From Jo Nova a look at how the MWP looks when other data is used, not just a few trees in Yamal.
These maps and graphs make it clear just how brazen the fraud of the Hockey Stick is.
Click to enlarge
It’s clear that the world was warmer during medieval times. Marked on the map are study after study (all peer-reviewed) from all around the world with results of temperatures from the medieval time compared to today. These use ice cores, stalagmites, sediments, and isotopes. They agree with 6,144 boreholes around the world which found that temperatures were about 0.5°C warmer world wide.
What follows is a sordid tale of a graph that overthrew decades of work, conveniently fitted the climate models, and was lauded triumphantly in glossy publication after publication. But then it was crushed when an unpaid analyst stripped it bare. It had been published in the highest most prestigious journal, Nature, but no one had checked it before or after it was spread far and wide. Not Nature, not the IPCC, not any other climate researcher.
In 1995 everyone agreed the world was warmer in medieval times, but CO2 was low then and that didn’t fit with climate models. In 1998, suddenly Michael Mann ignored the other studies and produced a graph that scared the world — tree rings show the “1990’s was the hottest decade for a thousand years”. Now temperatures exactly “fit” the rise in carbon! The IPCC used the graph all over their 2001 report. Government departments copied it. The media told everyone.
But Steven McIntyre was suspicious. He wanted to verify it, yet Mann repeatedly refused to provide his data or methods — normally a basic requirement of any scientific paper. It took legal action to get the information that should have been freely available. Within days McIntyre showed that the statistics were so flawed that you could feed in random data, and still make the same hockey stick shape nine times out of ten. Mann had left out some tree rings he said he’d included. If someone did a graph like this in a stock prospectus, they would be jailed.
Astonishingly, Nature refused to publish the correction. It was published elsewhere, and backed up by the Wegman Report, an independent committee of statistical experts.
In 2009 McIntyre did it again with Briffa’s Hockey Stick. After asking and waiting three years for the data, it took just three days to expose it too as baseless. For nine years Briffa had concealed that he only had 12 trees in the sample from 1990 onwards, and that one freakish tree virtually transformed the graph. When McIntyre graphed another 34 trees from the same region of Russia, there was no Hockey Stick.
The sharp upward swing of the graph was due to one single tree in Yamal.
Skeptical scientists have literally hundreds of samples. Unskeptical scientists have one tree in Yamal, and a few flawed bristlecones…
…
Climate models don’t know why it was warmer 800 years ago.
The models are wrong.
The so-called “expert review” is meaningless. The IPCC say 2,500 experts review their reports, but those same “experts” made the baseless Hockey Stick graph their logo in 2001.
Craig Loehle used 18 other proxies. Temperatures were higher 1000 years ago, & cooler 300 years ago. We started warming long before cars and powerstations were invented. There’s little correlation with CO2 levels.
Sources: Loehle 2007, Haung and Pollack 1997, See co2science.org for all the other peer reviewed studies to go with every orange dot on the map. McIntyre & McKitrick 2003 and 2005, and update, Mann et al 1998, Briffa 2006, read McIntyre at climateaudit.com, see “ClimateGate”, and Monckton “What Hockey Stick” (Science and Public Policy Institute paper)
This is Page 8 & 9 The Skeptics Handbook II. 20 page PDF
I know a similar graph went up a couple of days ago around the web. The skeptics Handbook II was published on Friday Nov 20.
ACKNOWLEDGEMENTS: Thanks to Craig Idso of CO2science.org for his fabulous collation of research and his Medieval Warming Project which is an excellent resource, try the animated map! A big thank you to John N for his work in helping to create the map.
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pwn3d
Seriously…it is beyond ridiculous how bad the science has been in this field the last two decades. 🙁
Bet you won’t find this debated at Copenhagen or reported on the BBC or Sky.
Is that because the science is proven and we only have, er, twenty or is it ten days to save the world?
CARBON TAX IS THEFT – PLAIN AND SIMPLE.
http://www.facebook.com/group.php?gid=181254384531#/group.php?gid=181254384531&v=wall
I don’t believe in AGW, but I have a question about the graph “The real shape of the last 2000 years”. That drawing shows that during the Medieval Warm Period the mean global temperature was only about 0.5 °C warmer than now, and the Little Ice Age only 0.5 °C cooler than now.
Can half a degree centigrade have such an influence on the climate? You can hardly feel such a very slight temperature difference!
A great short summary that is something that canbe given to those currently bemused by the conflict between the science and Goreism. Thank you.
Well that’s thrown a falx in the works…..
I understand from reading your blogs some months ago that other researchers were trying to piece together reports from the UK navy over a few centuries to determine the extent of ice around the world, particularly at the entry to the NW passage.
Has that been completed yet as its answers might prove most informative at this epochal time…..?
Now the “tone” on CNBC has completely changed, skeptics are coming out of the woodwork! ClimateChange is now referred to as a “theory”. I wonder if this has anything to do with the fact that NBC/MSNBC/CNBC is no longer owned by GE?
I have waited for this article for two years. I have in parallel studied WUWT and Co2 Science, and what they have refered has been the ultimate argument against Mann-made anihilation of the Medieval Warm Period. Well good that this finally reaches the 100.000 readers of WUWT today.
I have in vain recommended journalists of the Mainstream Media in Sweden to interview the scientific foot soldiers, doing this type of research in Scandinavia. No interest. I have also contacted some of the foot soldiers and asked why they do not speak up. Their answers made me think of McIntyres phrase “the silence of the lambs”.
Gösta Oscarsson
Stockholm
link to map wont work – –
Switzerland is a very small country with a surprising number of daily newspapers, but not one good one amongst them. The voters have decided – in another matter – to completely disregard them. They “inform” about the MWP like this:
There were settlements in Greenland. The arctic sea was almost ice-free. Farmer plant in places higher up. THERE ARE NO INDICATIONS that is was warmer than today.
An excellent summary of the Hockey stick fraud versus the MWP truth. I have a feeling that if the mercury thermometer had been invented in the year 1000AD instead of 1714 ( and in the depths of the LIA to compound the issue) we would not have the current climate panic.
Rhys Jaggar (04:30:02),
This might be what you’re looking for: click
Is there another multiproxy global reconstruction except Loehle 2007, not made by Team?
Besides his fantastic work on the MWP, I also want to thank Craig Idso for his fantastic compilation of peer-reviewed studies at his website that I used as part of my research,
450 Peer-Reviewed Papers Supporting Skepticism of “Man-Made” Global Warming
His epic 868 page report refuting global warming hysteria is available for free online,
Climate Change Reconsidered (PDF) (NIPCC)
Check it out!
A poster (Charlie) over on eureferendum just posted this:
“Gorgeous busty Maundy Minimum has bust out with news of her three[check data]-in-a-bed romp with top Climate Professor Jones. Maundy, 34-28-36 [originally 32-30-42], said: ‘Well, when he asked me to massage his figures, who was I to argue? I called on my friend Climey Gate [36-24-36 – check figues with MM], and she said she’d be happy to help.’ Prof Jones, said the girls, needed help with his ‘hockey stick’ – although Maudy claimed that all that was needed was a good puck. ‘We sure put the upcurve in his stick!’ giggled the voluptuous Maundy. ‘Although, come to think of it, things did grind to a premature halt. Last we saw of the foxy prof was as he ran from the hotel room, hiding his figure in a towel, mumbling about losing his hard drive and “hiding the decline”……’
;D
The only climate catastrophe is in the minds of those in government that want to increase taxes to increase their importance. So far the MSM has not even twitched on this hoax that dwarfs Madoff’s efforts.
Really enlightening. All these graphs are for saving!
I Found This reference to wattsupwiththat in the hacked emails
(memo to tom wrigley) see 1254751382.txt
Tom:
Briffa has already made a preliminary response and he failed to explain his selection procedure. Further, he refused to give up the data for several years, and was forced to do so only when he submitted to a journal that demanded data archiving and actually enforced the practice.
