IPCC changed viewpoint on the MWP in 2001 – did this have effect on scientific results?
Guest post by Frank Lansner Latest News (hidethedecline)
A brief check indicates a “warm MWP-consensus” before IPCC published the Mann hockey stick graph in 2001. But after 2001, results on MWP seems to approach the IPCC viewpoint.
In April 2009 I collected a series of results concerning Holocene, Historic and recent temperatures for an article on WattsUpWithThat.
Here I found approximately 54 datasets (almost 100% peer reviewed results) that I used for analyzing the claimed difference on MWP on the Northern vs. the Southern hemisphere. I also used the 54 datasets to see if the tree ring method has an impact on MWP results.
Another aspect of MWP results caught my interest:
fig. 1.
It is often debated how IPCC changed its viewpoint concerning the Medieval Warm Period in 2001.
– Was the pre-2001 MWP viewpoint simply “wrong” ?
– When IPCC launched their new viewpoint on MWP in 2001, was this new viewpoint in fact the consensus in 2001?
– Or did the IPCC actually claim to know better than the consensus in 2001?
– What is the consensus on the MWP today?
– And finally, did the results after IPCC change of viewpoint in 2001 have changed, how can this be explained?
Here are the 54 temperature datasets covering the MWP divided in two groups :
1) 1976-2000 vs 2) 2001-2009
fig. 2. (Geographical origin see)
First we see that both 1) and 2) shows the MWP was warmer than today. (This is partly due to my criteria for the 54 datasets: Max 15% tree ring data, due to possible problems with tree ring data and thus a need to see data not dominated by this one method. Quite a few of the excluded tree ring data are frequently used by the IPCC, yielding the well known hockey shapes from IPCC AR4, 2007.)
Second, we see a MWP for group 1) 1976-2000 more than twice as warm, compared to recent years, as the group 2) 2001-2009. A significant and surprising finding. The distance between 1) and the IPCC hockey sticks, with all the tree graphs of recent years, is even bigger.
One might argue that the data choice for my Watts article was not quantitative, fully exact, etc. But I simply cannot come up with any explanation for such a big change in the trend of results when just dividing by the year of publishing. Therefore I will assume that there is in fact a development in the results regarding the MWP after 2001.
Further, if you compare graph 1) 1976-2000 on fig. 2 with the original temperature graph IPCC 1990-2001 on fig.1., you will see a stunning match. This indicates that the consensus of a WARM middle age before year 2001 was likely to be a real consensus. If true:
How could the IPCC publish the hockey stick in 2001 and ignore the consensus at the time?
Several results came later that confirmed the IPCC’s 2001 Opinion: Hockey sticks, mainly tree lines. But how could the IPCC know what the future results on the MWP would be?
If the conclusions of “climate gate” are even remotely true, then this would explain that the IPCC controlled the future results.
2 issues with your short post.
1. If the Northern Hemisphere was so “warm”, why did it not affect the average global Temperature (was the southern hemisphere so cold?). Hat tip – Frank Lansner
2. If the discovery opinion is correct, why did the vikings farm permafrost up to the 14th century (according to Church Records, which are still accurate to this day)?
Well Frank Lansner deserves a big round of thanks to all who believe the CAGW hypothesis is a scam, thank you Frank. The evidence is clear that the IPCC cabal of climate ‘scientists’ fudged the numbers to match the prediction.
This needs maximum publicity to what’s left of the pro-CAGW crowd.
Juanslayton.
I was actually more interested in climatologist David Morrison’s science here, rather than Mark’s rehash.
But while on that note, to say it is “cooling” of late is a little bit misleading regardless of who says it, or to claim that a hellish heat wave has “come to and end.” Only in the sense that the hottest decade in human history has merely LEVELED OFF. That’s about it.
It does NOT mean AGW has come to a grinding, screeching halt. It means there’s a temporary reprieve, at most, to what promises to be a disaster decades from now if things are not changed.
As Morrison points out, there is a 15-20 year lag of CO2 belches to heating, so we’re not out of the woods on this by a long shot.
Phil Jourdan
1. I earlier did a Northern/Southern hemispheric analysis on the 54 datasets, it seems that the trends are rather stable geographically:
http://wattsupwiththat.files.wordpress.com/2009/04/lanser_holocene_figure61.png
A very little difference between NH and SH trend.
So those who believe that there should be BIG trend differences between SH and NH or the like, should first prove this.
Its well known that SH and NH reacts differently – to begin with – during global temperature change. But its quite another thing to claim LARGE differences between SH anf NH for centuries. For example, its take a lot of heat for a long time to grow trees 1000 km north of Angmasalik in Greenland as we see for the MWP, “Greenland, Medieval warm period”:
http://hidethedecline.eu/pages/g.php
So we have to se similar COLD evidence from the SH before anyone should believe in a colder MWP. Remember, even if SH was just as cold as the NH was Warm during MWP, then the average global temperature in MWP was like today for centuries, and still todays temperatures are not alarming.
