you are referring to is more to do with population growth, industry and agriculture pushing up demand and urbanisation and drainage preventing the water soaking in than global warming.

 

[Linford]

If he is really the expert he claims he could simply have explained to the OP that the overwhelming body of scientific evidence shows that global warming is taking place and remains the most serious threat facing the planet.

After taking the time to have a look at this in a bit more detail, I would say that global warming isn't the most serious threat facing the planet. It is only one of the problems being exagerated by the growth in the human population.

When you say 'threat to the planet', can you elaborate on this, as the way I see it, the planet will still be here long after its vast human population has dwindled!

 

[Archie_tect]

Water? ...just don't try nicking ours.

 

[jonesy]

Actually I think we both get that distinction very clearly and I did take the time to read up on a few of those articles. Failing to damn some one is not the same as proclaiming them totally innocent, and that seems to be the extent of the support.

Don't you think that if someone's reputation is being smeared on a public forum that evidence to support the claim has to be a bit stronger than that?

In support of his arguments VamP quotes a statement by North, in which he specifically states " I don't think there is anything dishonest about it or anything like that."

Who are you giving the benefit of the doubt to here?

Though science of this nature should be far more honest, and less corrupt, than economics and high finance, I can still see similarities in the structure of the debate. With the latter I know enough to be able to recognise when someone is a damned liar and a cheat, and there are plenty of them...regardless of what's provable in court or what the stock party/MSM line is.

Science isn't finance, so you should be rather more cautious about making assumptions from your personal experience. Proving dishonesty is s much harder thing than identifying flaws in the methodology.

So what I'm getting is VamP is claiming enough knowledge to be able to recognise a liar and cheat on the facts/maths/science. Whereas yourself, User482, and to a lesser extent FM, are following the party line. But you're failing to, or not able to, address the specific mathematical points raised.

But I've already made clear that I'm not an expert. I'm not arguing from authority, I'm pointing out inconsistencies in the accusation being made. So if you are looking for an argument from authority then my failure, as you see it, to address VamP's statistical questions should make no difference to your own interpretation of whether VamP's scientific arguments are valid. We don't know VamP's credentials, but we do know, as has been pointed out by several people in this discussion, that there is by no means a consensus amongst expert opinion that Mann's methodology is as flawed as VamP claims it to be. This is now a fairly old controversy, there has been plenty of time for experts across the world to review the evidence, form an opinion and publish their conclusions. And furthermore, despite repeated questioning, VamP has not provided any evidence that his views on Mann's alleged dishonesty are widely shared amongst expert opinion (as was implied by some of his first posts on this subject). Indeed, as pointed out above, some of those he cites specifically disagree with this charge. So are you really going to accept an accusation of 'cheating and lying' against a named person by an anonymous forum poster, when that person has not been able to cite any authoritative supporting opinion, and has admitted that this is actually his own interpretation of the situation?

 

[jonesy]

After taking the time to have a look at this in a bit more detail, I would say that global warming isn't the most serious threat facing the planet. It is only one of the problems being exagerated by the growth in the human population.

When you say 'threat to the planet', can you elaborate on this, as the way I see it, the planet will still be here long after its vast human population has dwindled!

I think it should be pretty clear by now that people use this expression to refer to those parts of the planet's environment on which we depend. Obviously the planet itself will survive, but no-one says otherwise. The risk of a massive deterioration in our planet's ability to feed our population and provide us with an acceptable quality of life is plenty to worry about, is it not? And yes, there are other environmental problems, but they tend to be more localised.

 

[lukesdad]

And having taken a back seat on this thread up until now, I think it is still unclear where VamP is coming from.

He claims he is not a "denier" but adopts the classic denier tactic of challenging the validity of the hockey stick model - and by implication much of the science which underpins our understanding of global warming.

If he is really the expert he claims he could simply have explained to the OP that the overwhelming body of scientific evidence shows that global warming is taking place and remains the most serious threat facing the planet.

" Back seat " my a*se, if you d had anything to offer to the debate, you would have thrown your weight behind your mates earlier than this !

 

[Archie_tect]

Danny,
VamP is not denying climate change... nor is he challenging the methodology... he's questioning some massve assumptions and manipulation of data.
....as should we all.

No-one has commented on the validation of the recording of the statistical data as yet, I have grave doubts aboyt the validity of the local temperature/ growth ring/ percentage analysis of the daily records and source material which are forming the inputs from which the the 'hockey stick' projections are being created.