This is interesting. While there’s much noise from alarmists that we are on an “Arctic death spiral” the team for this paper’s press release today found evidence that ice levels were about 50% lower 5,000 years ago. The paper references changes to wind systems which can slow down the rate of melting (something we’ve seen on the short term, even NASA points this out for recent historic ice retreats). They also suggest that a tipping point under current scenarios is unlikely saying that even with a reduction to less than 50% of the current amount of sea ice the ice will not reach a point of no return (i.e. a tipping point). From the University of Copenhagen:
Large variations in Arctic sea ice
For the last 10,000 years, summer sea ice in the Arctic Ocean has been far from constant. For several thousand years, there was much less sea ice in The Arctic Ocean – probably less than half of current amounts. This is indicated by new findings by the Danish National Research Foundation for Geogenetics at the University of Copenhagen. The results of the study will be published in the journal Science.
Sea ice comes and goes without leaving a record. For this reason, our knowledge about its variations and extent was limited before we had satellite surveillance or observations from airplanes and ships. But now researchers at the Danish National Research Foundation for Geogenetics at the Natural History Museum of Denmark (University of Copenhagen) have developed a method by which it is possible to measure the variations in the ice several millennia back in time.
The results are based on material gathered along the coast of northern Greenland, which scientists expect will be the final place summer ice will survive, if global temperatures continue to rise.
This means that the results from northern Greenland also indicate what the conditions are like in the ocean.
Less ice than today
Team leader Svend Funder, and two other team members and co-authors of the Science article, Eske Willerslev and Kurt Kjær, are all associated with the Danish Research Foundation at the University of Copenhagen.
Regarding the research results, Funder says, “Our studies show that there have been large fluctuations in the amount of summer sea ice during the last 10,000 years. During the so-called Holocene Climate Optimum, from approximately 8000 to 5000 years ago, when the temperatures were somewhat warmer than today, there was significantly less sea ice in the Arctic Ocean, probably less than 50% of the summer 2007 coverage, which was absolutely lowest on record. Our studies also show that when the ice disappears in one area, it may accumulate in another. We have discovered this by comparing our results with observations from northern Canada. While the amount of sea ice decreased in northern Greenland, it increased in Canada. This is probably due to changes in the prevailing wind systems. This factor has not been sufficiently taken into account when forecasting the imminent disappearance of sea ice in the Arctic Ocean.”
Driftwood unlocks mystery
In order to reach their surprising conclusions, Funder and the rest of the team organised several expeditions to Peary Land in northern Greenland. Named after American Polar explorer Robert E. Peary, the region is an inhospitable and rarely visited area, where summer blizzards are not uncommon.
” Our key to the mystery of the extent of sea ice during earlier epochs lies in the driftwood we found along the coast. One might think that it had floated across sea, but such a journey takes several years, and driftwood would not be able to stay afloat for that long. The driftwood is from the outset embedded in sea ice, and reaches the north Greenland coast along with it. The amount of driftwood therefore indicates how much multiyear sea ice there was in the ocean back then. And this is precisely the type of ice that is in danger of disappearing today,” Funder says.
After the expeditions had been completed, the team needed to study the wood they had collected: wood types had to be determined and it had to be carbon-14 dated. The driftwood originated near the great rivers of present-day North America and Siberia. The wood types were almost entirely spruce, which is widespread in the Boreal forest of North America, and larch, which is dominates the Siberian taiga. The different wood types therefore are evidence of changing travel routes and altered current and wind conditions in the ocean.
Beach ridges and wave breaking
The team also examined the beach ridges along the coast. Today, perennial ice prevents any sort of beach from forming along the coasts of northern Greenland. But this had not always been the case. Behind the present shore long rows of beach ridges show that at one time waves could break onto the beach unhindered by sea ice. The beach ridges were mapped for 500 kilometres along the coast, and carbon-14 dating has shown that during the warm period from about 8000 until 4000 years ago, there was more open water and less coastal ice than today.
