Let's focus this time on the comments, since I had a letter published.
First, Greig, a regular contributor:
Philip Machanick in the past you have vehemently argued that it is CO2, and not the sun, which is the major driver of observed global warming. And now, year after year, global temperatures stubbornly refuse to climb in correlation with CO2, and so you revert to using the sun to explain. Like Dr Kevin Trenberth you are wedded to an opinion which you want the data to fit, and like him you saying “there should be even more warming . . . the data are surely wrong.”
Greig, CO2 drives the trend for the simple reason that there is no trend in natural factors, whereas atmospheric CO2 is increasing exponentially. The science says there's a logarithmic relationship between climate sensitivity and CO2 levels, implying we should over the long term see a linear increase in temperatures if the basic science is correct. The purpose of detailed models is to narrow the range of uncertainty, not to predict the basic effect. We are currently at a solar low, but the multi-decadal trend in solar insolation is flat. Same for ENSO. We had a big El Niño in 1998 and more recently a La Niña. The net effect of these things is zero, but pick a time when they are all pointing up or all pointing down, and you get a short-term high or low. Trenberth's comments were in a private email, a musing with colleagues, who pointed him to evidence that he was wrong. Much as I am loath to use stolen material, since it's out there and being misused, here is one of the responses by a colleague to Dr Trenberth:
I look at this in two ways. The first is to look at the difference between the observed and expected anthropogenic trend relative to the pdf for unforced variability. The second is to remove ENSO, volcanoes and TSI variations from the observed data.
Both methods show that what we are seeing is not unusual. The second method leaves a significant warming over the past decade.
Next, Ian 11:39am (you will have to page through the online comments to find all of these):
Philip Machanick Did the models predict that the global temperature increase would lessen over the last 10 years?. That these years are the hottest 10 since whenever really isn’t a valid argument despite those such as v who claim it is. Fact is that the increase over the decade has been less than predicted. Now why is that? [snip] And incidentally Professor Latif who is a climate scientist, has made and is still making comments that suggest the world is not about to turn into a heat ravaged dust bowl just yet
No, the models do not make predictions for as short a period as 10 years. But see above about removing known effects like ENSO. See also here how solar output does not correlate with temperature as it should if there were no interfering artificial effect, and another very clear illustration here of how temperature and solar output have diverged. Also, I illustrate that you can add a strong artificial upward trend to a temperature record that is essentially flat and still find a 10-year period with a strong downward trend.
You are wrong in your interpretation of Latif's comments, as I've indicated before on this site and in more detail elsewhere.
Philip (not me) 2:27pm:
Gosh all these people ignoring the hacked emails and documents showing what nasty little con artists the CRU are. In ignoring them they are behaving just like ahh… I don’t know maybe like holocaust deniers.
Or maybe they don't agree with the principle of stealing private communications? How about challenging the deniers to reveal all their emails for public scrutiny? That would make for interesting reading. Things colleagues say between each other are often unguarded, said without thought as to correctness or unintended consequences. Why should we all take exquisite care in every private conversation that we don't ever say anything we don't really mean, in case someone is eavesdropping? What kind of world would that be?
de Brere 01:27pm
Philip Machanick. Spot on, you do validate a theory by testing its predictions against observations. However, the prediction-observation link needs to be 100% accurate once other factors are taken into account. Otherwise the other unknown or unaccounted factors may themselves be the source of the observed variation, and not the theorised cause; in this case, GHGs. In that respect, all the tens, hundreds of billions invested in the “science” of AGW in the last two decades has spectacularly failed to come up with models that provide even moderately accurate prediction (or explanation) of observed climate change; far less of the individual weather events that go to make CC up.
De Brere, I've covered your misconceptions about how science works earlier. For your benefit I'll summarise again briefly here. Science in the real world is never 100% exact. Handling errors and uncertainties is a standard part of applied science. If you want exact answers, do pure mathematics. As for these astronomical numbers for the cost of climate research, what are your sources? I found a comparison of current US military and climate change-related funding and:
- excluding the recovery package, US military spending outranks climate spending 90:1
- even within climate spending, much more is spent on energy that on climate science
And finally, climate science is not about predicting tomorrow's weather. ENSO and the solar cycle are not fully understood, and have a bigger short-term impact than increasing CO2. However, if you keep increasing greenhouse gases long enough, you create a trend that breaks out of short-term variation. Where's your evidence that that is not happening? How do you explain that contrary to the strong downward pull of natural factors the last 10 years or so, the temperature trend is still slightly up?
