In a paper published in the Journal of Quaternary Science, Esper et al. (2014) write that tree-ring chronologies of maximum latewood density (MXD) “are most suitable to reconstruct annually resolved summer temperature variations of the late Holocene.” And working with what they call “the world’s two longest MXD-based climate reconstructions” – those of Melvin et al. (2013) and Esper et al. (2012) – they combined portions of each to produce a new-and-improved summer temperature history for northern Europe that stretches all the way “from 17 BC to the present.” And what did they thereby learn?
As the international team of researchers from the Czech Republic, Finland, Germany, Greece, Sweden and Switzerland describes it, this history depicts “a long-term cooling trend of -0.30°C per 1,000 years over the Common Era in northern Europe” (see figure below). Most important of all, however, they note that their temperature reconstruction “has centennial-scale variations superimposed on this trend,” which indicate that “conditions during Medieval and Roman times were probably warmer than in the late 20th century,” when the previously-rising post-Little Ice Age mean global air temperature hit a ceiling of sorts above which it has yet to penetrate.
And so we continue to collect ever more real-world evidence for the fact, that there is nothing unusual, unnatural or unprecedented about the Earth’s current level of warmth.
Paper Reviewed
Esper, J., Duthorn, E., Krusic, P.J., Timonen, M. and Buntgen, U. 2014. Northern European summer temperature variations over the Common Era from integrated tree-ring density records. Journal of Quaternary Science 29: 487-494. http://onlinelibrary.wiley.com/doi/10.1002/jqs.2726/full
Full paper PDF: http://www.blogs.uni-mainz.de/fb09climatology/files/2012/03/Esper_2014_JQS.pdf
References
Esper, J., Frank, D.C., Timonen, M., Zorita, E., Wilson, R.J.S., Luterbacher, J., Holzkamper, S., Fischer, N., Wagner, S., Nievergelt, D., Verstege, A. and Buntgen, U. 2012. Orbital forcing of tree-ring data. Nature Climate Change 2: 862-866.
Melvin, T.M., Grudd, H. and Briffa, K.R. 2013. Potential bias in ‘updating’ tree-ring chronologies using Regional Curve Standardization: reprocessing the Tornetrask maximum-latewood-density data. The Holocene 23: 364-373.
h/t to CO2science.org and D.W. Schnare
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The hockey stick replaced by a pool cue. Looks promising to me, if elegance and precision is promoted instead of gang fights.
Michael Mann will be right on this. Tree rings at thirty paces. I don’t have much confidence in tree rings, even if they do give the result I think is correct.
Cool…..
Hmmmm.
Since these tree-rings are recording moisture, more than temperature, they seem to have proven that it was:
Wet in the Roman period. 0AD
Dry as the Western Roman Empire fell. 400 AD
Wet in the late Dark Age. 1000 AD
Dry in the Middle Ages onwards. 1400 AD plus.
Or am I missing something here……?
Ralph
ralferris No – in general cooler periods are dryer and warmer periods more humid – although there is considerable regional variation as the climate belts and winds shift north and south.
Whether tree growth correlates with temp or moisture depends upon which is the limiting factor in a given area. Rainfall is high in Northern Europe, so it is not the limiting factor there. Temperature is probably the controlling factor, but what aspect of temperature? Length of growing season in Northern Europe is probably more of a factor for tree growth than peak summer temperature.
The 2 may correlate. If they do, since humans tend to measure summer warming by peak temperatures, the trees and humans may even agree on which summers are weak, which strong.
SR
They say this is based on density of late season wood rather than ring thickness. That may correlate better with temperature, but than again it may not. I imagine one would have to do a very detailed (and probably impossibly expensive) botany experiment with these species of trees where one had thousands of green houses set up to control for all the various temperature, nutrient, CO2, and water profiles and grow trees for a hundred years and see how the ring characteristics lined up against the control parameters. Then we might get to the bottom of the whole treemometer problem.
Treemometers may not be a reliable source for the temperature record but they may be a good guide to general liveability conditions for life on the Earth.
Interestingly we were always told the Viking raids and settlement were due to poor cold seasons but this record seems to suggest the warming of the Eighth, ninth and tenth centuries allowed their expansion, particularly into a less frozen Russia. Not so much victims of climate shift but rather opportunists.