Point of no return
“Our studies show that there are great natural variations in the amount of Arctic sea ice. The bad news is that there is a clear connection between temperature and the amount of sea ice. And there is no doubt that continued global warming will lead to a reduction in the amount of summer sea ice in the Arctic Ocean. The good news is that even with a reduction to less than 50% of the current amount of sea ice the ice will not reach a point of no return: a level where the ice no longer can regenerate itself even if the climate was to return to cooler temperatures. Finally, our studies show that the changes to a large degree are caused by the effect that temperature has on the prevailing wind systems. This has not been sufficiently taken into account when forecasting the imminent disappearance of the ice, as often portrayed in the media,” Funder says.
Research could also benefit polar bears
In addition to giving us a better understanding of what the climate in northern Greenland was like thousands of years ago, it could also reveal how polar bears fared in warmer climate. The team plans to use DNA in fossil polar bear bones to study polar bear population levels during the Holocene Climate Optimum.
The team’s findings are to be published in the journal Science.
“So we know why sea ice might have been lower during the Holocene optimum…it was pretty much the forcing caused by Milankovitch cycles”
WRONG!!
The huge temperature swings over very short periods of time (10-20 degrees in less than a century) that were discovered in isotope studies of the Greenland ice cores caused a major change in hypotheses of what causes ice ages. These multiple, abrupt, high intensity, climate fluctuations proved that they could not be caused by Milankovitch cycles because Milankovitch cycles are slow, long term changes incapable of causing such sudden climate fluctuations. This is true of the early Holocene–a sudden global cooling and warming that lasted only a few hundred years occurred 8,200 years ago so the ‘early Holocene climatic optimum’ was caused by the same process that caused many severe, abrupt climate changes in the late Pleistocene 10–15,000 years ago–NOT slow, long term Milankovitch changes.
What this means, of course, is that we must look elsewhere for the cause not only of these ancient climate changes, but also for the cause of modern climate changes.
*****
The good news is that even with a reduction to less than 50% of the current amount of sea ice the ice will not reach a point of no return: a level where the ice no longer can regenerate itself even if the climate was to return to cooler temperatures.
*****
Ridiculous. How are the Arctic landmasses gonna stop cooling to -40(F or C) or colder during the winter? And -40 air is gonna freeze ocean on/near the shore. Once that starts, it’s impossible to keep the adjacent open water from freezing if the frigid air continues forming. And so sea-ice expands.
At present winter temps, the Arctic ocean is gonna freeze in winter, unless there is some unprecedented warm-water flow (much more than now) into it.
Cassandra King,
When you say…”Some kind of forcing mechanism like NATURAL cycles maybe?”
This says nothing. You need to be specific when talking about forcing…i.e. where is the extra insolation or trapping of heat coming from? Milankovitch, Volcanoes, large comet strikes, and yes, even anthropogenic gases such as CO2, black carbon, and sulfates can be forcing, but “natural cycles” are not a forcing, as it says nothing. The climate (unlike the very short term weather) is NOT a random walk (as 800,000 years of ice cores clearly tell us). What most fail to realize is that we can tell you a lot about the climate of 800,000 years ago, but almost nothing about specific weather in two weeks…this is the difference between a random walk (i.e. natural variability) and something like the climate, which changes from SPECIFIC changes in the heat balance of earth.
About 5000 years ago the current Inuit crossed the Arctic from Alaska and found an existing people, the Dorset present. They were impressed with these people who existed from Greenland down into Newfoundland, where, among other things, they produced soapstone bowls for trading purposes. The Dorset people lived in a difficult environment of much ice that limited their numbers and prevented village style lives. Apparently they lost the ability to make boats and bows and arrows over time, living by spearing their food from the edges of the ice. When the Inuit arrived in boats – the Northwest Passage was open enough for the migration – the Dorset were in terminal decline and disappeared soon after, probably without the help of the Inuit, who would have found the Dorset people no threat and no challenge to the resources of the region.
