Friday
Jun012012
by 
Bishop Hill
Bishop Hill Joelle Gergis talks up her results
Jun 1, 2012 Climate: MWP Further to the last post, I came across this recent interview with Joelle Gergis, in which she discusses her recent paper. It's remarkable to see her making the same claims of hockey-stickdom that have caused so much of a furore over the last 15 years or so.
When you realise that the whole thing is based on a logical fallacy, it's hard not to become angry. [Update: but see caveats on the update to the earlier post.
Reader Comments (80)
I've thought for years there's science, poor science, junk science, climate science, and girlie science. Classic.
re: Hockey Stick
This is something of a tangent but I hope not OT, since it casts light on why the Team loves hockey sticks. It is a candid acknowledgement from one of the leading lights (Prof. Ray Pierrehumbert of U. of Chicago) of just how valuable a hockey stick graph is as an "educational tool" for the general public. This relates to the general question, why does the Team fight so hard for a hockey stick whenever possible? (this is a reply comment on Real Climate, March 1, 2005):
23 Raymond T. Pierrehumbert says:
1 Mar 2005 at 6:32 PM
It is true that, as evidence that global warming is underway in accord with basic physics,
the hockey stick is just one item of evidence among many, and not even the most important one. However, there is a legitimate reason for putting so much energy into defending it. The “hockey stick” is an excellent educational tool. Much of the evidence and theory is complex and hard to explain. We are short on scientifically respectable arguments that can be immediately grasped by the public. I know from my own use of Mann et al when it first came out that it was a very good aid to public education about the nature of the problem. This is what it means to be an “icon.” The downside of an icon is that if it turns out to be wrong, or vulnerable, then skeptics can just try to pull down your icon and imply that everything else comes down with it. The Kilimanjaro glacier is also an icon of sorts, and Crichton’s disinformation on tropical mountain glaciers has similarly started working its way into the press.
(Note in passing: Skeptics have their icon’s too. Remember the satellite data that was supposed to show there was no warming? Why is it that there was not as much press attention paid to how wrong skeptics were about this? It’s as if they’re coated with teflon; they look bad to us, but I don’t think they look as bad as they ought to to other folks.)
Not entirely O/T, but I've just been watching a couple of episodes of ghost hunting on Yesterday TV, and I can't help noticing the remarkable similarity between the bullsh** spouted by 'paranormal scientists' and 'climate scientists'.
"Skeptics have their icon’s too. Remember the satellite data that was supposed to show there was no warming? Why is it that there was not as much press attention paid to how wrong skeptics were about this? It’s as if they’re coated with teflon; they look bad to us, but I don’t think they look as bad as they ought to to other folks."
If skeptics don't get it right, they look foolish.
If alarmists don't get it right, it potentially costs us trillions.
The difference in impact is not trivial, and the standards of proof for the alarmists should be higher by several orders of magnitude.
@Salopian:
We are practically at "Climate Change with Girls Aloud".
From the abstract, it is possible to say current temperatures are likely to be the warmest for a thousand years.
However. the borderline nature of the result makes the study highly sensitive to which studies are included.
Although the paper also includes coral studies and an Antarctic ice core studies from Vostok. There are a few points to note.
1. The tree-ring proxies are all from either Tasmania or New Zealand.
2. It is the Coral Studies that enable the study to claim to be Australasian in character - with studies from Western Australia, Papua New Guinea and the Pacific Islands.
3. It is only the tree-rings proxy studies that enable the 1,000 year study, with 2 pre-1430. Though one is from Tasmania, and the other from New Zealand, both are from the same peer-reviewed paper. A coral study goes back to 1149.
4. The two ice core studies are from just one location – Vostok - and only goes back to 1774. This is a little odd, as the Vostok data goes back over 400,000 years. Data from the last 10,000 years shows higher temperatures than today on more than one occasion.
In other words, to claim current temperatures in Australasia are the warmest in a millennium is to rely on two studies by the same authors in a small corner of the region. It is simply not a robust result.
WOW, now Joelle Gergis has deleted her radical loon blog:
joellegergis.wordpress.com is no longer available.
The authors have deleted this blog.
Did anyone download all the content somewhere? There's always the Wayback archive, I suppose....
@Skiphil
I was just about to post the same - great minds and all that....
If the answer to searching questions and rigorous criticism is to delete, lie, ignore, delete again and hide - how can these people look at themselves in the mirror in the morning?
Skiphil’s quote from Pierrhumbert reminds me that, in the media reports on the hockeystick that I recall, it was the sharply upswinging blade which always caught the journalist’s attention, not the flat handle. It would be interesting to go back and look at interviews with scientists, to see if they pointed out that it was the flat temperatures in the past which were the findings; the vertical blade was simply function of the scale of the graph. Any scientist who failed to point this out would surely be guilty of lying by omission.
