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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Yeah, but THIS TIME, it’s OUR fault!!!!!!!!!!!!!!!
snark – off
”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.
An interesting study, including the standard disclaimer:
“Changes that took place 6000-7000 years ago were controlled by other climatic forces than those which seem to dominate today,” Astrid Lyså believes.
Even good studies have to protect themselves from charges of going against the prevailing orthodoxy. Sad.
Anthony, you know this doesn’t matter, only the trend over the last 30 years matters. :/
The study suggests that the Arctic Ocean may have been ice free 6,000 years ago, but we know that can’t be true. The Independent wrote this summer “Scientists warn….for the first time in human history, ice is on course to disappear entirely from the North Pole this year.
http://www.independent.co.uk/environment/climate-change/exclusive-no-ice-at-the-north-pole-855406.html
The Telegraph wrote The North Pole has become an island for the first time in human history
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/08/31/eaarctic131.xml
And respected scientists corroborated for National Geographic “We’re actually projecting this year that the North Pole may be free of ice for the first time [in history],” David Barber, of the University of Manitoba
http://news.nationalgeographic.com/news/2008/06/080620-north-pole.html
6k to 7k years ago the Sahara was wet and green. I think the only deserts that expanded during that time was in the western USA (per some article I read years back).
Yet the global warmers always show deserts expanding as a result of warming…..
Leif,
What is your point about sunspots? The graph you linked to showed very high sunspot activity 7,000 years ago.
Leif Svalgaard (16:07:17)
Leif, pardon my ignorance, but I’m missing your point. I haven’t seen a temperature reconstruction for that period of time, so I’m not getting what you’re driving at.
Hmm. Didn’t Greenland have a heck of a lot less ice 1000 years ago?
Sorry Leon,
ANTI-AGW Rant Begins.
The “obvious conclusion” is that the laws of physics are unstable – they must have been different 6000 to 7000 years ago to allow the arctic ice to disappear without high levels of man-made CO2 – Golly.
Obviously the polar bears must have been decimated at the same time due to the reduced ice – I suspect that the members of the Independence I Culture probably ate all the easy to catch starving and drowning polar bears.
Of course once it got cold again, the bears would have proliferated and fattened up, becoming fierce and difficult to catch. Hence the subsequent retreat of the Independence I Culture from those inhospitable shores.
The fact that these scientists can’t (draw and) state the obvious conclusions that 20th century warming is not UNPrecendented and have to tip their hat at the AGW Mantra is no longer sad – it is pathetic cowardice of the first order.
Where’s their self respect.
ANTI-AGW Rant Ends.
Patrick Henry (17:15:38) :
What is your point about sunspots? The graph you linked to showed very high sunspot activity 7,000 years ago.
7000 years ago was 5000 BC …
PearlandAggie (17:19:54) :
I haven’t seen a temperature reconstruction for that period of time, so I’m not getting what you’re driving at.
The post has two data points:
4000-5000 BC: “The climate in the northern regions has never been milder since the last Ice Age than it was about 6000-7000 years ago”
2000 BC : “succumbed to the elements nearly 4000 years ago, when the climate became colder again”
Patrick Henry (17:13:00) :
Come, come now, that’s only the “popular media” (you missed the recent WWF press release BTW). There’s nothing in the “peer reviewed literature”.
Tut tut tut
Harumph harumph harumph
Leif, slightly off topic, but I would love to know if you perceive a variation in the earths received solar wind as its orbital inclination drops to zero?
Leif,
The article said “than it was about 6000-7000 years ago” In geology speak, the “about” easily covers anywhere from about 3000BC to 7000BC. The sunspot graph is probably also of similar imprecision. I don’t think your assertion carries much weight.
Ahh, I see your point, Leif.
~7000 years ago, sunspot activity was low, but the arctic seems to have been warm, while ~4000 years ago sunspot activity was high, but the arctic was cold.
BTW, nice rifle she is carrying in that photo. I wonder if she kills polar bears should she need to? Maybe she is friends with Palin.
Leif,
Do you have any good links on solar isolation changes over the last 20000 years?
Leif, far be it for me to suggest but it was obviously warmer at the time these sea edges were made. If that means it was earlier than the researchers think or your sunspot data is wrong than that is where logic leads. All you do is dismiss I don’t think you can be so sure.
