Nicola Scafetta sends this along, I found this figure quite interesting, but there are many more in the full PDF available below.
A regional approach to the medieval warm period and the little ice age
Fredrik Charpentier Ljungqvist
Stockholm University
Sweden
1. Introduction
In order to gain knowledge of the temperature variability prior to the establishment of a widespread network of instrumental measurements c. AD 1850, we have to draw information from proxy data sensitive to temperature variations. Such data can be extracted from various natural recorders of climate variability, such as corals, fossil pollen, ice-cores, lake and marine sediments, speleothems, and tree-ring width and density, as well as from historical records (for a review, see IPCC 2007; Jones et al. 2009; NRC 2006). Considerable effort has been made during the last decade to reconstruct global or northern hemispheric temperatures for the past 1000 to 2000 years in order to place the observed 20th century warming in a long-term perspective (e.g., Briffa, 2000; Cook et al., 2004; Crowley and Lowery, 2000; D’Arrigo, 2006; Esper et al., 2002; Hegerl et al., 2007; Jones et al., 1998; Jones and Mann, 2004; Juckes et al., 2007; Ljungqvist, 2010; Loehle, 2007; Mann et al., 1999; Mann et al., 2008; Mann et al., 2009; Mann and Jones, 2003; Moberg et al., 2005; Osborn and Briffa, 2006).
Less effort has been put into investigating the key question of to what extent earlier warm periods have been as homogeneous in timing and amplitude in different geographical regions as the present warming.
It has been suggested that late-Holocene long-term temperature variations, such as the Medieval Warm Period (MWP) and the Little Ice Age (LIA), have been restricted to the circum-North Atlantic region (including Europe) and have not occurred synchronic in time with warm and cold periods respectively in other regions (Hughes and Diaz, 1994; Mann et al., 1999; Mann and Jones, 2003). This view has, however, been increasingly challenged through the ever growing amount of evidence of a global (or at least northern hemispheric) extent of the MWP and the LIA that have become available (see, for example, Esper and Frank, 2009; Ljungqvist, 2009, 2010; Moberg et al., 2005; Wanner et al., 2008).
A main obstacle in large-scale temperature reconstructions continues to be the limited and unevenly distributed number of quantitative palaeotemperature records extending back a millennium or more. The limited number of records have rendered it impossible to be very
selective in the choice of data. Palaeotemperature records used in a large-scale temperature reconstruction should preferably be accurately dated, have a high sample resolution and have a high correlation with the local instrumental temperature record in the calibration period (see the discussion in Jones et al., 2009).
The number of long quantitative palaeotemperature records from across the globe, of which a majority are well suited for being used in large-scale temperature reconstructions, have been rapidly increasing in recent years (Ljungqvist, 2009). Thus, it has now become possible to make regional temperature reconstructions for many regions that can help us to assess the spatio-temporal pattern and the MWP and LIA. Only by a regional approach can we truly gain an understanding of the temperature variability in the past 1–2 millennia and assess the possible occurrence of globally coherent warm and cold periods. Presently, only four regional multi-proxy temperature reconstructions exist: two for eastern Asia (Yang et al., 2002; Ge et al., 2010), one for the Arctic (Kaufman et al., 2009), and one for South America (Neukom et al., 2010). Six new quantitative regional multi-proxy temperature reconstructions will here be presented in order to improve our understanding of the regional patterns of past temperature variability.
…
4. Conclusion
The presently available palaeotemperature proxy data records do not support the
assumption that late 20th century temperatures exceeded those of the MWP in most regions, although it is clear that the temperatures of the last few decades exceed those of any multidecadal period in the last 700–800 years. Previous conclusions (e.g., IPCC, 2007) in the opposite direction have either been based on too few proxy records or been based on instrumental temperatures spliced to the proxy reconstructions. It is also clear that temperature changes, on centennial time-scales, occurred rather coherently in all the investigated regions – Scandinavia, Siberia, Greenland, Central Europe, China, and North
America – with data coverage to enable regional reconstructions. Large-scale patterns as the MWP, the LIA and the 20th century warming occur quite coherently in all the regional reconstructions presented here but both their relative and absolute amplitude are not always the same. Exceptional warming in the 10th century is seen in all six regional reconstructions.
