text:
This is what global cooling really looks like – new tree ring study shows 2000 years of cooling – previous studies underestimated temperatures of Roman and Medieval Warm Periods
Since Princeton's Dr. Michael Oppenheimer conflated weather with climate last week, proclaiming a short lived heat wave as "This is what global warming really looks like" in a media interview, it seems only fair to show what real science rather than what he and Dr. Trenberth's government funded advocacy looks like. I can't wait to see how Dr. Michael Mann tries to poo-poo this one. – Anthony
From Johannes Gutenberg-Universität Mainz: Climate in northern Europe reconstructed for the past 2,000 years: Cooling trend calculated precisely for the first time
Calculations prepared by Mainz scientists will also influence the way current climate change is perceived / Publication of results in Nature Climate Change
The reconstruction provides a high-resolution representation of temperature patterns in the Roman and Medieval warm periods, but also shows the cold phases that occurred during the Migration Period and the later Little Ice Age. – Click to enlarge
An international team including scientists from Johannes Gutenberg University Mainz (JGU) has published a reconstruction of the climate in northern Europe over the last 2,000 years based on the information provided by tree-rings. Professor Dr. Jan Esper's group at the Institute of Geography at JGU used tree-ring density measurements from sub-fossil pine trees originating from Finnish Lapland to produce a reconstruction reaching back to 138 BC. In so doing, the researchers have been able for the first time to precisely demonstrate that the long-term trend over the past two millennia has been towards climatic cooling.
"We found that previous estimates of historical temperatures during the Roman era and the Middle Ages were too low," says Esper. "Such findings are also significant with regard to climate policy, as they will influence the way today's climate changes are seen in context of historical warm periods."
The new study has been published in the journal Nature Climate Change.Was the climate during Roman and Medieval times warmer than today? And why are these earlier warm periods important when assessing the global climate changes we are experiencing today? The discipline of paleoclimatology attempts to answer such questions. Scientists analyze indirect evidence of climate variability, such as ice cores and ocean sediments, and so reconstruct the climate of the past. The annual growth rings in trees are the most important witnesses over the past 1,000 to 2,000 years as they indicate how warm and cool past climate conditions were.
Researchers from Germany, Finland, Scotland, and Switzerland examined tree-ring density profiles in trees from Finnish Lapland. In this cold environment, trees often collapse into one of the numerous lakes, where they remain well preserved for thousands of years.The international research team used these density measurements from sub-fossil pine trees in northern Scandinavia to create a sequence reaching back to 138 BC. The density measurements correlate closely with the summer temperatures in this area on the edge of the Nordic taiga.
The researchers were thus able to create a temperature reconstruction of unprecedented quality. The reconstruction provides a high-resolution representation of temperature patterns in the Roman and Medieval Warm periods, but also shows the cold phases that occurred during the Migration Period and the later Little Ice Age.In addition to the cold and warm phases, the new climate curve also exhibits a phenomenon that was not expected in this form.
For the first time, researchers have now been able to use the data derived from tree-rings to precisely calculate a much longer-term cooling trend that has been playing out over the past 2,000 years.
Their findings demonstrate that this trend involves a cooling of -0.3°C per millennium due to gradual changes to the position of the sun and an increase in the distance between the Earth and the sun."This figure we calculated may not seem particularly significant," says Esper. "However, it is also not negligible when compared to global warming, which up to now has been less than 1°C. Our results suggest that the large-scale climate reconstruction shown by the Intergovernmental Panel on Climate Change (IPCC) likely underestimate this long-term cooling trend over the past few millennia."
Orbital forcing of tree-ring data
Jan Esper, David C. Frank, Mauri Timonen, Eduardo Zorita, Rob J. S. Wilson, Jürg Luterbacher, Steffen Holzkämper, Nils Fischer, Sebastian Wagner, Daniel Nievergelt, Anne Verstege & Ulf Büntgen
Nature Climate Change (2012) doi:10.1038/nclimate1589
Received 27 March 2012 Accepted 15 May 2012 Published online 08 July 2012
Solar insolation changes, resulting from long-term oscillations of orbital configurations1, are an important driver of Holocene climate2, 3. 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 (ref. 4), but the trend varies considerably over time, space and with season5. Using numerous high-latitude proxy records, slow orbital changes have recently been shown6 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 models7, 8 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 reconstructions9, 10, 11, 12, 13 relying on tree-ring data may underestimate pre-instrumental temperatures including warmth during Medieval and Roman times.
a, The reconstruction extends back to 138 BC highlighting extreme cool and warm summers (blue curve), cool and warm periods on decadal to centennial scales (black curve, 100-year spline filter) and a long-term cooling trend (dashed red curve; linear regression fit to the reconstruction over the 138 BC–AD 1900 period). Estimation of uncertainty of the reconstruction (grey area) integrates the validation standard error (±2 × root mean square error) and bootstrap confidence estimates. b, Regression of the MXD chronology (blue curve) against JJA temperatures (red curve) over the 1876–2006 common period. Correlations between MXD and instrumental data are 0.77 (full period), 0.78 (1876–1941 period), and 0.75 (1942–2006 period).
I'm sure Steve McIntyre will give this paper a thorough examination for the same sorts of issues we've seen before in MBH98. Hopefully he won't have to beg for years to get the data for replication like he did with Mann.
h/t to WUWT readers "Typhoon" and Dr. Leif Svalgaard
Tags: climate change, Dendrochronology, Global cooling, Intergovernmental Panel on Climate Change, Jan Esper, Lapland (Finland), Michael Oppenheimer, Northern Europe, University of Mainz
Here we go again: row, row, row, your boat – Arctic edition
John Nielsen-Gammon: Skeptics Are Not Deniers
Flat Earther
Don't worry about the decline. Once NASA GISS changes that algorithm to its v3.1 version, cooling will become warming!
Sean Peake
How did that ever get out of peer review?
Holy Roman Empire! This is big.
tornadomark
How many want to bet that the Warmists will now declare tree rings unreliable?
milodonharlani
Since the Holocene Climatic Optimum was even warmer than the Roman & Medieval Periods, the cooling trend would be yet more pronounced if extended back another 3000 years or more. Modern warmth is not exceptional, having been exceeded in at least two periods during the past 2000 years.
Perhaps even more tellingly, the previous Eemian Interglacial (114 to 130 kya), was much warmer than today's Holocene Interglacial. As most here must know, Scandinavia was then an island, hippos swam in the Thames at the site of London, & the raised beaches of Alaska & fossil reefs of the Bahamas were formed. The interglacial before the Eemian (Hoxnian in the UK, Holstein in N. Europe & Mindel-Riss in the Alps, corresponding to Marine Isotope Stage 11, from 374 to 424 kya) was also warmer than our present Holocene. All this without benefit of a Neanderthal or Homo heidelbergensis industrial age burning copious quantities of coal, or even wood, & with "pre-industrial" CO2 levels.
Regional! Regional! Regional!!! Just like the Medieval Warming Period!! (sarc.)
R Taylor
The authors had the decency not to note that CO2 has done nothing but increase during this 2000 years of cooling.
Billy Liar
No wonder the Team like trees; you can get them to reveal anything you want about past climate.
Why not just accept that they are unreliable indicators of past climate?
Is that a broom handle or a mop, with bulges in a couple of places? Or a hockey stick with the hook broken off?
Coalsoffire
Divergence problem solved!
timg56
Just curious, but if people have doubts about the quality of tree rings as temperature gauges, is there any reason to accept this with open arms?
I'd be interested in a discussion of the quality of data, methods and processes. It is from evaluating this among various studies that we might get a decent idea of how good tree ring data is and who is coming up with the most accurate interpretation of the data.
AnonyMoose
Release the hounds scientists!
ken Methven
Did they forget the "hockey schtick" post processor?
Jim G
Looks like Dr. Iben Browning was right, however, possibly for the wrong reasons, and in a much more gradual manner than he was predicting. But he was predicting global cooling. Looks like it has been going on for some time. Wonder when we can expect the glaciers to return to the midwest?
BarryW
Can't be right. It actually shows the Roman and Medieval Warm periods. 😉
Of course Mannian science says that those are only local phenomena.
jcbmack
This coincides with what Bob Carter has been saying for years.
otsar
The cynic in me says that that we will see more publications like this pass peer review as policy makers try to extricate themselves from the corner they have painted themselves into. When I read temperature reconstructions, tree rings, and precisely calculate in the same article my scepticism goes up. I hope they make all of their reasoning and work available. Having said that, I hope this is good work and that there is more forthcoming.
Frank Lansner
What a relief: Some climate scientists are returning to science. Perhaps to avoid issues later, but they are doing the right thing. I hope others will follow.
Yes, a big step, wonderful.
K.R. Frank
Stephen Rasey
If I'm skeptical about tree ring data showing no trend prior to 1900, why should I accept a study that shows cooling using diffrent tree ring data?
What sort of "density" are they refering to? Acutal wood density? or Rings per cm?
How good is the correlation with density to "summer" temperatures?
Do winter temperatures matter in debate about cooling or warming trends over 2000 years?
Were the individual tree-ring source proxies equally weighted (unbiased), or weighted by training on a hypothetical target?
My gut is giveing me red flags over the concept that this paper has too much in it. It simultaneously puts forth a Lapland dendochron-thermal reconstruction with an orbital cooling configuration and solar insolation changes. Each of these would warrent its own paper.
Interesting paper, but my skepticism works both ways.
Just a few questions. Does this only apply to the NH? Are there SH studies that show a similar result? The LIA seems to be earlier or pre 1500 at coldest period. Is the MWP a bit earlier? Seems to start 700AD and finish about 1200AD. Dark age cooling seems very pronounced.
ExWarmist
"The annual growth rings in trees are the most important witnesses over the past 1,000 to 2,000 years as they indicate how warm and cool past climate conditions were."
So Trees are Thermometers after all?
Whether you have a warming narrative, or a cooling narrative, it's still only proxy data. Frankly I don't trust any tree ring results now.
RE: otsar 3:41 pm:The cynic in me says that that we will see more publications like this pass peer review ….
The cynic in me agrees we'll see more cooling papers pass peer review now that the door for AR5 has closed.
Doesn't ice core data show a gradual cooling over the whole Holocene? like this.
How well doe sthis match up against other reconstructions of the same period?
ntesdorf
This looks uncannily like real Scientific Work for a change. Some climate scientists seem to have recalled that they are supposed to be doing rigorous science. Perhaps others will have the courage to follow them now.
Joachim Seifert
Anthony, give credit to whom it belongs: The number of – 0.3 C
downslope cooling per each millenium was already provided some
months ago by DONALD ARCHIBALD, in Figure 5,
Due 3 Temp Record 22 years smoothed, in your WUWT post "Ap
Index, Neutrons and Climate"…..
These above Mainz guys just repeat Donald and conclude their study with "this all
SUGGESTS that the IPCC MAY UNDERESTIMATE….." ??
…..If someone cheats on my return change, should I day the next time:
Excuse cashier, I suggest that you may underestimate my due change??
[REPLY: Uhh, did you mean David Archibald? -REP]
Green Sand
Stephen Rasey says:
…….now that the door for AR5 has closed.
Not quite there yet:-
"Cut-Off Dates for literature to be considered for AR5"
http://www.ipcc.ch/pdf/ar5/ar5-cut-off-dates.pdf
There will be lots going on that are not yet in the public domain.
Rob L
Too bad that it is treemometers, they will always have questionable validity.
That said as with ice-cores we see the 1000 year warming-cooling cycle that produced the Minoan, Roman, Medieval and now Modern warming, on this graph it appears to have an amplitude of about 0.5-0.7 deg (1-1.5 deg C peak to trough from linear trend). That this cycle coincides with modern warming (which started before significant CO2 rise) is very powerful evidence against "strong" CAGW. Gisp2 cores have similar amplitude, though the long term cooling trend is steeper at about 0.7deg/millenium.