Having dealt with comments about my letter and comments, I'll let Stephen Morgan 05:47pm have the last word:
Okay - so apparently these hacked emails are SO important that they change the case. So, can somebody tell me what they say. Only not just the ones that apparently give reasonable cause to doubt a few scientists, but every single one of these thousands of emails?
If you think the emails matter, then you will obviously review ALL of them, understand the context of ALL of them, be able to balance the views presented by ALL of them, and be able to come up with a reasonable theory that is supported by the contents of ALL of them.
To do otherwise is selective, prejudicial, and inevitably driven by a desire to support or discredit a specific cause rather than to seek any reasonable explaination.
It’s called denialism for a reason - it is the methodology of those who seek to deny rather than to discover, to obfuscate rather than to explain.
AGW IS widely accepted because it IS widely understood by those who support it. It is popular because it is far more reliable and consistent than any other option.
Is it proven - NO! Is it undeniable - NO! Just do as I asked - come up with something positive that offers an alternative, not just continued hackneyed attempts to sink a battleship with a pin-prick!
Well, quite.
19 comments:
"We had a big El Niño in 1998 and more recently a La Niña."
Incorrect, as any cursory glance at the actual data would show. In fact El Nino events in 2005 and 2009 are directly linked to observed warmer temperatures in those years.
And in answer to your recent letter in the Australian:
Philip Machanick Fri 08 Jan 10 (11:05am)
Greig, your claim that all recent variation has been shown to be explained by ENSO and PDO is wrong, if you are referring to the 2009 paper by McLean, De Freitas and Carter. This paper used an analysis method that deleted any aspect of the data that amounted to a linear trend. More on that here http://tamino.wordpress.com/2009/07/24/old-news/ and here http://deepclimate.org/2009/07/30/is-enso-responsible-for-recent-global-warming-no/
Amazing how quick the denial side is to cry “fraud” when a reputable scientist makes a mistake. What do you call something this flakey? Answer: if you are in denial, “sound science”.
As to your suggestion that warmth of the last few years is caused by these processes, look up “La Niña”. At least we have resiled from the nonsense that the sun is the sole driver of short-term variation.
---
Philip Machanick, as I have previously demonstrated to you, the Tamino analysis is in error because it fails to understand the scope of the Maclean et al study. Maclean himself responded to the Tamino analysis by saying: “Let's "duke it out" in the peer-reviewed literature, shall we? Expect a comment on your paper to appear soon in JGR. I can hardly wait to see how you'll respond there.”
And we haven’t seen anything in the peer-reviewed literature, have we? I wonder why?
Philip, the fact that you would post these URLs demonstrates to all the folly of trying to deny the conclusions of a peer reviewed scientific study, by posting links to a blog by an amateurish analysis by an unashamed conspiracy theorist which provides no references to peer-reviewed literature. In other words, you are guilty of committing the same sins that you accuse so-called denialists. And it demonstrates to all here, that it is you who is actually in denial of climate science.
If a paper is seriously flawed it may be hard to get a peer-reviewed response published. The flaw in this case is obvious; at best you could get a letter published pointing it out (in fact that is what Tamino predicts will happen). You don't even need first year calculus to know that subtracting differences removes a linear trend from any data. Your ad hominem attack on Tamino does you no credit. I don't agree with his tactic of not using his real name but he claims to be a published statistician, and I don't see the flaw in his argument. If you do, post it here.
Finally, the "duke it out" comment is a response by Tamino to McLean. Unless you saw this somewhere else, you have this backwards.
Sorry about delays in posting: to filter spam, I moderate all responses to articles more than 10 days old.
Greig, you are very quick to say "Incorrect". I didn't say there had been no El Niña since 1998. I should have said specifically that the La Niña in 2006 coincident with a relatively low point in the solar cycle did not pull temperatures far below record highs.
The point is not that ENSO has no effect on temperature but that it's an oscillation: highs and lows cancel out and do not constitute an ongoing trend. Over a period of a few years, they may obscure the trend. Of course if you use a neat trick like taking the first derivative of a time series to eliminate a trend, the oscillations become more prominent.
One more thing. I found a response to the McLean et al. paper that hasn't appeared in print yet as far as I can tell.
Philip,
I notice that the unpublished response to the Maclean paper is co-authored by Mann (of Hockey Stick infamy) and Trenberth (of UEA infamy). What a surprise! I wonder if it will ever be published. I doubt it, because it clearly has not understood the Maclean et al study.
The constant claiming that the Maclean et al paper is flawed because it doesn’t show trends is bordering on sheer stupidity. The paper is not a study of trends. It is a study about natural variability. The only reference to trends refers to the possibility that current trends are partially explained by changes in natural variability. Such a conclusion is obvious to any statistician. So the study is not flawed, it just doesn’t prove that AGW is not real. But (blow me down) as Maclean explains, it does not try to disprove AGW as so many appear to think, but rather it goes some way towards quantifying the degree of human influence on climate.
