Since there is so much worry about the Arctic Sea Ice extent this time of year, it is always good to get some historical perspective. According to this study, our current low Arctic ice extents are not unprecedented.
From a press release of the Geological Survey of Norway:
Less ice in the Arctic Ocean 6000-7000 years ago
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.
The complete story follows.
”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
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.
”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.
===========================
h/t to Ecotretas
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Tom Fuller said:
“First, it should be obvious that the manipulation of the messages isn’t coming from scientists.”
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dp says:
September 8, 2010 at 9:37 am
Weasel word alert:
‘“Changes that took place 6000-7000 years ago were controlled by other climatic forces than those which seem to dominate today,” Astrid Lyså believes.’
======================================================
Start paying attention Tom………….
R. Gates says:
September 8, 2010 at 3:34 pm
“But even more importantly, the melting 6,000 or 7,000 years ago was caused most likely from Milankovitch cycles, whereas the most likely mechanism today is the 40% higher CO2 we have now than we had during that period of the Holocene. ”
Or it could be we don’t have a clue about what causes what. Further, I find these exercises of what causes what entirely academic. I could assert that the most natural state of H2O, throughout time, is liquid and that man’s experience and knowledge of the globe is an aberration. What is certain, is that our knowledge of a “natural” state of the globe is woefully inadequate to come to any determination. There’s plenty of evidence that shows CO2 was at a higher concentration in the past, so does it matter if man puts out CO2 or not? Intuitively, I’d say no. Especially if it is given that man cannot create matter. Mankind has shown an incredible knack for adaptation, the earth has shown a great affinity to continue to rotate and equalize whatever is occurring on its surface. I think things will be fine. Milankovitch cycles or not.
James Sexton says:
September 8, 2010 at 3:19 pm
I haven’t read all the comments, so, if its been said already, it bears repeating anyway. We’ve had less ice in the arctic in the last 30-70 years.
http://www.csp.navy.mil/asl/Timeline.htm ……… and, of course, http://wattsupwiththat.com/2009/04/26/ice-at-the-north-pole-in-1958-not-so-thick/
See the open water?
______________________
Haha, yeah, and I read this bit there too-
“The Ice at the polar ice cap is an average of 6-8 feet thick, but with the wind and tides the ice will crack and open into large polynyas (areas of open water), these areas will refreeze over with thin ice. We had sonar equipment that would find these open or thin areas to come up through, thus limiting any damage to the submarine. The ice would also close in and cover these areas crushing together making large ice ridges both above and below the water. We came up through a very large opening in 1958 that was 1/2 mile long and 200 yards wide. The wind came up and closed the opening within 2 hours. ”
Have you seen the Pole waters today?
http://exploreourpla.net/explorer/?map=Arc&sat=ter&lon=0&lat=89,9&lvl=6&yir=2010&dag=250
Susan said (September 8, 2010 at 10:40 am)
Anthony, I have been looking for a peer-reviewed paper on this study ever since that press release was issued. No sign of it yet. If they haven’t been able to get it published, we should be asking ourselves, why not?
I am not Antony,but Susan, how do you know this article has not been peer-reviewed? Or do you mean you have been looking for an endorsement from the IPCC or any other high ranking AGW organization?
Peer-review in scientific research articles/ papers only means that a particular article/ paper has been inspected by the writer’s peers and should therefore not contain any glaring scientific mistakes or conclusions.
Peer-review is not supposed to be some kind of gate-valve keeping out scientific research findings of any kind.
Werner Weber says:
September 8, 2010 at 2:02 pm
“an answer to the problem why in present days a series of positive feedbacks such as permafrost thawing and consecutive methane release should occur, while for reasons unknown to me they have not occurred in early holocene.”
Those areas were covered by receding continental ice sheets.
Mr. Werme: this is well known enough to have appeared on PBS “History’s Mysteries”.
Further South, the Kansas-Nebraska area was actually a SAND-DUNE DESERT roughly contemporary to the Wettest Sahara period. A few of the Dunes survive as a National Monument.
Jimbo says:
September 8, 2010 at 3:21 pm
R. Gates says:
September 8, 2010 at 11:59 am
I do find the sudden posting of this study from two years ago to be a curious event however, as no new study or research on this seems to have precipitated this posting.
R. Gates,
Forget that study. The main point of the post was:
“….our current low Arctic ice extents are not unprecedented.”