Would be nice to see an expanded vertical axis and a few grid lines to get a better view of the temperature variation, that graph they produced is near useless without a vertical reference.
"This is what global cooling really looks like"?
No wonder I haven't had to turn on the A/C–or a fan, for that matter–so far this summer.
Ally E.
Excellent! I bet they used more than one tree. 🙂
Tim Ball
Apart from the fact that trees rings don't, for the most part, reflect temperature, this study is even more problematic because it only looks at summer temperatures. All the actual records show that it is winter temperatures that change the most.
For example, summer temperatures were about the same at the nadir of the Little Ice Age around 1680, but winters were much colder, Since then summer temperatures have remained about the same and winter temperatures have increased creating an increase in annual average.
Summary; Trees don't represent temperature and half a year doesn't represent an annual record.
There have been similar studies of petrified trees from millions of years ago. As I recall all they showed was a distinct solar cycle. But that is not surprising because that was the original reasonable application of tree ring studies by Douglass.
A. E. Douglass was an astronomer whose main interest was dendroclimatology, particularly the relationship between midlatitude precipitation patterns, especially drought cycles.
http://ltrr.arizona.edu/sites/ltrr.arizona.edu/files/bibliodocs/Douglass, AE_Evidence of Climatic Effects in the Annual Rings of Trees_1920.pdf
I used his work because I found a similar 22 year drought cycle in a spectral analysis of approximately 200 years of precipitation data for York Factory on Hudson Bay that appeared correlated with sunspot activity. It was an alien idea even then (1982) as my doctoral committee initially rejected that portion of the work. I risked failure but insisted on its inclusion, which, to their credit, they approved.
Theodor Landscheidt later developed the relationship between solar activity and midlatitude droughts.
http://www.john-daly.com/solar/US-drought.htm
Richard M
This could be used to explain why the temperatures have not been rising. They just need a slight addition to the models to handle this new information. Of course, continued CO2 emissions will swamp this forcing and we will still all burn to death. It will just a couple of years later.
Is there any graph that shows the holocene temp both from Antarctica and Greenland ice cores?( together)
If so is the graph reliable and drawn in both cases from the data? I've never seen a reliable comparison on the same page that covers the last 11,000+ years.
I believe there have been other subfossil trees and stumps located in the Dead Sea region that show cooling started about 4000 to 5000 years ago. There was a great reduction in the level of the Dead Sea and a significant climate regime change when the Levant region assumed its current dry regime. Prior to that it was much wetter and the Dead Sea surface level was much higher than it is now. I believe it was this paper that I am thinking about from A. Frumkin (Quaternary Research, 2009)
http://geography.huji.ac.il/personal/Frumkin/pdf/QR%20Sedom%20wood%202009%5B1%5D.pdf
Lucy Skywalker
Esper the Non-Archiver… Timonen… Zorita… Luterbacher… all well-known names from Climate Audit and elsewhere. But this time the Medieval Warm Period is returned where it belongs, and the Roman Warm Period is there too. And overall there is temperature loss. What amazing news.
Luther Wu
Yeah, but what about the really top notch researchers at really top notch universities like Penn State and UVa and East Anglia and…
What? Coverups? Their reputations are tarnished? Oh, well… never mind.
Greg House
…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 …high-latitude proxy records…data from northern Scandinavia…cooling trend…signature… tree-ring proxy records… in line with coupled general circulation models…substantial summer cooling over the past two millennia…missing orbital signature…near-surface air-temperature reconstructions… relying on tree-ring data…
I don't know… proxies-schmucksies again.. and of course anthropogenic "forcing" is not absent… That's the climate science "methods" as we know it… shouldn't we be over it by now?
kencoffman (@kencoffman)
Occasionally you'll see Warmistas talk about how they wish they could be found wrong so they can breathe a sigh of relief about humankind's dire prospects. Well, this would be a good time for them to celebrate, in my humble opinion.
Tree rings do not, for the most part, represent temperature. Worse, this study only looks at summer temperatures when all the records show changes are almost always in winter temperatures.
For example, summer temperatures are essentially the same as they were at the nadir of the Little Ice Age in 1680 AD. SInce then the warming has been mostly in winter temperatures.
Summary; Tree rings don't represent temperature and summer doesn't represent an annual average.
A few years ago studies of petrified forest wood millions of years old showed a solar cycle. This is not surprising since that was the main objective of dendroclimate studies in the first place – the relationship between sun, precipitation and tree growth.
Theodor Landscheidt later also developed the relationship between solar activity and midlatitude droughts.
Robert of Ottawa
Fun to see the tables turned on Mann & Co, but I don't by the tree-ring thing.
Appears Real Climate and Michael Mann began their spin a day ago on this story:
http://www.realclimate.org/index.php/archives/2012/07/tree-rings-and-climate-some-recent-developments/#more-12427
KnR
To be consistent if we claim trees are rubbish at recording temperature we have to accept that is the case when the results don't support 'the cause ' leave the picking of cherries to those who regard 'useful data' to be worth more than 'valid data '.
jaycurrie
I am curious why they felt obliged to add the "instrumental" data. Which "instrumental" data? Global? NH? Finnish Lapland?
It just seems an odd thing to add a set of thermometers to a set of treerings.
Toby Nixon
Does anyone know the background of these researchers — what they've previously published? Will CAGW proponents be able to dismiss this as more ravings of known skeptics?
Scottish Sceptic
I've no more confidence in these tree rings than I have in any other tree rings.
Remember, the problem with the hockey stick, is not the up-swing at the end. That is an inevitable consequence of picking tree-rings which match the apparent 20th century rise. The problem, is the lack of variation in the handle. Likewise, this series "smells" like noise.
I've got to the stage where I think all tree-rings tell us is how much people want to believe in climate proxies.
Babsy
Bob Tisdale says:
Hey, Bob! I thrilled beyond description it hasn't been 120 so far this summer in North Texas. It's raining today and *COOL* LOL!!
While tree rings by themselves may not represent temperature, the combination of tree rings and the isotopes contained in the wood together can be a pretty good indication.
We are cooling, folks; for how long even kim doesn't know.
Go, Baby Warming, Go.
leftinbrooklyn
Whether this data is accurate or not, or whether the warmist's data is accurate or not, doesn't even seem to matter anymore at this point, IMO. With so much 'evidence' pro & con, I think the only obvious answer can be: there is no change, man-made or otherwise, in the degree, in variations in speed, or in ways that the climate's been changing since there's been a climate.
We've just developed some really nifty technology to measure all these 'changes', which aren't really 'changes' at all…
George E. Smith;
Dang ! I'll have to check my 45,000 year old Kauri picture frame, and see what Temperature it was growing at.
Speaking of Temperature proxies; anyone know what is the Temperature at which asphalt melts so that aeroplanes can get stuck to the tarmac. Why the hell, didn't somebody measure the runway Temperature, when that plane got stuck to the ground, in molten asphalt. I used to figure my upper air Temperature of +60 deg C went along with maybe as much as +90 deg C ground, but now I may have to revise my ground Temperature extreme to a higher value. That has all kinds of connotations re the cooling benefits of UHIs, with a bigger Wien shift, and higher surface gray body Temperature, radiating faster.
Either (mad) Mann will respond that he's Bored of the (tree) RIngs,
or he'll complain that:
"I talk to the trees
But they don't listen to me"….
er, no, we should be listening to them (provided it's more than one, and not cherry-picked
(shades of George Washington saying, 'I cannot tell a lie, I cherry-picked that tree….').
Good to see that a study comes out that corroborates what rational minds have been
saying and observing about climate/weather and cycles thereof: even better to see that
it's passed the gauntlet of peer review.
Hope that we can get more data from various sources in case the Mann-handlers
want to use these trees to create hockey sticks. Briing on the ents….
Difficult that there are more factors than just temperature that affect tree growth,
though I imagine there are ways to check if environmental stress (nutrients,
competition from other trees, fires, etc.) is also involved…
Let the "War of the Rings" begin!
Leo G
At RC, the take away message I got, was that this study has a unique feature, in that the divergence from the modern temps does not happen. Therefore MM, ES and GS say that this has a very good chance to help move the science along. (They are not all ogres all of the time). As always, we must wait for the next crew to use the new method to see if there are serious flaws in it.
Ric Werme
Neville says:
> Does this only apply to the NH? Are there SH studies that show a similar result?
The title says "Northern Europe", the abstract says "trees originating from Finnish Lapland," so I imagine the answer to the first is they don't know, and the latter probably doesn't have much terrain that has a similar overall thermal regime with trees.
kadaka (KD Knoebel)
Their findings demonstrate that this trend involves a cooling of -0.3°C per millennium due to gradual changes to the position of the sun and an increase in the distance between the Earth and the sun.
The Earth keeps gaining a relatively small amount of mass, online I see estimates from 10^7 to 10^9 kg per day, with the mass of the Earth about 6*10^24 kg. The Earth's orbital speed over time should be slightly slowing due to drag from whatever particles are out there. I would think both of those would lead to the Earth getting closer to the Sun.
So why is the Earth moving away from the Sun? Is the Sun shedding so much mass (and energy that was mass) that its gravitational force is weakening?
John Brookes
Looks like an interesting study of summer temperatures in northern Europe over the last couple of thousand years.
If you look at http://en.wikipedia.org/wiki/File:Holocene_Temperature_Variations.png it seems to match the long term decline in temperatures over the last 8000 years.
Wagathon
I guess the Romans were more industrialized than we ever imagined. Since global warming has been a hoax, can we get our money back?
Antbones
Wow… And just last year you were posting stories about how bad tree ring proxies were… I guess if it fits your agenda it's ok?
http://wattsupwiththat.com/2012/03/20/another-reason-trees-dont-make-good-treemometers-new-tree-ring-data-bias-discovered/
When the vikings found Greenland, it was green. They had to move when it got cold again.
ferdberple
Billy Liar says:
It isn't the trees that are unreliable, it is the "calibration" methodology used by some climate scientists. A Lucia showed on her web-site, the divergence problem is a result of calibration.
It is interesting to note that this study does not demonstrate the divergence problem, which suggests that it does not have the calibration flaw found in the papers such and Mann and more recently Gergis.
My latest study of ring around the collar has determined that climate change is caused by switching from using Tide in my laundry.
Leo G says:
At RC, the take away message I got, was that this study has a unique feature, in that the divergence from the modern temps does not happen.
The divergence problem is a mathematical artifact of calibration. Formally known as "selection on the dependent variable", it is a statistical flaw in the methodology that creates bias in the results. This bias leads to divergence at the calibration boundaries, and misleading results over the proxy period.
In other words, it isn't the trees that are at fault. It is the knuckleheads looking at the tree cores that have improperly applied amplifier technology to statistics, thinking they were inventing a better way to look at noisy data. What they invented instead was a way to amplify noise, while making it look like signal. They fooled not only themselves, but most of the world as well.
OssQss
Wow, the Medieval and Roman Tag Team has been undisappeared?
Antbones:
Thanks for pointing out the dichotomy here. I don't want to be "hoisted on my own petard" as it t'war.
I have YET to see someone give a straightfoward explanation of the HOW and WHY "tree rings" can determine ANYTHING except the favorable or unfavorable nature of the growing season. Certainly it's ONE data point, but a 130 year old tree, cut on the grounds of my church in 1996 has a growth ring from 1988 which is MINIMAL, and comes from a "drought" type summer. I'm certain there are some "over all average warm due to moisture trapping" summers, which could be found on that tree, which would show "phenominal" growth.
Then we have that old 018/016 "chestnut". Aside from the isotope enrichment which has been established in tropical thunderstorms (can readily be measured) I've found the arguements with regard to fractional distilation and snow fall/other precipitation in general and the "correllation" to tropospheric temperatures to be completely bogus!