Assumptions that, in particular, the MWP was restricted to the North Atlantic region can be rejected. Generally, temperature changes during the past 12 centuries in the high latitudes are larger than those in the lower latitudes and changes in annual temperatures also seem to be larger than those of warm season temperatures. In order to truly assess the possible global or hemispheric significance of the observed pattern, we need much more data. The
unevenly distributed palaeotemperature data coverage still seriously restricts our possibility to set the observed 20th century warming in a global long-term perspective and investigate the relative importance of natural and anthropogenic forcings behind the modern warming.
Full report here (PDF)
a_regional_approach_to_the_medieval_warm_period_and_the_little_ice_age
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Is this in press or what?
Eight of 26 pages are references. Just sayin…
Interesting things. Recent May-Sept temps are not as elevated as winter. China and Europe are only regions as warm today as during MWP. That must be where the people most responsible for post-industrial warming are residing. Nice.
Ljungqvist’s blog is here (in Swedish)
http://blogs.su.se/fchar/
and Google translate here
http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=sv&tl=en&u=http%3A%2F%2Fblogs.su.se%2Ffchar%2F
The paper was self-published apparently and available as part of an anthology here
http://www.intechopen.com/books/show/title/climate-change-and-variability
He does not mention whether he tried to publish it in a peer reviewed journal.
Craig Loehle has compared another paper by Ljungqvist with his own results on extratropical northern hemisphere temperature reconstructions here at WUWT and found a good correlation.
http://wattsupwiththat.com/2010/09/28/loehle-vindication/
The assumption that late 20th century warming is man made rests on two lines of “evidence”:
1. Present warming is unprecedented for the last 2000 years (hockey stick, etc)
2. Climate models can not reproduce 20th century warming without man made CO2 as a decisive factor in the equation.
Both have now been called into question.
1. Present warming is not unprecedented on at least a hemispheric scale.
2. If there was a similar warming 1000 years ago, we know that present warming can also be caused by natural variability, no matter if models can not reproduce it.
It will be interesting to see how the IPCC will deal with this. My guess is that the Team Machine will kick into action, that there will be serial “debunkings” of these results, and that the IPCC will stick to the good old story.
eadler says:
November 24, 2010 at 3:15 pm
I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.
Oh, dear! It may have slipped past the climate gatekeepers.
Alan Simpson etc. – tonyb is hardly a paid alarmist . I suggest you review his comments and occasional posts here .
eadler says: November 24, 2010 at 3:15 pm
I never heard of Fredrik Charpentier Ljungqvist, so I tried to find out using Google. It seems he is a graduate student in the department of history at Stockholm U. It was published in the Journal of the Swedish Society for Anthropology and Geography. I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.
——————————————————————————–
Eadler This statement says more about you than it does Ljungqvist. Why don’t you try to ‘deconstruct’ it yourself and give us the benefit of your endeavours.
Douglas
Nice hockey stick. The blade is a bit small, though.
All Your Base Are Belong To Us
.
EW says: November 24, 2010 at 4:15 pm
“that Briffa’s (2000) Yamal trees show too much of an increase in 20th century compared to other circum-Arctic”
Those other circum-Arctic trees were missing the necessary Briffa adjustments.
valadj=[0.,0.,0.,0.,0.,-0.1,-0.25,-0.3,0.,-0.1,0.3,0.8,1.2,1.7,2.5,2.6,2.6,2.6,2.6,2.6]*0.75 ; fudge factor
yearlyadj=interpol(valadj,yrloc,x)
densall=densall+yearlyadj
Source of above IDL Source Code:
“FOI2009/FOIA/documents/harris-tree/briffa_sep98_e.pro”.
