Guest post by Frank Lansner
IPCC – How not to compare temperatures – if you seek the truth.
There are numerous issues discussed intensely when it comes to IPCC-illustrations of historic temperatures, here for example the illustration from IPCC Third Assessment Report:
Fig 1. Taken from IPCC TAR
In short we have heard of problems with 1) the Mann material, 2) the Briffa material, 3) The cherry picking done by IPCC to predominantly choose data supporting colder Medieval Warm Period, 4) Problems joining proxy data with temperature data mostly obtained from cities or airports etc, 5) Cutting proxy data of when it doesn’t fit temperatures from cities, 6) Creating and Using programs that induces global warming to the data and finally 7) reusing for example Mann and Briffa data endlessly (Moberg, Rutherford, Kaufmann, AR4 etcetcetc).
But, as I believe another banal error needs more attention:
8) Wrong compare.
Imagine for a moment that none of the above mentioned problems 1) – 7) has any impact and then lets just focus on the comparing itself. The data of the proxies suffer from 2 impacts:
A) “Technical averaging” – Impact of many series of date summarized.
Check out what happens when summarizing many datasets of temperatures, an example, the cooling episode 8200 years ago:
Fig 2.
Data taken from: http://wattsupwiththat.com/2009/04/11/making-holocene-spaghetti-sauce-by-proxy/
The white graph with the red squares are the resulting average graph: More temperature sets added together tends to flatten the average. Notice for example how many datasets certainly has a down peak between 8000 and 9000 years ago, but the timing for these datasets are slightly off, and so the down peak is almost gone.
So, to some degree we can expect multi proxies to yield an averaged overall graph.
B) “Direct averaging” – on top of the technical averaging, the data series are often averaged further to some degree using 30, 40 and 50 years Gaussian filters.
The result of averaging by A) and B) is, that the variability of the IPCC graphs on a decadal ´timescale are limited to just tenths of a degree K. But in reality, if there where any real temperature peaks on decadal time scale in the Medieval period, we will would not see these much in the typical data series IPCC shows.
Is this a problem?
Well, it certainly becomes a problem if these “super averaged” data are compared with data that is NOT quite as “super averaged”. And this faulty compare is just what IPCC do.
IPCC “Super averaged” data from proxies, are typically compared to “Observed” temperatures, that is, recent temperatures not at all submitted to the same degree of averaging.
Technical averaging – type A) – is to some degree not happening for observed temperatures, so how about type B), the direct averaging, filtering?
Well, For the IPCC graphis shown in fig 1 above, the IPCC text says: “All series were smoothed with a 40-year Hamming-weights lowpass filter, with boundary constraints imposed by padding the series with its mean values during the first and last 25 years.”
Explanation: If your data ends in year 2000, then the last genuine 40-year averaged/filtered point on the graph would be a point for 1980 with average of 1960-2000 near +0,2K anomaly. But the IPCC graph for observed temperatures ends at +0,43 K around year 2000. This more resembles the normal five years average of GISS year 2000 data:
Fig 3. Giss temperatures illustrated in year 2001.
So for IPCC/Mann etc. to get a year 2000 temperature as high as +0,43K, they must have used just normal 5 yr avg. A longer average period would yield lower temperature for the last year.
So, when IPCC wrote “with boundary constraints imposed by padding the series with its mean values during the first and last 25 years.” – they mean: “We don’t use 40 year average/filter in the last 25 years…!”
So the bottom line is: IPCC compares “super averaged” temperatures of the medieval period with a peak in modern temperatures only submitted to 5 years average.
IPCC basically compares a peak in temperatures in recent years with super averaged medieval data where peaks are more suppressed to conclude how much it is warmer today than in the MWP.
This is a problem !
From this illustration it appears that the peak after 1998 to some degree appears related to the big El Nino 1998 peak, here from appinsys:
Fig 4.
So, where there no El Nino peaks in the medieval period that could have affected the compare with recent temperatures? Yes, there where: http://co2science.org/articles/V12/N5/C2.php
So we have every reason to believe that there where also temperature peaks in the medieval period – peaks that just might resemble the recent El Nino Peak.
So no excuse for the IPCC to compare a modern temperature peak with medieval average temperatures.
This is banal, of course, and even IPCC must have been aware of this, one should think.
Here: An illustration where the single year 2004 for observed temperature data explicitly is used in comparison with the super averaged medieval temperature data.
Fig 5. (from here)
Cheers!
Many thanks Frank for this very informative article. Also “mange tak” for the article on http://www.klimadebat.dk/frank-lansner-klimadebat-a-z-del-1-r141.php
A goldmine of information 🙂
Mikkel (22:51:19) :
This post is written in good quality Danglish, which should not be difficult for native English speakers to understand.
As native speaker of a world language, one must be able to decipher its use by non-native speakers.
I have seen far worse examples in reports and blog entries linked-to from WUWT.
/Mikkel
Well said Mikkel, even in England (not to mention the UK) there many variants of spoken English. If we can cope with that then a few mixed up Where, were, we’re and wear shouldn’t be too hard to cope with. Admonishing a non-native speaker is no way to teach them the nuances of a language.