Thus when it comes to the SURFACE (say 0 feet above ground level) to 1000 feet above ground level temperatures, aside from the "instrumental record" dating back to the advent of themometry, I think really…we are clueless. AND NO ONE WANTS TO ADMIT IT!
Paul Westhaver
I don't see a hockey stick.
1. Did they archive and make available ALL data, used and not used, meta-data, and code?
2. I don't see the instrumental temperature tacked on to the end. Doesn't that invalidate the study?
Anybody got Mann's twitter ravings on this paper?
I wonder if they're going to try and get another editor fired/resigned/demoted? Maybe the publisher will opt to post all email correspondence to them about this paper?
And I'm not convinced anyone really knows temperatures convincingly from past eras based on wood core studies. Manipulated tree ring prophecizing by the 'team', (I wish I could make team in even lower lowercase. Is there a bottomcase we can use for the team?), has soured me on wood seers and seeresses. I'd like to see some extraordinary evidence to prove correlation of tree rings to definitive temperature measurments (in hundreths of a degree or tens of degrees, whatever).
Louis Hooffstetter
Climastrology 101: Pay attention students. In this class we will learn that:
1. Treemometers accurately record maximum summer temperatures as variations in the density of the wood in their rings.
2. Wood density variations in their rings also accurately reflect changes in solar insolation through time.
3. Solar insolation changes since the time of Jesus are unquestionably the result of long-term oscillations of orbital configurations.
4. Therefore, from the rings, we will be able to calculate that the forcing of solar insolation changes since the time of Jesus was up to four times as large as the net anthropogenic forcing since 1750.
5. Finally, we will correlate the wood density data with coupled general circulation models that take into account albedo-driven feedback mechanisms (since the time of Jesus) to conclusively demonstrate summers have cooled substantially since the time of Jesus.
eyesonu
The day will come that it will be regarded that it is a fools errand to use tree rings as a proxy for annual temperatures. It will be noted that temp, H2O, timing of the delivery of the H2O, and many other variables affect the growth of a tree.
However, since Mann began this game and made the rules, the hand must be played. The players in Mann's game of tree tricks have/will be exposed. In the end, tree ring tricks and omissions can and will be used in the upcoming racketeering trials.
In the meantime I will use tree posts to attach my glass bulb thermometer for temp with an accuracy of about +- 1F, depending on the lighting.
I believe the big takeaway from this study is the solar forcing methodology. It appears to indicate we are headed towards another glaciation in the not too distant future. That is something we should all be concerned about.
"an increase in the distance between the Earth and the sun."
The Earth is moving away from the sun?
We're doomed!
At least they seem to have a biologist, maybe dendrochronology?
Can't see an actual statistician… but there could be one with that sort of major among that group..
Anyway, sure beats Mann, who knows very little about either dendrochronolgy or statistics.
JohnB
I must echo the concerns of others here, specifically;
1. If tree rings aren't great thermometers, then they aren't great thermometers. Agreeing or disagreeing with your position neither increases or decreases their accuracy.
2. These are summer temperatures and the changes in warming/cooling are mostly in the winter. So it is another piece of the puzzle but hardly a game changer.
3. The trees are from a smalll geographical region in Northern Europe. This is a regional study and is no more indicitive of global temps than the CET or GISP2 ice cores.
4. It's a tree ring data set. As Max points out above, tree rings only really show whether it was a good or bad growing season. I have yet to see a paper that explains why we can assume that a particular season was good or bad due to temperature and not due to other factors effecting growth.
It is an interesting paper, but I'm sceptical about the validity of tree rings.
They used to have good parties at JGU 🙂
No coverage on this yet at NYT, BBC, CNN, or NPR. Set the clock and the countdown to historic bias.
R Barker
I have been skeptical of the claim that tree rings are a reliable indicator of temperature and I still am.
What would be more credible is to suggest that tree rings are a reasonable indicator of the relative goodness of a sequence of growing seasons regardless of the combination of conditions that caused them.
The subject study results appear to be in accord with the anecdotal climate evidence accumulated over that period of recorded history, something the "hockey stick" fails to do.
A string of favorable growing seasons may be most important measure of the quality of a climate rather than just temperature alone because it would be an indicator of the abundance of the food supply for the time period. Of course this does nothing to make the case for catastrophic global warming due to fossil fuels.
Density measurements? How did they control for the other factors besides temperature that can influence tree ring density?
I wonder how many people like Mann back then were blaming Jesus for causing global warming. Bush got off easy…
In the top right of the second graph in this article, if one clicks to enlarge, the late 1930s are seen to be as warm as the final years in the graph extending up to 2006. That is also what is seen in http://earthobservatory.nasa.gov/Features/ArcticIce/Images/arctic_temp_trends_rt.gif
(Within the timeframe of the past century, in overall shape of the trends, such basically supports the Loethle reconstruction too, within its margin of error, which used only non-tree-ring proxies in contrast, which I graphed in http://www.freeimagehosting.net/newuploads/319xq.jpg using data from http://www.ncasi.org/programs/areas/climate/LoehleE&E2007.csv — which includes likewise seeing a major temperature decline in the mid 20th century to a bit afterwards).
A similar pattern is observed again, for the late 1930s being as warm as today, including 0.7 degrees Celsius decline 1930s->1960s for the entire northern hemisphere average, in the original National Academy of Sciences graph discussed at http://antigreen.blogspot.com/2012/05/rare-corporate-courage-and-common-sense.html
Contrast to how, for instance, the CAGW movement's "official" Hadcrut 4 temperature reconstruction shows a totally different temperature trend for the northern hemisphere specifically just as it does for its global temperature reconstruction; due to convenient hockey stick type adjustments, it is wrong both in the northern hemisphere and globally. (If such is plotted for the northern hemisphere at http://www.woodfortrees.org/plot/hadcrut4nh/from:1880/to:2013/plot/hadcrut4nh/from:1880/to:2013/mean:60 there is not just a small deviation but a totally vastly different trend with the 1940s-1960s conveniently revised to be about flat to hide the decline).
Meanwhile, as an example of cross-checking with other considerations, the global cooling fear of the 1960s-1970s did not occur for just no reason. In other words, true temperature history is not even close to that seen on most widely publicized graphs today but rather is one where:
* Temperatures rose from the 1910s-1930s, to a level roughly as high as now.
* Temperatures then had a major decline in the 1950s-1960s, a decline about as much as the entire global warming of the more recent past several decades.
* Then temperatures rose in the 1970s-1990s up to current temperatures which have been at a temporary near-plateau but slightly declined 1997-2012 after the 1997 albedo change.
Such is a particularly big deal as it utterly effects whether there is any actual large deviation from overall solar-GCR forcing trends beyond the fluctuations reasonable to expect from ocean oscillations on top (60-year cycle AMO+PDO and shorter fluctuations such as El Ninos and La Ninas).
Combine true temperature data with true solar data showing major rise in solar activity since the Little Ice Age, as in http://www.appinsys.com/globalwarming/GW_Part6_SolarEvidence_files/image008.jpg where the open circles are even cross-checking with aurora incidence (one way to cross-check whether a particular numerical percentage adjustment of sunspot counts over time is reasonable or not), also as in http://www.appinsys.com/globalwarming/GW_Part6_SolarEvidence_files/image023.gif — and all fits in overall trends. The CAGW proponent claims that there is excessive mismatch actually rests on pillars of fudging the temperature and solar data in convenient revisions.
The first step in creating a true model of climate would be carefully sticking to non-fudged data alone to help avoid GIGO, which is tricky since the dishonest kind is so widely publicized today that few climate scientists fully know the real picture even amongst those honestly trying. Someday I'm going to try to find some non-fudged southern hemisphere temperature data too to further complete the picture, but the global average is going to approximately fit what the more reliable indirect proxy figures show, such as http://www.agu.org/pubs/crossref/2007/2006GL028492.shtml which notes:
"The rate of sea level change was found to be larger in the early part of last century (2.03 ± 0.35 mm/yr 1904–1953), in comparison with the latter part (1.45 ± 0.34 mm/yr 1954–2003). The highest decadal rate of rise occurred in the decade centred on 1980 (5.31 mm/yr) with the lowest rate of rise occurring in the decade centred on 1964 (−1.49 mm/yr)."
G. Karst
Y'all don't suppose? – that these results are the real reason "the great ice melt" was cancelled?!
http://wattsupwiththat.com/2012/07/07/350-org-cancels-melting-hoax-ice-sculpture/
Could we actually be seeing some impact? GK
The temperatures "rose in the 1970s-1990s" in my immediately prior comment was minor mistyping; I mean from the end of the 1970s through up to the 1997 albedo shift and 1998 El Nino, before how since then there has been decline (slight decline so far but wait for beyond around 2014).
Ken McMurtrie
Reblogged this on The GOLDEN RULE and commented:
Many thoughts arise from this article.
Mainly that there are numerable ways of measuring or estimating the global temperature trend, numerable ways of interpreting such measurements,
SteveSadlov
In a relatively moisture rich environment in the mid latitudes treemometers sort of work. Elsewhere, not so much.
And Gutenberg cast down Mann's hockey stick in the presence of the peers, and lo! it became a serpent!
Steve Keohane
Compared to GISP2, Alley 2000, the above temperature profile does not exactly match, but the GISP2 profile shows a greater rate of cooling than the trees, added here in black:
http://i49.tinypic.com/9prvqh.jpg
Lance Wallace
I loved Table S4 in the Supplemental Data, where they take their own shot at the 10 warmest years. The top 3 were 125 BC, 1937 AD, and 4 BC. I suspect this to be a bit tongue-in-cheek, but it's a great play on the endless attempts to show that the hottest year is 1998, no it's 2007, no, it's 2010….
Johnny Terawatt
The truth is also best served cold.
Alex the skeptic
T'was the Roman chariots that done it. Then Rome fell and cooling commenced…
Seriously, what happens now? Do all the warmists go back home from the battlefield after realising that the enemy was non-existent? No, they will invent another enemy….
All them horses, Alex..
And all that marchin' about everywhere.. way to much CO2 and methane produced.
Almost a Laplander
@R Barker
I have read previous studies using trees from lapland as a temperature proxy. Why these are so good proxies is that unlike many other trees, the only limiting factor for their growth is the temperature.
Those trees start growing only after the temperature stays above 5C and continue to grow until it doesn't. There is more than enough water even in a dry year and the sun shines 24/7 throughout the exceptionally short growing season.
Winter temperatures do affect the the growth, since the depth of the permafrost, lake ice coverage etc. depends on the harshness of the winter.
The treeline in the scandinavian mountains was much higher during the MWP, so the temperature certainly was much higher than today.
Decreasing temperatures over the last 2000, 9000 and 12000 years are well known from high quality reconstructions such as
http://www.essc.psu.edu/essc_web/seminars/spring2006/Mar1/Bond%20et%20al%202001.pdf
(figure 3, which is upside down in temperature)
Mr Watts You comment "I can't wait to see how Dr. Michael Mann tries to poo-poo this one. – Anthony" If you look at RealClimate you'll find out. In an article on tree ring data Mann, Schmidt and Steig ignore it totally.
As well as temperature, and moisture, and horse manure….trees like CO2 🙂
So I would like to put forward the hypothesis that tree ring evidence of the RWP and MWP was cause by horses.. one way or another.
Now I know we haven't an abundance of horses at the moment, be have got lots more humans and more luvly CO2.
blackswhitewash.com
This paper is as suspect as those delivering the "we are all going to fry and drown" message. Only summer reconstruction, dodgy proxies. Meaningless.
As Dr. Ball points out, the trees at best measure summer changes, while warming/cooling affect winter temps first and most. Anyone got any brilliant suggestions for a winter temp paleo-proxy? Formanifora?
"Their findings demonstrate that this trend involves a cooling of -0.3°C per millennium".