The arrival of the current Inuit depended on an opening of the NW passage, of seas open enough for the Inuit to use their kayaks etc. not just for travel but for the type of fishing and seal-hunting that fed their lifestyle. This article talks about a major melt of the Arctic ice at the same time as the Inuit arrived: the same fact by different routes.
The cyclicity of our climate is far greater than the accounts given by the IPCC/Hansen. But then, the point is not really about the climate, it is about creating a “just” and “moral” society on a global basis. CAGW is the trigger, but socio-political engineering is the reason.
Bob Tisdale says:
August 5, 2011 at 2:05 am
“Climate models have no basis in reality.”
Respectfully Bob, I disagree. They are some of the most complex mathematical models we’ve ever created and are firmly based on our known laws of physics, chemistry, thermodynamics, etc. Are they a perfect presentation of reality? Of course not! And as we learn more about the climate, they are always being improved. They are the best way for us to have a control and tests of input to earth’s climate, unless you happen to know of a duplicate earth somewhere we can use.
I think most climate scientists are well aware of the limitations of global climate models, but to suggest they have “no” basis in reality is an extremely skeptical position which I completely disagree with.
@R. Gates
Maybe it has something to do with the fact that we have been undergoing the strongest grand solar maximum in thousands of years?
I think milankovich cycles drives the long term trend of climate, while solar activity affects the short term climate.
Don Easterbrook,
I disagree with your assessment. Glacial and interglacials (including the last several) are generally caused by Milankovitch cycles. The Holocene Optimum is no different. Now, under the initial forcing of Milankovtich cycles, a whole host of other feedbacks can be initiated, such as outgassing of CO2 from the oceans, changes in ocean currents, chemistry, etc. Also, because the climate exists on the edge of chaos, we know that sudden changes in climate can also happen as secondary effects to the solar insolation changes from Milankovitch. For example, as earth was coming out of the last glacial period (based again, on Milankovitch cycles) we know that the earth was suddenly cast back into a glacial period for over a thousand years. This Younger Dryas cooling was likely caused by the sudden release of a great deal of fresh water from glacial melt, which altered deep ocean circulation. This sudden cooling happened even thought the Milankovitch cycle was trending toward warming. As stated, it took over a thousand years for the earth to get back on track to the longer-term warming that the Mllankovitch forcing was moving it towards…and of course, that longer-term Milankovitch warming resulted in the Holocene Optimum which really followed pretty rapidly geologically speaking after the extreme cooling of the Younger Dryas. Of course, the planet has generally been cooling very slowly since the Holocene Optimum, with the exception of course, our modern warming.
R Gates; You are hopeless. But I would say that we a trend of a little warming since 1970 is not climate. What you are taking about is over a much larger time period there for the so called forcing are clearer. But when we are talking about 50-100 years it really is such a short period of time compared to the time frame of what you are talking about that we cannot easily see the small natural changes that have lead to the very slight warming we observe during this short time period, but, CO2 is not the cause. But you are hopeless and nothing anybody says will get through to you.
tommy says:
August 5, 2011 at 10:41 am
@R. Gates
Maybe it has something to do with the fact that we have been undergoing the strongest grand solar maximum in thousands of years?
I think milankovich cycles drives the long term trend of climate, while solar activity affects the short term climate.
___
I would not disagree with your assessment of the relatively long-term/short-term effects on climate with regard to Milankovitch cycles and solar forcings. Up until the past few decades, I would say these two were the long-term/short-term drivers of climate, but with GHG’s now breaking away from their entrainment to the Milankovitch cycle based on human activity, all bets are off…i.e. enter the Anthropocene.
Tom T says:
August 5, 2011 at 10:54 am
R Gates; You are hopeless.
___
Nope, I still have lots of hope.
Be in regards to your ad hominem, best to stick to the science.