See Also: http://www.thespoof.com/news/spoof.cfm?headline=s5i64103
Billy Liar says:
Oh, dear! It may have slipped past the climate gatekeepers.
Here, let me fix that for you…
It may have slipped past the climategate keepers.
Leif… I’d be interested in your thoughts on the following passage starting at the bottom of page 17:
Although it is outside the scope of this article, we can briefly discuss the possible influence of variations in solar and volcanic forcing on the reconstructed temperatures. All the six 18 Climate Change and Variability regional temperature reconstructions show some agreement with the assumed lowfrequency variability in solar forcing of the last 12 centuries (Bard et al., 2000). The medieval period, with high temperatures, had a general high solar activity, whereas the cold LIA was dominated by lower solar activity (Ammann et al., 2007). The warming in the 20th century coincides with an increase in solar forcing, although the warming trend has probably also been amplified in the last decades by anthropogenic greenhouse gas emissions (IPCC, 2007).
AJ says:
November 24, 2010 at 7:38 pm
All the six 18 Climate Change and Variability regional temperature reconstructions show some agreement with the assumed lowfrequency variability in solar forcing of the last 12 centuries (Bard et al., 2000).
The ‘some agreement’ is very weak [and mostly a hangover from Jack Eddy’s notion of the Little Ice Age caused by the Maunder minimum]. If we look at modern reconstructions there is no agreement of significance: http://www.leif.org/research/Loehle-Temps-and-TSI.png
The top panel is a temperature reconstruction, the middle panel a recent reconstruction of solar activity [expressed as TSI]. The bottom panel is a comparison of 10Be [blue] and 14C [red] variations. I recently gave an invited lecture at the University of Tromsoe on this: http://www.leif.org/research/Does%20The%20Sun%20Vary%20Enough.pdf
This is, of course, just my [reasoned] opinion.
Pamela Gray,
Relax, let the ice sublime.
I found my self uplifted by Fredrik Charpentier Ljungqvist’s blog, education and his understanding of history and climate. He brings an honest well-researched picture of weather and climate history. He writes well, is peer reviewed and published. I have reached to the conclusion that he is the real thing and a breath of fresh air. He has a brilliant future in his profession, as long as he can stay untainted and on the path of honesty and integrity. Please look him up and see if you agree.
Ted.
————————————————————————————–
Speaking of “An Inconvenient Truth: The Earth’s climate has always changed.
The drama documentary “An Inconvenient Truth by Al Gore in 2006 painted a dramatic picture up of global warming, as in the movie entirely attributed to emissions from burning fossil fuels.
The problem with film is that today’s warming is not at all put into a historical perspective.
In An Inconvenient Truth produced it as if today’s temperatures were higher than they’ve ever been before and it is presented as if no climate change of significance had not occurred in history before the 1900s.
The climate has always been highly variable.
In addition, measurable amounts of global warming over the last hundred years to no more than about 0.7 to 0.8 ° C
Disaster scenarios for future warming of as much as 5-6 ° C based on computer models, based on hypotheses about how climate is affected by the emission of a certain quantity of greenhouse gases. “An Inconvenient Truth will be biased by failing to mention that the earth from the 1300s until about in 1900 were in the world’s coldest climate period since the last ice age.
A serious debate about global warming would require a discussion of not warming during the 1900s at least partly be interpreted as a natural recovery from the “Little Ice Age” that lasted between 1300 and 1900.
We have actually returned to an environment similar to what has been the mainstream in a longer historical perspective (any cause)
It may be appropriate to give examples of some past climate changes.
So, for example, large parts of the Sahara were a fertile savannah for only 3000 or 4000 years ago.
Some research indicates that the Mediterranean climate was far up in Central Europe at the time around the birth of Christ.
Climate variations in the last 2000 years has been all cultures to join in the marginal areas as climate and vegetation zones ever been on “walk”.
