I love field work. I think any climate scientist that basically becomes a data jockey should be forced to go out and examine real world measurement systems and weather stations once a year so that they don’t lose touch with the source of the data they study. That’s why I’m pleased to see that scientists at the Geological Survey of Norway (NGU ) did some good old fashioned field work to look at geologic residues of past climate.
What they found was intriguing. The arctic may have periodically been nearly ice free in recent geologic history, after the last ice age. It is clear from this that we don’t really know as much as some think they do about climatic and ice cycles of our planet.
Recent mapping of a number of raised beach ridges on the north coast of Greenland suggests that the ice cover in the Arctic Ocean was greatly reduced some 6000-7000 years ago. The Arctic Ocean may have been periodically ice free.
BEACH RIDGE: The scientists believe that this beach ridge in North Greenland formed by wave activity about 6000-7000 years ago. This implies that there was more open sea in this region than there is today. (Click the picture for a larger image) Photo: Astrid Lyså, NGU
”The climate in the northern regions has never been milder since the last Ice Age than it was about 6000-7000 years ago. We still don’t know whether the Arctic Ocean was completely ice free, but there was more open water in the area north of Greenland than there is today,” says Astrid Lyså, a geologist and researcher at the Geological Survey of Norway (NGU).
Shore features
ICE COVER: Today, at the mouth of Independence Fjord in North Greenland, drift ice forms a continuous cover from the land. (Click for a larger image) Photo: Eiliv Larsen, NGU
Together with her NGU colleague, Eiliv Larsen, she has worked on the north coast of Greenland with a group of scientists from the University of Copenhagen, mapping sea-level changes and studying a number of shore features. She has also collected samples of driftwood that originated from Siberia or Alaska and had these dated, and has collected shells and microfossils from shore sediments.
SETTLEMENT: Astrid Lyså in August 2007 in the ruined settlement left by the Independence I Culture in North Greenland. The first immigrants to these inhospitable regions succumbed to the elements nearly 4000 years ago, when the climate became colder again. (Click for a larger image) Photo: Eiliv Larsen, NGU
”The architecture of a sandy shore depends partly on whether wave activity or pack ice has influenced its formation. Beach ridges, which are generally distinct, very long, broad features running parallel to the shoreline, form when there is wave activity and occasional storms. This requires periodically open water,” Astrid Lyså tells me.
Pack-ice ridges which form when drift ice is pressed onto the seashore piling up shore sediments that lie in its path, have a completely different character. They are generally shorter, narrower and more irregular in shape.
Open sea
”The beach ridges which we have had dated to about 6000-7000 years ago were shaped by wave activity,” says Astrid Lyså. They are located at the mouth of Independence Fjord in North Greenland, on an open, flat plain facing directly onto the Arctic Ocean. Today, drift ice forms a continuous cover from the land here.
Astrid Lyså says that such old beach formations require that the sea all the way to the North Pole was periodically ice free for a long time.
”This stands in sharp contrast to the present-day situation where only ridges piled up by pack ice are being formed,” she says.
However, the scientists are very careful about drawing parallels with the present-day trend in the Arctic Ocean where the cover of sea ice seems to be decreasing.
“Changes that took place 6000-7000 years ago were controlled by other climatic forces than those which seem to dominate today,” Astrid Lyså believes.
Inuit immigration
The mapping at 82 degrees North took place in summer 2007 as part of the LongTerm project, a sub-project of the major International Polar Year project, SciencePub. The scientists also studied ruined settlements dating from the first Inuit immigration to these desolate coasts.
The first people from Alaska and Canada, called the Independence I Culture, travelled north-east as far as they could go on land as long ago as 4000-4500 years ago. The scientists have found out that drift ice had formed on the sea again in this period, which was essential for the Inuit in connection with their hunting. No beach ridges have been formed since then.
”Seals and driftwood were absolutely vital if they were to survive. They needed seals for food and clothing, and driftwood for fuel when the temperature crept towards minus 50 degrees. For us, it is inconceivable and extremely impressive,” says Eiliv Larsen, the NGU scientist and geologist.
(hat tip to many commenters and emailers, too numerous to mention, but thanks to all)
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Dr. Lief:
wrote David Vermette (19:01:46) :
Anybody know how accurate that chart of historical sunspots numbers is likely to be? This is all I could find on it:
11,000 Year Sunspot Number Reconstruction
From the link:
DESCRIPTION:
The series of reconstructed 10-yr averaged sunspot numbers with their 68% uncertainty.