Maclean et al have drawn attention to the fact that natural variability is potentially a significant influence on global temperatures, far more than the IPCC cabal would want us to know. The faithful are now scrambling to put the fire out. But it’s too late now. The general public have discovered the fraud perpetrated of the climate change alarmists in the name of political ideology (in the guise of environmentalism).
Greig, McLean et al.. paper claims that they have shown there's no room for AGW by their analysis. Their analysis uses a technique that eliminates any linear trend in the data. The growth in CO_2 is exponential, hence the theory predicts a linear increase in the greenhouse effect. If you apply the differences method they used to a time series that contains various oscillations on top of which you've overlaid a linear trend, you get rid of the linear trend. If you then state that the factor causing the linear trend is not discernible in the data, what do you think you have achieved?
It is in any case absurd to say that climate modellers do not know about natural influences on climate. To claim that McLean et al. have shed new light on natural variability is odd. There are many papers out there that quantify ENSO for example, and it's well known that these effects are major drivers of short-term variation.
The whole point of understanding natural variability as the norm is to quantify variation outside that norm. Obviously you cannot do so if you don't have a handle on the scale of natural variability. Try using Google Scholar and you'll find ENSO and its effects on climate is well studied in the academic literature (of which a sufficient fraction is available to the public to get the big picture).
Note the following quote from the press release announcing the paper:
"The close relationship between ENSO and global temperature, as described in the paper, leaves little room for any warming driven by human carbon dioxide emissions. The available data indicate that future global temperatures will continue to change primarily in response to ENSO cycling, volcanic activity and solar changes.
It is disingenuous in view of this to say the paper is not about trends. If a theory predicts a trend and you claim that you have shown that the prediction of the theory is incorrect, you are talking about a trend.
All of this guff is a cover for the fact that they have used a data analysis technique that deletes any linear trend and hence the very effect that they claim does not show up in their analysis.
If you still don't get it, please don't be so vehement in accusing others of failure to understand. When you finally do get it you'll feel a right fool, and no one wants that.
Philip,
I will try once more to explain.
The reason why Maclean et al say they have shown there is no room for AGW, is that that they have shown the potential of natural mechanisms to account for most of the temperature variation over the last century. The paper shows that that ENSO via ocean circulation and heat exchange is the primary driver of global temperature. i.e. Hadley circulation, SST and Walker Circulation (ENSO) processes are significant factors in affecting net solar heating as well as the transfer of heat from Earth to space.
At no point does the paper discuss trends. It does not study trends. Therefore claiming it is flawed because it doesn’t account for trends is simply a strawman. It is not disingenuous, as you say, for the paper to claim that natural variation is implied in MGT, because it doesn’t seek to disprove that global temperatures are rising (i.e. that there is a trend). It seeks to demonstrate that natural variation may be a cause of the trend. It thereby disproves that CO2 is necessarily the cause of rising MGT.
Remember, correlation does not mean causation. The correlation between CO2 and global warming has been assumed by the IPCC and others to imply causation, by virtue of there being no alternative adequate explanation. The Maclean et al paper, along with the work of Roy Spencer and Richard Lindzen, has blown a hole in the assumption that there are no other mechanisms that might cause global warming.
Greig, look at figures 4 and 5 of the paper, which illustrate very clearly what the problem is. Fig. 4 plots temperature and SOI on the same axes, and even without analysis, it's clear that the temperature graph is of similar shape to the SOI graph, but the temperature graph is a little lower than the SOI graph on the left, and a little higher on the right – i.e., it slopes up. Fig 5 plots the derivatives, and the slope of the temperature graph is flattened out. So they have changed the nature of the data, not merely smoothed it to remove noise as they claim. If this was all, there would be no problem. It's just confirmation that if you eliminate the AGW signal, ENSO jumps out as the major effect. It's just doubtful that this is a big enough contribution to publish. The problem is in extending this to conclusions that some have made as in their press release that this eliminates the possibility of significant AGW. As you can see from the difference between Figs 4 and 5, their data manipulation has removed the AGW signal.
It's true that correlation on its own is not causation, but when you have a mechanism for causation and find a correlation that matches your expectation, it's confirming evidence.
On the other hand if you manipulate the data to force a correlation, you need to be sure that your manipulation is physically meaningful, and that you have not overfitted your analysis to the data. The approach McLean et al. used of plotting a variety of correlations and choosing the best one (Fig. 3) carries that risk.