So for todays temperatures to be alarmin we need evidense that the SH was VERY cold in the MWP. A SH MCP.
So dont accept cold MWP before we see solid proof for very cold MCP in the SH.
I fail to understand what a handful of trees in Northern Russia tell us about ~global~ climate. At best, they can trace climate changes in Northern Russia. WUWT posts complain about the drop in thermometres from 7000 to 1000 compromising the global temperature record; but Mann, et.al. expect us to accept that 40 Russian trees can provide an accurate ~global~ temperature record? The question isn’t just how could IPCC ignore scientific consensus: it should be “Why did any scientist believe that a handful of proxies could accurately portray historical ~global~ temperatures?”
Even with thousands of thermometres, there seems to have been a lot of data “infill” and adjustment going on. How much infill and adjustment is required to get a reasonably reliable global temperature record from a handful of bore hole, ocean sediment and tree ring readings? Until a study comes out that contains thousands of reliable proxies sampled from around the entire globe, I will remain sceptical of any so-called historical temperature record.
Zoon (18:52:57) :
I feel quite sorry for you.
Osborn.
I’ll be sure to forward that brilliant input to the real climatologists, like Dr. Morrison. I’m sure that’ll blow him out of his office.
Nice handy quips, boy. That’ll SHOW his tail up!
Thanks so much.
Ref – Pascvaks (11:45:27) :
“Three things to remember about the IPCC – AGW – Mann – Jones – and Fat Albert & Friends..
“Those with the Biggest Soap Box will live to fight another day,
and another,
and another,..”
__________________________
Amendment – unless scuttled and sunk and sent to the bottom of the Philippine Trench by an iddy-biddy old and long dead clam
http://wattsupwiththat.com/2010/03/10/paleo-clamatology/
Zoon (09:00:09) :
I was talking to you not “real climatologists”.
Whatever happened to the CO2 lags Temperature by 800 years, you believe what you want and I will believe what I want.
Anybody that quotes” “Only in the sense that the hottest decade in human history” on this thread, which discounts 1000s of years of written history and preferrs instead to believe massaged “Global Temperatures”, really needs help.
Don’t bother quoting Satellites at me, they weren’t here in the Medieval Warming period.
[snip]
Calling others “denialists” is not accepted here. ~dbs, mod.
..and as New Scientist has pointed out, we don’t need the input of satellites or even much of the data we have now to confirm what the human eye can readily see and track. The shifting of numerous animal migration patterns adjusting to warmer temperatures, the opening now the the legendary northwest passage, the dying off of a number of amphibian species sensitive to temperature, the appearance of cold-sensitive birds in regions never seen before or recorded by Native Americans, including hummingbirds now moving into Siberia. The budding of trees earlier than anything recorded all across the temperate zones. Winter is not even technically over and my yard is green and the flower bulbs have come up earlier than ever. (March is generally not safe planting time even in Atlanta, historically, but IS now.)
The list of changes that even the alleged “MWP” did not give us in North America would go on for 50 blackboards.
Wikipedia says it was published in 1961. I remember reading it when it came out in paperback in 1962.
R. Craigen (10:19:19) :
Just a thought: I suppose tree-ring proxies were selected because Mann et al understand that the best hockey sticks are still made of wood…?
Rather… because the best woodies are shaped like hockey sticks…
T-Bone
Nick Good (11:10:06) :
“This post needs some proof reading, there is some rather tortured English.”
Maybe change your mind-set to;
People in different nations strive to write in english, so we can all understand each other. Fantastic!!!
(How many languages do you understand?)
Dr. David Deming’s Hearing Statement to the US Senate Committee on Environment & Public Works sheds some light on part of the process by which the MWP was “disappeared”.
http://epw.senate.gov/hearing_statements.cfm?id=266543
Frank Lansner,
Keep on posting. Appreciated your decision to post on WUWT.
Thanks.
John
Zoon (10:15:04) :
Winter is not even technically over and my yard is green and the flower bulbs have come up earlier than ever. (March is generally not safe planting time even in Atlanta, historically, but IS now.)
I just took a little jaunt to Accuweather. com. According to their info, in the 47 days since 31 Jan, Atlanta has had a daily high that exceeded the historical average 9 times, 4 of which were +1deg. The highest positive departure was 11 degrees which occurred twice. There were negative departures of 11degrees or more ten times with a max of 22 degrees.
You seem to think this kind of weather is a sure sign of an impending apocalypse. It doesn’t strike me that way.
oops, I double counted one week which was repeated on 2 pages, should have been 40 days not 47
Frank Lansner (06:52:09) :
“So for todays temperatures to be alarmin we need evidense that the SH was VERY cold in the MWP. A SH MCP.