Years are given BP (before present), i.e. the calendar AD year, Yad, is related to the BP year, Ybp, as Yc=1950-Ybp.
Does this mean that 30,000 suspots could be anywhere between say 15,000 and 45,000, and that 50,000 sunspots could be as low as say 25,000?
Does it say that 1000 ybp might be 1500 ybp, or perhaps 6,000 ybp could be 9,000??
Also, one other question (at the moment!)
You seem to believe that sunspot activity does not affect earth’s climate in a substantial amount compared to GHG.
Do you also believe that all solar variance (is that TSI?) is relatively immaterial?
Thanks.
Just a small correction to Leif Svalgaard’s comment concerning estimation of the cosmic ray flux.
The primary production mechanism for carbon-14 (the radio isotope of carbon used in carbon dating) is not the transformation of carbon-12 to carbon-14. Rather it is the interaction between slow cosmic ray induced neutrons and nitrogen-14 to produce carbon-14 and a proton.
However, Leif is absolutely right that measurement of carbon-14 in tree rings that have been independently dated using dendrochronology allows us to calculate the production rate of carbon-14 and therefore estimate the cosmic ray flux.
Leif Svalgaard (16:07:17) :
”The climate in the northern regions has never been milder since the last Ice Age than it was about 6000-7000 years ago.”
And those who believe that the correlation between climate and solar activity is ‘obvious’ can compare with one reconstruction of solar activity [Usoskin et al.] at 4000-5000 BC:
http://upload.wikimedia.org/wikipedia/commons/thumb/2/27/Sunspots_11000_years.svg/800px-Sunspots_11000_years.svg.png
Low spots -> cold, remember.
Leif,
That’s an interesting graph. I wonder if there is a version that just shows the minimums?
Warmer back then? No way! That can’t possibly be!
The models and climate prophets say it isn’t possible. I think the proxy data is wrong, and thus needs to be adjusted.
Abolish the Holocene!
It’s so sad when scientists feel the need to qualify their results with statements like “Changes that took place 6000-7000 years ago were controlled by other climatic forces than those which seem to dominate today.” Astrid Lyså is a geologist, not a climate scientist. It would help if she said what she thought the climatic forces were 6000-7000 years ago and what she thought the forces are that seem to dominate today. Perhaps she is being very clever and the forces which seem to dominate today may not be climatic forces, but forces to conform for the sake of career or funding. Or the use of the word “seem” could imply she does not totally believe in the forces that seem to dominate today.
Leif said:-
“Another problem is that if two .. participating scientists were disagreeing..their exchanges would..become technical and incomprehensible to the majority of the readers”
I have to confess that my vision goes swimmy at MOST the technicalities on here already!! 🙂
Patrick Henry:) How old was that tree Anthony Watts reported on in a recent post a few months ago? It was in one of the Scandanavian countries, I thought it was definitely around 1,000 yo? Can’t remember to be honest.
Generally:- Stonehenge may have been demoted by 1,000 years by recent analysis. However, there is ALWAYS a possibility that they have got it wrong somehow, it does happen you know. It is & always has been a fact of life that present generations seem to think that everyone before was as thick as two short planks! Yet, deeper & more careful scrutiny often reveals that our forefathers may have just been on to something! At 50 yoa I now see what my late father was on about when he used to laugh at some “modern” pronouncements! As a practicing (I will one day perfect the art) structural engineer I am astonished how even in this profession, fashion & attitude & thinking seem to change as knowledge increases, new practices are developed, systems & ways of doing things are changed over time, only to end up going back to something tried & tested years ago that worked but delivered as something new! I am sure it’s the same in science & climatology too!
Shame about the qualification in the article but one can understand their position & as someone noted the need to “CMA”!
Love this site. It’s so refreshing.
I wonder how much confusion this difference BP-BC has caused? I just
got reminded of when I first became aware of it, it was an article in
Microsoft Encarta, swedish edition, that stated that the last ice age
ended 9998 years ago, or something like that I don’t have it installed today.
I was amazed, how could they state that so exactly? After some thinking
I realised that the probable explanation was that the original article used
the BC system, the last ice age ended 8000 BC, and some computer
generated locale conversion had just added he current year to the BC
value.
Leif
says: “If the correlations support one’s pet theory then clearly the data is good. If not, then clearly the data is bad.”
So how do you feel about the data showing that CO2 levels measured directly in the atmosphere around 1940´ies was higher than CO2 levels today?