More significantly, Briffa’s analysis is irrelevant. Dendrochonology is a bankrupt
approach. They admit that they cannot distiguish causal elements contributing to tree
ring size. Further, they rely on recent temperature data by which to select recent tree
data (excluding other data) and then turn around and claim that the tree ring data
explains the recent temperature data. If you can give a principled and reasoned defense of Briffa (see the discussion on Watt’s website) then go for it. I’d be fascinated, as would a rather large number of others.
” Jean Meeus (04:26:21) :
I don’t believe in AGW, but I have a question about the graph “The real shape of the last 2000 years”. That drawing shows that during the Medieval Warm Period the mean global temperature was only about 0.5 °C warmer than now, and the Little Ice Age only 0.5 °C cooler than now.
Can half a degree centigrade have such an influence on the climate? You can hardly feel such a very slight temperature difference!
”
The reason is that the 0.5C is a smoothed average and over time this can impact glacier formation and sea level etc.
Please change Link to map to :
http://joannenova.com.au/globalwarming/skeptics-handbook-ii/ppt/mwp-global-studies-map-i-ppt.gif
Thanks
At some point in the future, hopefully, we may all sit around and laugh about the dead moose (or some other slow release fertilizer) that almost changed the world.
Here’s another source for Medieval Warming & Little Ice Cooling graphs, confirming what JoNova’s work.
http://www.c3headlines.com/temperature-charts-historical-proxies.html
‘All models are wrong – but some are useful’ ; this quote, I think, due to George Box (sometime of Madison-Wisconsin).
The usefulness of any model is usually dependent on the adequacy of the assumptions underlying it. Nobody associated with driving the global warming/climate change/carbon dioxide scenario and its ramifications seems to have thought this to be important.
I notice that the widget showing the temperature anomaly has jumped from 0.28 to 0.5, which is getting close to the MWP.
The BBC did mention the Climategate scandal on the radio 4 Today programme. There is going to be another radio programme called ‘the Report’ discussing the issue some time in the coming days. They said that the the blogosphere is awash with Climategate and that it will be difficult to persuade the US senate to ratify what Obama has signed up to.
It’s not only dead, Jim, it’s annihilated, gone, it has ceased to be.
Here lies the Hockey Stick. Rest in pieces.
3×2 (05:09:29) :
At some point in the future, hopefully, we may all sit around and laugh about the dead moose (or some other slow release fertilizer) that almost changed the world.
Yes that is funny. However, centralized power is not. Let us be glad for every hindrance to the power of would-be tyrants.
Not suggesting he is right or wrong (or even in/out the ball park) but he certainly has something to say on the subject. I would suggest that his “credentials” should not be taken lightly.
Regarding the hockey stick, here’s Monckton’s long paper describing the shenanigans behind protecting it from criticism and “verifying” it, followed (pages 16-29) by summaries of 21 published papers that provide evidence of warming during the MWP. (Ten papers deal with Europe and the North Atlantic, eleven scientific papers address the period elsewhere on the planet.) Each summary occupies about half a page and contains a graph that illustrates key data points.
http://scienceandpublicpolicy.org/images/stories/papers/monckton/monckton_what_hockey_stick.pdf
But none of this will even be revealed at Copenhagen. The fraud will be perpetuated because too much money now rides on continuing the fraud!
Jean Meeus (04:26:21) :
The key is that it applies over the entire year(s).
Here are a few examples:
If you integrate that 0.5°C over the course of a heating season, it turns into a measurable amount of fuel use.
Imagine a mountain with a glacier and an environment with very little variability in the weather. Now decrease the temperature throughout the year by 0.5°C. The glacier terminus will move downhill some amount. A first order estimate might be to reach a point where the annual average is the same as it was before. The adiabatic lapse rate is, umm 1°F per 200 feet, so call it 1°C per 100 meters, so the terminus will be 50 m lower than before. If the pitch isn’t very steep, this could be a few hundred meters.
If you look at the length of the growing season (defined as the date of last frost to the date of first frost), then take the average temperature curve over the season and shift it down by 0.5°C you’ll see that the length of the growing season has gotten a few days shorter. Not only that, but the number of “growing degree days” has gone down. (GDD is a function of species and other stuff, but the sum will go down.) This caught some corn growers in the American midwest – they bought seed expecting that global warming would give them a long enough season. Didn’t work out.
ONE international is sending emails all over the web. once you click the link in the invitation, you sign their petition. you can sign as many times as you want by just clicking, which i find to be in bad taste.
for more info visit http://one.org/international/actnow/copenhagen/index.html?rc=copenhagenconfemail
and pls write about this ongoing unfair effort. thanks
Michael Mann attacks AGW goalie Phil Jones for letting the deniers hockey puck cross goal line
http://www.thestar.com/sports/hockey/nhl/article/732877–florida-player-slashes-his-own-goalie-in-the-head
All of this makes my blood absolutely boil! I know so many people who are totally ignorant of all this and Climategate, because they get their information from the mainstream “news”. And many of those same people are blind supporters of AGW. It’s time for me to take some action.
“Jo Nova finds the MWP.”
I didn’t know it was missing !!
Chuckle!!!
While I agree with the sentiment I have to say that while we argue the “toss” over 0.x°C warming or “climategate” Copenhagen will take place and agreement will be reached. Copenhagen is nothing to do with “Global Warming” it is about thieves agreeing how divide up the proceeds from “Carbon Trading”. It is without doubt the largest robbery in human history and everyone wants their cut.
Post Copenhagen there will be a new world reality. Everything you do, post Copenhagen, will be taxed. It will be a universal tax set at a level “decided” by “the market”.
As you can see the “market” consists of the same rent seekers that caused the last bubble and bale out. They just can’t stop themselves.
What makes me laugh most about all this is that the wind up toys that have been used so effectively are about to see reality. Watch them squirm. Hansen is right,
if the real object were ever a reduction in consumption your Government would have simply levied a 15% tax on your utility bills. The real object is a tithe on your labour that goes straight to the bottom line of monoliths such as Goldman Sachs. They are on the Copenhagen runway waiting to re-fuel the next bubble. Follow the money (and your extra hours at work).
This is all so far beyond robbery that new words will be required to describe it. Even if temperatures dropped back to 1970’s levels tomorrow morning this train will not be stopped. All the conspiracy theories (on both sides) are just that. You really don’t need a formal conspiracy when I offer you a reasonable share of a Trillion dollar pot of money from fresh air. Your answer is .. sign me up.
Jo Nova
With reference to the Loehle 2007 paper, this was supplemented and superseded by Loehle and J.H. McCulloch 2008 ( http://www.econ.ohio-state.edu/jhm/AGW/Loehle/Loehle_McC_E&E_2008.pdf. )
These papers collate 18 other studies which do NOT contain tree ring data to obtain a graph of global temperatures for the last two thousand years.
Let’s take Loehle and McCulloch’s 2008 as it is and see what it tells us.
Their results of the 2008 paper do NOT show what you claim, ie, that ‘Temperatures were higher 1000 years ago’, nor do they make that claim. The reason is that their graph that you reproduce does not end ‘today’ as you have labelled it.
Their proxy results END with the 29 year average temperature for 1935 (ie the average from 1921 to 1949 inclusive, of which 1935 is the mid-point). Loehle states, “Accordingly, the corrected estimates only run from 16 AD to 1935
AD, rather than to 1980 as in Loehle (2007).” What you have labelled as ‘Today’ in the Loehle graph corresponds to 1935.
Since the proxy data ends in 1935 Loehle then, quite reasonably, looks at the latest (for him) 29 year average which is centred on 1992 (ie from 1978-2006) and finds (correctly) that that period was +0.341C above the 1935 average (using GISS Land+ocean) and 0.07C BELOW the highest peak of the Medieval Warm Period.