It may also show that the soil is leaching vital nutrients, it may also show that some kind of growth inhibitor (like insect disease) is increasing in the area. It may show the area is getting wetter/drier, that wind damage is increasing (hence less growth). It may show a slow decolonisation by something that used to keep the tree numbers down and so used to allow individual trees to grow more. (Have wolf numbers been increasing, so keeping grazing animals in check.
Indeed, the whole "temperature" series may be nothing more than a proxy for the population of wolves in the area.
As I've said before, what Mann's hockey stick proves is that if you correlate series for their fit with modern temperature (the blade), there is next to no correlation historically – i.e. they show no historical temperature. In other words:
a) either temperature did not vary in the past (Mann's false assertion)
b) Tree rings are not a temperature proxy (the proper conclusion of the hockey stick)
So, the idea that tree rings are a better proxy than other methods is laughable.
davidmhoffer
Almost a Laplander;
>>>>>>>>>>>>>>
Ever see what a late frost after initial leafing out does to tree growth for the season? Ever seen what pestilence (tent caterpillars in my neck of the woods, but I'm certain there's something similar in Lapland) does to growth for a year? How about disease? What about foraging animals? How about other plants that come and go, like pine trees, that make the soil and groundwater in the area more acidic? What about migrating birds which may choose that spot as a way station for a period of time, causing the soil and the groundwater to become more basic (goose pooh! oooh!). And once we get beyond all of THAT, we still don't have a clue if the winter was abnormaly cold, abnormaly warm, or abnormaly normal.
Two big problems with this paper.
1 It's using tree rings as a proxy for temperature when other limiting factors (water, sunlight, nutrients, etc) are important.
2 It's published in Nature Climate Change which has demonstrated no ability to organise legitimate peer review. So much junk science has got published in there that I doubt anything that it deems worthy of publication.
It is interesting that this did get published anywhere, though.
Perhaps peer review needs redefinitioin, again?
Hari Seldon
Wonder how gavin and joe will try to knock this into the long grass?
stevenmosher
timg56 says:
1. Maximum latewood density
2. Esper
3. rob wilson
4. Zorita
That's 4 reasons. 1 technical and 3 based on the quality of prior work,
son of mulder
Why should I suddenly start to believe any study involving tree rings as a proxy for temperature?
Ken Hall
I maintain that tree rings are an unreliable thermometer and any reconstruction based on tree rings cannot accurately show temperature. If you combine this reconstruction with Briffa's and Mann's and all the others, you get a mess of contradictory information whose only worth is to tell you that tree ring based reconstructions are complete bunkum.
Which is also a useful way to show, categorically, that Mann's Hockey stick is utter rubbish.
MangoChutney
Really not sure about the use of tree rings to tell us anything other than growth rate & age of a tree. Dendrochronology has it's place for dating trees, but for me dendrochronology when used as a thrermometer is akin to phrenology to determine a psycholigical profile
At least, this study makes sense.
climatereason
Bearing in mind how sceptical we are of Manns tree rings- or indeed any tree rings- we should not get excited because this one shows a story we like. Tree rings ae terrible proxies for temperatures for reasons previously cited, including their recordng a signal only during a short active growin season.
The lack of an LIA during the 17th Century when we have extremely good records for this period and other periodic cold bursts later, suggests that the study should be taken with a pinch of salt. Incidentally pre Mann we had always known of the greater warmth of the Minoan and Roman and MWP compared to today
sorry. Just noticed the caption that this chart shows summer temperatures. which reduces the studies usefulness somewhat. It wasthe winters that dragged the overall mean temperature down-many LIA summers were very hot
tornadomark says: July 9, 2012 at 3:23 pm How many want to bet that the Warmists will now declare tree rings unreliable?
I've already declared that for me, tree rings are unreliable for thermometry reconstruction. Nothing in this paper changes my attitude. My attitude is not driven by "like" or "dislike" of the outcome. Look past the pretty picture and remember the many pages of discussions of unsolved and unsolvable problems with the method.
It's not particularly important to estimate temperatures over the last 2,000 years. It's more important to decide NOW if there is a real and present threat to an important part of the globe or its products and to remediate if wise.
As for me and where I live, nature's impact on my life is much like 60 years ago. Can't see why people are getting so fussed. My main problem is a decline in the quality of Science. I nearly died from laughter at Climategate, catching the kids with their hands in the cookie jars. One cartoon vignette followed another.
Here's to Climategate Tranche #3.
SteveSadlov "In a relatively moisture rich environment in the mid latitudes treemometers sort of work. Elsewhere, not so much."
Trees respond to the dominant controlling factor. If that is not water, then it allows more influence of temperature, but we are still left with the problem of "canopy adaptation". The problem is that trees will grow until no more trees can grow. It does not matter whether it is the middle of the tropical jungle, or the sparse canopy of the north, the fact is that if more trees could grow, they would. So, if conditions "improve" the result may be a spurt in growth for individual trees, but it is also likely that more trees can grow, and fairly rapidly (a few decades), there will be more trees, these trees then compete reducing growth for other trees so that any individual tree will tend towards its optimum growing conditions.
A better analogy would be rats … if you put out a tonne of rubbish … there will be a tonne's worth of rats. Put out two tonnes or rubbish, suddenly all the rats are a lot bigger — hey presto, it appears that rat size is a proxy for food output (just like trees and growing conditions) but then, they all grow quickly until, there is a population of rats that can be sustained by 2tonnes of rubbish and (unless something else limits them) each individual rat will grow as quickly with 2 tonnes of rubbish as with one. … and in the long term the size of rats tells you nothing about the availability of foot … only the number of rats is a proxy for food, not the size.
Likewise, with trees. Over the lifetime of any tree, the whole canopy will adapt so that the number of trees tend toward the same growing conditions for any one tree. The total bulk of wood is a proxy for growing conditions, the growth of any tree is dependent on canopy density and growing conditions. Of course, it's more complicated than this, but fundamentally, the long term response is that of a population of trees which is very different from the short term response of any single tree.
But, the big problem with all tree-ring studies, is that they calibrate temperature response against the response of individual trees (before the canopy can adapt), whereas the key signal we want to know about is long term change which is dominated by the response such as changes in tree density of the canopy as a whole
To give another analogy, tree rings are a bit like measuring sea level changes (aka waves) by watching the water on the side of a ship. This method is very good at spotting rough seas where the change is smaller than the length of the ship … because the ship's position doesn't change much. But as soon as you start getting waves longer than the ship, the whole ship starts moving up and down. And when you look at changes in tide-level, there is absolutely no response (unless the ship grounds) … in which case, you tend to get a non-linear (lopsided) response.
Gaudenz Mischol
And the skeptics will now accept the tree ring reconstructions…. :-))))))))))
logicophilosophicus
The paper cuts both ways. The cooling trend makes MWP less dramatic compared to the trend rather than the long term average. (Of course the Hockey Stick had long term gentle cooling already.) I suspect this result will be welcomed into the fold.
Addendum (to last comment on canopy adaptation)
Paradoxically, the best proxies to use are:
1. Those with a lifetime much less than the available temperature record. Which means typically less than 10 years, as it is possible to calibrate for canopy adaptation using available temperature data (ideally annuals are best … as the canopy grows each year). Alternatively, the lifetime should be much much greater than the period of reconstruction, so that over the period of reconstruction there is almost no canopy change. So that means e.g. that a 1000year old tree, is probably only reliable as a proxy for around 100years – which makes all trees practically useless – we would need trees around since the ice-age to get anything decent for the last 1000 years.
So, As a rule of thumb, trees are only a reliable proxy for changes occurring within 10% (an engineer, not biologist's guess for the rate of canopy adaptation) of their lifetime. So, e.g. a tree that lives for 400 years, may be able to tell us a great deal about a decade of cooler temperature due to some volcano (which is why some academic are so deluded about their ability), but it is completely useless at telling us whether the climate was generally cooler or warmer 400 years ago.
Gaudenz Mischol says:
And the skeptics will now accept the tree ring reconstructions…. :-))))
NO !!! , only as another possible piece of the puzzle
Mann's use of trees was basically fraud on the statistical side of things, these guys look like they may have a bit better understanding. We will see if they produce the data and how they came to their conclusions so others can check it.. That is a VERY GOOD pointer to scientific honesty, sadly missing in most climate science.
SS;
Nice point; measure the forest, not the trees. It's even more directly relevant; after all, we're trying to project the fate of the human forest.
of course…. penny just dropped. Zorita, Luterbacher, Esper, Timonen…
This is the way the Team are distancing themselves from Mikey Mann.
Now Mann's cover is blown, with everyone knowing exactly why, the others still need to keep the grants flowing. Cynical, but realistic. But also, with no acknowledgement to Steve McIntyre evident here, it means that this portion of Climate Science looks set on the road to recovery….
If the data and metadata are archived and auditable…
According to this their instrumental data and the tree ring data shows no significant warming since WWII. So the weather in Finland isn't getting any better then!
I suspect that tree ring data will go the way of ice-core data and gradually cease to be mentioned. Team-AGW will be left with snail shells and thermometers placed at airports soon.
I suspect their slight bow to 'anthropogenic forcing' is the main reason this got published in this journal… without it, would we have seen it?
fredberple:
For me this is an eye-opener. Suppose you have a complex sound as produced by thousands of sound sources. Next, you silence those sources having the lowest correlations with the envelope. Repeat this procedure again and again and you will have in the end an artificial signal. This is precisely what happened during the great dying of the thermometers late twentieth century. No wonder that the surface and satellite records diverged.
@davidmhoffer
A single tree doesn't tell us anything. IIRC Finnish Forestry Institute uses minimum of 50 trees to determine the temperature for each year.
And the treeline on mountains is a good calibrator. If the trees cannot grow nowhere near where they grew 800 years ago because it is too cold, then we can reasonably conclude that it was warmer previously.
But there are other ways to determine the temperature. I know people from the Finnish Geology Department and they say that meltwater runoff is not detectable during the MWP anywhere on Finland south of Jyväskylä. This translates to snowless winters in areas we now have typically around 100cm of sno every winter. The tree rings confirm this.
Paul Beckwith
Reading this caused me to go back and reread a paper from 2005 by Ulrich Joerin et al at the University of Bern http://www.climate.unibe.ch/~stocker/papers/joerin06hol.pdf. They study tree trunks and peat deposits that are released from melting glaciers in the Swiss alps. Of course a tree can only get in to a glacier in the first place if at some time in the past the tree line was significantly higher than today, as the tree line today is at the altitude of the glacial tongue (ie approx 2,000m in the Alps). Thus their method is very good at giving information on glacial recessions, ie periods when glaciers and temperatures were higher than today in the Alps. They indeed provide further evidence that glaciers were much higher in the Alps than today during the MWP and RWP and others. But the really interesting conclusion , which links to today's post, is in the conclusion of the Joerin paper: "….it is suggested that major glacier fluctuations
occurred on a multicentennial scale and that their pattern changed from long recessions ( /500 yr) interrupted by short advances (B/200 yr) during the early Holocene to the opposite pattern with relatively short recessions and prolonged advances during the late Holocene (after 3.3 cal. kyr BP). It is important to recognize that this natural variability of glacier extent, which occurs on a centennial timescale, is superimposed on a much longer term, multimillennial-scale trend towards increased glacier extent culminating in the 'Little Ice Age'.
In other words, they conclude that throughout the Holocene, the warm periods have been getting shorter and the cool periods longer. If that is indeed the case thank god for AGW for saving is from an accelerated decline into re-glaciation!
Niels A Nielsen
Where are the error bars on the reconstruction?
What is the instrumental record they use where the 40's are warmer than now?
Old Arrhenius was right. We have to fear the ice age and pump CO2 like the world's about to end.