Overall, not a great piece of work that probably would not have excited any interest had it not been trumpeted as another nail in the AGW coffin which it is not.
I would be really happy if someone could show definitively that the mainstream was wrong. I was pleased to see the claims that the Himalayan glaciers would be all but gone by 2035 were implausible. This is not about scoring points. I do science on a daily basis, and know that the best results come from finding mistakes.
I think it's much easier than the whole lot of words both of you spent.
McLean et al. paper is not wrong in the data and analisys but in the wording of their claims. Throughout the paper they say something like "consistent influence on mean global temperature" or "ENSO signal is correlated with climate variation, which in turn is reflected in mean global temperature".
All too generic making them able to easily rebut criticism that they were talking about temperature trends. They played with the words.
Their very last sentence reads "this study has shown that natural climate forcing associated with ENSO is a major cntributor to variability and perhaps recent trends in global temperature".
The first part is correct but is no news at all; the second part is "perhaps", but nothing in the paper shows why "perhaps" it should matter, it's not a paper on trends.
A sort of nasty game, a careful choice of the words; probably they got help from some public relation expert :)
One more thing. Among the stolen University of East Anglia emails, you can find the reviewers' comments and the decision of the editor to accept the rebuttal by Foster et al. So no doubt it will show up in JGR in due course.
Philip,
I agree with the comments of Anonymous above. The Maclean et al paper is not claiming trends, and the conclusions are not as ground-breaking as people think. It doesn't disprove AGW, doesn't claim to either. It merely quantifies the degree to which CO2 and MGT are linked relative to other factors, and thereby draws into question the IPCC's assumption that CO2 causes most of observed global warming.
The Foster et al rebuttal is nonsense, because it doesn't understand the Maclean et al paper, and is getting in a froth about nothing. The fact that a bunch of peer reviewers would make a similar mistake, and shamelessly cheer the rebuttal, and wave it through for publication, illustrates more about the failings of the peer review process than it does about the Maclean et al paper, or the climate change issue.
Greig, the paper contains one unsubstantiated claim in the conclusions and some of the data manipulations are a bit suspect. If that was all, no problem. I've read many papers with more serious errors than that, which may or may not be debunked in good time by follow-up publications and certainly don't make it to the media as a big issue. However this search reveals that the authors were representing the paper as overthrowing any possibility of AGW. It is this that has excited interest and the need to check the paper in detail and debunk it.
If you agree with "Anonymous", I can't see how you can't be offended by the wording of their press release (assuming dozens of people who have quoted it haven't garbled it).
Greig, I don't mind if you want the last word here because this has gone on a long time and I think we've covered all that needs to be said. My main point is that I would really like to see evidence that the mainstream is wrong, because we're screwed if they aren't: nothing is being done that will change enough in time. This paper is not that evidence, nor is anything else I've seen. Opposition to AGW science is mostly ideological as far as I can tell, predicated on a world view that government interventions in economies have to be negative. Unfortunately that world view doesn't constitute a scientific argument.
I'm looking for scientific argument: theory backed by observation that stacks up against rebuttal. Not happening. Let me know if you spot it.
Philip,
As I said, I believe (like Anonymous) that the Maclean etc al paper does not make any unsubstantiated claims, it is only that the claims are misinterpreted. It is possible that the authors intended this misinterpretation.
The “search” you posted demonstrates the way that YOU are misinterpreting the papers claims (ie you have fallen for their ploy). It is an accepted fact that “natural forces are the dominant influence on climate”, eg sun, orbital variation, ocean circulation, etc are all known to have significant influence on climate, and the paper indeed confirms and quantifies this fact, so what this search demonstrates is not earth shattering. And the authors were NOT, repeat, NOT “representing the paper as overthrowing any possibility of AGW”. They are only showing that natural variability has a significant quantifiable influence. That you think that by merely demonstrating that natural forces are part of observed global warming is somehow “overthrowing any possibility of AGW” only shows how rigidly wedded you are to the political dogma surrounding this issue.
You call for scientific evidence “that the mainstream is wrong”. And that “we’re screwed if they aren’t” And this illustrates the whole problem with the alarmist view, which cannot accept that AGW may be real, that humans may be responsible for some warming, and that natural forces may also be involved, and that this does not mean we face imminent disaster. The alarmist view cannot separate itself from the view that if AGW is real (regardless of quantification) that we must immediately stop it, or the world will end.
Sceptics such as Maclean et al, are not saying that humans have no influence on climate, but are merely showing that when you quantify the effects, the argument for immediate and urgent action to reduce emissions is replaced by a rational debate about economic growth and pragmatic responses to environmental pressures.
