New paper finds temperatures were as much as 0.5c warmer in the Arctic during the MWP than today.
The Hockeyschtick reports: A paper published yesterday in Global and Planetary Change reconstructs temperatures in Northern Fennoscandia [within the Arctic circle] over the past 1,600 years and finds more non-hockey-sticks clearly demonstrating that the Arctic was warmer than the present during the Medieval Warm Period. The paper adds to over 1,000 peer-reviewed published non-hockey-sticks finding the Medieval Warm Period was global, as warm or warmer than the present, and that there is nothing unusual, unnatural, or unprecedented about the current warm period.
Furthermore, the authors find a natural 70-80 year oscillation of temperatures, similar to the 60-70 year oscillation of the natural Pacific Decadal Oscillation [PDO].
So much for “Arctic amplification.”
All four of these temperature reconstructions show the Medieval Warm Period ~1000 years ago was warmer than the present [year 2000].
Fig. 1. Different estimates of Northern Fennoscandian temperature anomalies between 400-2000 AD. Shown are the present conventional estimate (Ttorn, green) which is rather close to that in Grudd08, the present filtered estimate (Tlong, blue), smoothed temperatures of Esper12 (Tesp, red) and smoothed August SST reconstruction from the Norwegian Sea (black).
Fig. 3. August SST [sea surface temperature] reconstructions from the south of Iceland (above, blue) and the Norwegian Sea (below, blue) (modified from Miettinen et al., 2012). Red solid lines show smoothed values.
The new temperature reconstruction presented by this paper shows the Medieval Warm Period [~1000 years ago] in the Arctic was warmer than the present [year 2000] temperatures.
Fig. 4. The present estimate of the climatic temperature anomalies (red, Tclim = Tesp + Tsea + Tvolc), and Tesp from Fig. 1 (thick blue).
The paper: http://www.sciencedirect.com/science/article/pii/S0921818114000253?np=y
A 70-80 year peridiocity identified from tree ring temperatures AD 550 – 1980 in Northern Scandinavia
Juhani Rinne, Mikko Alestalo, Arto Miettinen
Highlights
• Volcanism and millennial variations
• Decadal (volcanic) variations
• Multidecadal (oceanic) variations
• Climate variations as seen in tree-ring temperatures
• Biases in the Torneträsk paleotemperatures
Abstract
The classical Maximum Density data of 65 Torneträsk trees from years 441-1980 AD are studied in millennial, centennial and volcanic scales. The millennial scale is analyzed applying a specific filtering method. In that scale, the climate is cool after 1200-1400 AD. This more or less steady period is suggested to be due to volcanic episodes, which reduced the northward heat transport in the North Atlantic. The century scale variation, on the other hand, is suggested to be due to [natural] internal oscillations in sea surface temperature (SST) and to be connected to variations in the Arctic sea ice. Specifically, these oscillations have caused an additional warming and cooling trend in Northern Fennoscandian temperatures before and after 1930’s, respectively.
Variations in the temperature estimates are explained by the results for different temporal scales. All of them show local impacts leading to differences when compared with hemispheric estimates. The long-term estimate of the temperature as derived from the present Torneträsk data is found to be biased. The source of that is unknown.
Source: The Hockeyshtick
Nick Stokes says:
January 28, 2014 at 11:24 pm
OK today (Wed) but 42°C yesterday. Heat forecast for the weekend.
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I see that. Then it drops back to high 70s on Monday. Enjoy the warmth. Ninety nine F is a nice temp.
goldminor says: January 29, 2014 at 1:45 am
I don’t think we’re seeing the same forecasts. Here it’s 41°C for Sunday. That’s 106°F. 95°’F for Saturday.
