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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James Sexton says:
September 8, 2010 at 6:12 pm
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.
So why did you bring the subject up?
rbateman says:
September 8, 2010 at 7:27 pm
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.
Then shoot it down with pertinent scientific facts not this nonsense.
I think that the world has only warmed a few tenths of a degree recently.How does that compare with the warming we saw in the htm? My opinion of this is shaped by watching Bob Carter videos on the causes of global warming though.The argument is the that the htm like the mwp was only local weather unlike the present day which is really global,I don’t buy this whatever the experts say. The present day warming is just another warm period in earths history and not “unusual” and does not require the explanation of agw caused by increased co2.
Phil. says:
September 8, 2010 at 9:52 pm
Then shoot it down with pertinent scientific facts not this nonsense.
=====================================
The only “nonsense” part of that was your response above, not his post.
Weak.
Chris
R. Gates, I believe that oceanic SST swings do a pretty good job of matching land temperature swings. And this phenomenon appears to be quite global. Would that not be a possible source of cause and effect?
R Gates said:
“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.”
I would dispute your confident assertion that human activities have caused a 40% rise in atmospheric CO2, we simply do not know the exact amount of extra CO2 humans have contributed over and above natural cyclic rises in atmospheric CO2.
What is the natural contribution to the measured rise and what is the estimated contribution of human activities? This is where proxies can tell us little and what they do suggest is not always accurate by any means. We know that as the oceans warm they release CO2 so is the 40% you claim solely down to human activities or does that figure include all known natural contributions?
We know that there are still gaping holes in our knowledge of the carbon cycle and so I think this 40% figure needs to be taken with a pinch of salt. Perhaps you can point to a definitive study that has calculated the 40% of which you speak, I would be grateful if you could supply information that backs up your claim.
I would expect that every warm period, which cycle around every 1000 years, would have less arctic ice than now. There are ice less periods as well even in recent history, before satellite cover started the scares. 1958 produced a pole ice free as photographs of three submarines at the pole in clear water show well. (Pictures on the US Navy site somewhere). I am sure that there are other years as well.
Certainly the Medieval and Roman warm periods had little summer ice in the Arctic because both were warmer than today.
Susan C. says:
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?
——————-
The reason the paper has not been published is simple – it is still in preparation. I understand from one of the authors that they intend to submit the manuscript to a high profile journal. I see no reason why it should not be published in a good journal. Less ice in the Arctic fits very well with what we know about Arctic summer temperatures in the early Holocene Thermal Maximum when there was higher summer insolation. It would be far more “inconvenient” is the ice had refused to melt despite the higher temperatures.
Did anybody else notice the rounded rocks around the firepits? Could those be the result of wave action or were they tumbled in a river-like setting over many millenia?
Dave
R. Gates says:
September 8, 2010 at 4:21 pm
Please provide evidence that the Arctic sea ice extent minimum since 1979 was caused by warming or co2. Before you reply please read first what NASA had to say on the matter. The point about bringing up past Holocene Arctic melt extents is to cast doubt on the assumptions that its co2 man-made warming. If it happened in the past without the extra co2 then why shouldn’t it happen in the present with the extra co2? We could simpy be seeing a naturally occuring Bond Event.
Jimbo says:
September 9, 2010 at 3:12 am
We could simpy be seeing a naturally occuring Bond Event.
————
Bond events are cold events. Since the temperature anomalies are warm, it would appear unlikely that we are experiencing a Bond event.
richard telford says:
September 9, 2010 at 3:36 am
Jimbo says: “We could simply be seeing a naturally occurring Bond Event.”
————
richard says: “Bond events are cold events. Since the temperature anomalies are warm, it would appear unlikely that we are experiencing a Bond event.”
The timing is about right for a Bond event. They happen every 1500y or so and the previous one happened around 500AD. All Bond events show a period of warming prior to the temperature drop – graph showing previous Bond events here:-
http://a.imageshack.us/img5/8862/holocenetemperaturevari.png
Quite worrying for the NH as cold kills.
Anu says: September 8, 2010 at 9:09 pm
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…
Sorry Anu, I have been thriving on these biscuits for fifty years. The ones you are selling have no nutritional value. Without a sense of history, any perspective on climate is clueless.
Policyguy says: September 8, 2010 at 9:36 pm
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.