In the longer term, climate variations have been even greater.
The best example of this is the Ice Ages: the whole of Sweden was covered by a three-kilometer thick ice.
Probably the climate was during the early Middle Ages as hot as it is now. Some studies suggest that average temperatures in many places even higher than today.
When the Arctic is now warming up, we must not forget that the polar regions were at least as hot a thousand years ago.
The tree line in the mountains was then further up and tundra was in many places
The sea ice was also rare along such large parts of Greenland’s coasts.
The reason for this has been left out in An Inconvenient Truth bottoms probably in large part to the impact that the prominent climatologist Michael E. Mann received.
His reconstruction of global mean temperature in the last thousand years does not permit any climate variability and omits both the Medieval Warm Period as the “Little Ice Age
Mann’s temperature reconstruction has been a kind of official status since it gained recognition from the UN’s climate panel (IPCC) and is often used as “evidence” that the current warming only be attributed to the burning of fossil fuels.
While this appears to climate reconstruction increasingly untenable
An increasing number of climate history data (drill samples from glaciers, pollen analysis and analysis of tree rings, etc.) was often indicates the presence of both the Medieval Warm Period and the Little Ice Age
[Comment: Mann published in 2008 a new temperature reconstruction that clearly showed the Medieval Warm Period and the Little Ice Age.]
However, it should not be denied that it is probably true that the enhanced greenhouse effect, as the burning of fossil fuels causes, is one of the factors affecting today’s climate.
But this is hardly the only factor. In a historical perspective, today’s warming to see as an expected and natural recovery after a cold spell.
A good indication that this case is that the global temperature actually fell slightly in 1950 – and 1960’s even though the burning of fossil fuels also increased exponentially.
Author: Fredrik Charpentier Ljungqvist ·
http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=sv&tl=en&u=http%3A%2F%2Fblogs.su.se%2Ffchar%2F
http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=sv&tl=en&u=http%3A%2F%2Fblogs.su.se%2Ffchar%2F
Good paper, So now it is not as bad as was thought!
Pamela Gray and others, I may have related this before, but I knew the last Flight Service Station manager that worked Meacham, Oregon back in the days of the old radio
range and airway beacons. Back in the 70’s I was a NOAA certified weather observer,
on a notably cold January day, Meacham was similarly cold. The FSS Fellow, Ron, as I
recall, said when I turned in the Observations for La Grande, “I see Meacham had another minus twenty today.” “Yep, third this week.” I replied, He said:” You know,
Meacham is a lot like Alaska, Spent a lot of time at North Pole, and Soldatna, Meacham’s
kind of like a little of both, ‘cept Soldatna’s a lot warmer…”
EW says: November 24, 2010 at 4:15 pm
“that Briffa’s (2000) Yamal trees show too much of an increase in 20th century compared to other circum-Arctic”
Those other circum-Arctic trees where missing the necessary briffa adjustments.
valadj=[0.,0.,0.,0.,0.,-0.1,-0.25,-0.3,0.,-0.1,0.3,0.8,1.2,1.7,2.5,2.6,2.6,2.6,2.6,2.6]*0.75 ; fudge factor
yearlyadj=interpol(valadj,yrloc,x)
densall=densall+yearlyadj
Source of above IDL Source Code:
“FOI2009/FOIA/documents/harris-tree/briffa_sep98_e.pro”
See Also:
http://www.thespoof.com/news/spoof.cfm?headline=s5i64103
[these are better posted to Tips & Notes . . mod]
OT but I don’t know if this has been posted on WUWT yet in any thread. This looks like a very important peer reviewed paper just published. This is strong support for Henrik Svensmark’s cosmic ray theory.