[Reply: Agree, Sandy. Native English speakers should try to learn the difference between “effect” (verb) and “affect” (noun). Example: “The effect of precipitation affects the climate.” This is the mistake I fix most often. (Many times I don’t bother because it’s hard to keep up.) ~dbs, mod.]
So much of the debate centers about wavy lines on graphs and what I pick up from this is how much of it is based on trickery and idiocy. I think the point being made here is akin to taking a graph of winter and summer temperatures over say 40 years and doing a chart of the average between winter and summer. But then takking onto the end of the chart the highest temperature of last summer. Result: Instant hockey stick.
Many thanks for all your hard work. Very interesting.
I am no mathematician, but I could follow, and I could see typos and cope with them. I am very grateful that someone is putting precious time into disentangling this scam.
PS meant to add
Neither does bad grammar/spelling mean that the truth of the content is negated.
Getting away from graphs for a moment, I was reading a book recently and came across some real world scientific evidence for climate change:
Medieval Frontier Societies (1989)
Chapter 1: Frontier and Settlement: Which Influenced Which? England and Scotland 1100 – 1300 by Geoffrey Barrow:
“Archaeological research, and especially intensive aerial photography in recent years, has made it impossible to doubt that the climate was more favourable for cereal cultivation than it is today: we have abundant traces of regular ploughing on ground which no modern farmer would dream of turning over even under the stimulus of huge barley or oil-seed rape subsidies, and at heights above sea level at which it is very doubtful if any modern varieties would ripen. These archaeological findings are particularly interesting because they abundantly corroborate surviving documentary evidence which showed that many Border parishes now drastically depopulated possessed large acreages of arable which must have required a sizeable number of inhabitants to be cultivated and harvested.”
Warmer than today means of course warmer than c 1989 when the book was published. But this is an illustration of how warming after 1989 would have a fair way to go to equal the historical record. It also shows how warmer temperatures supported a larger population without the world being drowned in rising seas.
Perhaps Mr. Lansner could lend a hand with this project:-
http://www.timesonline.co.uk/tol/news/environment/article7039264.ece
The Met Office are going to “re-examine” their figures to “look at the data in much greater detail than previous attempts and provide more information about which regions are suffering extreme heat waves and the greatest average changes in climate. The Met Office said that this would allow international funding to be directed to where it was most needed.”
It’s going to cost millions and they have already stated the outcome.
O/T
Roger Pielke Snr has a scoop.
http://pielkeclimatesci.wordpress.com/2010/03/30/guest-post-by-hiroshi-l-tanaka-on-the-new-paper-data-analysis-of-recent-warming-pattern-in-the-arctic-by-ohashi-and-tanaka/
Pete Olson (21:33:46) :
Somebody needs to proofread this stuff before posting it. Legitimate points get lost in poor grammar, spelling, and use of language.
George Turner (21:45:29) :
Good point!
Small note: A few places after figure 4 the text said “where” instead of “were”.
“SpellCheck: The Model”…
In the first graph, what does it mean, when the smoothed average lines
go outside the grey area?
Reminds me of this:
How the ipcc invented a new calculus
It is amazing, in retrospect, that the ‘hockey stick’ graph could have been accepted by (allegedly) trained scientists.
The more proxy data you throw in, the flatter the ‘handle’ becomes (the LIA is an accepted fact by all).
Any part of the error bars (grey area) could represent an approximation of the temperature at that particular time (we’re talking about fractions of °C).
Then to graft on to the end the instrumental data (with all its pre-’79 uncertainty together with the more reliable post-satellite data tacked on for good measure), well…….words fail.
I’ve wondered why no one at the time questioned the first part of the ‘blade’ (pre-c.1940)– it could not possibly be due to human CO2 emissions:
http://photos.mongabay.com/09/0323co2emissions_global.jpg
A trivial point, perhaps, but irritating to someone who believes in precision in science:
Temperature is measured in Kelvin, not deg. Kelvin.
You are correct when you use 2K or similar. Please, don’t give people an excuse to ignore the key point being made.
[Reply: Agree, Sandy. Native English speakers should try to learn the difference between “effect” (verb) and “affect” (noun). Example: “The effect of precipitation affects the climate.” This is the mistake I fix most often. (Many times I don’t bother because it’s hard to keep up.) ~dbs, mod.]
Forget that. What irks me is the inability to differentiate between the effect they’re having on their affect!
(I know it makes no sense, but it was as good as I can get after a longer Easter w/e 😉
Sheesh!
“longer” w/e than what?
me <= idiot
You tell us how the Holocene average is calculated.
You tell us how the modern average is calculated.
You don’t tell us how the MWP average is calculated.
You can’t just assume that the method used for the MWP is the same as that used for the Holocene, you have to prove it. Without this step, your conclusion is unproven.
Wikipedia entry for Maurice Strong. Hello. There was a photograph of Mr.Strong in his entry which was later removed.I wonder if there is some way I can find this picture? Is each Wikipedia editing instance noted or recorded somewhere?