Here you are : http://www.spiritofmaat.com/announce/oldcity.htm
Dave Trimble says: September 9, 2010 at 2:10 am
Did anybody else notice the rounded rocks around the firepits? Could those be the result of wave action or were they tumbled in a river-like setting over many millenia?
Dave
From my rockhounding experience, I would have to flip the rocks over to see if they were rounded in situ. lacking that ability, I would generally suspect them to have been rounded in flowing water, tidal or river would do. However, I have rocks, amorphous quartz, with a natural high polish on one side, found in the high plains, polished by windblown sand, presumably over centuries. They didn’t tumble as the side in the ground is unpolished.
Susan C. says:
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 have come across no other evidence that the Arctic was ice-free in this region during the Holocene….
____________________________________________________
There is this paper:
Temperature and precipitation history of the Arctic
“….Solar energy reached a summer maximum (9% higher than at present) ca 11 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 1-3° C 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… 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…”
Is that what you are looking for?
John Marshall says:
September 9, 2010 at 1:32 am
I would expect that every warm period, which cycle around every 1000 years, would have less arctic ice than now. There are ice less periods as well even in recent history, before satellite cover started the scares. 1958 produced a pole ice free as photographs of three submarines at the pole in clear water show well. (Pictures on the US Navy site somewhere). I am sure that there are other years as well.
——————————-
How many times do we have to hear about the submarines! Ice free – I really don’t think so! I posted this earlier – http://wattsupwiththat.com/2010/09/08/inconvenient-ice-study-less-ice-in-the-arctic-ocean-6000-7000-years-ago/#comment-478023
And gee, look at the pole today and think about a sub – http://wattsupwiththat.com/2010/09/08/inconvenient-ice-study-less-ice-in-the-arctic-ocean-6000-7000-years-ago/#comment-478023
http://exploreourpla.net/explorer/?map=Arc&sat=ter&lon=0&lat=89,9&lvl=7&yir=2010&dag=251
#
#
JimBob says:
September 8, 2010 at 6:28 pm
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….
_____________________________________________________
Yes. It is amazing how information like this is over looked:
Solar activity reaches new high – Dec 2, 2003
” Geophysicists in Finland and Germany have calculated that the Sun is more magnetically active now than it has been for over a 1000 years. Ilya Usoskin and colleagues at the University of Oulu and the Max-Planck Institute for Aeronomy say that their technique – which relies on a radioactive dating technique – is the first direct quantitative reconstruction of solar activity based on physical, rather than statistical, models (I G Usoskin et al. 2003 Phys. Rev. Lett. 91 211101)
… the Finnish team was able to extend data on solar activity back to 850 AD. The researchers found that there has been a sharp increase in the number of sunspots since the beginning of the 20th century. They calculated that the average number was about 30 per year between 850 and 1900, and then increased to 60 between 1900 and 1944, and is now at its highest ever value of 76.
“We need to understand this unprecedented level of activity,” Usoskin told PhysicsWeb.”
Or this:
Study of Dust in Ice Cores Shows Volcanic Eruptions Interfere with the Effect of Sunspots on Global Climate
(Seems Sunspots DO correlate with climate…. Unless volcanic action interferes according to this study of dust in Greenland ice cores, sunspots, and volcanoes.)
“The research, published in a paper in the May 15 [2002] issue of Geophysical Research Letters, provides striking evidence that sunspots — blemishes on the sun’s surface indicating strong solar activity — do influence global climate change, but that explosive volcanic eruptions on Earth can completely reverse those influences.
It is the first time that volcanic eruptions have been identified as the atmospheric event responsible for the sudden and baffling reversals that scientists have seen in correlations between sunspots and climate…
“By carefully studying the timing of other volcanic eruptions, we found that they coincided with all of the correlation reversals between sunspots and climate,” said Ram.
….The UB team discovered that these additional sulfates cause cosmic rays to have a more pronounced effect on Earth by spurring the formation of small droplets in the atmosphere that, in turn, cause the formation of a type of cloud that does not produce rain.
“During these times of high volcanic activity, the sunspot/climate correlation reverses and dust levels rise, even in the absence of high sunspots,” explained Stolz. ”
The Physical Evidence of Earth’s Unstoppable 1,500-Year Climate Cycle
http://www.ncpa.org/pub/st279/
Possible solar origin of the 1,470-year glacial climate cycle demonstrated in a coupled model
http://www.nature.com/nature/journal/v438/n7065/abs/nature04121.html
NOPE, only CO2 could possible regulate the climate…
Cassandra King says:
September 8, 2010 at 11:53 pm
R Gates said:
“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.”