So, according to Loehle 2008, the 29 year average global temperature centred on 1992 was marginally (indeed insignificantly) below the MWP peak by 0.07C.
However, 1992 is not ‘Today’ either. If we wish to see how ‘Today’s’ temperatures compare with the peak of the MWP, (according to Loehle and his use of non-tree-ring proxies), then we can get an indication by taking five year averages to smooth values to see how temperatures have changed since 1992. We find that 2006 (the latest year for which a five year average can be taken) is 0.29C above 1992 (five year GISS anomaly 1992=+0.24C, 2006=+0.53C). Therefore, ‘Today’ (or as close to today as we can reasonably get) is 0.22C ABOVE the highest peak of the MWP, based on the data in Loehle 2008. [Of course, in order to make that point conclusively, we would need the 29 year global average centred on 2006, but we won’t get that until after 2200.]
Thus, present temperatures are +0.22C ABOVE the peak of the Medieval Warm Period, based on information from the author you chose, Loehle, who used non-tree-ring proxies for his source..
Why did you not report this, rather than show your readers a graph that leaves them with the impression that ‘Today’s’ global average temperatures are about 0.3C below that of the MWP peak?
That widget jump is due to El Nino building-in November the .5 for the MWP is the average,BTW we are heading for Near zero F lows here in NE Oregon with snow on the
way….
Another excellent post, very didactic, simple and comprehensible by everyone. This will work also for the msm.
Back2Bat (05:35:50)
“Yes that is funny. However, centralized power is not. Let us be glad for every hindrance to the power of would-be tyrants”
However the CLIMATEGATE leakage proves that there is an internal division (or call it ambition) among those who allucinate themselves as future world tyrants.
Once people realise that this is a new universal tax with no escape route I’m sure this country (UK) will react (turn volume down) in much the same way it always has. Especially once people realise where the “tax” is actually going.
Slioch wrote:
Thus, present temperatures are +0.22C ABOVE the peak of the Medieval Warm Period, based on information from the author you chose, Loehle, who used non-tree-ring proxies for his source..
Why does Loehle decide to use corrected smoothed data? Steve Mcintyre has shown that if you start to smooth data then you miss out important anomalies, like smoothing out the way a drunken person walks, which hides the fact that they are drunk.
But the “true believers” will not give up. Johann Hari actually writes that hundreds of thousands of scientists have independently reached the conclusion that burning fossil fuels will have terrible consequences. You will not believe what else he writes…
http://www.independent.co.uk/opinion/commentators/johann-hari/johann-hari-how-i-wish-that-the-global-warming-deniers-were-right-1833728.html
On page 3 of Jasper Kirkby’s report explaining the justification for CERN conducting experiments to test Henrik Svensmark’s theories linking solar activity, cosmic rays, clouds and climate, are graphs of various proxies showing the MWP and the LIA.
http://aps.arxiv.org/PS_cache/arxiv/pdf/0804/0804.1938v1.pdf
Oops. I forgot to mention that the CERN graph of temperature proxies also shows Mann’s hockey stick for comparison; Kirkby mocks the hockey stick, in the understated academic way.
Wait a minute…
Craig Loehle’s reconstruction shows the MWP centered around AD 950 and down to 0C by AD 1250. McIntyre’s reconstruction shows the MWP as warm as +0.5C around 1400. There must be some uncertainty in those reconstructions. Oh, there it is in the error bars of the Mann et al reconstruction.
If I remember right, Loehle also used 30 year averages with data ending around 1950. The warming since the mid-century is basically excluded from Loehle’s reconstruction. If you are comparing the MWP to the early part of the century (before significant AGW), then why are you calling it “today”?
The boreholes seem to match McIntyre’s reconstruction but not Loehle’s. I believe they also have a very coarse resolution in time and can’t resolve changes over less than about 50 years. That means they also exclude the warming of the last few decades.
Houston this morning broke a record with the earliest snowfall ever recorded in the city’s history.
this is reported by the MSM.
December on track to be coldest December evah. Poor Houston.
Don B (07:12:03) :
Nice catch. Like I said “wind up toys”.
Falling Arctic ice shelves, of countries being swallowed by the sea, of vicious wars for the water and land that remains.
Is he planning a new Sci-fi series? Does the Arctic have ice shelves (being an Ocean)?
It is a good thing in the end that these people exist and get exposure. How else will “regular folk” come to see them for the eco-loons they really are.
Check out the chart of the temperature cycle here:
http://www.climate-skeptic.com/2009/12/a-total-bluff.html
It supports the cyclical temperature graph shown above.
Guys…lets not ‘Do A Phil’ here…….Sliochs comment, if true, blows this whole thread out of the water.
Look…my own view is that AGW is more political sham than real, but, I’m not going to stick fingers in my ears when one on ‘our side’ presents a graph that is pulled down so easily by the ‘other side’.
Crowing about Jo Nova graph – if it is indeed dodgy – makes us look silly, and would be the cause of sarcastic emails at CRU yes?
Soooooooooo…..can someone come back on Sliochs points, or is that poster correct….Craig, are you lurking?
Just Googled ‘Climategate’ 26,800,000
anyone know which one of these is Obama ?
The BBC programme, “The Report” is, I believe, the one for which Bishop Hill was interviewed. Keep an eye on his site for more details.
Agreed, using smoothed data is fine for certain charts and graphs but you must always refer to the RAW base data. If you keep smoothing and massaging the data, it stops being data and therefore useless.
Henry chance (07:34:45) :
said, “Houston this morning broke a record with the earliest snowfall ever recorded in the city’s history.”
There have been 1268 record temperature, rainfall and snowfall events in the continental USA during the past week, including 147 record high temperatures. Many records are broken almost every week.
If you want to mislead people you just pick out one of these (eg record early snowfall in Houston) and don’t mention any of the others. And if you want to be misled, because the tale you are being told corresponds with what you want to hear, then you don’t bother to look any further to check out the partial information you are being fed.
You don’t have to lie to people to mislead them – you just give them partial information and let them reach the wrong conclusion all by themselves.
Here is the summary of record events in the continental USA over the last week:
Continental USA
Record Events for Fri Nov 27, 2009 through Thu Dec 3, 2009
Total Records: 1268
Rainfall: 687
Snowfall: 83
High Temperatures: 147
Low Temperatures: 74
Lowest Max Temperatures: 153
Highest Min Temperatures: 124
See: http://mapcenter.hamweather.com/records/7day/us.html?c=maxtemp,mintemp,lowmax,highmin&s=20091204&e=20091204
3×2 (06:40:06) :
“You really don’t need a formal conspiracy when I offer you a reasonable share of a Trillion dollar pot of money from fresh air. Your answer is .. sign me up.”
Money would not work with me but maybe a redhead. Oops! They require money!
Seriously though, evil need not win every inning or even ANY inning. When it becomes obvious to the greediest among us that they risk killing the goose that lays the golden eggs then maybe they will quit playing games with our common future.
If not, I am hedged with respect to the end of the world.
JohnV (07:30:07) :
“McIntyre’s reconstruction shows the MWP as warm as+0.5C around 1400”
Careful, Steve McIntyre would be the first to say the his work merely corrects the statistical errors in Mann’s processing. He states that he does not agree that tree ring width == temperature!
My reading of his comments is that he believes it is conceptually possible to get temperatures from tree data, but the dedrocronologist methodology (in the litrichur) is not yet adequate to reliably retrieve temperatures.