Re; John Peter (00:59:23)
Booker has presented a slanted article: the costs are shown in an assesment report which you can download here http://www.decc.gov.uk/en/content/cms/legislation/cc_act_08/cc_act_08.aspx and range from £14.7 to 18.3 billion/year but our infamous correspondent neglects to mention the benefits which range from £20.7 – 46.2 billion/year.
Christopher Hanley (03:12:18) :
“It is amazing, in retrospect, that the ‘hockey stick’ graph could have been accepted by (allegedly) trained scientists.”
I dont think it is amazing at all. It is done on purpose, Christopher. Remember the IPCC objective paragraph?
Thank you Frank for this interesting post.
Never mind how carefully one tries to callibrate, the use of different proxies means not only bigger or smaller timing problems, but also different reaction patterns for the proxi on temperature. For example a pollen proxy reflects a response from the entire flora of an area whereas tree rings reflects changes of individual trees. The latter wont show if the same area as a response to heat produces more trees etc. Different tree sorts reacts differently from each other. Ice cores has a very smoothed temperature profile generally etc.etc.etc.
I DO believe that the sum of a large number of different types of proxies are valuable, but perhaps mostly valuable as a mean-temperature-indicator for a period. INot the best conditions to show an El Nino peak.
Perhaps variability should be estimated from individual proxies, whereas mean values from a greater number of proxies?
By the way, the use of 5 year evg. (or similar) of recent temperature data compared with 30-50 year gaussian foltered data is obviously a problem even though one thinks im not correct about the impacts of summing more types of proxy data.
The error of this wrong compare is so obvious that it puzzles me that some comments seems to ignore this?
PS: THANKYOU ALL for comments! Its higly appreciated!
K.R. Frank Lansner
Frank, this was a great post again!
People are easily fooled by the IPCC’s shiny brochures. You’re doing a great job pointing this out.
The important part is this:
“So, when IPCC wrote “with boundary constraints imposed by padding the series with its mean values during the first and last 25 years.” – they mean: “We don’t use 40 year average/filter in the last 25 years…!”
”
This is a deception ON PAR WITH THE ORIGINAL HOCKEY STICK !
I have never seen a Hamming filter used like this. You pad your data with averages, extrapolated values, whatever, the best thing is, stop the filter run BEFORE the shoulder of the Hamming filter runs out of data.
But that would mean that the shiny brochure’s horror scenario ends at 1980 – not nearly frightening enough. Reminds me of Mann’s padding with a mirrored image of the end of the data series (mirrored in x and y direction!).
Mannian Padding – see here :
http://climateaudit.org/2009/07/03/the-secret-of-the-rahmstorf-non-linear-trend/
These guys are either clueless or criminals.
“Agust H. Bjarnason (02:03:58) :
Many thanks Frank for this very informative article. Also “mange tak” for the article on http://www.klimadebat.dk/frank-lansner-klimadebat-a-z-del-1-r141.php
A goldmine of information 🙂
”
Im greatful and its nice to hear that the A-Z is being used ! Its a wide info source in easy understandable language.
The A-Z has been translated to English (or Danglish) and more articles has been added and can be found using the A-Z letters in the menu line of http://www.hidethedecline.eu
K.R. Frank Lansner
Stephen Brown (02:36:40) :
Oh, you mean the Money Laundering part of Cap ‘n’ Trade. The most $$$ will go to those places where they are ‘hep’ on taking a healthy fee in exchange for circulating the funds back into the awaiting war chests. Actual investments for the specified purpose of funds will consist of a token facade.
The crazed drooling over piles of money to rake in was evident at Copenhagen.
Re Turboblocke
From the report you reference
It would seem that the costs are actual and the benefits are largely hypothetical and based upon the Stern Review as stated in Annex H
“Turboblocke (03:43:15) :
Re; John Peter (00:59:23)
Booker has presented a slanted article: the costs are shown in an assesment report which you can download here http://www.decc.gov.uk/en/content/cms/legislation/cc_act_08/cc_act_08.aspx and range from £14.7 to 18.3 billion/year but our infamous correspondent neglects to mention the benefits which range from £20.7 – 46.2 billion/year.”
==============================================
The benefits look like fantasy. And they are all predicated on Dangerous Climate Change as can be seen from page 3 of the report which says.
“What are the policy objectives and the intended effects?
1. To avoid dangerous climate change in an economically sound way. In particular by:
Demonstrating the UK’s leadership in tackling climate change – to increase the chances of a binding international emissions reduction agreement that would stabilize concentrations of greenhouse gases at a level that would avoid dangerous climate change;
Establishing an economically credible emissions reduction pathway to 2050; and
Providing greater clarity and predictability for UK industry to plan effectively for, and invest in, a low-carbon economy.
2. To put in place a framework that commits the Government to assess and address climatic impacts so that the UK is better able to respond to the unavoidable impacts of climate change.”
Well nothing dangerous has happened yet and nothing has convinced me that “do nothing” will lead to anything dangerous. So looks like fantasy benefits.