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.
There can be no “tipping point” of any relevance for arctic sea ice during the interglacial. Every bit that vanishes leaves that much less contribute to albedo feedback…and its going to tend to be in areas with less and less direct sunlight as the coverage decreases. The “tipping point” was reached waaaaaay back as the interglacial started when there was about ten times as much sea ice that extended to within 50 degrees of the equator. Even in the dead of winter much of that sea ice contributed to earth’s albedo.
The only substantial (natural) albedo feedback available is desert albedo feedback…but having he deserts shrink due to higher rainfall and increased drought resistance (caused by CO2) would be a GOOD thing.
The concept of a ‘tipping point’ is extremely dubious per se.
The tipping point might mean ‘unable to recover within 20 years’, ‘unable to recover within 1000 years’ or ‘unable to recover within 100,000 years’.
The first is irrelevant geologically whereas the third is significant since that is the length of time of a ice-age-interglacial cycle. The second is significant for human beings in terms of a requirement for long-term adaptation, but is consistent with return to equilibrium sometimes occurring over millenia not decades.
Perhaps before any more soundbite-catching use of the term ‘tipping point’ takes place, climate scientists might like to expound on what a useful, workable definition of the term actually is?
The jetsam of: “Our key to the mystery of the extent of sea ice during earlier epochs lies in the driftwood we found along the coast.” ……..Driftwood – how scientific can that be?
““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.”…
Agreed absolutely, since the LIA, global warming has been shown to be beneficial and rather significant for the NH.
For this, we have cause to give thanks to mother nature and we are most grateful for her benificence, though we know, she is apt to change her mind – at any time, Caprice be thy name.
Lloyd Burt says: The “tipping point” was reached waaaaaay back as the interglacial started when there was about ten times as much sea ice that extended to within 50 degrees of the equator.
Good point. This is one reason why one shouldn’t use data from the previous glacial period to estimate climate sensitivity. A cold climate like during the past glaciation is far more unstable than the current warm climate.
@John Vonderlin
OT, but I’m just irrationally delighted that someone’s an expert in this.
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.
So it was warmer, and the sea levels weren’t significantly higher than today! Another nail in the coffin of the CAGW claims.
http://upload.wikimedia.org/wikipedia/commons/4/4e/Precession_and_seasons.jpg
let’s see. 5.000 years ago, summer was shorter but warmer, spring began colder but ended warmer etc .This must have something to do with climate change.
It’s cyclic like all climate change.
R. Gates says: “Skeptics have no answers, but global climate models do.”
Climate models have no basis in reality, R. Gates. Have you investigated them? Do you understand that? The model mean of the IPCC hindcasts/projections for the past 30 years do not come close to simulating satellite-era Sea Surface Temperatures. The following posts were cross posted here at WUWT. Do you recall them?
http://bobtisdale.wordpress.com/2011/04/10/part-1-%e2%80%93-satellite-era-sea-surface-temperature-versus-ipcc-hindcastprojections/
AND:
http://bobtisdale.wordpress.com/2011/04/19/492/
And skeptics do have answers. Unfortunately for alarmists such as you, I can find no evidence of an anthropogenic global warming signal in Sea Surface Temperatures for the past 30 years, and the oceans cover 70% of the planet. Here’s the latest of my posts on the multiyear aftereffects of ENSO:
http://bobtisdale.wordpress.com/2011/07/26/enso-indices-do-not-represent-the-process-of-enso-or-its-impact-on-global-temperature/
It’s written at an introductory level so it should be pretty easy to understand.
RE: timetochooseagain says:
August 4, 2011 at 8:37 pm
“…the Arctic has been much warmer in the past without killing of the Polar Bears or ruining the livelihood of the Inuit (despite present whining)…”
Actually there have been people thriving, and then getting pretty much wiped out, in the Arctic for roughly 5000 years. The Vikings were not the only culture driven off by a turn towards Little Ice Age conditions. The non-Viking (Thule or perhaps late Dorset) sites on the Southeast coast of Greenland were also abandoned, including a few which held Viking trade items, (or else items scavenged from abandoned Viking sites.)
The ancestors of the Inuit (Eskimo) are called the “Thule.” There is dispute about how closely related earlier peoples are to the Inuit.
The earliest peoples in Greenland are called the Independence I, and the Saqqaq. If you search and study, you notice there’s quite a lot of variance in the ideas about where, when and how these cultures came and went.
Even if winter nights were warmer in the Holocene, they were just as dark and long as they are today. It is interesting to note that the Independence I culture apparently burned driftwood to stay warm, if not to have light. There must have been a lot more driftwood along the arctic coasts than there remains today.
Perhaps that culture ran into problems when it burned up all the driftwood, but in no case that I know of did warming harm a culture. It is always the cold that crushes them. The Inuit seem to be the most superbly adapted arctic culture ever, and best at enduring the cold. Their demise may not be warming, but welfare.