I seem to recall something like Briffa’s tree ring data graphs showed only one tree with a hockey stick, and that was the one used by Mann. Can anyone confirm that?
You’re way off. In Mann’s original hockey stick, Briffa’s Yamal series was not used. Mann obtained his HS by overweighting one set of cores (American Southwest Bristlecones) over all others. Briffa did something similar with his One Tree in Yamal, but his is a different reconstruction.
The trouble is if we argue that tree make has good a guide to past temperatures has pine cones do to future temperatures , when it comes to Mann and co ‘work ‘ Then we cannot be happy with them when the produce data we like .
The reality is any historic proxies in this area are ‘problematic’ to say the least , ‘better than nothing ‘ and ‘we think’ are issues which dog proxies to such an extent that in reality their value , for or against , AGW has to be consider as poor at best. We would never expect such poor quality modern measurements, can we really justify accepting them from the past on the grounds of ‘there better than nothing ‘ given what is being based on them?
+1
I always take proxies with a pinch of salt.
What do you do when six or seven different “proxies” all show the same thing?
No one says that tree rings don’t respond to local climate, David. But temperature is a thermodynamic quantity. There is no physical theory that permits converting tree ring metrics into temperature degrees. Term assignment by statistical fiat is not science.
You didn’t answer my question.
Here’s your answer, David:
You take it to Climate Audit and watch the experts take it apart.
Mpainter…
What do YOU say when six or seven different “proxies” are all in agreement?
Here’s a specific answer David. When several proxies show the same thing, what “thing” are they showing?
Your question implies that the shapes of proxy series are uniquely determined, i.e., by a single causal element.
Your implicit assumption is unwarranted. Proxy shapes are multiply determined. The impact of each causal element is unknown. Different arrays of multiple causes can produce a proxy series of similar shape.
That means proxy series can have similar shapes even when the array of causal determinants is disparate. The proxies then are not showing the same “thing.” They are merely statistically correlated. No specific physical meaning can be extracted from that correlation. No one knows what “thing” it was that caused the proxy series to have that shape, because there is no valid physical theory of proxy structure.
That judgment includes proxies that happen to be correlated with measured temperatures. No one knows why certain proxies correlate with temperatures. It’s just asserted in the field that correlation with temperature implies causation by temperature. That assertion is entirely unjustifiable, physically.
The take-home realization as regards science, David, is that when an experiment cannot produce a unique solution, any specific interpretation of the observable is impossible. Any interpretation that is forced, such as we see in the Esper paper (the forced interpretation is, ring density = temperature), is spurious and physically meaningless.
The fact that such nonsense is ubiquitous in proxy climate studies, has been so for 20 years, and is generally unchallenged, indicates only that the entire field has descended into pseudo-science.
Pat Frank — I second that
David,
I have seen so many of these multiproxy studies examined in detail at Climate Audit.
It is clear that there is only one temp. proxy that has any demonstrate temp. dependency: d18O.
Even that proxy is tricky in such applications as cave deposits.
Otherwise, the temperature proxies fall short of my standards of scientific rigor. So, no thanks. As Pat Frank points out, these temp. proxies are just bs flung on the wall.
Guess David Socrates had nothing left to say.
Reblogged this on The GOLDEN RULE and commented:
So where is the evidence that Carbon is a significant factor in global temperature trends?
Air pollution needs controlling, but what has that to do with carbon controls and costs?
So where is the justification for the political and financial controls?
Perhaps world government agenda is the real reason!
Esper always comes out with some cool stuff. Me. I think it was “Dark” during the Dark Ages.
Reblogged this on Public Secrets and commented:
Bad news for the Warmist cult: Empirical evidence shows not only a millennia-long cooling trend, but that prior warming periods were warmer than the late-20th century peaks. Darn those “inconvenient truths.”
Please find here the complete paper
The next thing you know Mike Mann will come out and say tree rings is a poor proxy for past temperatures.
It’all a question of ethics 😀
Additional to Jan Esper:
A certainly well known paper from 2012
Does a tree core produce the same results if you core the tree from the north side, the east side, the west side or the south side? Nope.
Does a tree core produce the same results if you core the tree 2 feet from the ground, 4 feet or 10 feet from the ground? Nope.