Nobody i have seen can argue that the data is wrong. But the data does not fit into the so far normal view of CO2 concentrations in the atmosphere.
And then data are just thrown away. Yes, Becks data.
How do you feel about that?
The article of the present thread shows evidence that it was warmer 6-7000 years ago. In order to discrediet the solar role, do you then accept the fact that earth was warmer 6-7000 years ago?
Finaly, you say that these findings from Greenland could not be 2000 years wrong, and/or that the solar readings canot be 2000 years wrong.
Maybe so. But if you examine study after study of temperature graphs in the last many thousand years, you will se that the datings are in fact differing quite markedly. So they cant all be right. There must be quite some unsecurities in the datings.
Here is a very nice collection of temperature/time studies:
http://www.co2science.org/data/mwp/mwpp.php
I’d be interested in learning more about this “Independence I Culture,” as well as the “Saqqaq Culture,” which lived in southern Greenland at the same time. They both vanished at the same time, replaced, after a 600 year hiatus, by the “Independence II Culture” in the north and the “Early Dorset” in the south.
There is plenty of archeological evidence for warm times and cold times in the Arctic. Very fascinating and difficult to verify (so far) is the slim evidence the Irish preceded the Vikings, during the MWP. (Google “Yarn Baffin Dorset.”)
Over at Climate Audit, somewhere in the archives, is mention of a study of driftwood found on beaches similar to the one described in this post. It was found above so-called “permanent ice.” It had drifted across from Siberia, and dated from the MWP, with a bit from Roman times.
The fact Hansen and Mann so blithely snoot the hard work of archeologists has always annoyed me. Mann couldn’t even leave his computer to go double-check his bristlecone pine data. Instead he wrote how much funding was required to double-check the data. Then McIntyre went and proved he could sip a Starbucks in the morning, go get cores from bristlecones, and be back for dinner.
Hansen and Mann display a peculiar double standard. On one hand they say warming will be more pronounced in the arctic, but on the other hand they say proof of the MWP should be ignored, because it is more pronounced in the arctic. They call the MWP “local,” and to disprove the MWP they send some poor sucker to the jungles of Borneo to look at stalagmites.
They themselves stay safely indoors, gazing with tunnel vision at their computers.
Worst is the sense I get that they bully any scientist who dares disagree with them. I feel the archeologists mentioned in this post are walking on eggs, when I read:
“However, the scientists are very careful about drawing parallels with the present-day trend in the Arctic Ocean where the cover of sea ice seems to be decreasing.
“Changes that took place 6000-7000 years ago were controlled by other climatic forces than those which seem to dominate today,” Astrid Lyså believes.”
If there is any funding to hand out, I think it ought go to archeologists who get out there and open our eyes with fresh data gathered from the field, rather than climate scientists afraid to leave their computors.
Sorry Im off topic..
http://gsc.nrcan.gc.ca/geomag/nmp/long_mvt_nmp2_e.php
Does anyone know of any more recent magnetic north sites? This ones interesting : stating “Changes in the magnetic field characterized by an abrupt change in the secular variation have been named “(geo)magnetic jerks” or “geomagnetic impulses”. Six jerks of global extent have occurred during the past century: in 1901, 1913, 1925, 1969, 1978 and 1992. ”
I wanted to do a little research into more current research:) I found another slightly more current nasa site but I would appreciate any credible sites additionally.. again, sorry for off topic.
Stories like this are probably the reason why realclimate.org has a problem with a rather large number of geologists being skeptics.
Another recent paper that shows a prolonged warm (+1-2K) period some 6000-7000 years ago as well as MWP and LIA based upon borehole data.
http://www.geo.lsa.umich.edu/~shaopeng/2008GL034187.pdf
Huang, S. P., H. N. Pollack, and P.-Y. Shen (2008)
A late Quaternary climate reconstruction based on borehole heat flux data, borehole temperature data, and the instrumental record
We present a suite of new 20,000 year reconstructions that integrate three types of geothermal information: a global database of terrestrial heat flux measurements,
another database of temperature versus depth observations, and the 20th century instrumental record of temperature, all referenced to the 1961–1990 mean of the
instrumental record. These reconstructions show the warming from the last glacial maximum, the occurrence of a mid-Holocene warm episode, a Medieval Warm Period (MWP), a Little Ice Age (LIA), and the rapid warming of the 20th century. The reconstructions show the temperatures of the mid-Holocene warm episode some 1–2 K above the reference level, the maximum of the MWP at or slightly below the reference level, the minimum of the LIA about 1 K below the reference level, and end-of-20th century temperatures about 0.5 K above the reference level.