Don Easterbrook says:
August 5, 2011 at 7:24 am
What this means, of course, is that we must look elsewhere for the cause not only of these ancient climate changes, but also for the cause of modern climate changes.
_____
One additional comment about this, similar effects can have different causes, and the earth of today is completely different than the earth has been for at least 800,000 years…i.e. based on the GHG concentrations. I have absolutely no doubt that the 8.2 ky event, and other such Bond Events and D-O Events have a strong solar component, but these are little ripples compared to the larger Milankovitch forcing, and it is likely that GHG concentrations can reach a level to overshadow solar forcing. Based on the current trajectory of GHG’s, we’d have to look back several million years, to the Pliocene to find a similar Milankovitch cycle/GHG concentration on this planet. And, not surprisingly, that’s exactly what climate scientists are doing in order to get a grasp of where we might be headed:
http://micropress.org/stratigraphy/papers/Stratigraphy_6_4_265-275.pdf
RE: Doug Proctor says:
August 5, 2011 at 9:06 am
“About 5000 years ago the current Inuit crossed the Arctic from Alaska and found an existing people, the Dorset present….”
Actually the current idea is that the early Inuit (“Thule”) arrived roughly 1000 years ago, but debate is welcome, if you wish.
Here is a fairly decent diagram of the “current wisdom,” regarding the chronology of early arctic peoples:
http://www.avataq.qc.ca/en/Institute/Departments/Archaeology/Discovering-Archaeology/Arctic-Chronology
I was hoping this link’s study of the beaches up in North Greenland might get past the search for a “tipping point,” and mention the discovery of a few archeological sites, though North Greenland is one of the harshest parts of the arctic, and may have never had much appeal to sensible people.
I wish scientists would study ancient people more, and CO2 less. There is something heroic about the peoples who wandered that landscape.
@R. Gates:
Can you show that the real climate works the way the climate models work? No?
When Bob Tisdale assets these models have no basis in reality, perhaps that’s exactly what he means. Yes, the models use facts such as the freezing point of water, but that does not mean the models realistically model the behavior of the actual climate.
But you’re deliberately missing the point by redirecting the conversation elsewhere.
BTW: What answers do we skeptics need to offer? We won’t know the answers until we finally stop trying to push the wrong answers (AGW) upon the public and start looking for better answers.
R. Gates says:
August 5, 2011 at 10:53 am
Don Easterbrook,
… Of course, the planet has generally been cooling very slowly since the Holocene Optimum, with the exception of course, our modern warming.
Correction – with the exception of modern post LIA warming and MWP warming.
Tried to sneak that one under the radar?
I think basic logic combined with un biased paleo studies all point to periods that had lower sea ice minima during the peak of the Holocene optimum. Even if AGW is a reality it has really only been a slight recovery from the general long downward slope leading to the cliff at the pending end of the interglacial.
R. Gates says:
August 5, 2011 at 9:05 am
Cassandra King,
When you say…”Some kind of forcing mechanism like NATURAL cycles maybe?”
This says nothing. You need to be specific when talking about forcing…i.e. where is the extra insolation or trapping of heat coming from? Milankovitch, Volcanoes, large comet strikes, and yes, even anthropogenic gases such as CO2, black carbon, and sulfates can be forcing, but “natural cycles” are not a forcing, as it says nothing. The climate (unlike the very short term weather) is NOT a random walk (as 800,000 years of ice cores clearly tell us). …
It always amazes me the effect of the word “natural” on the AGW camp – something like the effect of salt on the back of a slug. You guys really hate it.
So you are joining Steve Mosher who takes Lindzen’s (ironic) static “climate perfection of the early 29th century” as the null hypothesis, and refuse to accept the possibliity of oscillations in a climate system that has been shown by voluminous published research to behave like a nonlinear oscillator.