Conclusions should not be taken too far. They calibrated against JJA temperatures of 3 stations in the common period:
"The MXD climate signal was assessed using Pearson correlation coefficients between the lakeshore subsets Ket-L (r = 0.74), Kir-L (r = 0.75) and Tor-L (r = 0.74) and mean JJA temperatures recorded at the global historical climatology network stations Haparanda, Karasjok and Sodankyla over the 1876–2006 common period. Running correlations were applied to analyse the temporal characteristics of the signal revealing reduced coherence among the station records as well as between the station and proxy data centred in the 1910s (Supplementary Fig. S10). The long-term N-scan record integrating lakeshore and subfossil MXD data correlates at 0.77 (r2 = 0.59) with regional JJA temperatures. We transferred this record into a JJA temperature reconstruction using ordinary least square regression with MXD as the independent variable. This approach provides conservative estimates—owing to the reduction of variability caused by unexplained variance29—of pre-instrumental climate variability and derived long-term trends."
They mention variance loss here!
Good comment by Henry Clark.
Tim Ball says: July 9, 2012 at 4:21 pm
All the actual records show that it is winter temperatures that change the most.
Exactly what CET the world longest and most accurate temperature record shows as plotted here:
http://www.vukcevic.talktalk.net/CETsw.htm
A problem is that if we don't believe treemometers for warming trends they should hold as much weight for cooling trends.
You have a good point but if they release ALL their data and methods then it's up to others to try to find fault with it. I too am sceptical about tree rings being thermometers.
Will Warmists accept this with open arms? If tree rings from Briffa and Mann was good enough for them then what about this study? Just questions.
They will call this "just regional." I may be wrong but I recall that Mann and Briffa's hockey sticks studies were also regional. The recent US heatwave was also regional.
The Medieval Warm Period was global.
http://www.co2science.org/data/mwp/mwpp.php
climatereason says:
……. this chart shows summer temperatures. which reduces the studies usefulness somewhat. It was the winters that dragged the overall mean temperature down-many LIA summers were very hot
Hi Tony
Summers are always warm enough for growth, I think it is rainfall which is reflected in the tree rings. My regular excursions to the Wimbledon common shows that everything grass, shrubs and the established trees have gone absolutely exuberant, not to mention a rhododendron and fatsia japonica in my garden.
Good score for the 'magnetics' on the solar thread, not a 'nonsense' any more just based 'on the flimsiest grounds'. ( It looks like as 'where vukcevic boldly goes, NASA cautiously follows')
Paul Coppin
Almost a Laplander says:
Nope. People really do need to get their head around the concept that a single tree lives in its own complex ecosystem which may share many similar variables with its neighbours. No one tree or small sample of trees is a proxy for anything. Geographic variation imposes large, mostly unreconcilable, constrants on sample homogeneity for statistical purposes.
Now this is a pursuable goal for the purpose of climate interpretation on a local basis, but again you have the problem of isolating climate from weather geography and other factors over the long term. Treelines will wax and wane with climatic and geographic influences – this is true of most terrestrial species at their environmental limits. However, the issue of isolating climate as the limiting factor is complex. The experimental scale is beyond most research methodology and budgets that I've seen so far. At best, the conclusions are mostly only anecdotal, notwithstanding the number of "names" on the citation.
Scottish Sceptic says:
Trees respond to the dominant controlling factor. If that is not water, then it allows more influence of temperature, but we are still left with the problem of "canopy adaptation". The problem is that trees will grow until no more trees can grow. …
Overly simplistic and not necessarily true. You are conflating trees with forests. Canopy is but one chaotic variable controlling the life of a tree in a forest. What is true is a tree will grow until it can grow no more. The limits to growth of an individual tree are not the same as the limits to growth of trees in a forest, but they are chaotically interconnected. A forest is the net sum of an almost unresolvable number of component ecosystems, each contributing to the other, but each standing alone on its own merits. The relationship is not synergistic, however. "Climate" scientists that don't understand this and persist on dabbling with cores have little hope of resolving climate….
MattN
"as they will influence the way today's climate changes are seen in context of historical warm periods."
I highly doubt it.
Just playing Devil's Advocate here, and it may have already been addressed, but if we don't believe the previous 1000 year reconstructions from tree rings showing warming because tree rings make lousy thermometers, why should be believe this one showing cooling?
Max_B
Very difficult proxy to use…
I can't shake the feeling that this paper is a strawman for the treehuggists to attack and try to vindicate their own tree ring noise plots.
kirkmyers
Tree rings are affected by rainfall, humidity, disease, soil composition, sunlight and other factors. Identifying the growth attributable to temperature is not a straightforward task. Call me skeptical.
The good news: The authors have not grafted thermometer measurements onto proxy data.
If the trees cannot grow nowhere near where they grew 800 years ago because it is too cold, then we can reasonably conclude that it was warmer previously.
Objection: tautological.
Craig Loehle
This long term cooling due to orbital effects is I believe correct. I found it to be about 0.2 deg C/1000 yrs in my 2004 paper:
Loehle, C. 2004. Climate Change: Detection and Attribution of Trends from Long Term Geologic Data. Ecological Modelling 171:433-450
and frequent evidence of similar cooling in more extensive data sets:
Loehle, C. and S.F. Singer. 2010. Holocene Temperature Records Show Millennial-Scale Periodicity. Canadian J. Earth Sciences 47: 1327-1336
It has even been found in Mann's work.
Note that 0.3 deg/1000 projected back to the Holocene warm peak gives 0.3×7000 = 2.2 deg C warmer, which matches various estimates I have seen (for at least northern hemisphere temps). Since polar bears and most everything else did just fine then, and that is when human agriculture began, it is hard to argue that a similar warming today will be catastrophic, unless you hold a Panglossian view of the world (what is can not be improved upon).
kirkmyers said:
In the actual published article in Nature Climate Change, they did overlap the instrumental data.
MikeN
Now all of a sudden tree rings are great predictors with fine resolution? And from a single place in Finland they predict the temperatures of all of Europe?
Properly statisticked tree rings show long term cooling, archived ice cores show long term cooling, glacial erratics stub the plow; folks, that's an iceberg ahead, not the Promised Warmer Land.
Even kim can't get a good rangefinding for the mountain of cold, but it is surely out there. All the confusing echoes confirm its reality, but not its location.
Scottish Sceptic writes:
The problem is that trees will grow until no more trees can grow. It does not matter whether it is the middle of the tropical jungle, or the sparse canopy of the north, the fact is that if more trees could grow, they would. So, if conditions "improve" the result may be a spurt in growth for individual trees, but it is also likely that more trees can grow, and fairly rapidly (a few decades), there will be more trees, these trees then compete reducing growth for other trees so that any individual tree will tend towards its optimum growing conditions.
But it occurs to me, looking at the the photos of the trees in their paper, leaning over the lake, that the effect of competition for sunlight with other trees may be mitigated by the trees being lakeside–basically always having a clearing. This may imply other sampling problems: is the open space created by the lake on the north side, south side (or does it matter since they are far north and the sun is shining nearly from every direction in summer?). Is there a sampling bias by taking the trees that fell in–the ones that stuck their neck out farthest?
Gail Combs
AndyG55 says:
Doesn't ice core data show a gradual cooling over the whole Holocene?
10,000 yrs Vostok: GRAPH
10,000 yrs Greenland: GRAPH
As far as this study goes, I still dislike tree ring data. There are just too many factors that influence growth in "tree-ring density measurements " All that can be said is the local conditions were favorable/not favorable for growth. Heck we have not had rain since June 23 until last night, my grass looks like hay but fifty miles north of me or fifty miles south got hit by thunderstorms and got at least three or four rain storms over the same period and their grass looks just fine.
So I will wait until I hear what Steve M. has to say about the study. If the amount of data is large enough and spread over a wide enough area you might be able to squeeze some general climate data out of it but I am not holding my breath.
On the other hand where plants will or will not grow seems to me to be a better indicator. You will not find orange trees or even poison ivy growing in northern Canada for example.
If I were just a little bit excited by temperatures than I am, I would surely conjecture that the Decline of the Roman Empire was sparked by the Decline of the temperatures.
Sorry, Anthony. This looks like another attempt to find a hockey stick where one doesn't exist. Wait until they graft the instrumental record on the end and then use it to say it's even worse than we thought because man is ending an inexorable period of global cooling. Fact is lots of scientists believe the warming is NATURAL and that the earth has been warming gradually since the last ice age! The Roman and Medieval Climatic Optimums were blips on a long-term warming, caused by increased solar and cosmic flare activity as well as a predominantly warm-phase of oceanic oscillations.
So we are trending towards an over due interglacial period. Makes Sense
Ian Weiss
But wait, where's the Little Ice Age? This graph actually looks very much like the Hockey Stick, just without the blade (which I suppose was the most important part). Let's not get prematurely excited about this.
Babsy says:
OT looks like the East Coast Heat Wave broke. Temps are back down into the 80's F for the rest of the week – tomorrow is supposed to have a high of 82F (77F in mid N. Carolind at 10:30 AM)
After reading Dr. Tim Ball's comment my distrust of treeometers is now complete. Thanks Dr. Ball especially for pointing out trees only record the growing season and not the winter temperatures where annual cooling shows the most. If it is the winter temperatures that are critical then the whole annual global temperature idea is bogus and it is the NH November through February temperatures where we should be looking and where the signal for 'climate change' is strongest. (SH doesn't show as much change either because of the amount of ocean.)
Crispin in Waterloo
@Tim Ball
"Theodor Landscheidt later developed the relationship between solar activity and midlatitude droughts. http://www.john-daly.com/solar/US-drought.htm"
This is going to be interesting: Landscheidt predicted a mega-drought in the US in 2018 not long before he died. If it happens, it will be trumpted (of course) by the warmistas as 'proof of global warming and expect more of this'. The fact that he was able to predict it more than a decade before by studying the acceleration of the sun around the barycentre is going to cause some serious cognitive dissonance because they will be claiming it is human-sourced CO2 which Landscheidt didn't factor in at all.
No doubt the Executive Summary of AR 7/8/9 will have some 'explanation' for the 'coincidence' and Theodor's 'lucky guess'. Maybe by then Peirs will have confessed he uses Tarot Cards and his long range weather forecasts are just 'lucky guesses' too. Interesting how people who study solar events and cycles are always such lucky guessers.
As you may have seen elsewhere, I do believe that tree rings are a reasonably good proxy for moisture but even in a small country like the uk rainfall varies greatly from place to place and year by year. So although rings might show moisture it is very localised. Look forward to seeing some of yoir studies in print.
Whilst everything may be vey green things havent set-i havent been able to grow outdoor tomatios for 5 years, which when you look at the cet decline over the last decade speaks volumes that we need a plan b (cooling) as well as a plan a (Warming)
Craig Loehle says:
Dr. Loehle
An unexpected vindication of strong correlation of your temperature reconstruction and the Earth's magnetic field, as I presented here
http://www.vukcevic.talktalk.net/LLa.htm
is coming from an unexpected source, no less than JPL/NASA
http://phys.org/news/2011-03-earth-core-climate-insights.html
evidence is overwhelming from data by: Wang &Lean, Svalgaard, Arctic temperature records, Arctic magnetic flux, data from Jackson & Bloxham and at least another half a dozen other sources. I am looking forward to the day when the Loehle's temperature reconstruction becomes the science's standard.
I was thinking the same thing (Shackleton's isotope work on deep-sea sediment cores) However that was not what was done here.
…used tree-ring density measurements from sub-fossil pine trees originating from Finnish Lapland …
One wonders why isotopes are not used since these are sub-fossil. Anyone know?
It also does not negate Dr. Tim Ball's observation about winter temperatures.
did anybody comment on the fact that the reconstruction is for Northern Scandinavia only?
Antbones says:
If you bothered to read all the comments you will see most of us are STILL saying tree rings are bad proxies.
Kelvin Vaughan
kadaka (KD Knoebel) says:
The Chinese are all jumping off the Great wall at Noon everyday.