I would dispute your confident assertion that human activities have caused a 40% rise in atmospheric CO2, we simply do not know the exact amount of extra CO2 humans have contributed over and above natural cyclic rises in atmospheric CO2.
_____
Nope, we do know nearly exactly how much of the extra CO2 has come from natural versus anthropogenic sources, by measuring the isotopes, which have a distinct signature between natural and anthropogenic. As an AGW skeptic, this particular line of attact is not an argument you can successfully make. It is pretty much not in dispute that the 40% rise in atmospheric CO2 since the 1700’s has been caused by human activities…primarily the burning of fossil fuels, which give a very characteristic signature in the CO2 isotope.
R. Gates says:
September 9, 2010 at 12:58 pm
“Nope, we do know nearly exactly how much of the extra CO2 has come from natural versus anthropogenic sources, by measuring the isotopes, which have a distinct signature between natural and anthropogenic.” As an AGW skeptic, this particular line of attact is not an argument you can successfully make.
It is pretty much not in dispute that the 40% rise in atmospheric CO2 since the 1700′s has been caused by human activities…primarily the burning of fossil fuels, which give a very characteristic signature in the CO2 isotope.
======================================
[/SNIP]
[Drop the vulgar name calling and keep it civil …. bl57~mod]
It very much IS in dispute.
http://www.drroyspencer.com/2009/01/increasing-atmospheric-co2-manmade…or-natural/
And your use of “we” in your quote is hilarious, as if you are one of the “we’s”.
You cannot say “we”, as you are not a researcher, nor are you a scientist. But thanks for the laugh.
Chris
Norfolk, VA, USA
Warmists point to the inertia of the current warm period trend implying that ten years of no warming will not effect the 300 year warming trend since the LIA.
Ice core temperature reconstructions especially those from recent high resolution reconstructions all demonstrate Holocene cooling over the last ten thousand years. If indeed there is radiative forcing from co2, good luck in changing the trend. After all we know within the next 2000 years we will fall of a cliff into the next ice age. Although orbital forcing is proposed as the main reason for the Holocene optimum I was surprised to read in one of Steig’s papers on Antarctica that He suggested a decline in solar insolation as the cause of Holocene cooling.
Nothing Surprising. We just need to be relentless in our science and the nutcases will gradually fall away. Like a dysfunctional mutation, diseased thinking cannot survive long because it has no connection to reality. We will outlast ’em.
It is good that Gudmund Lovö and Astrid Lyså, (NGU) came with their study about the the beaches in Northern Greenland, (82 degrees North). I worked in the 1960s and 70s in Vilhelmina, Lapland, Sweden . I visited than a few places, very well protected areas in steep southern slopes where old trees of the Ulmus species grew. One of the places is now a forest reserv Skikkisjoberget (about 65 degree N. and 16 30 East) above 600 metres over sea level. They are old relicts. They could be from the same period as the beaches . I have never heard that any research has been done. I believe that Ulmus species to day are growing in stands in Southern Sweden about 58 degrees North but not North of 60 degrees N.
richcar 1225 says:
September 9, 2010 at 9:02 pm
Although orbital forcing is proposed as the main reason for the Holocene optimum I was surprised to read in one of Steig’s papers on Antarctica that He suggested a decline in solar insolation as the cause of Holocene cooling.
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Orbital forcing works by changing the distribution of insolation.
savethesharks says:
September 9, 2010 at 8:41 pm
You are full of sh**, R Gates.
Mods, can we have some consistency regarding abusive posts please.
bl57~mod would you please email me personally on this? You must be a new moderator, as I do not recognize your signature.
sharkhearted@gmail.com
That was not a name call, it was a blanked out expletive, which many times in the past we were able to use.
To say someone is full of it….is not a name call….it is a figure of speech.
I noticed that one moderator [Maybe it was Anthony] had allowed it up there, otherwise it would not have been posted….only for it to get snipped later
I have given money to the surfacstations.org cause and been a loyal poster on here for a long time.
Also I readily give out my name and email for folks to contact me personally if they like, if they have a problem.
Thanks,
Chris
[REPLY: It is a “figure of speech” which is vulgar and uncivil as I noted with the snip. Refer to the policy link in the task bar and note…
“Respect is given to those with manners, those without manners that insult others or begin starting flame wars may find their posts deleted.” ….bl57~mod]