But then a few posts further on you appeal to chaotic dynamics:
R. Gates says:
August 5, 2011 at 10:53 am
… Also, because the climate exists on the edge of chaos
If you constantly refer to climate as chaotic, then please accept the implication of this that nonlinear oscillations are overwhelmingly probable in such a system.
How then can you say that in the climate system which is chaotic / nonlinear and characterised by nonlinear oscilators such as the ENSO system, that the expectation of oscillation as a null hypothesis is unacceptable? Or in simpler terms, that you wont accept the possibility of cycles as being natural.
In climate, oscillation is the null hypothesis, NOT stasis (which is a bizzare and never observed phenomenon).
@phlogiston says:
August 5, 2011 at 1:03 pm
(Response to R. Gates)
Yeah, but.. but… this time it’s different! ;o)
P.S. Loved your last sentence there. Well said.
R. Gates – Simple question: do you believe that AGW will overcome the pending end of the interglacial, thereby stalling or eliminating it?
I think that when we talk about the long term changes in climate then we have to be talking about geological ages,the ice is so thick in Antartica because for millions of years it has been three degrees colder then it was in the previous geological period.When certain people try to say that we maybe warming the Earth to the same extent that was present in the previous geological era in a shorter time fail to recognise that we would have to provide that extra heat for millions of years to get rid of the ice in Antartica when in reality our supply of fossil fuels will run out in a few hundred years and that over a geological period any increased co2 will be turned into rock and it is likely to remain cold.
When it comes to arctic ice why does the danish folks seem to be so objective and know so much … oh right, they’ve ruled and respected Greenland for a thousand years.
As you may have heard there was a tragedy in the Norwegian Arctic yesterday where one person (a 17 year old on an eco-expediition) was mauled to death by polar bears and others injured.
The BBC reported that Norwegian arctic experts were saying that there was more sea ice than expected giving the bears more freedom to roam in search of prey.
Add that to the cause of the tragedy: the camp’s perimeter trip wires (designed to fire blanks to scare away the bears) had frozen and so failed to operate.
You will be interested in this fact , c02 dry ice http://www.dryiceinfo.com/ It sure puts holes in their c02 melting ice argument
Anthony writes The paper references changes to wind systems which can slow down the rate of melting
Considering the fact that the IPCC GCMs project a 7 million km^2 September minimum for 2011, I’m not so impressed if any researcher claims that there are effects that winds can ‘slow down the rate of melting’.
I would be much more impressed by research that explains why on Earth the Arctic summer minimum is reducing so much more rapidly than anyone anticipated (including WUWT reader polls
).
Also, I’m not sure why Anthony hails a paper as contradicting “noise from the alarmists” when it starts with the sentence Global warming will probably cause the disappearance of summer sea ice in the Arctic Ocean during this century and that does not even mention the words “Tipping Point” anywhere in the publication.
Philip Foster says:
August 5, 2011 at 3:06 pm
Unfortunately all the youngsters involved have been, for several years, ‘educated’ in the UK which means that they will have had an unrestricted diet of CAGW rammed down their throats since they started. Tragically, this probably means that they all assumed that there would be no polar bears left, and no sea ice for the deceased bears to cross anyway.
Re: “Arctic ‘tipping point’ may not be reached”
The arctic warming during the Holocene Climate Optimum was caused by a huge solar forcing. That solar forcing has since receded allowing ice to accumulate again. But today’s melting of the arctic is not due to solar forcing, but a small anthropogenic CO2 forcing. However the change in albedo when the arctic melts will result in a forcing greater than our anthropogenic CO2 forcing. This is the point of no return – the tipping point which climatoligists are so worried about – because they know that once this point is reached, any reductions in CO2 emissions will not be able to overcome the albedo forcing.
Any suggestion that once arctic sea ice completely melts, that it can not return again, can definitely be viewed as a tipping point, but as indicated by Dr Svend Funder’s paper, a large change in forcing can let arctic ice build up again. Unfortunately we are not expecting such a large change in forcing to happen any time soon.