All this tells me is that if you try hard enough, you can find a piece of data to say whatever the hell you want it to say. Tree ring chronologies are by-and-large complete junk…
Using the same proxy, tree rings, allows you to construct both a cooling trend and an accellerating warming trend. This is enough evidence to completely discredit tree rings as a reliable indicator of temperature. Move on, nothing to see here.
Paul Coppin,
Yes, agree on most of the point. The key is that the tree/tree-ring is a quick response, whereas the canopy changes more slowly and in the end it is the competition within the canopy between trees which dictates the individual growth of the tree. There is a reason trees are fairly equally spaced whether in a tropical jungle or the siberian wilderness … and that is tree to tree competition … unless or until you get to the tree line.
However, I accept that the "optimum growth" within a canopy may also change, so that even in the long term, individual trees in a canopy may grow more in better conditions. Although it is not impossible they grow less as individual trees in overall better conditions! But it really matters very little, because there is no practical way to calibrate how growth of the canopy effects the growth of the individual tree.
"You are conflating trees with forests."
Paul, I was very careful not to use the word "forest", because by the time you are very far north, the canopy is so spread out that most people would not call it a forest. It is a patchwork of isolated trees whose spacing is largely dictated by available sunlight (a facet of the canopy)
Forest is an indication of the density of trees, canopy (as I use it) is an indication of the density of trees intercepting sunlight — the idea I'm trying to emphasise is that trees in the canopy are fighting "tooth and nail" (not sure what that is for a tree) to gain as much of the canopy as possible.
I agree with you, Oxford and Cambridge Universities have kept excellent records and are only about 100km apart but their rainfall is very different, don't know why Mann had to go to Yamal, unless the area was made physically accessible by oil majors who do lot of explorations around there.
http://www.vukcevic.talktalk.net/Oxbridge.htm
As for good tomatoes take a fortnightly trip on the Scillonian.
J says: But it occurs to me, looking at the the photos of the trees in their paper, leaning over the lake, that the effect of competition for sunlight with other trees may be mitigated by the trees being lakeside
A shrewd observation – but it is still a competitive position, but the canopy now consists of any trees that can push out into the lake to catch the sunlight. However, that is why you often get specialist trees like willows that are evolved to maximise the opportunity in this particular niche.
I changed the proxy reconstruction graph to expand the y-axis and give it a zero line. It makes the warm/cool periods more obvious.
http://i46.tinypic.com/21oowag.jpg
With apologies to J.R.R. Tolkien…
One tree ring to rule them all,
One tree ring to follow,
No other rings above Yamal,
Lest warmist claims prove hollow.
Bill Parsons
Lubos Motl says:
Roman habiliments did not lend themselves to population booms. Colder weather affects all toga-wearers the same way: with decreased libido comes inevitable… er, decline.
I will buy some of the astrophysics and leave the tree rings for another day.
….Now I know we haven't an abundance of horses at the moment, be have got lots more humans and more luvly CO2.
ERRRrrrr, I hate to break it to you Andy but there are still a lot of horses now, at least in the USA. In 1850 there were only 4.3 million horses, by 1900 there were 21.5 million and by 1920, at the peak there were 25 million.
Today the Ag census lists 3.7 million equines but the National Horse Council lists 9.2 million. I would go with the National Horse Council numbers since the current Ag survey is only counting horses on "registered farms" (sells over $1000 of Ag products) and misses all the backyard horses like my 23 and all of the equines owned by my neighbors.
The 1911 world census listed in an article indicates a world population of about 90.9 million This would be near peak population. link
In the 2006 world census report, there are 58,372,106 horses in the world. I wonder if that "Official figure" is as far off as the USDA is from the National Horse Council figure.
Maybe those high temperatures in 1930 were because there were so many horses…
Think about this. If the USDA can not even get an accurate count of the number of horses in the USA how do we expect the "Government " to be able to get an accurate reading of US temperature?
DOPE, bad science is STILL bad science and tree-ometers are bad science unless someone has managed a quantum leap discovery like isotope analysis in sea cores by Shacklton
….And the treeline on mountains is a good calibrator. If the trees cannot grow nowhere near where they grew 800 years ago because it is too cold, then we can reasonably conclude that it was warmer previously…..
Now that is an excellent use of trees to determine temperature/climate.
Hugh K
So Time in 1974 and Newsweek in 1975 actually got it right?!?
Just make that optimal growing conditions instead of just temperature. Temperature shifts also seem somewhat correlated to rain fall pattern shifts and poor harvests can do a tap dance on any civilization even ours.
with a little help from my ancestors fighting not only Romans but your ancestors too, across frizzing Europe all the way from Baltic down to the Balkans, ending the Roman rule there.
We are all friends now, until the next big freeze.
Dan Marsh
The Earth is cooling 0.3 degrees C per millennium, because … increases in the distance between the Earth and the sun. WAIT, WHAT?!!!
Since when is the earth rapidly flying away from the Sun? I mean if distance to the sun is even a 1% factor in that, within a few million years, life on Earth would be doomed!
Stephen Garland
I hope the circular reasoning demonstrated in the last two sentences of the abstract are not an indication of the quality of the work
djaces
It seems to be time to remind people of this work
http://wattsupwiththat.com/2008/06/13/surprise-leaves-maintain-temperature-new-findings-may-put-dendroclimatology-as-metric-of-past-temp
The post refers to this study
http://www.nature.com/nature/journal/v454/n7203/abs/nature07031.html
I used to have a link to an unpaywalled version of the complete work, but it has gone dead. Here is the abstract
"The oxygen isotope ratio (18O) of cellulose is thought to provide a record of ambient temperature and relative humidity during periods of carbon assimilation1, 2. Here we introduce a method to resolve tree-canopy leaf temperature with the use of 18O of cellulose in 39 tree species. We show a remarkably constant leaf temperature of 21.4 +/- 2.2 °C across 50° of latitude, from subtropical to boreal biomes. This means that when carbon assimilation is maximal, the physiological and morphological properties of tree branches serve to raise leaf temperature above air temperature to a much greater extent in more northern latitudes. A main assumption underlying the use of 18O to reconstruct climate history is that the temperature and relative humidity of an actively photosynthesizing leaf are the same as those of the surrounding air3, 4. Our data are contrary to that assumption and show that plant physiological ecology must be considered when reconstructing climate through isotope analysis. Furthermore, our results may explain why climate has only a modest effect on leaf economic traits5 in general."
Trees grow in the ground but, like all photosynthesizing plant species, they grow from the air. A tree's root system provides water and nutrients that can influence or limit plant growth, but the variable record provided by tree rings is primarily a record of the photosynthesis occurring in the tree canopy. If that canopy, where all the controlling reactions are happening, is maintaining itself within a much narrower range of temperatures than the ambient air, it would seem to be very difficult to construct any logical biological or chemical pathway for a tree to be able to encode an accurate record of the ambient temperature within itself.
This work enjoyed an almost Warhol like brief moment of celebrity, not much more than a couple of weeks, and then pretty much went down the memory hole.
tonyb says:
Yes that is what is really worrisome about the whole mess and I do not see our governments addressing the issue instead I see governments catering to corporate greed.
"In summary, we have record low grain inventories globally as we move into a new crop year. We have demand growing strongly. Which means that going forward even small crop failures are going to drive grain prices to record levels. As an investor, we continue to find these long term trends…very attractive." Food shortfalls predicted: 2008 http://www.financialsense.com/fsu/editorials/dancy/2008/0104.html
"Recently there have been increased calls for the development of a U.S. or international grain reserve to provide priority access to food supplies for Humanitarian needs. The National Grain and Feed Association (NGFA) and the North American Export Grain Association (NAEGA) strongly advise against this concept..Stock reserves have a documented depressing effect on prices… and resulted in less aggressive market bidding for the grains." July 22, 2008 letter to President Bush http://www.naega.org/images/pdf/grain_reserves_for_food_aid.pdf
In march of 2008 …USDA Undersecretary Mark Keenum, [said] "Our cupboard is bare." U.S. government food surpluses have evaporated…
The following are the big winners in the biofuel scam and the 2008 food riots in over thirty countries.
Archer Daniels Midland profits soar to 550 percent
Archer Daniels Midland, Monsanto, Cargill,
Monsanto record breaking profits
Cargill record breaking profits
This is where it gets very interesting.
How Goldman Sachs Created the Food Crisis
…hedgers followed Goldman's lead and joined the commodities index game, including Barclays, Deutsche Bank, Pimco, JP Morgan Chase, AIG, Bear Stearns, and Lehman Brothers, to name but a few purveyors of commodity index funds….
…and the bankers were ready with a sparkling new casino of food derivatives. Spearheaded by oil and gas prices (the dominant commodities of the index funds) the new investment products ignited the markets of all the other indexed commodities, which led to a problem familiar to those versed in the history of tulips, dot-coms, and cheap real estate: a food bubble. Hard red spring wheat, which usually trades in the $4 to $6 dollar range per 60-pound bushel, broke all previous records as the futures contract climbed into the teens and kept on going until it topped $25. And so, from 2005 to 2008, the worldwide price of food rose 80 percent — and has kept rising. "It's unprecedented how much investment capital we've seen in commodity markets,"…
Today, bankers and traders sit at the top of the food chain — the carnivores of the system, devouring everyone and everything below. Near the bottom toils the farmer. For him, the rising price of grain should have been a windfall, but speculation has also created spikes in everything the farmer must buy to grow his grain — from seed to fertilizer to diesel fuel. At the very bottom lies the consumer. The average American, who spends roughly 8 to 12 percent of her weekly paycheck on food, did not immediately feel the crunch of rising costs. But for the roughly 2-billion people across the world who spend more than 50 percent of their income on food, the effects have been staggering: 250 million people joined the ranks of the hungry in 2008, bringing the total of the world's "food insecure" to a peak of 1 billion — a number never seen before…..
And that is the complex interplay between the speculators in food derivatives, bankers lending "investment capital " to those speculators and the corporations like Monsanto (seeds) Cargill (grain traders) and Archer Daniels Midland (biofuel producer) who have "Convinced" governments that grain storage is so passé. The starvation related deaths of children has no real place in that interplay.
Bill Clinton: "We Blew It" On Global Food
Today's global food crisis shows "we all blew it, including me when I was president," by treating food crops as commodities….
Clinton took aim at decades of international policymaking by the World Bank, the International Monetary Fund and others, encouraged by the U.S., that pressured Africans in particular into dropping government subsidies for fertilizer, improved seed and other farm inputs, in economic "structural adjustments" required to win northern aid. Africa's food self-sufficiency subsequently declined and food imports rose.
Now skyrocketing prices in the international grain trade – on average more than doubling between 2006 and early 2008 – have pushed many in poor countries deeper into poverty….
In light of that information Lester Brown's "Grain Reserves" Shell Game is an interesting read. The shearing of the sheep or insider trading comes to mind.
The recent trumpeting of the hot weather in the USA might also have something to do with grain trading as well as CAGW. Global Wheat, Soy and Corn Reserves Decline as Demand Grows, Crops Falter
Lester Brown on the Russian wheat crop failure last year.
…Brown noted that the bottom line indicator for global food security is world carryover stocks or the amount of grain in the bin when the new harvest begins.
"The rule of thumb is that world grain reserves should not drop below 70 days of consumption,"
However, the USDA's Aug. 12 World Agricultural Supply and Demand Estimates report the ending stocks of grain is enough to meet 72 days of consumption, which Brown said is moving uncomfortably close to the 64 days of carryover stocks in 2007 that caused the large spike in world food prices….
http://agweekly.com/articles/2010/08/13/news/ag_news/news32.txt
So a 2+1/2 months supply is now the rule of thumb for the world's grain reserves. The US government has made "Hoarding" sort of illegal BTW.