Leif, You could just as easily say you are making an extra assumption to confirm your theory specifically that the discovered shore edge was not caused by sea water.
The only place nearly everyone including me on this site wants to go is where the facts lead.
What does your temperature equation for the cycle comparison mean in real terms i.e temperature for a Dalton and temperature for an average cycle. Comparing 15000 spots with 50000 spots that’s 3 1/3 times as many. Ed
Ron (00:46:25) :
The series of reconstructed 10-yr averaged sunspot numbers with their 68% uncertainty. Years are given BP (before present), i.e. the calendar AD year, Yad, is related to the BP year, Ybp, as Yc=1950-Ybp. Does this mean that 30,000 sunspots could be anywhere between say 15,000 and 45,000,
No, it means that the error bars are ‘one sigma’ meaning that there is a 68% chance that the true value is within an interval of the value given plus or minus the size of the error bar. Somewhere it might say [or show on the graph] what the error bar is. My guess would be 200. Say this is correct then there is a 68% chance that the true value [more precisely: the expected value] would be between 29,800 and 30,200.
Ron (00:50:38) :
You seem to believe that sunspot activity does not affect earth’s climate in a substantial amount compared to GHG.
No, i do not believe that. You should have said “compared to all other causes”.
Do you also believe that all solar variance (is that TSI?) is relatively immaterial?
Yes, as far as the climate is concerned.
Paul Dennis (01:14:26) :
Just a small correction to Leif Svalgaard’s comment concerning estimation of the cosmic ray flux.
[…] Rather it is the interaction between slow cosmic ray induced neutrons and nitrogen-14 to produce carbon-14 and a proton.
I stand corrected
This may be a silly, but looking at Lief’s example of sunspot reconstruction, I’m wondering the following concerning accuracy of reconstructions.
Lief rightly points at correlation between sunspot number and temperature or lack thereof 6-7k ybp.
I’m assuming that reconstruction is done by measuring radioactive beryllium 10 at different layers of ice. The further down you drill, the further back in time you go.
Has anyone considered that during warmer periods such as 6-7k ybp, more ice melts than is “layed down”, essentially erasing those time periods from the record. Wouldn’t extended cold periods contain more data, and much of extended warm periods be missing?
I.e. if the Arctic was ice free 6-7ybp, so for an extended period of time, then couldn’t there be extensive melting of ice on Greenland and/or Antarctica as the same time?
Does anyone have a definitive answer as to whether something like this has ever been considered?
I’ve been looking at the AIRS video of rising CO2 and thinking it looked somewhat like the ozone maps I’ve been checking every day, not that they may or may not be closely correlated, but they do have something in common. The Sun’s radiation produces carbon 14, an isotope of carbon that ends up in CO2. During minimums, CO2 with carbon 14 measures rise. During maximums, CO2 with carbon 14 decrease. My observation of ozone is that it also changes with Sun exposure, decreasing during the day, and recovering at night (how I don’t know). It has also been theorized that cosmic ray bombardment destroys ozone. So it is true that cosmic rays, solar wind decreases, magnetic field weakness, etc, can change the chemical makeup of CO2 in the atmosphere. Is it possible that the AIRS map has not differentiated between CO2-14 with CO2-12 or 13 and is actually measuring the Sun’s production of CO2-14 as cycle 23 ramped down and we are in a slumbering minimum?
Patrick Henry (22:13:28) :
Carbon dating is not accurate within 1,000 years for a “6,000 year old” sample. (Stonehenge’s age was just demoted 1,000 years this summer.) Tree ring dating is problematic because there are no living trees that old.
The raw 14C counts have to be calibrated using samples of known age. Standard calibration curves are available, based on comparison of radiocarbon dates of samples that can be dated independently by other methods such as examination of tree growth rings (dendrochronology), deep ocean sediment cores, lake sediment varves, coral samples, and speleothems (cave deposits).
The 2004 version of the calibration curve extends back quite accurately to 26,000 years BP. Any errors in the calibration curve do not contribute more than ±16 years to the measurement error during the historic and late prehistoric periods (0 – 6,000 yrs BP) and no more than ±163 years over the entire 26,000 years of the curve
So 14C is quite reliable for 6000-7000 years ago.
