More on the Marcott et al “hockey stick”. All of the ‘Marcott 9’ had altered dates.
![marcott-A-1000[1]](http://wattsupwiththat.files.wordpress.com/2013/03/marcott-a-10001.jpg?quality=83)
While it took me a while to get the time together to write an article about the Marcott paper, that does not mean I have not been looking at it and discussing it from nearly the day it was released. There has been volumes of discussion within The Right Climate Stuff group that I have been involved with. The ones that lean towards CO2 as something to be concerned about were initially rather excited about this paper, but that has taken a course correction as it has become clear how poor the science is in the Marcott paper.
Many skeptics are calling this the newest hockey stick and there is certainly some accuracy to that, but what I initially found interesting was the Holocene cooling that he shows. In one respect his paper is different because it shows the cooling that has been taking place for thousands of years. That also makes the stick at the end more extreme, but it is something most will not show.
For those who missed the details of the Marcott paper I will provide a brief summary. The paper was published on March 8th in the ultimate of peer-reviewed journals, Science Magazine. The paper was loudly broadcast by the media as further proof of global warming. The paper basically says that the most modern period of the Holocene (the current interglacial which the Marcott paper states as 11,300 years) has been warmer than ~75% of the Holocene. The paper states that this is especially significant as the Holocene has shown steady cooling for the past few thousand years, but that has now completely reversed. The conclusion is that mankind has drastically altered the natural climate of the Earth.
The paper itself is a composite of 73 different temperature proxies. These proxies were used to reconstruct the Earth’s climate over the past 11,300 years. The 73 proxies were not uniformly distributed around the world. The following is a summary of the spatial distribution.
Tropics: 33 proxies
NH Polar: 12 proxies
NH Mid: 20 proxies
NH Tropics: 16 proxies
SH Polar: 4 proxies
SH Mid: 9 proxies
SH Tropics: 12 proxies
NH Total: 48 proxies
SH Total: 25 proxies
The NH is over represented by 3x in the polar region and 2x in the mid-latitudes. This of course can be dealt with easily enough, but the real resolution in the NH is better than the SH. None of this is directly critical to the paper, but it is something worth noting.
Far more troublesome to the conclusion of the paper is the dating of the proxies. Other sites have some excellent write-ups on the re-dating in the paper itself and I will touch on it, but my more immediate concern is how recent most of the proxies are based on the published data of the proxies.
Here is the breakdown of the last date in the proxies he used.
1950+ 9 proxies (1960, 1970, 1991, 3x 1995, 1998, 1999, 2000)
1900-1950: 16 proxies
1800-1899: 11 proxies
1600-1799: 7 proxies
1000-1599: 14 proxies
< 1000: 15 proxies
This leaves one proxy (GeoB 3313-1) with the last known data of ~1750 AD. There are 3 data points for temp after that, but no dates associated.
Since the modern period by almost everyone is considered to be post 1950, only 9 of the 73 proxies contain any data that can be relevant to the global warming issue. Right away that concerned me, but when I looked at the data for those 9 proxies something very interesting became apparent.
I will be referring to those 9 proxies as the Marcott 9. They are perhaps the most interesting proxies that he used and those proxies disprove the conclusion of his paper. In order of the most modern data, the Marcott 9 are:
Lake 850, most recent data is from 2000.
Flarken Lake, most recent data is from 1999.
Lake Nujulla, most recent data is from 1998.
Tsuolbmajavri Lake, most recent data is from 1995.
Homestead Scarp, most recent data is from 1995
Mount Honey, most recent data is from 1995
Composite MD01-2421…, most recent data is from 1991
Moose Lake, most recent data is from 1970
Agassiz & Renland, most recent data is from 1960
What is most interesting about all of these proxies is that none of them show the warming result the paper ended up with. Not a single one.
Without further ado, here are charts for the Marcott 9.
These nine proxies are the only ones of the 73 that Marcott used that have data past 1950. The only one that shows any kind of warming is the last one which is the Agassiz-Renland ice core and the warm point was not the most recent, but the proxy from 1940. The last point which is 1960 shows as cooler than the data from 1940. The ice core certainly does indicate that the warming in the 1930-1940 period was impressive, but few claim that mankind caused that warming.
There is far more to discuss about this paper. I have an idea where I am going to go with my research, but others may beat me to it which will alter the path I take. Based on what information is being found by others, primarily by Steve McIntyre over at Climate Audit is that Marcott re-dated data that didn’t fit into the hockey-stick result.