@Slioch (06:44:29) :
I am afraid that you may be relying on GISS and related databases more than they deserve. As E.M. Smith (http://chiefio.wordpress.com/) has documented extensively, it would appear that none of the land temperatures are comparing apples to apples. Let me explain. In the last several decades, there has been a great change in the number and location of the thermometers/stations that are used to calculate the global anomalies and the “Global Average Temperature”. As a result, the thermometers from 1978 to 2006 are being compared to different thermometers that were used in the period 1921 to 1949. Indeed, Mr. Smith has documented huge differences in thermometers used within the period 1978 to 2006. These changes do not appear to have been documented or justified within the peer reviewed literature. Until Mr. Smith started posting his analysis, the only inkling of these very large changes was that the total count of thermometers used for the land temperature data worldwide had decreased sharply in the last couple of decades, although there did not appear to be any explanation or justification for why these changes were appropriate. In the U.S. alone, all but 136 thermometers were deleted from the land temperature data used to calculate anomalies and the “Global Average Temperature.” For example, the entire state of California was represented by only 4 thermometers – all of them on the beach (IIRC, San Francisco, Santa Maria, Los Angeles and San Diego). After Mr. Smith published his work on his blog, NASA very quietly a couple of weeks ago reinstated about 2000 thermometeres in the U.S. that had previously been deleted. As far as I know, this major change was only noted on Mr. Smith’s blog (other than a circumspect notice posted by NASA I believe). In conclusion, it is fair to question whether any reasonable conclusions can be drawn from the dog’s breakfast that the land temperature data apparently is and that is not counting micro-siting issues (such as those documented on http://www.surfacestations.org), macro-siting issues (such as urban heat islands or UHI), instrumentation issues (such as MMTS vs. Stevenson screens), etc., etc., etc. The sea surface temperatures also have issues (such as buckets vs. engine intake temperatures). Given all of this, differences in the tenths let alone hundredths of degrees C may not have any significance.
Slioch,
I think the point of the article is that the MWP is real and global. Mann and Briffa doctored their data to eradicate it.
You say that the Loehle dataset doesn’t go far enough and today is still warmer than the MWP. You may be correct. Isn’t that why we need access to all the data, code and methods?
I find Ja Nova’s work to be consistent with the hundreds of studies that I have read on proxy studies and analyses of temperatures through the centuries. One note of curiosity: Recently, I read a statement by Mann that he recognized that medieval times were warmer in Europe and maybe other parts of world, but these regions were offset by cold anomalies in the southern Pacific Ocean. Interesting claim. We can verify proxy studies in most of the world by looking at physical evidence – such barley fields in Greenland, northern migration of tropical plants in China, trees and other organics uncovered as glaciers retreat in North America, South America, Asia, and so forth. However, it is difficult to find physical evidence in the South Pacific Ocean to either confirm or disprove Mann’s claim.
Phil (10:21:50) :
said, “I am afraid that you may be relying on GISS and related databases more than they deserve.”
It is not I that started using the GISS data – it was Loehle. Loehle used GISS land+ocean without any suggestion on his part that it was considered unreliable.
Loehle’s paper was cited with approval by Jo Nova because she considered that it showed that the MWP was warmer than “today”.
Now that I have shown that that conclusion is false, suddenly you pop up to claim that we can’t rely on the GISS data.
So, when it is considered that Loehle’s paper supports the belief that “today” is cooler than the MWP then it’s ok to use GISS. When the opposite is shown, suddenly it is not.
Do I really have to say what I think about that?
But, if you wish, let us use UAH to estimate the change in average global temperature since 1992. Here is the information about the difference between the five year averages based on 1992 and 2006according to UAH:
UAH 1992 5 year average = -0.032C
UAH 2006 5 year average = +0.225C
So, GISS gives an increase of 0.29C from 1992 to 2006, and UAH gives an increase of 0.26C.
Which translates as the 5-year average based on 2006 being 0.19C above the peak of the MWP.
If you want to use that figure instead, that’s fine by me. But I won’t hold my breath.
[REPLY – Actually, Dr. Loehle has stated quite strongly that it is impossible to know for sure if the MWP was warmer or cooler than today. (I heard him state it.) ~ Evan]
“Dr. Loehle has stated quite strongly that it is impossible to know for sure if the MWP was warmer or cooler than today. (I heard him state it.) ~ Evan]”
Yet you allow an article to be published on your site that refers to Loehle’s paper, with a graph that shows temperatures in the MWP c.0.3C warmer than today and with the associated statement, “Temperatures were higher 1000 years ago”, without any qualification from you. What sort of editorial control is that?
Actually, I would tend to agree with Loehle that it is “impossible to be sure”, because of various uncertainties. But what we can be absolutely sure about is that if we take the data and methodology of Loehle’s papers as given, then the conclusion is that today is warmer than the MWP. The only way to escape from that conclusion is to disregard either Loehle’s data or his methodology.
[REPLY – I did not post the article. I did not write the editorial. Dr. Loehle’s 2008 graphs I have seen indicate the MWP was a bit warmer, but he is not sure and has said so. (There is a mountain of non-climatology evidence, of course.) ~ Evan]
Jean Meeus (04:26:21)
If the people who generate all these wonderful proxy graphs of the paleoclimate really wanted to provide an accurate representation of the strength of the information they are offering, the pale grey areas, which represent the uncertainty range of the data, would be drawn in dominant colors and the squiggly lines, often graphed to a hundredth of a degree, would be drawn in the palest greys and pastels the printers could produce. This would provide anyone viewing the graphs with a more accurate notion of the level of information they demonstrate.
If you have followed the main data sets for the present day avg. global temp., you may have noted that from day to day, month to month, and year to year it is a rarity for all of them to provide the same number within +/- 0.1 degree and quite often the range is a half degree or more. If that’s the best all of our heralded modern technology can do, the implicit suggestion provided by almost all these graphs I’ve seen, that the various proxy media [tree rings, corals,sediments,ice cores, etc,] can encode a temperature signal that is better by an order of magnitude or two, is one of many reasons my response to much this completely “settled science” has always been similar to the comments of the gentleman from the CBC in the post from earlier today
http://wattsupwiththat.com/2009/12/03/you-wouldnt-accept-that-at-a-grade-9-science-fair-cbc-finds-a-moment-of-clarity/
Yes there has been. You might want to look at this report:
Atmospheric CO2 and Global Warming (Jaworowski & Segalstad)
http://folk.uio.no/tomvs/esef/np-m-119.pdf
Larry
To me Loehle’s results look something of a dog’s breakfast:
http://www.climateaudit.org/?p=2393
The peak temperature around 1960 or so, followed by a decline looks very suspicious.
I also find it strange why Briffa is using 12 trees in the graph above (2000 I think ?), when he was using 400 in 1998, resulting in strong cooling after 1940.
Particularly with the big UHI component of hadcrut3, to me, it seems possible that there is no warming at all after 1940. Ironically, after 1945, the rate of fossil fuel burning increased 12 fold.
Back to basics.
Why is the past so important ? To indicate if measures warming and cooling is natural or not. To understand if the patient is sick or not. Thanks to climategate – noone knows.
I do not believe one can read temperature witihin 0,1 C accuracy from trees or mud 50 years later. Not even from fresh tree or last year. This can be conformed. I can bet a Jack Danies on that if it solved the global debate. Perhaps one can compare two trees or just hug them.
The tree ring data does not correlate with instrumental data and that why it was supressed after 1960 in IPCC ‘approved’ or ‘certified’ papers. That was the needed wooden hockey stick handle. The proxies are subjective bad data and leads to artistic and imaginative mathematics. That was the way to ‘hide the rise’ or MWP. At the same time there was measurements starting from year 1600 and 1800 with historical accuracy.
Tree rings depend on soil, chemicals, water, clould, CO2, insects, sun, other plans, other animals, fire etc. Wide ring does not necessary mean +0,4 C.
One can not say yes or no to this religion ‘fact’ of the history. Eg. Years 1400 was +0,5 C above average. Or +10 C ? How to conform ? Either you believe it or not. There is no truth available out there.
We are talking about mean temperature of a year= very complex problem=integral of the year devided with time.
Is the integral continuous or samples once a day at noon ? How to count dirrerent places with different temperatures ?