So dont accept cold MWP before we see solid proof for very cold MCP in the SH.”
Hmmm. Didnt think of that!
Good logic, me thinks.
John Whtman, thankyou so much.
For equally “provoking” stuff from my part see:
http://wattsupwiththat.com/2009/01/30/co2-temperatures-and-ice-ages/
http://wattsupwiththat.com/2008/12/17/the-co2-temperature-link/
http://wattsupwiththat.com/2009/04/11/making-holocene-spaghetti-sauce-by-proxy/
or our stories on the front of http://www.hidethedecline.eu/
or all the A – Z stories also on http://www.hidethedecline.eu/
Kwik: GOOD to hear that point come through – its rather effective in debates… 🙂
To counter skeptics by stating “the MWP only happened in Europe” is a standard “talking point,” and is a reply given to Alarmists on sites like “How To Respond To Skeptics.” People who use this rebuttal seldom have read any of the few papers which actually make this claim. They are just parrots.
Just for the fun of it, try to devise a weather pattern that would make it so warm in Europe, but not in other parts of the Northern Hemisphere. The jet stream would have to loop far to the north, and then loop back south, and never budge from that track.
Even this past winter’s “blocking pattern,” due to the negative AO, could only create a warm anomaly in Greenland. It couldn’t extend the warmth to Europe, which was very cold. And such a pattern tends to destroy itself after a period of several months. In order to create a “local MWP” the pattern would have to lock in for several hundred years.
In other words, such a pattern is likely impossible. Even if you tried to tweak a model by popping in things that don’t happen in nature, I doubt you could create such a bizarre imbalance, unless you temporarily moved the North Pole to the Bering Straits, and then moved it back.
“Also, the IPCC red herring that the MWP was not global: http://www.appinsys.com/GlobalWarming/MWP_Globality.htm
”
Well, if the clam proxies hold up to scrutiny (and it looks very promising!) then it should be easy enough to compare the oxygen isotopes for the nothern hemisphere to the southern hemisphere and verify whether they were similar or not during the Medival Warm Period and periods before/after.
If they are similar, then the whole “shifting heat” arguement should be effectively dead. If you see the south getting cooler as the north gets warmer, then apparently such an effect is in play somehow and you’d need to work out the whys.
juanslayton (21:08:06) :
Zoon:
“The attacks had become increasingly vile as the past decade, the hottest in human history, came to an end. ”
-Mark Boslough
I hope Mark’s physics is better than his history.
Remember, just to be sure:
Mark was saying the DECADE came to an end–Not the heat. And of course, the very vile and unprofessional nature of the attacks over the minutia of men doing their jobs at CRU, and the whole hoopla over “missing data” that myseriously can easily be found elsewhere, and other nefarious allegations of men on marionette strings, et al.
In all probability, the next decades will end up being hotter than the last.
Zoon (06:07:31):
“And of course, the very vile and unprofessional nature of the attacks over the minutia of men doing their jobs at CRU…”
Phil Jones was not removed from his job because he was being honest.
Simply put, the hockey stick is not, and has never been, the consensus view of paleoclimate studies. Everyone knew that at the time. It was sold as being ‘knew and improved’, but was actually found to be ‘knew and disproved’.
When the weakness of the hockey stick science was brought to light, the argument shifted to “paleoclimate really doesn’t matter, because our models (which could never dublicate the MWP) are correct anyway. There is no other way to explain the current warming.” Even people I respect, like Roger Pielke jr., could not understand why the hockey stick controversy was important:
1. If the MWP was as warm as today, than today’s warmth may not be the result of human influence. True, it didn’t really prove anything one way or another, but it did indicate that there was more to the equation than the IPCC was considering.
2. More importantly, the acceptance of the hockey stick, against the consensus, shows beyond a doubt that the IPCC is agenda driven! This was not an oversight on there part, as has been claimed about some of the other ‘errors’ that have been found. There is no way that one climate scientist could have missed this one, much less dozens or hundreds. The hockey stick was front page news and continued that way even after it was debunked, because, in the eyes of the public, it bolstered the AGW agenda more than any other single component of the AGW argument.
I was always amazed that smart, rational people could not understand these two points from the very beginning. Slowly, the obvious conclusions are beginning to sink in, but why is it taking so long?
The IPCC may have been ‘neutral’ for about a minute or two after its conception, but all evidence since then is that it is an agenda driven agency. To my knowledge, no error found in IPCC documents has ever been an underestimation of danger. All errors inflate the danger. They always have and always will, because that is the purpose of the IPCC, to scare the global population into giving up measures of their wealth and freedom, under the guise of good science.