This article shows just how 'interconnected' and vulnerable our food supply now is http://www.businessweek.com/articles/2012-07-05/drought-stalks-the-global-food-supply
Michael D Smith
At least it matches up now with other studies showing the LIA to be the coldest period in the Holocene, with an overall downtrend.
I believe this data to be reliable. But I also believe this chart supports that increased CO2 may contribute to warming.
Yes, this trendline shows cooling…from zero AD. But take a close look at the data from time point of the industrial revolution, or even as recent as the turn of the 20th century. if you did, the trend line would steeply incline upward.
I didn't think this had to be pointed out but I guess it does. The issues is NOT that the earth has never been warmer, can't get warm on its own, etc. The issue is does adding CO2 above and beyond naturual causes increase the rate of warming beyond what we can safely adopt to.
Johanus
Gail Combs says:
The signal coming from trees is very noisy, because they are very robust and adaptive, which makes them unreliable as thermometers. (That's why some of the oldest living things on Earth are trees).
Instead pick some other plant or crop which is known to be temperature sensitive. Then look for its presence or absence in historical layers. When it gets warm, it should be able to thrive further northwards.
Vinyards, for example.
I was just watching an old 1990 episode of Agatha Christie's Poirot the detective and he said to his sidekick Hastings, "Did you know the world is cooling 3 degres every 12,000 years.
Either we believe in treemometers or we don't. It seems to me a bit hypocritical to rage against them when they support the warmist hypothesis and for them when they don't!
Gary Pearse
Surely history has relevance and why it tends to be pushed aside by the "consensus" speaks volumes about academic historians today who seem to sit idly by while their climate academic colleagues run amok over the same period that is rightfully theirs. How can climate alarm believers toss the following aside:
1) Knowing that Medieval Scotland's wines were much enjoyed in Europe at the time.
2) Knowing that the present warm period has only begun to uncover Viking farmsteads in Greenland – we need maybe another degree or so over the next 50 to 100yrs to permit archeologists to properly examine the settlements.
3) Knowing that New York Harbor, the Thames and the Bosphorus froze over during the LIA and Swiss villages of hundreds of years old in the valleys were crushed under advancing glaciers.
4) Rome's most feared enemy, Hannibal Barca of Carthage in about 200BC, circled around through Spain, over the Pyrennes, up the Rhone River in Switzerland and over the alps with his elephants to surprise the Romans. I skiied in the Canton Vaud overlooking the Rhone in the early 1960s – no elephant could have negotiated the crossing under present conditions.
5) Oezti, the neolithic European, mummified under mountain ice in the Alps, finally thawed out in 1991 on a mountain pass where he died of wounds, with his weapons and belongings neatly laid beside a rock, after being ice bound for over 5000 years. This isn't a bad proxy for a warm period approximately like now over 5000 years ago.
Can we inveigle a timorous historian to come forth and write a historical-based chronicle of the earth's climate over the past 10,000 years or so. It would be understandable to the layman and would be entertaining to see how the hottest-period- of-the-last-millennium cheering section would handle it. It would have enhanced the current U of Mainz paper had it included such.
Gail Combs: "If you bothered to read all the comments you will see most of us are STILL saying tree rings are bad proxies."
This isn't pointed at you, but there's a depressing lack of awareness about what 'evidence' is, what it signifies, and its use in discussion and thought. Especially as to the general idea of displaying or highlighting incoherence and inconsistency. It's about impossible for me to produce evidence of why your position is incoherent. But if you produce evidence that your position is incoherent then the best thing I can do is put that up in marquee lights until awareness of your own position is hammered into your own skull.
*If* you accept that Global Warming is occurring and/or unprecedented. *And* you accept that treemometers are good proxies. *And* you accept that peer review prevents errors then:
The science shows that we will burst into flames at the same time that we are buried under glaciers.
Give up whichever position you prefer, but you cannot hold all of them. Tim Ball modified hangout of seasonally selective global warming is an interesting notion. But then if we accept that summers are getting colder and that winters are getting warmer it is not Global Warming, but advancing toward a Climatic Equilibrium. But if that's the case then we cannot claim that CO2 is the responsible party unless we claim that CO2 does not play catch and release with photons. But that it saves summer photons as currency to pay for lift passes when the powder is fresh on the ski slopes.
Dan Marsh says:
Orbits vary due to interaction with other planets' orbits in the solar system. Earth Sun distances vary but do not simply increase or decrease in a linear fashion. The Earth's orbital shape vassilates over time causing the Earth Sun distance to change to closer at times and farther at other times. See the Milankovich cylcles for more on this.
My layman's take away on this is that tree are still a poor proxy for past temperature but these guys were more thorough and honest with their work and research than Mann "et al" have been. It contradicts what the tree-ring channeler concluded. So now what is he going to say?
(PS I didn't have time to read all the comments so I may be repeating what someone else has already said.)
Very interesting. One of the ways that farmers survived during the lia is that they had mixed farms so if one crop failed another grew. The trouble today is that modern farming and economics are based around single crops. Hence the need for a plan b
Snowlover123
This paper is big because not only does it confirm skeptic arguments about the MWP/RWP, but it also confirms low climate sensitivity.
In the paper, they state that the orbital forcing over the last 2000 years was 6 w/m^2, which gave a temperature response of around -0.6 Degrees C.
This would give you a sensitivity of around 10 w/m^2/K which would represent very low climate sensitivity.
This would mean that the total net anthropogenic contribution to the warming observed of 0.8 Kelvin would be only 0.15 K, which would be around 18-19% for the contribution of the anthropogenic forcing to Global Warming.
"Medieval Scotland's wines were much enjoyed in Europe" – who says? Let's not over-egg the cake.
Charles S. Opalek, PE
Now you know why Mann chose to go back only 1000 years. If he went back any further. his scam would be exposed.
This is why Gore only goes back to 1958 to see CO2 rising. If he went back 6E8 years like Berner, you would see CO2 18 times higher than today.
If you look at Scotese's Paleotemp you would see today's temperature is only 25% off the bottom of a normal range for the last 5E8 years.
@Gail.
gees Gail, I live in a city, ain't no horses here..
Just saying that in medieval and roman times.. there were lots of horses, knights in armour, roman legions with chariots etc and there seems to be a definite correlation.. dark ages was cold, and all the horse got et…. and now you tell me that there are STILL lots of horses.. and we are in another warm period.. so there …. further proof of my hypothesis. :-))
at least as solid as the CO2 hypothesis, anyway.
This tutorial on the Milancovitch cycles gives an excellent visual of what is meant in that comment. He is talking about Eccentricity.
From Lubos Motl excellent site, an article by Gerald RoeIn Defense of Milankovitch
http://www.gov/projects/ A quick background to the last ice age
Another graphic explanation
http://deschutes.gso.uri.edu/~rutherfo/milankovitch.html
And just for the added info.
Ice ages Confirmed
Sun's movement around galaxy
Galaxy's Spiral Arms, Ice-Age Epochs and the Cosmic Ray Connection By Nir J. Shaviv
Lesson from the past: Present Insolation Minimum Holds Potential for Glacial Inception 31 July 2006
Temperature and precipitation history of the Arctic:… Solar energy reached a summer maximum (9% higher than at present) w11 ka ago…
http://wattsupwiththat.com/2010/10/30/new-peer-reviewed-paper-says-there-appear-to-have-been-periods-of-ice-free-summers-in-the-central-arctic-ocean/
G.S. Williams
Hey, I've realised that Mike Mann must have used cherry trees for his proxies. What do all of you think?
"but these guys were more thorough and honest with their work and research than Mann "et al" have been"
No, not possible
Mann is the epitomy of honesty and transparency, and highly knowedgable on stats / biology etc etc ..
/sarc !!!
RACookPE1978
Yah know Gail ….
Fer a dumb hick farmer from them there upstate Piedmont hills 'n hollars of rural Podunk Appalachia, you shore do have good research abilities …. 8<)
Kelvin Vaughan says:
Again, this perposterous implication of linearity. ;-))
……. The issue is does adding CO2 above and beyond naturual causes increase the rate of warming beyond what we can safely adopt to.
No Will, you are missing the really big picture and therefore the actual issues.
#1. CO2 levels were actually getting dangerously low for continued plant life. So low plants had evolved the C$ and CAM mechanisms to cope with the starvation level CO2 during periods of glaciation when CO2 is absorbed by the colder water and the level falls dramatically.
Here is a peer reviewed paper on the subject:
Carbon starvation in glacial trees recovered from the La Brea tar pits, southern California
#2. If CO2 causes some warming, ~ a climate sensitity to CO2 (doubling) of 0.3C is one calculation without adding in the amplification that is not a proven fact – then given we are at the END of this interglacial and the temperature is headed DOWN due to the increase in the distance of the earth from the sun, the more CO2 the better!
GRAPH: five interglacials and CO2 Present is on the right and the CO2 although higher is NOT causing a major increase in the temperature. As shown on this graph the temperature is gradually falling throughout the Holocene interglacial and we are at the bitter end.
Again a couple of peer reviewed papers:
Temperature and precipitation history of the Arctic
….Solar energy reached a summer maximum (9% higher than at present) w11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1-3C above 20th century averages, enough to completely melt many small glaciers throughout the Arctic, although the Greenland Ice Sheet was only slightly smaller than at present. Early Holocene summer sea ice limits were substantially smaller than their 20th century average, and the flow of Atlantic water into the Arctic Ocean was substantially greater. As summer solar energy decreased in the second half of the Holocene, glaciers reestablished or advanced, sea ice expanded, and the flow of warm Atlantic water into the Arctic Ocean diminished. Late Holocene cooling reached its nadir during the Little Ice Age (about 1250-1850 AD), when sun-blocking volcanic eruptions and perhaps other causes added to the orbital cooling, allowing most Arctic glaciers to reach their maximum Holocene extent….
Arctic temperatures falling
The reconstruction shows lower summer temperatures from A.D. 1630 to 1840, a subsequent warming up to the mid-20th century and a cooling trend afterwards. According to our data, a temperature increase is observed during the past decade. The good coherence of multi-decadal to secular trends of our reconstruction and series of observed solar activity indicate that solar activity may have been one major driving factor of past climate on Kola Peninsula.
600 million year graph of global temperatures – various proxies showing we are at near glacial temps….
Lesson from the past: present insolation minimum holds potential for glacial inception (2007)
Because the intensities of the 397 ka BP and present insolation minima are very similar, we conclude that under natural boundary conditions the present insolation minimum holds the potential to terminate the Holocene interglacial. Our findings support the Ruddiman hypothesis [Ruddiman, W., 2003. The Anthropogenic Greenhouse Era began thousands of years ago. Climate Change 61, 261–293], which proposes that early anthropogenic greenhouse gas emission prevented the inception of a glacial that would otherwise already have started….
Abrupt Climate Change: Should We Be Worried? – Woods Hole Oceanographic Institution
"Most of the studies and debates on potential climate change, along with its ecological and economic impacts, have focused on the ongoing buildup of industrial greenhouse gases in the atmosphere and a gradual increase in global temperatures. This line of thinking, however, fails to consider another potentially disruptive climate scenario. It ignores recent and rapidly advancing evidence that Earth's climate repeatedly has shifted abruptly and dramatically in the past, and is capable of doing so in the future.
Fossil evidence clearly demonstrates that Earth's climate can shift gears within a decade….
But the concept remains little known and scarcely appreciated in the wider community of scientists, economists, policy makers, and world political and business leaders. Thus, world leaders may be planning for climate scenarios of global warming that are opposite to what might actually occur…"
There is a bunch more discussion on the subject here: The End Holocene, or How to Make Out Like a 'Madoff' Climate Change Insurer
At this point I much rather chance higher temperatures than a return to Little Ice Age conditions or worse.
jrwakefield
Comparing contemporary temperature records with tree ring proxy data is mixing apples and oranges. They are measuring two different things. Thermometer temp records are year round, where as tree ring data omits winter because the trees are dormant. Thus, as noted in the abstract, this is changes only of summer growing conditions (including a rainfall component) and fundementally cannot be knitted with thermometer data averaged for the year. This was a major mistake of The Team as well.