You say that “opposition to AGW science is mostly ideological”, and I would agree. The alarmist view fails to address “AGW science” such as that presented in the Maclean et al paper, which demonstrates that nature is a big part of this picture. This is “predicated on a world view that government interventions in economies” are required to resolve the world’s environmental ills. Indeed that world view doesn't constitute a scientific argument, and yet the IPCC has managed to fool a large section of the general public into believing there is a scientific argument underlining the political motives of the environmental movement. The same political motivations and environmentalist dogma that you are championing at the ballot box.
Finally, like you, I'm looking for a fully quantified scientific argument that actually demonstrates that greenhouse emissions herald doom. Let me know if you spot it.
And it demonstrates to all here, that it is you who is actually in denial of climate science.
It doesn't demonstrate that to those who are intellectually honest.
P.S.
"We had a big El Niño in 1998 and more recently a La Niña."
Incorrect
Since there was a big El Niño in 1998 and there and there has been a La Niña more recently than 1998, the statement is obviously not incorrect.
In fact El Nino events in 2005 and 2009 are directly linked to observed warmer temperatures in those years.
Non sequitur strawman.
I notice that the unpublished response to the Maclean paper is co-authored by Mann (of Hockey Stick infamy) and Trenberth (of UEA infamy). What a surprise!
Your ad hominem is no surprise.
It seeks to demonstrate that natural variation may be a cause of the trend.
Nice to see you admit that the paper was about trends.
The correlation between CO2 and global warming has been assumed by the IPCC and others to imply causation, by virtue of there being no alternative adequate explanation.
This is false and either grossly ignorant or grossly dishonest -- it is radiation physics that implies causation.
Marcel,
Regarding ENSO, you are ignoring the implication of the simplistic response: that we have been experiencing La Nina since 1998. This is clearly incorrect as I stated. It is relevant to point out that we have experienced both La Nina and El Nino states since 1998.
That Mann (of Hockey Stick infamy) and Trenberth (of UEA infamy) are a part of the review process is illustrative of the weakness of the peer review process. It defies belief that individuals whose scientific credibility is so highly questionable, are part of any scientific peer review process.
[i][Marcel] “Nice to see you admit that the paper was about trends.”[/i]
I make no such admission, as the authors state, the paper is not about trends. The paper is about quantifying the component of natural variability in observed global temperature changes. The only reference to trends refers to the possibility that current trends (which are acknowledged as showing some warming) are at least partially explained by changes in natural variability. Such a conclusion is obvious to any statistician.
[i][Marcel] “it is radiation physics that implies causation.”[/i]
Indeed, and I did not state otherwise. My point is: that it is a lack of alternative explanation to this theory that leads the IPCC to conclude that CO2changes are the major cause of observed warming. But the Maclean et al paper shows (and quantifies) that other factors are a significant contributor. Thus it draws into question the IPCC’s conclusion that CO2 changes are a MAJOR cause, and perhaps relegates CO2 as being a factor of lower import than previously assumed. This does not mean that AGW is to be dismissed, rather it draws into question that alarmist predictions of impending climate change catastrophe, and the calls for immediate action or we are all doomed. Such reactions are not justified when we are still measuring and debating on the degree of human influence on climate.
Greig, it's also obvious to any statistician that for them to talk about trends at all when they've eliminated any linear trend from the data is meaningless. And since the AGW temperature trend is linear, subtracting out a linear trend leaves you with short-term variation, which everyone knows is dominated by ENSO, so the paper is a tiny contribution, and using it to quantify the AGW signal in any way is ridiculous.
And why the attack on Mann and Trenberth? There's no evidence they were involved in reviewing this paper: they are co-authors on the rebuttal, which is not the same thing. They have every right to rebut it if they find it to be flawed. Your assertion that their "credibility is so highly questionable" is just your opinion. Mann in particular has been subject to various inquiries, none of which has turned up anything of substance. It is disgusting that people can be treated in this way, just because their scientific findings are an inconvenience. See for example Pen State's inquiry into the stolen emails. Can you imagine what it's like to have your credibility constantly questioned, to have every tiny error amplified, to have your emails dumped out for the whole world to see, and having hundreds of blogs around the world spewing hatred in your direction? Probably not, otherwise you wouldn't have joined the cacophony. At least I hope not.
If you do not recognise the massive propaganda attack on climate science for what it is, there's not much I can do for you. If your main method of argument is ad hominem you certainly are not going to convince me of anything.
I strongly recommend that anyone who thinks there's a conspiracy afoot reads John Mashey's extensive exposé. He reveals just how large the scale is of the war on climate science, and how a small number of individuals have been targeted as if making them crack is a valid way to establish an alternative theory.
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