Does a tree core match a nearby tree that has the same age? Nope.
If you core a bristlecone pine tree, what do you get? Nothing of any use. The tree is three-quarters dead on a continual basis and the 3 quarters is constantly moving around the tree throughout its 5,000 year lifespan. It tells you nothing about temperature, just which one-quarter of the tree was alive in the year 553 AD. Naturally, these trees form the main part of the hockey stick. Random cherry-picking potential that is.
The current tree ring science is more like astrology.
They could make it a real science again, If they used carbon dating and proved a dO18 isotope-temperature relationship. Then they could use the carbon dates and the dO18 isotopes like the ice cores do. But i think this has only been tried one time.
The other use of tree rings and carbon dating is to find the northern tree line limit with fossil trees. Naturally, this shows a warm Holocene and a warm MWP and a cold Little Ice Age and no northern expansion of the tree line in recent times. Plant a tree in the Yamal Peninsula where forests grew naturally 5,000 years ago. Will it survive today? Nope.
My feelings exactly . When we took the children on country walks and came across the stump of a cut tree we would get them to count the rings and estimate the tree age and also told them that the pattern of thick and thin rings could be used to determine the age of timbers in , say , an old manor house because thickness depended on how good a summer it was that corresponding year..
Then of course their little fingers would trace the same ring around the trunk and point out that it was thick in one part and thin in another and they would look to me , a bit suspiciously, for an explanation . A bit of waffling , then the walk resumed with 3 small boys having a somewhat diminished respect for the superiority of adult knowledge.
Ha, nice one – your kids did the same, eh?
This is the trouble with kids, they have no preconceived ideas, no specific creed to follow, and a degree of honesty boardering on the suicidal. (quote: ” Granny, why did you not shave this morning…….?”)
And yes, the tree rings are all different shapes and sizes around the tree, as they gleefully pointed out. How can dendrothermists possibly derive a tree-ring profile, based upon any degree of scientific honesty?
If you were coring trees [from] London in many decades time (the ash, I think), you would see that London was gripped by a severe Ice Age from 2010 to 2014, with tree rings measured in micrometers. Actually, it was a severe blight infestation – but not according to the dedrothermists…..
Ralph
Remember that a cut tree stump is but a two dimensional sample of a three dimensional object, and that just one of many such objects.
Tree core boring, is even worse. You get a one dimensional sample of a four dimensional object.
Pick a lucky angle at a lucky height on a lucky tree, and you might believe anything, you find.
If somebody had bored a six inch hole 18 feet deep in South Africa back a100 or more years, they might have concluded that the whole of Africa was sitting on a layer of flawless type II-A diamond, from the core that they retrieved.
Instead they had just found the smaller piece of the Cullinan Diamond. Well actually it was sitting in the wall of an 18 ft deep tunnel somebody had already cut, destroying the other piece in the process (maybe).
That is why we have a Nyquist Sampling Theorem.
To stop people supposing, what that object really is, that they are touching in the dark.
Oooops!
If I read the comments above correctly, a person should never put a solved-for trend line on climate data. Person A will say it’s cherry picking, and Person B will say there’s not enough data, or not the right kind of data, to put a valid trend line on.
That’s cool. Sauce/goose/gander. Let the data speak for itself, and let each person draw their own conclusions, because the so-called “experts” are certainly not in agreement.
Re:Dr Page @ur momisugly 12:15 The present solar cycle is not yet down for the count. Instead of a couple months, try 2-3 years or more.
Victor See graph at
http://www.ips.gov.au/Solar/1/6
The Nov number was 70.1 and needs to be added
Peak cycle 24 SSN was Feb 2014 – the neutron count low ( activity peak) usually lags by 1yr+/- so we are getting close to neutron count low ( activity high )
The actual SSN will vary widely above and below the blue line on the way down.
Are you really suggesting that the 24 SSN peak is still 2 – 3 years away? That would be a very unusually long cycle.
The problem with proxy data is that they only approximately record conditions in one particular location.
As a geologist, I’m more swayed by “macro” data that reflect (at least) regional changes over long periods.
Where dead-tree forests are found above modern tree-lines, I have to conclude that conditions were more favorable (warmer, wetter) than today when those dead-tree forests grew.