I only remind – for those denying the credibility of the data from the Torneträsk, this paper:
Potential bias in ‘updating’ tree-ring chronologies using regional curve standardisation: Re-processing 1500 years of Torneträsk density and ring-width data, T. M. Melvin, H. Grudd & K. R. Briffa , 2012-13 (http://hol.sagepub.com/content/23/3/364.abstract): “Some previous work found that MXD and TRW chronologies from Torneträsk were inconsistent over the most recent 200 years, even though they both reflect predominantly summer temperature influences on tree growth. We show that this was partly a result of systematic bias in MXD data measurements and partly a result of inhomogeneous sample selection from living trees (modern sample bias). We use refinements of the simple Regional Curve Standardisation (RCS) method of chronology construction to identify and mitigate these biases. The new MXD and TRW chronologies now present a largely consistent picture of long-timescale changes in past summer temperature in this region over their full length, indicating similar levels of summer warmth in the medieval period (MWP, c. ce 900–1100) and the LATTER HALF of the 20th century.”
Also I remind that not only the MWP-MCA had “… similar levels of … … warmth …” as “… the latter half of the 20th century.”
For example 20 December 2013 was published paper : “External forcing of the early 20th century Arctic warming.”, Suo et al. :
“The observed Arctic warming during the early 20th century was comparable to present-day warming in terms of magnitude.”
“… intensified solar radiation and a lull in volcanic activity during the 1920s–1950s can explain much of the early 20th century Arctic warming.”
“… the local solar irradiation changes play a crucial role in driving the Arctic early 20th century warming.”
P.S. The conclusions of the work Suo et al. (and another similar papers) very well correspond with the conclusions Semenov and Latif 2012 (http://www.the-cryosphere.net/6/1231/2012/tc-6-1231-2012.pdf): “This suggests that a significant reduction of winter Arctic sea ice extent may have also accompanied the early twentieth century warming …”
… what “breaks” hockey stick for the arctic ice: arctic ice extent now and in the 20 – 30’s are probably similar (just like its surface).
Should the sub-title not read “New paper finds temperatures were as much as 0.5c warmer in the Arctic during the MWP than the year 2000.”?
Has anyone any information on arctic temperature anomalies since 2000?
goldminor says: @ur momisugly January 28, 2014 at 6:13 pm
You might want to look at this: http://images.remss.com/data/msu/graphics/tlt/medium/global/MSU_AMSU_Channel_tlt_Trend_Map_v03_3_1979_2013.730_450.png
It does a very nice job of illustrating the Bipolar Seesaw<
Nick Stokes says:
January 29, 2014 at 3:22 am
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I was looking at Meteo/France24 weather site. I see that they have changed their forecast from 99F to 102F for this coming Saturday. They also added an extra 5 degrees to the next two days, Sunday and Monday.
@ur momisugly Gail…thanks for the link!
Just to echo TimTheToolMan:
One theory being put out today is that the temps are really still going up, but it’s hiding in the Arctic where they have a dearth of data. So how do some warmers reconcile calling the MWP a regional warming while calling the exact same warming today global?
Has anyone published what % of the earth has participated in the fractional degree of warming over the last three decades? For the last thirty years, at least, it appears Antarctica has not. Just how global has the warming been?
I wonder, has anyone bothered to dig through the records of the Hanseatic traders? It might be interesting to see how their records correlate with the tree records. Doing tangentially related research, I did hit a comment in a Norwegian court record stating that the last Hanseatic trade ship visited Greenland in 1386. Now granted, it was buried in a non-indexed court roll written in Old Norse circa 1400…
There is loads of evidence for how the end of the MWR directly affected politics, economy, social structure. I’ve always thought it might be a valuable lesson from history. But it would mean acknowledging that Climate Change is not the end of the world…
RichieP says:
“This is not remotely the case.”
But it is! There is also truth in what you say. I did not say this was their total history but it was, indeed, a part of their early history. The very term “to go Viking” referred to raiding up channels, inlets and bays. It was a part of their history, as with many other peoples who learned to sail the early oceans and rivers and had the military skills to raid along the waterways. No shame in ths since most everywhere people live today was taken by force from one group by another at some point. Trade and warfare commingled during many eras.
Janice Moore says:
“I sure hope those words aren’t saying anything disgusting… I have no idea!”
Well then, time for a lesson in Swedish!