See article here:
http://hockeyschtick.blogspot.com/2010/11/paper-compelling-evidence-of-cosmic-ray.html
and the paper here:
http://www.pdfdownload.org/pdf2html/view_online.php?url=http%3A%2F%2Fwww.atmos-chem-phys.net%2F10%2F10941%2F2010%2Facp-10-10941-2010.pdf
In Atmospheric Chemistry and Physics 10, 10941-10948, 2010 doi:10.5194/acp-10-10941-2010
Cosmic rays linked to rapid mid-latitude cloud changes
B. A. Laken 1,2, D. R. Kniveton 1, and M. R. Frogley 1
1Department of Geography, University of Sussex, Falmer, Brighton, England, BN1 9QJ, UK
2Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain
Svensmark’s co-author of The Chilling Stars, Nigel Calder, has been hinting on his blog that we will soon see the first results from Svensmark’s CLOUD experiments at CERN. This paper comes as possibly a surprise precursor (at least to me).
Be on the lookout for tampon bombers!
Please don’t ban me for this.
You will make history by not doing so.
Indulge me;
Frau’s ‘ultimate’ weapon unveiled !
[ http://www.youtube.com/watch?v=WtTNkL3q12Q&feature=related ]
eadler says:
November 24, 2010 at 3:15 pm
“I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.”
Why is it only the ones that support CAGW need to be “deconstructed”?
Where is your concern for these papers and their “deconstruction”:
Briffa, 2000; Cook et al., 2004; Crowley and Lowery, 2000; D’Arrigo, 2006; Esper et al., 2002; Hegerl et al., 2007; Jones et al., 1998; Jones and Mann, 2004; Juckes et al., 2007; Loehle, 2007; Mann et al., 1999; Mann et al., 2008; Mann et al., 2009; Mann and Jones, 2003; Moberg et al., 2005; Osborn and Briffa, 2006).
Sorry, mod, somehow the existence of “Tips and Notes” has escaped this long time WUWT reader.
I have done as you suggested and you can remove the post in this thread if you so desire.
“Less effort has been put into investigating the key question of to what extent earlier warm periods have been as homogeneous in timing and amplitude in different geographical regions as the present warming.”
Is homogeneous really preferable to similar?
Pamela Gray says: (November 24, 2010 at 4:11 pm) I’ve been cleaning house at the ranch in frigid Wallowa County. ..
How did grandma do it, Pamela? Back in the late 1800s? Lysol? where the secret was in the scrubbing…
Stephen Wilde says:
November 24, 2010 at 2:37 pm
Now, the critical question:
Could every one of those observed regional climate changes be accounted for by a simple latitudinal shift of the air circulation systems above the regions concerned ?
But that also begs another question: What would have caused those shifts?
Further, what would have been the cause (driver) of that particular cause?
To presume one thing of necessity demands that its driver be identified.
It’s not unlike this: The spoon stirred the coffee. A hand caused the spoon to move. The brain of the owner of that hand caused the hand to move and stir the coffee.
If we look only at the spoon, we’ll miss/neglect its driver. Heck we might even misattribute the cause to something entirely unrelated.
With all of the various data which have been collected, and all of the anecdotes (historical references) from ages past, with all of the ice core data and the sun spot data having been analysed, there are few other effects which haven’t been otherwise determined as having affect, such as planetary gravitational influences and the Sun’s current sheets inducing heating in the upper atmosphere by interacting with the Earth’s own magnetosphere.
Knowing what we know already, even if we don’t completely comprehend the lot of it, the correlations in all of the collected information are overwhelmingly in favor of external forces as having the greatest affect upon this planet’s climate and weather.
With the mass of information available, there’s just no way that humans could have caused any of the past events, and since the past events happened when humans weren’t a viable cause for those, and those past events are cyclic in nature, and because the current event is happening with the same periodicity, then there’s no way that humans could even be considered as any kind of agent.
It’s staring us in the face, and yet there are people with a vested interest telling us to ‘Don’t look behind the curtain!!!’
Gee, I wonder why?
Why? They’ll see Al Gore and his banker buddies staring back at us, with the greedy smiles of vampires just waiting for darkness to set in.