Be10 concentrations are affected by climate, weather and changes in the earth’s magnetic field which also impact cosmic rays.
The bigger effect is that of the Earth’s magnetic field and rest assured that scientists are not complete morons, so this effect has been corrected for.
The NGU age estimate was clearly a WAG. It could easily be off by a couple of thousand years.
I don’t think you have any evidence for that.
You were attempting to draw a conclusion based on alignment of two data sets, both with error bars too great to have any significance.
I think the error bars in the ‘vertical’ direction is of most concern. The timing error is not ‘a couple thousand year’.
Nick Yates (01:24:05) :
That’s an interesting graph. I wonder if there is a version that just shows the minimums?
Without trying to be facetious, can you not just put a big blob on each of the minima shown on the graph and just look at the blobs? or maybe I didn’t understand your question…
Lansner, Frank (03:26:32) :
So how do you feel about the data showing that CO2 levels measured directly in the atmosphere around 1940´ies was higher than CO2 levels today? And then data are just thrown away. Yes, Becks data. How do you feel about that?
“If the correlations support one’s pet theory then clearly the data is good. If not, then clearly the data is bad.”
I don’t really care what the CO2 levels were. What has that to do with the Sun and its influence?
The article of the present thread shows evidence that it was warmer 6-7000 years ago. In order to discrediet the solar role, do you then accept the fact that earth was warmer 6-7000 years ago?
At least in Greenland. There is also other evidence [from boreholes on the Ice] that this was the case, so no problem there. Why do you ask? And please don’t answer by saying that that disproves AGW, because that is an invalid argument. For it to be valid you would have to posit that AGW is the only cause of climate variability.
Finaly, you say that these findings from Greenland could not be 2000 years wrong, and/or that the solar readings canot be 2000 years wrong.
Maybe so. But if you examine study after study of temperature graphs in the last many thousand years, you will se that the datings are in fact differing quite markedly.
Clearly if you go back far enough the timing errors get larger, but 6000 years is not far and we can count both tree rings and ice annual layers individually so timing errors are small for those methods.
So they cant all be right. There must be quite some unsecurities in the datings.
Yes, but not 2000 years for an age of 6000.
But it comes down to this:
If the data does not conform to your pet theory, your pet theory to be viable will now have to be extended with the additional assumption that the data is bad. This can go on indefinitely, but the more such extensions are needed the less likely your pet theory becomes.
Dave (06:16:06) :
I.e. if the Arctic was ice free 6-7ybp, so for an extended period of time, then couldn’t there be extensive melting of ice on Greenland and/or Antarctica as the same time?
The ice that is used for 10Be work comes from the top of the ice caps at 12,000 [Antarctica] and10,000 feet [Greenland]. Up there it is always cold [I know, because I have spent six months there 🙂 ]. During the summer [i.e. the day] the very top few inches might partly melt to slush, but during the winter [i.e. the night] that layer freezes solid. The slush takes up air bubbles that scatter light, while the ‘night ice’ is clear. In this way annual layers build up that are easily counted. And none go missing, because at night everything is frozen.
Leif,
No one is saying that most scientists are “morons,” but they are often wrong.
Having been through a graduate program in geochemistry with a an emphasis on isotope dating, my confidence in age claims by geologists is usually +/- about 20%. That range allows for any possible interpretation of the Be10/ice correlation.
I am not arguing for or against sunspots as a cause of climate change, but the LIA is problematic to explain in the absence of another theory.
For some, this ice-free Arctic Ocean phase 6-7,000 years ago isn’t all that unexpected. For people like William Ruddiman the advent of agriculture was the proximate cause of this warming. The hypothesis goes that once humans developed agricultural practices that they engaged in the first of the all-out wars against the environment, clearing the land and burning things down to make way for the hoe and sickle. This released large quantities of CO2 and other greenhouse gases which prevented another ice age. Perhaps the climate sensitivity for CO2 is so high that even the relatively small impact of early farmers caused this ice-free Arctic scenario!
See http://en.wikipedia.org/wiki/William_Ruddiman
Its a plausible hypothesis, and I imagine there is some truth to it. But I would almost imagine that impacts from humans would have been higher during a hunter-gatherer period than during the agricultural period. I would say this because a lot of hunter-gatherers seem to have used fire as a major environmental management technique (N. American prairies, Australia perhaps). It also hinges on a very large forcing from a small amount of CO2 and CH4 increase, which may not be plausible at all.