Now please read and comment on the following papers and studies:
http://www.agu.org/pubs/crossref/2010/2009PA001817.shtml
http://hol.sagepub.com/content/12/1/49.abstract
http://www.jstor.org/stable/1550979
http://www.sciencemag.org/cgi/content/abstract/278/5341/1257
http://agwobserver.wordpress.com/2009/08/29/papers-on-1500-year-climatic-cycle/
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Jimbo, see my previous post. The point here is not about whether or not there has been periods of lower Arctic sea ice in the past– as undoubtedly the Holocene Optimum saw periods of reduced Arctic Sea ice. I don’t think anyone would dispute this who has seriously studied the period. The more interesting issue should focus on cause, and the differences between the Holocene Optimum and the effects on Arctic Sea ice and our current period. We have far more CO2 in the atmosphere now than during the Holocene Optimum, and the current Milankovitch cycles would not support the warming we are seeing though they were favorable for the N. Hemisphere warming (especially during summer) that we saw during the Holocene Optimum. Note, most studies show that the Holocene Optimum had it’s greatest effect at the northern latitudes and during the summer months and corresponds well with the astronomical causes (i.e. Milankovitch). The current period of global warming, which is similar to the Holocene Optimum, except that the current period is more global, and has no other known natural or astronomical cyclical causes and so we are left with CO2.
This is a good overviw of the period:
http://www.ncdc.noaa.gov/paleo/globalwarming/holocene.html
James Sexton says:
September 8, 2010 at 4:04 pm
R. Gates says:
September 8, 2010 at 3:34 pm
“But even more importantly, the melting 6,000 or 7,000 years ago was caused most likely from Milankovitch cycles, whereas the most likely mechanism today is the 40% higher CO2 we have now than we had during that period of the Holocene. ”
Or it could be we don’t have a clue about what causes what. Further, I find these exercises of what causes what entirely academic. I could assert that the most natural state of H2O, throughout time, is liquid and that man’s experience and knowledge of the globe is an aberration. What is certain, is that our knowledge of a “natural” state of the globe is woefully inadequate to come to any determination. There’s plenty of evidence that shows CO2 was at a higher concentration in the past, so does it matter if man puts out CO2 or not? Intuitively, I’d say no. Especially if it is given that man cannot create matter. Mankind has shown an incredible knack for adaptation, the earth has shown a great affinity to continue to rotate and equalize whatever is occurring on its surface. I think things will be fine. Milankovitch cycles or not.
______
You are very correct in your general statement, and I have stated repeatedly that some species will win and some will lose as the climate changes–no matter what the cause of that change. You are also correct that humans have shown a very strong ability to adapt to change. One point about the concentration of CO2 in the past however– yes it has been higher in the past, but not in at least the past 400,000 years. The 40% increase in CO2 that humans have caused in just a few hundred years is akin to a human CO2 “volcano” erupting on the planet, and it continues to erupt. Yes, life goes on and eventually recovers after such events, but the landscape is forever changed, and some species win and some lose. Such is the nature of our living planet.
Now R. Gates all you need do is demonstrate that even Greenland is warmer today than the 1930’s. I don’t know, is it?
I think that James Sexton’s comment of 8th September 4.04 pm to be smack on target. This is exactly as I see it. We do not know enough about how the climate works and what affects what and how this works. All we know is that after 4.5 billion years and a torid and at times a catastrophiic past, the world is still here as a habital place. This suggests that it is self regulating and a tipping point cannot easily be reached. Further, we do not know whether a warmer plannet would cause serios problems for mankind. Personally I doubt that it will. I consider that on the whole it will be beneficial. Since there is a real probability that we are powerless to prevent any warming, there is gross uncertainty as to its cause and whether that cause can effectively be controlled or reversed, whether warming will be a severe problem or no problem at all and given the adaptability of mankind, we should simply wait and see what happens preparing to react as necessary to any problem that truly causes mankind a significant trouble.
My take on the cautionary principle is that we should not waste trillions on limiting CO2 when we do not know whether it is the devil that it is made out to be. If the planet still warms but does not cause man any significant problems, then those would be trillions wasted. If the planet still warms despite limiting CO2 and this causes a problem then we shall have to spend further trillions adapting, ie., pay twice over. The cautionary take is therefore to do nothing and just spend money adapting to the extent that adaption is truly necessary. If no adaption is required, we save trillions rather than having wasted it.
When one considers the past history of the Earth, AGW appear a lot of hype about nothing.
RE: Peter Plail says:
September 8, 2010 at 11:32 am
I thought the same thing. I also think it didn’t work. This sort of study is too threatening. These scholars received no further funding that I ever heard of.
I actually saved this article when it first came out, along with others, especially those involving Vikings and the MWP. Such people never seem to receive funding.
I think the arctic was ice free during the summers of the MWP. Or at least ice free enough to make the Northwest Passage passable by both Vikings and Chinese Junks. But I expect to see no hurry to research such things.
What is most interesting about the period 6000 years ago is that the amassed driftwood was enough for the Independence 1 Culture to burn wood for a long period of time. Driftwood now is quite rare. I wonder if they burned it all up, and faced the first “energy crisis” we know of.
I’m glad this article was resurrected. The history of past peoples fascinates me. I’m looking forward to reading all the comments this posting has generated, when I find time.