Even the main definiton changes because the measuring poists/ time changes and now one should use 0,1 C accuracy ?
Scientics can use their imagination and subjective mind to create the formulas and graphs. Just pick the right data and formulas.
The main AGW is science man made. I believe 50 % of the heating is such. The thermometers are heated with cities and kerosine at airports and warming pipes at thundra . The number of measuring points have declined globally recently to include mainly only UHI points. That does not make any sense if the climate is in danger. The rural points were bad for the warming, which they did not have. The raw city data indicates warming. Surface data indicates twice the warming of other instruments. Because it should at cities. After 1990 more money has been given to science and less measurents is the result. Perhaps CO2 heated 0,5 C or not. UHI is 0…10 C. There is no ‘consensus’ on that.
‘Idea of the consensus in the western critical science is mental illness’. (me)
But the is more data; data from year 1930 even though the measure site was found and manufactured 1952 at Helsinki,Finland site. Many measurents are artificial. The thundra measurement ordered from Russia were propably paid with black money to avoid tax according to CRU emails. It was cheap and easy. The best place to read the measurent is close to heat source, pipe or close to houses. The best measurements to ‘hide the decline’ are far away and hard to confirm.
What is the precision we can get from this data?
The series of comments I have read after this post are reason enough for me to believe that if I were a policymaker, I would definitely say the science is “not settled” and that far more research and long-term study is necessary before ANY policy is made in regard to CO2.
Enlarge picture not available.
http://joannenove.com.au/globalwarming/skeptics-handbook-ii/ppt/mwp-global-studies-map-i-ppt.gif
That top picture doesn’t make sense. It says it shows the results of 752 scientists etc, but there are just 24 numbers. OK, joint authorships, but not averaging 31 per paper. So are we just seeing the top few?
@Slioch (12:06:27) :
Dr. Loehle only specifically refers to GISS one single time in Loehle and McCulloch 2008 and that only in an aside where he states:
In addition, I would also say that the results that E.M. Smith is posting are very recent and surprising and therefore unknown to Dr. Loehle in 2007 and 2008.
Slioch:
Other than the single instance cited in the previous paragraph, I have found no other reference to his using GISS land+ocean.
Slioch:
3 points:
First, I don’t think it is fair that say that is is “ok to use GISS” when “Loehle’s paper supports the belief that “today” is cooler” than the MWP. IIRC, all of Dr. Loehle’s work was not based on GISS, but rather on previously published peer-reviewed proxy reconstructions.
Second, Dr. Loehle, as I have quoted above, says that the instrumental data is not strictly comparable to the proxy reconstructions. I would suggest that the appropriate method to bring this study forward into more recent decades would be to update the proxies, so that apples can be compared to apples, but that may not be possible for Dr. Loehle to do personally.
Third, given the developing story about GISTemp that E.M. Smith is posting, I would have to preliminarily disagree. The results that Mr. Smith is posting are suggestive of an artificial positive anomaly in recent decades, since colder thermometers appear to have been replaced with warmer thermometers over time in many places around the world. However, I will grant you that his work is still developing and I probably do not have enough certainty at this time to say categorically that you are wrong.
Slioch:
I apologize if I wasn’t clear before, but I was focusing on the comparison between this decade and the thirties. I don’t believe that UAH can be used to compare these two decades.
Let me close by quoting the final statement in Loehle and McCullock 2008, as I think it is very appropriate to this discussion:
Alexey (21:50:29) :
“Enlarge picture not available.”
Reply: Picture is available on this link:-
http://joannenova.com.au/globalwarming/skeptics-handbook-ii/web-pics/mwp-global-studies-map-i-ppt.gif
We will never have an accurate global average temperature for the long-term historic record due to the number of assumptions made for each proxy measure and the assumptions made about how a spatially sparse data-set can be scaled to give a global result. The fact we are dealing with a highly turbulent dynamic non-linear system only serves to compound the problem. Thanks to CRU/GISS it looks like the short-term record has been lost, due to there destroying the raw temperature data records.
Unprovable assumptions are the kiss of death for any science, as this allows anyone to find a basis to confirm what they believe, as exampled by the IPCC data and hockey stick graph. The anecdotal historic record, however, does confirm that the MWP and LIA exist, beyond that, science can say no more.
Phil (23:23:12)
Your query concerning the NASA GISS results is little more than a smokescreen.
The bottom line, as far as this thread is concerned, is that Jo Nova presented a graph, hosted on this site, in which the temperature for 1935 was falsely labelled as “today” and where it was falsely stated that “Temperatures were higher 1000 years ago”.
Neither conclusion is either present in or supported by the Loehle paper and is contradicted by the use of either NASA GISS or UAH data (or, indeed, HADCRUT3 or RSS) to update the Loehle data.
It is yet another example of how people are being misled by false information.
As for some of the details of your post, briefly:
1. Phil: ” “though the difference is not significant”. (emphasis added) ”
Why add emphasis? Did you not notice that I said the same earlier?: “according to Loehle 2008, the 29 year average global temperature centred on 1992 was marginally (indeed insignificantly) below the MWP peak by 0.07C.”
2. Phil: “Other than the single instance cited in the previous paragraph, I have found no other reference to his using GISS land+ocean.”
Loehle used the NASA GISS series to update his proxy data from 1935 to 1992.
I used it to update it from 1992 to 2006.
Of course, he didn’t use it elsewhere – the bulk of the paper was concerned with proxies. What is the point of your statement? It has none.
3. Phil: “so that apples can be compared to apples”.
Are you seriously suggesting that we should not make comparisons of temperatures derived from proxies with those derived from direct instrumental records? That if a proxy record gives a temperature for 1935, and we have evidence of global temperature changes since 1935, that we should just ignore such evidence and pretend that nothing has changed in the meantime? Of course, we should always use evidence with caution and with full cognisance of the errors involved, but your stance seems very similar to that frequent redoubt of those who refuse to accept AGW: that because we don’t know everything and that errors exist in our data, that therefore we can know nothing. It’s a very handy last ditch defence against inconvenient evidence.
Incidentally, there is reasonably good agreement between the four temperature series, NASA GISS, HADCRUT3, RSS and UAH, as shown here:
http://cce.890m.com/temp-compare.jpg
The average of the temperatures shown on the map is 0.86. As I suppose the map is meant to be representative, I assume that is the established temperature anomaly of the MWP from the literature cited. Also, I assume that ‘above present’ means above the 1989-2008 global mean.
It would be very interesting to have some of the scientists whose work is cited comment on this.
Jo Nova finds the Medieval Warm Period
was it in the couch cushions?
[REPLY – Actually, Dr. Loehle has stated quite strongly that it is impossible to know for sure if the MWP was warmer or cooler than today. (I heard him state it.) ~ Evan]
impossible is a strong word
did he mean ‘with 100% certainty’?
anecdotal is fine—Vikings called it Greenland. receding glaciers are exposing tree stumps, extinct tree lines in high elevations of lower elevation trees in california from 1000 years ago
class dismissed
“The Wels is Europe’s largest freshwater fish, capable of reaching over 200lbs and attacks on humans have been reported across Eastern Europe from Russia to Poland through the ages right up to the present day.”
http://www.itv.com/presscentre/rivermonsters/ep3wk49/default.html
Jeremy says: “There are three reasons why the Wels catfish are growing so big in this river, it’s a mixture of man made and natural. For a start you’ve got three of these huge dams and it just means there’s so much more water, more space for the fish to live in. On top of that, this water is hot. The fish being a cold blooded animal can just feed and grow for more months of the year than they do in Eastern Europe and in Berlin.”
http://media.photobucket.com/image/wells%20catfish/pause4thought/bigcats2.jpg
It would appear that a warm climate makes for bigger catfish.
What to do now when the bull dust blows over?