Can you answer me what differences to world temperature you feel fifty sunspots like a Dalton minimum versus an ‘averagish’ 50000 sunspot cycle would make to the climate? I know this isn’t accurate but it would give us some idea of where your coming from. You seem to feel that this thousand times difference is a pretty minor affair. We can all visualise the difference, so to go alongside that what do you say the temperature difference would be e.g Dalton’s 50 spots down ? degrees. Average 50000 spots up ? degrees. Ed.
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
Do we really have precise enough measurements about sunspot numbers, arctic ice levels, or temperatures from 6,000 – 7,000 years ago to be able to make any meaningful correlations?
Steve M had some rather interesting threads over a year ago, on the Quaternary and particularly Holocene history of the Northern shore of Greenland, and Ellesmere Island. Ice free conditions during the past million or even 10000 years can not be dis proven at this time.
Patrick Henry (17:15:38) :
What is your point about sunspots? The graph you linked to showed very high sunspot activity 7,000 years ago.
Patrick Henry (18:29:28) :
The article said “than it was about 6000-7000 years ago” In geology speak, the “about” easily covers anywhere from about 3000BC to 7000BC. The sunspot graph is probably also of similar imprecision. I don’t think your assertion carries much weight.
If so, neither does yours. It is more likely that you overlooked the 2000-year difference between BC and BP.
David Vermette (19:01:46) :
Do we really have precise enough measurements about sunspot numbers, arctic ice levels, or temperatures from 6,000 – 7,000 years ago to be able to make any meaningful correlations?
If the correlations support one’s pet theory then clearly the data is good. If not, then clearly the data is bad. The data is however not total garbage. It is unlikely that the timing is more than a thousand years off.
Just an observation: Leif opens his mouth and he gets half a dozen questions in return. Not that this is a bad thing (it isn’t) and not that it doesn’t happen on plenty of other postings (it does), but I was just thinking…
Wouldn’t it be great if more scientists took the time to talk to the general public like Leif does here? I mean, I have learned a ton of stuff from this blog and the presence of various scientists, though particularly Leif since he posts the most I think. It is always important, I think, that the public understand the research and that scientists are able to explain it in a way the man on the street can understand without overdiluting or being untrue to their work. Anyway, totally OT, but I thought I would post it.
Leon Brozyna (16:14:02) : Even good studies have to protect themselves from charges of going against the prevailing orthodoxy. Sad.
That’s exactly what I thought when I first read it too. However, even as I endorse that line of thinking, I also wonder if the AGW propaganda (surely the greatest in the world!) doesn’t have a tight grip on her too. Remember, many scientists like Dr. Meier have said that “well, since we are not able to account for it naturally, it must be man-made CO2.” There seems to be a leve of dissonance involved in the work. And I wonder what reasoning she would give apart from AGW that would fit her definition of the climactic forces at work today. But I am also open to the line of thinking that says that statement may also be not just KMA but also to make sure the grant-funding spigot stays on so they can continue researching.
Edward Morgan (18:57:12) :
If that means it was earlier than the researchers think or your sunspot data is wrong than that is where logic leads. All you do is dismiss I don’t think you can be so sure.
If the correlations support one’s pet theory then clearly the data is good. If not, then clearly the data is bad. The data is however not total garbage. It is unlikely that the timing is more than a thousand years off.
And I’m not dismissing because I’m sure. What I’m saying is that in order for you to maintain the sunspot-climate link, you will now had to add the extra assumption that this particular data is bad. It is usually a sign of a weakness in a theory that one has to add further assumptions as new data becomes available.
Can you answer me what differences to world temperature you feel fifty sunspots like a Dalton minimum versus an ‘averagish’ 50,000 sunspot cycle would make to the climate?
First, a Dalton minimum cycle didn’t have but 50 spots, but more like 15,000. So, no factor of a thousand. Perhaps you meant the Maunder Minimum?
Second, TSI for a Dalton cycle was 1365.8, and for a modern cycle 1366.2. A difference of 0.03%. This, on its own, would cause a temperature difference of 0.03%/4 = 0.0075% of 300K = 0.02K.
And 0.03K for the Maunder Minimum.
I should say CMA not KMA, sorry.
Bobby Lane (19:30:21) :
Wouldn’t it be great if more scientists took the time to talk to the general public like Leif does here?
There has been some posts from Roy Spencer and Douglas Hoyt. A problem is that most scientists would be put off by the tone of some comments and feel that they have better thing to do than suffer the abuse. Most are not as thick-skinned as I am and are also too busy to take an interest. But it would be great.
Another problem is that if two such participating scientists were disagreeing on something, their exchanges would rapidly become technical and incomprehensible to the majority of the readers.