If you consider where the CO2 is most likely coming from, its from coal that WAS ONCE TREES.
It got buried, lots of it, which greatly depleted the NATURAL level of CO2 in the atmosphere.
If you know anything about predetor/prey or food scarity algorithms, then it is pretty obvious that for many thousands of years the level of CO2 has been BARELY AT PLANT SUSTAINABLITY levels. (this is further confirmed when you consider that plants, and animals can survive, and indeed flourish, in CO2 levels many multiples of what we currently have.)
Finally, we are releasing some of this long lost carbon, and restoring the proper balance !!!
pinetree3
Well, as to be expected, over at Realclimate they are already ridiculing the "denier" response to this study and saying we are ignoring the rise in temps. since 1900.
Arno Arrak
This is an impressive study and it corroborates previous observations of a slow cooling Arctic. Thus Kaufman et al. (Science, 4 September 2009) published an Arctic temperature curve based on lake sediments that showed a two thousand year, linear, slow cooling that was followed by sudden warming at the start of the twentieth century. They attributed the cooling to a steady, orbitally-driven reduction in summer insolation. Spielhagen et al. (Science, 28 January 2011) likewise observed a similar slow cooling followed by sudden warming at the beginning of the twentieth century. Their data were obtained from a foraminiferal core taken from the Arctic Ocean near Svalbard. Combine this with the current study from the Johannes Gutenberg Universität and we have multiple independent confirmations of a two thousand year cooling trend. As to the warming that began in the Arctic with the twentieth century, I have determined that its cause was warm water carried north by by Atlantic Ocean currents and not any greenhouse effect. For the full story of Arctic warming, download this article:
http://curryja.files.wordpress.com/2011/12/arno-arrak.pdf
I suspect this is a far more rigorous methodology than the half baked Michael Mann approach with data he either did not know how to work with or data he manipulated and then hid the methodology bias. I'll withhold final judgement though for the real experts to be validated and cross corroboration to shine through. That process will further isolate the hiders and weak model methods even if the concealment continues.
Erkki Saarikoski
In order to really understand the meaningfulness and validity of this study you have to understand the very specific arctic conditions of the Finnish Lapland. Temprature is and has always been the limiting growth factor for this location. This fact vastly increases the scientific credibility of the results.
A Finn who knows Lapland
mchughjj
"Or a hockey stick with the hook broken off?"
Well, to be fair, it's actually a blade, which has mathematically less severe consequences (thinking hyperbola vs. parabola). An extrapolated hook could have us all dead generations ago.
In all seriousness, I don't hold much stock in tree rings (also not my field), but touché.
Erkki Saarikoski says:
The nice thing about WUWT is the number of experts who can increase your knowledge if you have an open mind.
I still want to see a critical analysis by some one like Steve M. and others. The amount of game playing with tree rings has left a nasty taste in the mouth of most of us.
Amino Acids in Meteorites
So if the Romans declined in power because of change in temperature why didn't the rest of the population of the world, i.e., outside of Rome, decline with the temperature in the same proportion—-meaning the Romans would have held the same level of power anyway?
Maybe it was something else?
Paul Homewood
To be fair, we are only talking about Finland here. We need more evidence in other areas before we can draw too many conclusions.
The hockey schtick seems explainable by simply screwing up basic statistics by cherry picking, perhaps intentionally. Take the batch of data sequences and select those that meet a criteria of following the temperature record (rising – or worse – just changing) over the most recent times. Even worse, make that criteria the anticipated global average rise rather than the actual temperature records at the locations of the various tree sites. Doing this makes sure that unless the actual site temperatures followed this anticipated gobal average rise, the selected data sequences would not be following a real temperature that they had been subject to. This becomes a recipe for selecting series that randomizes the collection of data sets and strips out any real signal that might actually exist in te overall collection. When averaged together, one gets the hockey stick because only those data series that meet the criteria of changing in modern times (and we already know that a decline automatically gets the data set inverted) so it's a done deal that there is a hockey stick blade. If one actually selects and filters out all of the data sets according to this criteria and destroys the temperature signal that might have existed in the whole collection, one is left with random noise – which averages out to zero – giving us the beautifully straight handle – simply providing us with no information that might have been present in the original data.
Also, by picking subsets of the collection, one then is violating the assumptions of statistics about the nature of the collection and the statistical processing and information is no longer valid. For instance, trying to evaluate a manufactured device by dividing the sample products used in a preliminary test into three groupings according to results and running different sets of tests on each and then trying to get statistical information about the overall manufacturing process based upon the original sample.
Just because mickie mann succeeded in eliminating the presence of a temperature signal doesn't mean that there wasn't one present in the original collection. The fact that these other researchers found something other than a flat line suggests they are actually looking at something in the data other than pure random noise. Just what they found might or might not be the signal of temperature or anything else related to climate, regional or global.
Ah – linearity breeds contempt!
berniel
How far have we come in 90 years of paleo-climatology? This graph has some striking similarities to Huntington's chart of Californian climate back 2000 years:
http://enthusiasmscepticismscience.wordpress.com/global-temperature-graphs/1924_huntington_civilizationandclimate_p321/
Tree – ring reconstructions may be flawed because trees respond positively to both temperature and moisture, but often if not most of the time these two are inversely correlated, at least as the CET's record shows:
http://www.vukcevic.talktalk.net/CET-R.htm
TonyG
Anthony doesn't always agree with or support what he posts – he's making it available for his readers, who then discuss it. And you appear to have missed the numerous posts pointing out that they still don't accept the tree ring proxies.
Face it, Mann had an agenda to support, whereas a less ideologically-bent view has shown an opposite trend.
One person made tons of money and fame; the others, not so much.
Who do you think is lying?
Look, if a warmist cites tree ring evidence as proof of CAGW, I see nothing wrong with nullifying it with better tree ring evidence. Skeptics are skeptical of tree ring methodology, due to the difficulty of extracting a pure temperature signal. Each extracted signal must be rigorously scrutinized and evaluated on integral and demonstrated merit. No one doubts the signal is there… somewhere… in the noise.
Sorry, Mann made temperature reconstructions, do not pass GO and he does NOT get to collect $200. GK
Reply to G. Karst
Have a look at RealClimate – as expected, they love this: the recent tree rings fit the instrumental record, and will handily supercede the Briffa declining sequence.
This proves nothing! Of course the climate change cabal will argue:
1. The data is misleading…
2. The data only relates to N Europe & thus a cooling climate in europe does not mean that [ man made] warming that wasn't/isn't happening elsewhere
Yeah right!
J Bowers
"This is what global cooling really looks like…"
Let me fix that headline for you:
"This is what northern Scandinavian cooling really looks like…"
Much better.
Reply to J Bowers
But it is not half of the story, because its only JJA, in the plant
growths phase……. in the LIA there were good high summer
temps, due to European dry high pressure weather conditions….
The LIA can really be judged based on the autumn/winter/spring
temps….. taking only JJA, this is talking the LIA down and producing
another hockey stick….JS
Anthony… what can I say? You know what I'm talking about. Five years from now…..
pinetree3 says:
It is of course the RealClimate crowd who are the true deniers (of climate history before 1850) and cherry-pickers. They focus myopically on the 20th century temperature rise and ignore similar or larger rises taking place in the palaeo proxy record in this paper at:
350 AD
The point has been made in previous posts here that over the Holocene there have been at least 20 temperature rises comparable to or greater than that of the 20th century.
Some European
Congratulations! You managed to get this study misrepresented on FOX News!
I would seem that the Pillars of support for the religion of Mann-made global warming are resting on the soft sand of bad data.
Jan P Perlwitz
Anthony Watts misleads the audience already in the title of his article:
However, the temperature reconstruction and the trend of -0.31 K/millennium is for Northern Scandinavia and the Arctic zone, but not for the global temperature anomaly. And conclusions about how the temperatures in Roman or Medieval times compare to present day temperatures can only be drawn for this region from this study, but not for the global temperature anomaly.
And most of the devote followers here don't notice or don't care about being misled. They just want to get confirmed their preconceived views.
Although I don't really understand why the fake skeptics crowd, except the ones who dismiss tree ring proxies altogether, is so excited about this study.
How do the results of the study contradict man-made global warming, as some seem to believe here? If the natural trend due to orbital forcing is cooling, then it rather supports the view that the warming trend in the 20th century, particularly the one since the mid 70ies is largely man-made.
Notable: One of the conclusions of the study is the better agreement (oh, oh!) of the new proxy reconstructions with the results from simulations using state-of-the-art coupled climate models, which take the variation of the orbital parameters into account.
Watts also writes:
"it seems only fair to show what real science rather than what he and Dr. Trenberth's government funded advocacy looks like. I can't wait to see how Dr. Michael Mann tries to poo-poo this one. "
These are the kind of personal, inciting statements, which don't belong in a scientific argument. But this here is just an opinion blog. Anthony Watts doesn't do any science. Thus, personal attacks against scientists are allowed.
REPLY: Even though this is an insulting and spiteful comment, I'm going to allow it as Dr. Perlwitz is entitled to his opinion. It should be noted that Dr. Perlwitz is on the government advocacy payroll at NASA GISS. His page is here: http://www.giss.nasa.gov/staff/jperlwitz.html
My issue, and the issue with many here, has been Mann's insistence that the MWP was a small event confined to sections of the NH, rather than broader, perhaps global. Dr. Mann (an the GISS team) has gone to great lengths to obscure and erase the MWP (as was done in the shoddy MBH98 paper), and that's the issue I'm addressing.
I'm not interested in a discussion, since there is no basis of trust between Dr. Perlwitz and myself, we aren't going to change each other's viewpoints. Ever since I found out your boss, Dr. James Hansen, resorted to stage theatrics in June 1988 with Tim Wirth, I have no trust whatsoever in GISS. At one time Dr. Hansen's work motivated me to do a nationwide project with the National Arbor Day Foundation in 1990 and 1991 to offset CO2 by planting trees with the help of weathercasters nationwide. Now, having seen what he is, I see him and GISS in general as nothing more than funding survivalists willing to distort science as needed to preserve the organization. Following your lead on wordplay, he's a "fake scientist", demonstrated by deeds to be mostly an activist now.
As for the "Anthony Watts doesn't do any science." comment, I'll see you in 2013.
Be as upset as you wish. But I'm entitled to my opinion too.
– Anthony
dbstealey
Anthony Watts has done more for honest science than Jan Perlwts and James Hansen put together. Doubled and squared.
Perlwitz says:
"…the temperature reconstruction and the trend of -0.31 K/millennium is for Northern Scandinavia and the Arctic zone, but not for the global temperature anomaly. And conclusions about how the temperatures in Roman or Medieval times compare to present day temperatures can only be drawn for this region from this study, but not for the global temperature anomaly."
Anomalies are simply deviations from the trend, or from a baseline, or average. Therefore, the only honest comparison is made by looking at the long term trend within its long term parameters. Since temperatures have not broken out above their long term parameters, the only logical conclusion is that the effect of CO2 on temperature is too small to measure.
That trend line shows that temperatures are not accelerating. The gradual rise in global temperatures has not deviated from the long term trend line since the end of the LIA, when CO2 was at ≈280 ppmv. CO2 is now at ≈392 ppmv. But that ≈40% rise in CO2 has not caused an accelerating warming trend.
Thus:
CO2 has no measurable effect on global temperatures. QED, Mr Perlwitz. QED.
[SNIP – like I said, not interested in a discussion right now. Have a nice weekend Dr. Perlwitz, and you too Smokey. I have better things to do than moderate this fight. – Anthony]