I suggest we start by asking more questions, and finding additional answers to compare, to give us a greater gathering of knowledge, to evaluate the hypothesis skeptically, while figuring out better questions, to ask for the next set of trials.
Diversity of thought into additional areas of knowledge, gives a more rounded vision, allowing for the formation of more complex answers, and resultant better focused questions. If you can then present data, in a format that is visual enough, that it shows the balancing of several forces at work, as they really do, it would make finding the solution easier.
From a viewpoint of how the assemblage of parts seamlessly fits together,the only thing you have to do, is to watch the (short but seemingly) endless stream of (every 15 minute) infrared and/or vapor satellite photos animated, (after fixing the jumping around of the originals, due to lack of foresight, that they might be useful some day), and synchronized by 27.32 days periods, to see the repeating cycles.
To set up five tiled windows, in the first show day #1 through #27 sequentially, then as they continue on in the same stream, the cycle of the first 27 days continues anew in window #2, synchronized by Lunar declination to #1. Till they spill over into window #3 stepping in phase with the other two, #4 the same idea gives you the four basic patterns of the Rossby wave 109.3 day cycle, of global circulation, that then repeat but seasonally shifted.
In window #5 then would be the first repeat of window #1 in the same phase of the same pattern, and should look a lot like window #1. As the progression through the total series, proceeds, when you get 6558 days into the five stacks, a 6th window opens and the original day #1 in window #1 opens as #1 in window #6. As the series progresses on, real data can be viewed, in the real interactions going on.
This would give you a look into the cyclic pattern that develops from the repetitive interaction of the inner planets, and tidal effects, caused by the Lunar declination, phase, perigee/ apogee cycles.
By adding a sliding ball, vertically moving up and down a +-30 degree scale bar (referenced from the Equator), on the side of each tile space, that shows the plot of the current Lunar declination for the time of each frame. Which will allow you to see the shifts in the Lunar declinational angle’s effects, as the 18.6 Mn signal progresses.
By adding another slide bar of +-30 degrees (with the heliocentric synod conjunction with Earth, as the zero reference), at the top, of each tile you could view each outer planet as we pass them, as color coded discs labeled, J, S,U, N, shifting from left to right. From viewing this progression of the outer planets, the merit of their influences, can then be seen in the additional surges in ion flux as they go by. You can watch the changes in the normal background, of the global circulation driven by the moon and inner planets, affected by the outer planets.
By adding in the surface maps for the past historic temperatures, dew points, precipitation, types, and amounts, as overlays onto the IR/VAPOR photos, the patterns will be abundantly clear to 10 year old school kids. At the same time, generating a good long term forecast, set of analogs to base the models upon.
Once the amount of additional angular momentum, and the process of it’s coming and goings can be clearly seen, it can then be measured, it’s effects calculated, and incorporated into the climate models, as a real quantized feedback. thereby giving us a much better picture, of the interactions, of all of the parts of the puzzle.
All of the necessary data is in the archives, and free to use, to those that have the where with all, to assemble the real truth, be it inconvenient or not. I will probably spend the rest of my life, trying to do it alone, out of my own funds, as I have done so far.
For application in Quake sightings, and subsequent formulating hypothesis and developing forecast parameters, you could substitute, or add (if your video resolutions is good enough), intensity quantified dots on the surface of occurring quakes (play with color coded shift and fade out time, to see time shifts etc.) and a corresponding moving open circle, showing the moving location of the earth/moon center line.
Slioch (01:55:07) : Incidentally, there is reasonably good agreement between the four temperature series, NASA GISS, HADCRUT3, RSS and UAH, You can be sure Hansen, Jones, et al work very hard to make their data look real enough to match the satellites. All they need is the general curve shape, and to lower the past temperatures, get rid of those pesky rural stations and count on UHI to yield their carefully calculated results.
@Slioch (01:55:07) :
The graph in question covers a period of about 2,000 years. If you look carefully at the graph, you can see ticks every hundred years. The data that is plotted ends somewhere between the tick for 1900 and the tick for 2000, so I don’t think that the graph is misleading. Your focus seems to be on the handwritten labels. Specifically, it seems you are taking issue with the label “today” (which I take to mean the end of the plot) as having a difference of about 50 years with the end of the graph (1949? to 2000?), which is a difference of about 2.5% with respect to the range of the whole graph. That appears to be what we are discussing.
Slioch:
It was not my intention to offend you by adding emphasis.
Slioch:
The point of my statement was that the bulk of the paper was concerned with proxies and was not based on GISS. I would strongly disagree with you that Dr. Loehle “updated” the proxy data using GISS. I took the single sentence comment that I quoted to be a comment at the end of the paper, prefaced with the very important caveat that the proxy data and the GISS anomalies were not “strictly comparable.” With all due respect, this caveat should not be disregarded. Furthermore, I think it would be completely inappropriate to graft the instrumental data onto the end of the proxy data, as was done with the hockey stick graph, et. al. and Dr. Loehle was correct in not doing so.
Furthermore, Dr. Loehle smoothed the Gistemp data with a 29-year smooth, whose midpoint ended in 1992. Dr. Loehle specifically states that the 1992 midpoint of the 29-year smooth contains data from “1978 to 2006,” so it would be completely inappropriate to update it further from 1992 to 2006, as you would need Gistemp data from 1992 to 2020 to continue the 29-year smooth to a midpoint of 2006.
Slioch:
Proxies are not thermometers, hence Dr. Loehle’s caution that the 2 are not “strictly comparable.” What is unusual about Dr. Loehle’s paper is that he restricted himself to proxies that had been calibrated to temperature and were thus expressed in degrees C. I don’t believe that Dr. Loehle tried to do any due diligence to determine how accurate or reliable the temperature calibrations were. I believe he just accepted them at face value, but I cannot be 100% sure of that. However, Dr. Loehle’s paper is very unusual, if not unique, in that all of this proxies were calibrated to temperature. More often, that is not the case. For example, tree ring proxies may be expressed in dimensionless standardized units based on width or they may be based on density. One of the issues with climatology is that changes in certain proxy properties are assumed to faithfully reflect changes in temperature, but these assumptions haven’t always been confirmed experimentally, so I would agree with Dr. Loehle that proxy records are not strictly comparable to modern instrumental records, but that is separate and apart from the issues I raised with GISS.
Specifically depending on GISS to compare the present decade with the thirties, given what E.M. Smith’s work is revealing, is where I urged you to be cautious. As I said before, these developments are very recent and would have been unknown to Dr. Loehle in 2007 and 2008 and I would surmise were probably unknown to you when you first commented in this thread. However, I don’t believe it is fair for you to characterize my caution as you have.
For example, look at http://chiefio.wordpress.com/2009/11/07/gistemp-ghcn-selection-bias-measured-0-6-c/#comments. I quote:
Dr. Loehle’s smoothed global data anomaly rise from 1935 to 1992 was 0.34 degrees C. Although, these two numbers (0.6 C “Selection Bias” and 0.34 C smoothed rise) are not directly comparable, the magnitudes of the two are such that there should be a strong presumption that E.M. Smith’s questions should not be considered to be trivial as you seem to imply in your generalizations about “those who refuse to accept AGW.”
Slioch:
This graph covers the period from 1979 to 2007, so it is not helpful in comparing the present decade with the thirties. Unfortunately, RSS and UAH don’t go back to the thirties. That leaves GISS and HADCRUT3. According to the CRU emails (please forgive the lack of a specific reference), most of the land temperature data for HADCRUT3 comes from GHCN, which is also used by GISS. That means that the thermometer issues raised by E.M. Smith about GISS may also be applicable to HADCRUT3. Furthermore in Gistemp, “Hadley CRU provides historical sea surface temperature anomalies that are merged at the very end, as an option” (http://chiefio.wordpress.com/2009/11/09/gistemp-a-human-view/). So, GISS and HADCRUT3 may not be truly independent temperature series that could serve as a crosscheck on each other.