Yes, it's always most been about the shaft, and it's always the deletion, the deletion.
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http://www.australianclimatemadness.com/2012/06/australian-scientists-refuse-access-to-data/?utm_source=rss&utm_medium=rss&utm_campaign=australian-scientists-refuse-access-to-data
Check this link out
Jun 2, 2012 at 5:26 AM | Skiphil
Courtesy of JimBoMo who made the following post on Climate Audit.
JimBoMo
Posted Jun 2, 2012 at 1:41 AM | Permalink | Reply
Curious?
Then you may be interested to know that her blog site has been archived by the Internet Archive Wayback Machine:
http://web.archive.org/web/20110207232359/http://joellegergis.com/
Wow! Joelle Gergis blog is definitely dead. I had 24 hours to visit the blog to learn a thing or two or even to have a laugh.
This zebra is on the run. But where can she hide?
Last week's zebra courageously stood his ground and tried to defend himself, albeit feebly. He won the hearts if not the minds, but that's enough for him to graze in peace among the lions.
Another day in the Serengeti.
ManicBeancounter 'It is simply not a robust result.' that means nothing what matters is does it keep the grant money following in and does it help 'the cause '. In climate science quality of the actual research comes poorly behind other far more important 'considerations'
'Ol Man River objected to the description of the river in drought, and now wonders why the body of the zebra hasn't been eaten by crocodiles yet.
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Not sure that detrending doesn't just replace one problem with another.
Without detrending, it's clear you will select proxies that mimic the trend rise in the surface temperature aggregates. So, automatic hockey stick blade at the end, even if you filter out some of it with a verification period.
With detrending, you select proxies where the change from one year to the next mimics that in the temperature record. But then how do we know this means that the long-term trend in the proxies is right?
Example: With detrended data, you pick the proxies that go up or down from one year to the next in line with temperatures. But trees grow faster with increased carbon dioxide. So, whichever tree-ring series you select on the basis of detrended data, they will all tend to show a "warming" trend over recent decades as the CO2 level rises.
I don't know why she deleted her site she must know that she is only making it slightly harder to access. I.e. the casual observer can't reference it. Although she seems aware of the value of what knowledge is shared and how it can be used, I know this because she says so on her About Page (very revealing as to her prejudgment of the science BTW):
So she is motivated to share scientific knowledge for an overt socio-political reason i.e. to aid what she percieves as the action required. This makes clear that if she perceives some request for technical materials as holding back this action she would not have this same motivation. It is not unreasonable to ask does this loss of motivation actually extend to obstruction, even if only at the passive aggresive level?
I think this provides a nice little snapshot of why climate science is a pathological science. Even if you can point to a sound hypothesis or examples of sound practice, an independent person has to acknowledge that nevertheless the whole field has normalised this underlying attitude of moral superiority: implicit justification as to who is qualified to practice, and what is allowed for testing, and for what eventual social purpose the science is designed for.
So let's recap (in as Aussie accent)
1) we looked at a whole bunch of natural things that can conceivably be affected by temperature.
2) we ignored the fact that many other environmental variables also affect these things
3) by trawling through the data we found some that significantly correlated with "detrended" instrumental temperature
4) we junked the majority of the data that didn't show this "correlation".
5) We dismissed/ignored the possibility that this correlation could be spurious
6) On the basis of (3) and (5) We then made the assumption that the selected datasets would continue to show this correlation for the 850 years or so of preinstrumental temperatures.
7) Lo and behold we find a "hockey stick"
8) Paper pal-reviewed and straight into the headlines and AR5.
Puh-leeze!
From the end of her biography captured in the wayback archive
(the webcitation capture shows 24, thought it would have captured a more recent version)
When these people start to behave as if they believe in what they preach I just might start to believe them.
And before anyone says that it's the activist fanatics and not the scientists who are doing the preaching I would point out that the scientists' silence on the subject makes them fully complicit.
I think it's worse than that.
Since Climategate, and certainly in the case of this lady - it's gradually become apparent that many of the scientists are the activist fanatics.
nice exchange at the end of that video.
Reporter: "How well do the models predict the future...?"
Gergis: "My model looked at history..."
Classic misdirection.
The interview is revealing in another way. If I remember rightly the conclusion to the HSI book was that Hockey Sticks were not fundamental to Climate Science. Dr Gergis contradicts this around 1min 30s. Temperature reconstructions are compared with the climate model data, which has both natural forcings and GHGs. Put simply, if there is a pure hockey stick, then natural forcings will have very little influence. If the MWP is larger than today, then natural forcings will be dominant.