R. Gates says:
September 8, 2010 at 3:34 pm
CO2, being a molecule, must re-radiate any energy it stores beyond it’s capacity, which is not infinite.
And, like someone posted on another thread, it can transport IR energy back to space just as easily as it absorbs it coming off the Earth’s surface. The back of the envelope on this one says that 1 in every 10,000 molecules in the atmosphere are the new C02 molecules. So we are limited to 1 in 10,000 new blackbodies of a ?higher? order.
To say or infer that the heat energy re-radiated by a new C02 molecule is only going to find another C02 molecule (1 in 2564) is astronomically bad.
Phil. says:
September 8, 2010 at 3:38 pm
“Plenty more open water there today James!”
As Jakers said, “http://exploreourpla.net/explorer/?map=Arc&sat=ter&lon=0&lat=89,9&lvl=6&yir=2010&dag=250
Have you seen the Pole waters today?”
The waters open and close. This is how it has always been in the arctic for all recordable history. The obsession over Arctic ice is superfluous. It doesn’t mean anything.
R. Gates says:
September 8, 2010 at 3:34 pm
The current period of global warming, which is similar to the Holocene Optimum, except that the current period is more global, and has no other known natural or astronomical cyclical causes and so we are left with CO2.
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With continued prose like that, I think you would be a fantastic summarizer for the next IPCC report.
[not a compliment]
Chris
Norfolk, VA, USA
R. Gates said: …except that the current period is more global, and has no other known natural or astronomical cyclical causes and so we are left with CO2.
Don’t take this personally, but it is a bit arrogant to claim that any recent rise has to be due to CO2 because there are “no other known natural or astronomical cyclical causes.” This implies that you have knowledge of all the known natural or astronomical cycles. Somehow I doubt that.
You seem really hung up on the fact that CO2 levels have increased and that global temperatures have (possibly) increased, therefore they must be related somehow. This website is full of various ideas and theories for why the temperature has increased or not. Some of them are a little off the wall, but there are quite a few ideas that are just as plausible, if not more plausible, than the CO2/temperature link.
Open your mind a little and actually read some of the alternate possibilities. Try this one for starters.
I have a gut feeling that we’re heading for a “science bubble”…kind of a knowledge version of the housing or dot-com bubbles. There seems to be a trend that we know it all, and something is going to come along and remind us just how ignorant we really are. Post-normal science meets the real world. Our great-grandkids (for those of us who aren’t participating in the population control efforts) are going to look back and shake their heads at the ridiculous things we just “knew” were right; right up there with bleeding patients to cure fevers. We are never as smart as we think we are. The Greeks had a word for it…hubris.
R. Gates says:
September 8, 2010 at 4:29 pm
“Yes, life goes on and eventually recovers after such events, but the landscape is forever changed, and some species win and some lose. Such is the nature of our living planet.”
Yes, I agree. I find that you and I agree on most things. The one part of the statement that I quoted from you that I find to be the crux of the discussion to be, your words, “but the landscape is forever changed”. At what point in time has the landscape not “forever changed”? Does it matter that one “species” changed it versus another?
I assert and maintain the earth has been and always will be in a constant state of “change”. Further, I assert and maintain that mankind is as much of part of nature as any other creature that walks or crawls on this earth. We are not an aberration of nature, but rather a precursor of perfection of Nature. We can do no more harm to Nature than to change our nature.
richard verney says:
September 8, 2010 at 5:05 pm
Only to expound on what Richard stated, history is replete of examples where mankind thrives in a warmer climate. Suddenly, we are to presuppose that mankind will suffer during a warming period? Let me model this on my server…………….nope, we’re ok. In fact, we’re better than just ok, because mankind thrives better in warmer climates. I don’t believe for a second that CO2 causes any discernible warmth, but if it did, it should be welcomed. But, that’s just me wishing for more agrigable land.
To say that current warming is only caused by an increase of 1 c02 molecule to replace an o2 molecule per 10,000 molecules is not plausible, nor does it even sound likely.
Leif made a convincing argument when he shot down TSI as the dominant factor in solar heating.
The numbers are not significant.
Likewise, 100ppm C02 rise, as the dominant factor in climate change today, deserves to be shot down. It makes for great sci-fi blockbuster movies, but that’s the extent of it.
The 2 asteriods coming withing 1 light second of Earth today, after being discovered only 3 day prior, is truly cause for concern.
JimBob says:
September 8, 2010 at 6:28 pm
@ur momisugly R. Gates
================================
Extremely well said, on all points!
Chris
Norfolk, VA, USA
rbateman says:
September 8, 2010 at 7:27 pm
Likewise, 100ppm C02 rise, as the dominant factor in climate change today, deserves to be shot down. It makes for great sci-fi blockbuster movies, but that’s the extent of it.