Phil (12:47:15)
So, you “don’t think that the graph is misleading” which claims temperatures “today” to be more than 0.6C (0.341c + 0.29C) COOLER than the best estimate we can make shows them to be?
Your comment about the time being “2.5%” different is utterly irrelevant. It is again another smokescreen. We are talking about the Y axis, temperature today, remember?
Other than mikef (08:23:57) :
Who said, “Guys…lets not ‘Do A Phil’ here…….Sliochs comment, if true, blows this whole thread out of the water.”
No-one has acknowledged that the Jo Nova article was feeding you misinformation on the MWP.
As an infrequent visitor to this site, I was puzzled by mikef’s reference to “lets not ‘Do A Phil’”. Have you just demonstrated what he meant?
Over and out.
History is not going to be kind to these people at all.
At some point they will be asked to produce more than their programs and raw data – which they could hide, or change. They’ll also be asked for the exact methods used to produce their published charts and graphs. That’s an extremely complex signature — like fingerprints — ones they won’t be able to duplicate with alternate methods.
What kind of “science” seeks to HIDE data and methodologies? What kind of science publications allow scientists to publish under these conditions? Damn them ALL (Nature, Science, Mann, Hansen, Jones et al) for keeping ANYTHING secret or hidden. IT WASN’T YOUR PRIVATE HOBBIES. YOU WERE PAID DEARLY! Did you really think it would last?
Time to come clean, and cough up some inconvenient facts. Don’t worry about the artificial Green Energy gravy train you’ve created. They’ll all rationalize why it’s still all viable and well and good for the earth DESPITE your obfuscation and deceptions. Who knows, they might even succeed in getting modified caps and taxes imposed — but they’ll have to do it for different reasons.
Conclusion…
Sadly I have to admit, at this time I’ve not seen a sustainable rebuttal, so Sliochs comment holds true, this thread is poorly presented and misrepresents the position.
Of course within error bars the whole thing is angels on the head of a pin, and the point is we can’t really say for sure that the MWP is much warmer than now, if at all, though we can prob say its much the same. This arguement is enough to dicredit “unprecedented recent warming”.
Look…we don’t like it when the NYT etc put out an obvioulsy stupid account of polar bears drowning etc, so we should hold ourselves to the same degree…it does mot help the “hold on, this AGW thing is not actually certain” cause if we turn into the same people as the alarmists.
Integrity is the key…maybe an editorial on the Jo Nova graph perhaps is needed (‘cos we always moan when the msm never corrects thier bad stuff). Sorry Anthony…!??
Re the borehole data, it’s unfortunate that the top article doesn’t mention the fact that Hunag and Pollock (what about Shen?) themselves have repeatedly pointed out that their own 1997 data cannot be used to assess the relationship between the MWP temperature and cureent temperature. As Huang Pollock and Shen (HPS) state, their 1997 analysis misses out the 20th century, and the data really only addresses the surface temperature up to the endo of the 19th century/start of the 20th. This is due to the concern that the top 100 metres of the borehole depth might be contaminated by non-climatic influences.
HPS have been working in this area for years and it’s curious that the top article would report on an analysis that the authors themselves have stated is misapplied when attempting to address the relationships between MWP and 20th century (let alone current) temperatures. Why show data that’s 10 years old without considering what’s been done in the intervening years?
In fact HPS determine that analysis of borehole temperature data indicates that the MWP was a little over 0.5 oC cooler than late 20th century temperatures [*]. In other words the borehole data is pretty much consistent with all of the other well-established temperature reconstructions in the scientific literature, namely that the MWP may have reached temperatures equivalent to the global temperatures in the middle of the 20th century, but well below current temperatures (by 0.5 oC, or 0.5-0.7 oC if one considers only the N. hemisphere which is the source of much of the paleodata….
S. P. Huang and H. N. Pollack P.-Y. Shen (2008) A late Quaternary climate reconstruction based on borehole heat flux data, borehole temperature data, and the instrumental record Geophys. Res. Lett. 35, L13703, doi:10.1029/2008GL034187
I can’t see that it really matters whether the MWP was a little lower or a little higher than today. I was quite a long period and I would guess that there were fluctuations during that time.
What seems to me to be important is that it clearly existed and there has been a warming trend for ~150 years which will probably peak at some point.
The clear issues for politicians is that:
1) This is not an unprecidented phase in our recent climatic history.
2) The current warming trend started long before we were pumping large amounts of CO2 into the atmosphere.
Is there some one who can help me with a statistical problem as regards temperature? When one takes two periods and says that there “statistically” different or not, how is this calculated from a quasi-continuous signal. What are the degrees of freedom of the estimate? I’ve come across this problem quite a lot in signal analysis and there are ways to estimate DoFs and reduce the signal to a set of uncorrelated obserations (one simple method is resanple on the basis of the zero crossing of the auto correlation function) and this has quite a marked influence of significance. I generally use Monte-Carlo methods where possible to model the process. With Climatic records built from proxies, which are relatively error prone and not regularly sampled in time, this seems quite difficult.
Just back briefly to say: thanks mikef.
With respect to foinavon’s observations concerning the borehole paper HPS 2008, the abstract states:
“The reconstructions show the temperatures of the mid-Holocene warm episode some 1–2 K above the reference level, the maximum of the MWP at or slightly below the reference level, the minimum of the LIA about 1 K below the reference level, and end-of-20th century temperatures about 0.5 K above the reference level.”
The reference level was the global average temperature 1961-1990.
In other words they find the maximum of the MWP was about 0.5C below today’s temperatures.
see: http://www.agu.org/pubs/crossref/2008/2008GL034187.shtml
This result is roughly similar to that of Loehle discussed above with respect to the MWP and refutes the (mis)information provided by Jo Nova above. (Loehle’s proxies may be expected to be more sensitive to short term temperature changes than borehole measurements and therefore more likely to pick up temperature peaks (or troughs) of short duration.)
Hi Slioch. Well, I’m hoping you’re wrong, and the MWP will turn out warmer rather than colder, but so far you’ve made a good case. Our side should err on the side of caution when there is doubt. We’ve got a winning hand, but we can lose by overplaying it. all we need is for there to be more exposures and an independent investigation of everything. That will come about if we keep the discussion focused on our strong points, namely the misbehavior of the team and its allies, and their possible biasing of the data, not on arguable interpretations of the data.
I like the low-key, minimalistic claim by RC Saumarez:
“The clear issues for politicians is [are] that:
1) This is not an unprecedented phase in our recent climatic history.
2) The current warming trend started long before we were pumping large amounts of CO2 into the atmosphere.”
@mikef (06:03:47) :
I think that this thread has been steered away from the main point (“Jo Nova finds the MWP”) to the side issue of whether the MWP was warmer, cooler or the same as the present. The main point of this post (i.e. that the hockey stick and related reconstructions incorrectly tried to erase the MWP and LIA out of climatic history) has not been refuted.
RE: Huang, Pollack and Shen (2008) (HPS 2008)
(http://www.geo.lsa.umich.edu/~shaopeng/2008GL034187.pdf)
Dr Loehle apparently uses only one borehole proxy: Dahl-Jensen et al., 1998, apparently collected in Greenland. There is a reference apparently to the same proxy in paragraph 20 on page 4 of HPS 2008. So it would appear that this proxy was used in both papers. In Dr. Loehle’s paper, he apparently tried to use many types of different proxies so that (I would presume) issues with one type of proxy would have a limited effect on the reconstruction as a whole.
However, I was intrigued by the point that the top 100 meters of the borehole depth might be contaminated by non-climatic influences. HPS 2008 say that, to avoid this issue, the proxy reconstructions need to be truncated at the end of the 19th century. However, HPS 2008 manages to compare the MWP with late 20th century temperatures. How was this possible, if the proxy reconstructions were truncated at the end of the 19th century? So I studied HPS 2008. Here appears to be the explanation of how they were able to do so (from paragraph 14 on page 3):
HPS00 appears to be a proxy reconstruction going back about 500 years done by them in 2000 and truncated at the end of the 19th century.