Where modern continental glaciers melt back and expose former forests and human habitations, I have to conclude that conditions were more favorable (warmer, wetter) than today prior to the advance of these Little Ice Age glaciers.
These observations are not local or sub-regional. They have been validated in both northern and southern hemispheres – these warmer past climates are truly global.
It’s also demonstrable that, prior to about 2 million years ago, the entire planet was far warmer than today – for millions and millions of years. Modern mammals, apes, poley bears, and homonids all evolved and survived those warmer conditions, and evolved to adapt to the anomalously cold conditions of the Pleistocene and Recent epochs
CO2 doesn’t make a bit of difference on the geologic timescale
Many of these posts are missing an important point. The tree ring data and the GL ice core data measure temperatures at very different parts of the globe. There is no reason to think northern Europe and high-altitude GL should change temperature proportionally to each other.
Tree are useless as a temperature proxy, because they react at least as much to precipitation. So this study is of zero value.
From Esper et al., 2012
http://www.nature.com/nclimate/journal/v2/n12/full/nclimate1589.html
Solar insolation [radiation] changes, resulting from long-term oscillations of orbital configurations, are an important driver of Holocene climate. The forcing is substantial over the past 2,000 years, up to four times as large as the 1.6 W m−2 net anthropogenic forcing since 1750, but the trend varies considerably over time, space and with season. Using numerous high-latitude proxy records, slow orbital changes have recently been shown to gradually force boreal summer temperature cooling over the common era. Here, we present new evidence based on maximum latewood density data from northern Scandinavia, indicating that this cooling trend was stronger (−0.31 °C per 1,000 years, ±0.03 °C) than previously reported, and demonstrate that this signature is missing in published tree-ring proxy records. The long-term trend now revealed in maximum latewood density data is in line with coupled general circulation models indicating albedo-driven feedback mechanisms and substantial summer cooling over the past two millennia in northern boreal and Arctic latitudes. These findings, together with the missing orbital signature in published dendrochronological records, suggest that large-scale near-surface air-temperature reconstructions relying on tree-ring data may underestimate pre-instrumental temperatures including warmth during Medieval and Roman times.
http://www.nature.com/nclimate/journal/v2/n12/images/nclimate1589-f2.jpg
Watch out! One might assume now that a postal Mann is going around….
Can I just go back some way to Janne’s posting of the two graphs. Call me old fashioned, call me a retired risk analyst (if you must), but I couldn’t help noticing that the time scale of the two graphs overlaps by a number of years and that to the nearest degree the GRIP data is roughly 5 degrees warmer during that period of overlap. That suggests to an old school chap like me that any comparison is utterly meaningless.
So Anthoy Watts has got his logic wires comprehensively tangled (once again).
“And so we continue to collect ever more real-world evidence for the fact, that there is nothing unusual, unnatural or unprecedented about the Earth’s current level of warmth.”
A study, not in Europe (a small part of the earth’s surface), a study not even covering Northern Europe (an even smaller place), but a study covering “northern Scandinavia” (part of Northern Europe) can be extrapolated world-wide??
Would one warming weather station’s data be considered “ever more real-world evidence for the fact that” the world was warming? I think not!
[ dear “idiot”, you’ve got some issues…
1. The article was written by Craig Idso at CO2 Science, not Anthony – note the hat tip http://www.co2science.org/articles/V17/dec/a19.php
2. Anthoy is actually spelled Anthony
3. You seem OK with small regional sampling such as Mann’s Sheep mountain Bristlecones, now debunked or Briffa’s Yamal YAD061, shown to be a sample bias of one.
You’ve definitely lived up to the ‘village idiot’ name you’ve given yourself, Rick. Keep it up, we need more idiots like you. – Anthony]
Paleoclimate data from all over the world show that the planet has been in a long term cooling trend for at least 3000 years. Take for example the polar regions. The Greenland ice sheet cores clearly show declining peak warmth from the Minoan Warm Period, c. 3300 years ago. The East Antarctic ice sheet, largest depository of fresh water on earth, quit retreating about 3000 years ago, as shown by soil radionuclides around it.
Sure, we have been seeing olive trees blooming North of Paris for ages. Are you pulling our leg? FM
Or should it be our legs, pardon my French! FM