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I doubt it even makes the cut for good sci-fi material, Robert.
I certainly wouldn’t pay to see it.
But then again I could never suffer all the way through An Inconvenient Truth, either.
Chris
Here is another known “inconvenience” for the region:
“Holocene Treeline History and Climate Change Across Northern Eurasia”
http://www.geog.ucla.edu/downloads/634/269.pdf
“Over most of Russia, forest advanced to or near the current arctic coastline between 9000 and 7000 yr B.P. and retreated to its present position by between 4000 and 3000 yr B.P. Forest establishment and retreat was roughly synchronous across most of northern Russia. … During the period of maximum forest extension, the mean July temperatures along the northern coastline of Russia may have been 2.5° to 7.0°C warmer than modern.”
One would wonder how these 200 miles of forest line are co-related with ice extent…
I guess all the “skepticism” goes out the window here when a science study gives a pleasing answer.
You know, “skepticism” – questioning every single statement, inference, data point, and conclusion of a study, and questioning the motives, competence, personal integrity and bathing habits of the scientists involved.
Like, exactly why is the landfast ice piled up by Canada and Greenland these days ? Ocean currents ? Temperature patterns ? Wind patterns ?
ftp://ftp-projects.zmaw.de/seaice/NEAR_REAL_TIME/Arc_latest_large.png
Were these factors different 6000 to 7000 years ago ? Maybe the thickest, landfast ice back then was on the Siberian side of the Arctic, and Greenland was open every summer like Siberia has been recently. How could you tell ? Have they studied “raised beach ridges” in Siberia, Alaska, Norway ?
What about the lower ocean levels back then ? Did this affect the water entering/leaving the Bering Strait ? What about all the receding ice sheets dumping freshwater into the rivers that feed the Arctic Ocean ? Was the salinity vastly different back then ? How did this affect ocean currents into/outof the Arctic ? What about the catastrophic drainage of glacial Lakes Agassiz and Ojibway around 8400 yrs ago – did this affect the jet stream and wind patterns for thousands of years ? What about the adjustments to Earth’s lithosphere after all those ice sheets melted (the rebound of the crust) – was the topography of the Arctic Ocean seabed all different then ? Maybe the warm Atlantic Ocean water had a channel directly under the Arctic basin back then.
Is Astrid Lyså, a geologist and researcher at the Geological Survey of Norway (NGU), qualified to say that the Arctic was sea ice free 7000 years ago because a few beaches in Greenland saw waves ? And why mention the Independence I Culture of Inuits who came to that area as “long ago as 4000-4500 years ago” if they are studying the period 7000 to 6000 years ago ? Some people came and went a couple thousand years after north Greenland was supposed to be ice free ? So what ?
I think the WUWT pack of skeptic attack dogs rolls over, smiles, and wags its tail when a scientist gives them a biscuit.
Imagine if this paper gave an answer the “skeptics” didn’t want to hear…
OH Dahlsveen (September 8, 2010 at 4:09 pm)
By “peer-reviewed literature” I only meant that I’d been looking for an-indepth description of the study in some scientific journal or other. It is the completeness of the description and the background details that I’m looking for. Its been 2 years since that press release from a study that apparently (from an earlier comment) started in 2006 or so.
I have grown weary and wary of “science by press release.” If the results are so all-fired important, it should be out in print by now for us to read and decide for ourselves. I cannot decide anything from this press release.
There have been numerous cites to paleo based information on WUWT.
All should be checked for validity.
It’s interesting that this post looks at 6000 to 7000 years ago. This is when the sea level stabilized and urbanic culture as we know it emerged and took hold as towns based upon ports located on the oceanic coast. Before this point, the rising sea levels prohibited this development. There is no known urbanic civilization older than 7000 years. Find one.
Susan C. says:
September 8, 2010 at 9:23 pm
“By “peer-reviewed literature” I only meant that I’d been looking for an-indepth description of the study in some scientific journal or other. …………I have grown weary and wary of “science by press release.”
Yes, in total agreement. But, as Dahlsveen stated, it isn’t a gatekeeper to thought. In fact, lately, in regards to the climate debate, it has been only a gatekeeper to “correct thought”. Obviously, there must be another mechanism to discern the validity of other thoughts. Until then, sadly, we are left to our own discernment. Hmm,……this isn’t as bad as I thought it may be……….Some one can give me a thought…..I can consider the thought……..take in all the arguments…..and discern for myself whether the thought is correct or not. ………………. Yeh, I’ll wait on a peer-reviewed blathering.
If you can understand the writing of a study, do you really need someone else to determine for you if you should believe it or not? Is the science or math is correct or not? Please, do not acquiesce. It is incumbent upon us all to discern reality from fiction. Other opinions. Absolutely! Discernment, ….that is the providence of self.