What was the source of the instrumental record “(land only)?” From the same paragraph on page 3:
So, once again, it would appear that a modern temperature record has been grafted onto a proxy reconstruction to “compare” the MWP to the late 20th century.
So why exactly were the proxy reconstructions truncated at the end of the 19th century? From paragraph 8 on page 2:
Sound familiar? The tree ring data was truncated in 1980 and 1960 for the hockey stick because it also apparently was “affected by non-climatic signals” (paraphrasing).
Further from paragraph 9 on the same page:
Doesn’t sound very different from what Jo Nova and Dr. Loehle did.
There seems to be a widespread misunderstandig about CO2 effects that should be corrected: The radiative effects of anthropogenic CO2 started with the emissions, not at some later time, say 1945. As the radiative effect increases with the logarithm of CO2 concentration, an exponential rise in CO2 only gives a linear rise in radiative forcing, and just comparing concentrations may easily lead to wrong ‘intuitions’ about what is going on.
For example, the rise from 280 to 300 ppm CO2 had the same radiative effect as the rise from 388 to 416 ppm. With zero feedbacks, I think it should be about a 0.1 deg C temperature rise. With the widely assumed 3 deg/doubling feedback, the rise would be about 0.3 deg C. This means that, a priori, one cannot disregard the contributions from early CO2 emissions to the LIA recovery. It is of course possible to say the radiative effect is smaller, the feedbacks are actually negative etc – but it is not possible to use the LIA recovery as evidence for that without a detailed analysis.
SNRAtio (00:24:29)
You may find the following of interest:
http://bartonpaullevenson.com/Correlation.html
I am but a humble physician, who have been dealing with logic and statistics for some 35 years, so I obviously have no idea of what I am talking about. But….if we have historical records indicating that you could grow grain in Greenland (and the name was not given for false advertising) until sometime in the 14th century, it would stand to reason that the temperature was somewhat higher than today. At the same time there is no current rush to grow temperate crops in Greenland. In the bronze age (danish) people appear to have been using much lighter clothes (Egtved Pigen etc), which would suggest the average temperature was a bit warmer than today – although you could claim that vikings were always more hardy than contemporary persons. I am still looking for their SUV’s or other polluting implements.
Bottom line – If you want me to take you seriously, you have to document to me what the real change is – above and beyond the natural and for us -so far – unpredictable change in climate.
I must admit that I find the correlation between sun-spots and temperature on earth much more convincing, than anything that has been promulgated by the climate ‘scientists’ so far.
By the way I do resent the idea, that it is a question of what you believe. I was brought up to think of science, not as a religion, but as a falsifiable attempt to describe the world we are living in. – and preparing myself for having my favorite (pet) superstitions revoked.
I am still trying to find out what little I know.
peace
hejde
One should never confuse the academically enlightened with facts that may pollute the purity of their prejudices.
I’m curious as to where the water will come from that is supposed to raise the sea level by, apparently, anything up to 6metres as claimed by various people. My understanding of ice is that it displaces its own volume of water already. Therefor if all floating ice melted, including the polar ice cap, it would not raise the sea level by one milimetre. Only land based snow and ice could affect sea levels. To have a 1 metre rise in sea level the equivalent of 3 metres of ice covering the entire land surface of the world would be needed. Have I got something seriously wrong here or have the doomsayers missed an obvious point?
So how is this being presented?
http://www.skepticalscience.com/Was-there-a-Medieval-Warm-Period.html
Sorry for the delay, but I handled the questions on my site. There is only one of me 🙂
People have lost the big picture in the details. Everything Slioch says (and others) doesn’t change the main points one iota, even if it was definitively correct, and it isn’t.
The main points:
1. The Hockey Stick was fraud. It bears no resemblance to literally hundreds of other studies which all agree in the main with each other and which are backed up by artifacts from archaeological digs as well.
2. The MWP existed – and no large models produce it, because CO2 was low then and they all exaggerate the effects of CO2. Ergo, the models are wrong about the past. They are wrong about the future.
3. The Little Ice Age was real – and the world was warming for a century at the same rate it is now, even before SUV’s and coal fired power stations. CO2 was not the driver.
4. Nit-picking on the difference from 1934 – 2000 using a different method of temperature measurement (thermometers) than what the other hundreds of studies use is not a serious blow to the other studies, indeed it’s a blow to the GISS dataset. We already know there are many many reasons to question the GISS version or the GHCN versions (Darwin, China, Russia, NZ…) It’s the divergence problem again. If the other studies show that the world has not warmed much since the 1930’s, maybe the surface thermometers (or the database of those records) is the real problem? Not that that was a point I was making in this post. My point was that the other records fit together reasonably well. The two standout sets that bear no resemblance to all the rest are Mann and Briffa, and for other reasons, (statistical analysis, missing data sets, one sigma-8 tree in Yamal etc) we know these graphs to be scientifically bogus.
Whether the MWP was 0 degrees warmer or 1 degree warmer doesn’t change the fact that the Hockey Stick was wrong, and the models are also flawed.
Having said that I still think it was warmer in the MWP and the “0.5 degrees” is reasonable.
There are hundreds of proxies that suggest it was of this rough order or even more. The boreholes suggest it was. (Craig Idso also tells me he has another 500 papers to enter into his database, and the trend looks similar, and he thinks the MWP was probably 1 degree warmer, see my update.) Plus we know europe was warmer, and Greenland was – (from bones in Permafrost, grapes in England, etc etc etc). Loehles graph was the icing on the cake.
Obviously the amount of warming is up for debate. But really, why would anyone assume that GISS is exactly right when other data disagrees? Anthony himself has shown there are problems with 89% of the station sitings.
Huang and Pollack make this mistake when they “debunk” their own earlier work. See my second update http://joannenova.com.au/2009/12/fraudulent-hockey-sticks-and-hidden-data
“Huang’s reasons for discounting his earlier work essentially say “my new graphs match the IPCC better”, but since ClimateGate blows away the pretense that the IPCC is a reasonable source of info, and that Mann, Briffa and all their derivatives are meaningful, I think we can discount Huang’s reasons.”
I studied paleo-climatology (ie. past climates) at uni only 2 years ago. I think what you are all getting confused about is you think that the presence of the MWP ‘debunks’ the global warming theory. In actual fact it supports it.
The medieval warm period did happen, no scientists or palaeo-climatologists deny that. BUT the MWP and the little ice age can both be explained by changes in the way the earth rotates around the sun. These changes happen in cycles, known as the Milankovitch-Croll cycles.
http://en.wikipedia.org/wiki/Milankovitch_cycles
They’ve been known about for ages, and are also the cause of the past ice ages. The difference with the CURRENT warming is that it is the only warming that CANNOT be explained by the Milankovitch-Croll cycles. This means that it has been induced by us. In addition to that, the RATE of warming is increasing.
Please, before reading these sceptics websites, go to an unbiased one. Or even better, go read the journal articals yourselves, and make your own conclusions. I don’t know any single scientist or anyone who has studied past climates who would argue against global warming. Do not assume that they don’t know what they are talking about, and don’t assume that they don’t know about the MWP!!
[REPLY – We have past posts on the Milankovitch Cycles, in case you didn’t know. Those occur over thousands of years and I have never seen the MWP ascribed to any of them. Which of the three (four, if you include Inclination) was responsible? Usually the MWP is correlated with grand solar minimums, but no direct causal link has been established as of yet. And as for “bias”, you’ll find less of it here than on almost any other site, including Wikipedia. And very few here dispute global warming. We question the amount, the metrics, the methods (esp. recently) and the cause(s). ~ Evan]