The whole premise of her research is based on the assumption that climate models are 100% correct and their inputs and corresponding interactions and influence on the climate system are also 100% correct. On this basis you can use climate models to test your theories and to even test other models!
This has to be the pinnacle of arrogance or ignorance (or both).
Jun 1, 2012 at 5:01 PM | James -- "I just find it hard to believe that a learned, intelligent, scientists would knowingly risk ditching their reputation and standing - on something that they knew to be flawed."
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Unless, of course, there's a pot of taxpayers largesse at the end of the rainbow ... however in this case the author is neither much "learned", "intelligent" not having "reputation" and "standing" outside her groupthink cadre. Australian academic institutions are up to their necks crawling up the derrier of the current illegitimate government to mine the CAGW gold.
I know we are meant to stick to the facts here, but Gergis' rude and arrogant response to Steve McIntyre deserves comment. When she has contributed, say, 25% of what McIntyre has to understanding climate studies - noting that, unlike her, he is not being paid for his work - she will still be a minnow.
What is it about rude and dismissive paid academics on the CAGW bandwagon vs polite and thoughtful skeptics like the Bish, McIntyre and Watts who do it because they think it is intrinsically worth doing? Why is lack of courtesy and respect from so-called professionals excused time and time again?
It is notable that the skeptical sites that won the Bloggies this year (Jo Nova, WUWT, Tallbloke, Climate Audit) all maintain high standards of courtesy and respect for their head posts, and have comment policies that discourage malice and mindless abuse.
My screening process rarely trusts an academic who starts a sentence with "So".
oops I just posted this on "Unthreaded" but realized I should have written it here since this thread is already up on Gergis et al (2012).
I think that Steve McIntyre just made some interesting observations that need investigation and follow-up by mathematically expert bloggers (which I am not). Or at least try to find ways to bring these questions/issues to the attention of scientists who might finally begin to examine some of the weaknesses of Mannian science. I can't judge the rights or wrongs of this approach from Mann/Jones to Gergis et al (2012) but it sure sounds dubious to me, or at least in need of a thorough justification:
[Steve McIntyre on Climate Audit on the thread "Myles Allen Calls for 'Name and Shame'"]:
I think that one of the main tricks in Gergis et al is one that was used in Jones et al 1998. It also looks like it affects Kinnard et al 2009. It’s a splicing issue.
Let’s say that you have one long proxy that has negligible long-term variation even from the LIA to the modern period. Now let’s suppose that you have some proxies that increase in the LIA-to-modern period.
Now do a “stepwise” procedure in Mann-Luterbacher style. The stepwiseness aspects of these algorithms has been very much understudied. because the long proxy has no long-term variability, you get a MWP of negligible ampliture attached to a LIA_to-modern transition with real amplitude.
The right answer is that because the proxies stretching back to the MWP do not replicate the amplitude of the LIA-to-modern transition, the error bars on the MWP recon are huge.
The calculation of confidence intervals in these Mann-style reconstructions has always been an area that is hard to understand. Not just us. It seems that Myles Allen also gave up trying to figure it out for Mann et al (from a Climategate letter.) My guess is that the Gergis confidence intervals are not calculated any more reasonably.
In fairness I don’t know what type of statistic they used to reconstruct temperatures but I suspect they probably used PCA which raises the question as to why they detrended the data?
If you do this properly, using a mulit-level spline with different levels of fit you should find that your “control” data becomes progressively stationary with each increase in level. But then PCA at this point becomes useless as you’re looking for principal components in variant-pairs with zero covariance. So the question remains why use detrending as the resulting statistical model will not return you a stationary series that you’ll need to add the trend back into - this gives much better confidence but only on the assumption that there was a statistically significant relationship to begin with, which you’ll need to prove by cross-correlation with the raw data. This is a common issue in statistics (particularly geostatistics) and one where you must be very careful.
The Gergis et al hockey stick has just been broken into tiny pieces at climate audit, by Jean S, Steve Mc, with, ironically, the coup de grace delivered by Nick Stokes.
It looks almost certain that despite the claim that proxies and instrumental target were de-trended, in order to avoid the 'bogus hockey-stick effect' (see comment here by Frank), in fact they weren't de-trended after all. When Jean and Steve tried to reproduce the significance results for the 27 selected proxies, as described in the paper, they couldn't. But when Nick did it without de-trending, it worked. So the proxy selection picks out those that rise in the 20th century, giving an 'automatic hockey stick' that works if you feed in random numbers.
Worse still, proxies were selected with positive or negative correlation. In other words, some were used 'upside-down'.