This agrees with what I have found as well. All of the Marcott 9 had altered dates associated with the last date with the Moose Lake data changing the least at 20 years. Flarken and Tsuolbmajarvi Lake were moved back into the 1800’s and the MD01 Composite removed the last 3 data points. The end-point strategy for this paper was full of shenanigans. Since it is only the end-point data that matters to the conclusion of the paper, well, let the Marcott 9 speak for themselves.
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John Kehr is a Chemical Engineer by schooling and Research and Development Process Engineer by profession. He has more than a decade of experience at the cutting edge of technology for a large semiconductor company. That experience was critical for him while wading through the often contradictory information that exists about global warming. He was generally neutral about the subject of global warming until he met and married a wonderful woman who challenged him to make a choice.
There are few things more dangerous than challenging an engineer to make a choice like that on a scientific topic. While occasionally taking a break from research to breathe and go on getaways with his beautiful wife, he spent many months deeply involved in his research. When he finally reached his conclusion, the only logical thing was to put all that research into a book, The Inconvenient Skeptic
Related articles
- McIntyre finds the Marcott ‘trick’ – How long before Science has to retract Marcott et al? (wattsupwiththat.com)
- How Marcottian Upticks Arise (climateaudit.org)
- Hiding the Decline: MD01-2421 (climateaudit.org)
- The Marcott-Shakun Dating Service (climateaudit.org)
- Marcott’s hockey stick uptick mystery – it didn’t used to be there (wattsupwiththat.com)
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Of course the Marcott study doesn’t tell you about warming past 1950. It was a study of the Holocene period. It used very long term proxies which do not have fine dating resolution.
For warming of the last century plus we have an extensive thermometer record. No need to look to proxies.
Any sign of the Marcott FAQ yet?
This post strongly suggests the FAQs are breeding at a rate faster than the authors can respond to.
Another decline that must be hidden?
No wonder Mann Ipulate was touting this as more evidence of hockey stick global warming, it was simply made to measure.
It’s bad enough when somebody cries “Wolf!” and none appears, but instead, a herd of Ice-Age Mastodons proceeds to trample your world. Marcott should be labeled as an empty wolf-crier.
Marcott’s “perturbations” are the 2nd key to his final output. After the final data were prepared, the last step was to permutate each datum 1000 times, using the age-uncertainty of that datum as bounds. Thus a datum dated 1700AD with an age-uncertainty of 100 years would be permutated into the range 1600AD-1800AD — thus its temperature value is distributed into those years. However, for the final 1940AD bin, Marcott set its age-uncertainty to zero. Therefore all those data were permutated only within the 1940AD bin. The result is that the 1940AD bin did not share its temperature values with its neighbors, and so was not flattened as were all other bins. It is just a mathematical trick which Marcotte used to guarantee that the 1940AD bin would preserve the same value after the perturbations, that it had before.
I have made this point repeatedly on other forums, but it seems to be outside of peoples’ understanding. In my field we work with large data all the time, and this method of perturbing is a substitute for doing excruciating statistical analysis. It smooths nicely, but to assign a governing zero-uncertainty to the end point of the distribution is an absolute abuse of the method. And this is the last time that I am posting on this topic.
Is it fraud to alter the dates to obtain a different conclusion to that which would be obtained had the dates not been ordered? Can a legal prosecution arise from this? It might be interesting to get a FOIA email dump from these guys to see what was discussed.
I think Marcott and Mann had orthogonal approaches to the hockey stick development.
Marcott adjusted the ‘x’ axis.
Mann adjusted the ‘y’ axis.
Well somebody had to say it!
Two suggestions: plot all proxies with the same Y-scale: Lake 850 only has a range of 2.5 deg C.
Lake Nujella squeezes 6 deg into the same space.
Create another set that zooms into the most recent 2063 years (YBP 2000 to today) and again uses a common Y-axis scale (cm per degree) would also expose the “shenanigans” (no more polite word for it).
Frankly, this “Years Before Present” while scientifically defensible, is an obfuscation to camouflage his shenanigans. If Marcott had shown the hockey stick at a year labeled “1940” instead of YBP 10, he would have been laughed out of the room. Instead, using YBP he attempts to fly under the radar to deliver his payload to the IPCC.
While I find the analysis of this paper by Steve McIntyre, John Kerr and others enlightening and instructional, I can’t help but note an amusing similarity between such analyses and a crash investigation of a kamikaze flight.