Let’s face it, this whole arctic tipping point idea is based on the daft concept that some (less physically minded) proponents of global warming theory are under the impression that if you put more CO2 in the atmosphere it will just get hotter and hotter and hotter. That just isn’t true. Even in the best case the CO2 cannot trap more energy in the atmosphere than is reaching the Earth from the sun. So if it doesn’t get hot enough during the day to melt ice now, then you can put as much CO2 into the atmosphere as you like and you still won’t melt it. There just isn’t enough energy reaching the poles from the sun to cause appreciable melting.
It’s really about time the physicists knocked this one on the head since it really should be easy to prove.
How long before the attack dogs start trying to link these authors to ‘big oil’
If you can’t argue the science kill the articles publication or smear the authors.
It is good to get continued confirmation of existing studies on the Arctic, It won’t make any difference, the major news media will not pick it up and run with it to challenge AGW and it will be forgotten, as the propaganda machines get into action ready for Durban in November and the Rio Earth Summit next June.
http://www.mnh.si.edu/vikings/voyage/subset/greenland/environment.html
Smithsonian Museum of Natural History
Cores taken from the ocean bottom west of Iceland show evidence that the ocean conditions between the 8th and 12th centuries were relatively calm and that little sea ice was present to hinder navigation. The build-up of sea ice beginning in the 13th century correspond with evidence from ice cores whose layers of annual snowfall show isotopic evidence that the 14th century had the coldest climate known in Greenland during the past 700 years. Such conditions would have severely strained the farming resources of the Western Settlement and could well have caused its collapse.
Climate and People in the Prehistoric Arctic – Robert McGhee
http://www.carc.org/pubs/v15no5/5.htm (Canadian Arctic Resources Committee)
By about 7000 years ago the massive glaciers of the last Ice Age had retreated to the mountain peaks of the eastern Canadian Arctic. Tundra vegetation had become established, and was grazed by caribou, muskoxen, and, in some areas, by bison. The gulfs and channels between the arctic islands had long been at least seasonally ice-free, and provided a home to populations of seals, walrus, and whales. There is considerable evidence that for the next 3500 years the arctic climate was noticeably warmer than today, the tree-line was north of its present position, sea ice was less extensive, and animal populations were large and well established.
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.
It would be interesting to see if the study could be used to show that during the warm period, trees grew larger and farther north where the wood had increased probability of finding its way into Arctic waters.
Warm weather is good for plant growth and agriculture.
Thought this all sounded familiar:
http://wattsupwiththat.com/2010/09/08/inconvenient-ice-study-less-ice-in-the-arctic-ocean-6000-7000-years-ago/
Different researchers verifying the previous study?
All the Danish warmists on retreat…except Prof. Aske Willerslev (one of the worlds leading DNA scientists)…what is next ?
The thing is that Gates etc make one massive assumptive error. They class the decline over the last 20 or so years as a long term trend. Its not, its a gnats chuff in an amphitheatre.
“The warmists will claim that the 50% less ice from long ago was good solid ice where the ice we have today, even if it is twice as much is rotten ice.”
In the immortal words of the late great Marty Feldman, “Ix-nay on the otten-ray”.
Tim Folkerts,
I would answer your questions as I usually do, but many other commentators have already provided excellent refutations.
However, one thing needs to be corrected in your post. You use the mendacious term “climate-change-skeptics”. Scientific skeptics have never denied that the climate changes. That belief is held by Michael Mann’s followers, who credulously believe there was no MWP or LIA, because Mann’s debunked chart omitted those historical events.
If you want to have credibility here, you had best stop parroting the “climate-change-skeptics” nonsense.
Folks – this is one study. The hand waving and comments like ” It displaces and discards a sh**-load of hand-waving that has been “informing” the AGW alarms and alarums.” is way too premature.
Just like you’d (fairly) jump all over a single study claiming to prove the Arctic reached a tipping point claims that this single paper somehow debunks all the other Arctic science is just silly.
Bystander,
As Albert Einstein made clear, all it takes is one fact to debunk nonsense.
Has anyone ever shown these “tipping points” actually exist in the real world?
Answers are cheap. Correct answers are going to cost you.
Speaking of the polar bears some people still are not exercising sufficient caution in known polar bear habitats. One person was killed and four injured in an attack on campers on Svalbard this morning.
http://news.yahoo.com/polar-bear-kills-1-injures-4-svalbard-102929780.html
Bystander-“claims that this single paper somehow debunks all the other Arctic science is just silly.”
Your claim presumes that “all the other Arctic science” comes to a different conclusion, and that this is somehow a strange, outlying finding that the Arctic can and has undergone big changes in the past that didn’t plunge the world into Armaggedon.
I hate to break it to you but this new finding in fact is strengthing a wealth of previous evidence, not just for the “Holocene Opitimum” in the Arctic, but for the fact that said Optimum didn’t cause any catastrophic destabilization-if it had, we wouldn’t be here to observe that it didn’t. According to popular alarmist theories, the Greenland ice sheet should have slid into the ocean (it didn’t) the polar bears should have perished (they didn’t) and the Inuit should have suffered (they radiated). One of the best examples of an earlier study showing the extensive Arctic warming in the early to mid Holocene would be this:
MacDonald, G.M., et al., 2000. Holocene treeline history and climate change across northern Eurasia. Quaternary Research, 53, 302-311.
But there are MANY more.