“All of the Marcott 9 had altered dates associated with the last date”
What are the odds of that being accidental and getting past the authors?
OT, Delingpole’s best ever. (See the last 3 paragraphs).
http://blogs.telegraph.co.uk/news/jamesdelingpole/100208918/global-warming-if-only-wed-listened-to-the-experts-eh/
Changing the data like this is either sloppiness, or deliberate fraud. Either way, it’s GIGO.
“Since it is only the end-point data that matters to the conclusion of the paper”
The end point is irrelevant to the conclusions of the paper.
REPLY: OK then, write to the journal, tell them to retract the paper, have Marcott remove the end point spike that has all the idiot journos in a tizzy, then republish it. Simple. – Anthony
Why would anyone use proxies in favour of actual temperature measurements when available?
There are numerous, supposedly rigorously adjusted & homogenised, temperature series from thermometers since the 1950s – why not use them, provided it is explained that this has been done (rather than hide any decline)?
Thanks for the summary. I’d like to see the same 9 after the re-dating. Do they show the kind of spike that shows in the final report? I wager there’s more to it, i.e. they also did something when setting up the parameters for the Monte-Carlo runs, or they re-dated some of the others to add data to the modern era.
the link to the book The Inconvenient Skeptic is broken
REPLY: Fixed thanks, wordpress can’t handle a missing http: – Anthony
“All of the Marcott 9 had altered dates associated with the last date with the Moose Lake data changing the least at 20 years.”
Does anyone have a plausible reason to offer for why the Marcott paper might legitimately do such wholesale altering of dates on the most recent data? Or did they think they could fool the world?
Given the controversial nature of the paper, and that others like it (Mann) have had – um – a chequered history, while others (Gergis) have had to be retracted, how come good folks like Steve McIntyre and John Kehr still have to spend time with these forensic dissections rather than it being the job of thesis advisors, peer reviewers or magazine editors?
Kudos to Steve, John et al; megaFAIL for the latter lot.
John Trigge (in Oz) says:
March 26, 2013 at 5:19 pm
Why would anyone use proxies in favour of actual temperature measurements when available?
There are numerous, supposedly rigorously adjusted & homogenised, temperature series from thermometers since the 1950s – why not use them, provided it is explained that this has been done (rather than hide any decline)
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Because we don’t have thermometer readings from 11,000 years ago and you should not splice thermometer records on to proxy records.
Not one dating error in favor of a non- AGW scenario? I’m sure the SI has a detailed justification an methodology for those date changes, when will Science release that information.
NZ Willy says:
March 26, 2013 at 4:42 pm
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Thanks, I’ve played around with many different smoothing methods to replicate Marcott’s end point and smoothed Holocene lines and couldn’t even come close so gave up.
Your explanation is the only thing that makes sense now, so thanks a bunch.
“John Trigge (in Oz) says:
Why would anyone use proxies in favour of actual temperature measurements when available?
There are numerous, supposedly rigorously adjusted & homogenised, temperature series from thermometers since the 1950s – why not use them, provided it is explained that this has been done (rather than hide any decline)?”
The instrumental record should be shown alongside the proxy data. However this may show that the proxy data does not align with the instrumental record and therefore indicate that one or more of these records is incorrect.
Stephen Rasey says: March 26, 2013 at 4:45 pm
“Create another set that zooms into the most recent 2063 years (YBP 2000 to today) and again uses a common Y-axis scale (cm per degree)”
Clay Marley says: March 26, 2013 at 5:25 pm
“Thanks for the summary. I’d like to see the same 9 after the re-dating. Do they show the kind of spike that shows in the final report?”
You can see them with re-dating here. You can set up a blink test to show the dating effect. There’s an option for last 2000 years, with common Y-axis.
Louis says: March 26, 2013 at 5:35 pm
‘“All of the Marcott 9 had altered dates associated with the last date with the Moose Lake data changing the least at 20 years.”
Does anyone have a plausible reason to offer for why the Marcott paper might legitimately do such wholesale altering of dates on the most recent data?’
Yes. All dates are inferred, by authors or others, usually from carbon dating. Marcott et al used the most recent programs to do this, systematically. The program they used (eg Marine09) won’t date beyond about 1954, because of atomic tests.
I found this article simply written, not too long and very useful. I was wondering what the fuss was about, and now I can see clearly. Thank you