From ETH in Zurich, this interesting essay on the last glacial period has some interesting points to ponder. h/t to Sid Stafford – Anthony
The last glacial period was characterised by strong climatic fluctuations. Scientists have now been able to prove very frequent and rapid climate change, particularly at the end of the Younger Dryas period, around 12,000 years ago. These fluctuations were accompanied by rapid changes in circulation in the oceans and the atmosphere.
Sediment deposits in lakes are the climate archives of the past. An international team of researchers from Norway, Switzerland and Germany have now examined sediments originating from the Younger Dryas period from the Kråkenes Lake in northwest Norway. In the sediments, they found clues that point to a “climate flicker” at the end of the last glacial period, oscillating between colder and warmer phases until the transition to the stable climate of the Holocene, our current interglacial period. The short-term, strong fluctuations of the Younger Dryas would have dwarfed the “extreme weather phenomena” seen today, according to Gerald Haug, professor at the Department for Earth Sciences at ETH Zürich and co-author of the study, which was published online yesterday in “Nature Geoscience”.
Seasonal sediment deposits
Seasonal sediment accumulation, for example, gave scientists clues to these strong climate fluctuations. They can be read in lakes in a similar way to reading rings on trees. In warmer phases and melting glaciers, the accumulation of sediments increases. More clues on the changes in glacier growth were given by the element titanium, which is present in the sediments. Glaciers erode their bedrock, and in doing so concentrate the titanium contained in the sediments they are carrying. The sediments containing titanium are washed into the glacier’s draining lakes in the meltwater. The amount of sediment and the titanium content can therefore allow us to deduce when the glaciers were stable and when they melted. The researchers interpreted the maxims, recurring every 10 years, as phases of strong glacier activity caused by temperature fluctuations and thus as warmer times.
A seemingly self-preserving cycle
The scientists also examined a sediment core from seabed deposits of the same age in the North Atlantic. They reconstructed the original temperature and salt concentration of the water based on microfossils and the oxygen isotope ratio in the sediment. It was shown that the results from the lake sediments corresponded to those from the sea sediments. “The melting of glaciers was caused by the warm Gulf stream advancing into this region,” Gerald Haug explains. This increase in temperature caused the west winds to shift to the north and brought warm air to northern Europe. However, the meltwater draining into the Atlantic lowered the salt concentration and the density of the surface water, changing the convection in the ocean, which in turn allowed new sea ice to form. Subsequently, the Gulf Stream and the west winds were again forced out of the North Atlantic area and the region cooled down once again. These processes were repeated for around 400 years, until the current interglacial period was able to stabilise itself.
The Würm glaciation began around 100,000 years ago and lasted until around 10,000 years ago. In this period, there were strong fluctuations between warm and cold phases, particularly in the North Atlantic area. The Younger Dryas, which ushered in the current interglacial period, is one of the best-known and best-researched abrupt climate changes of that glaciation. It began around 12,900 years ago and at first caused an abrupt temperature drop in the northern hemisphere, as well as a temperature rise of up to 10°C in less than 20 years towards the end, around 11,700 years ago.
Unclear mechanisms
Up until now, there have been several studies which document the glacial conditions during the Younger Dryas period of 1,200 years. However, the mechanisms which caused it, sustained it and finally led to an interglacial period have yet to be fully understood. The researchers believe that further high-resolution studies of this type could give insights into how glacial periods are triggered and how they are brought to an end.
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While large natural climate fluctuations undoutably occur – temperatures fell (we think) by between 2C and 4C in a single decade at the start of the LIA – the Younger Dryas may not have been part of the ‘natural’ climate fluctuations and may have been caused by a swarm of comets impacting Earth.
http://en.wikipedia.org/wiki/Younger_Dryas_impact_event
Regarding:
“John Galt (10:58:02) :”
and his respone to “David / PlanetThoughts.org (08:39:04) :”
John, your response was point by point perfect!
David,
The best way to solve the problems that you address is by implementing the free market system across the globe. I know what you are thinking, but stay with me.
The free market system allows for a standard of wealth that can afford the environmental outcomes that you wish for; economies whose decisions are based on environment fear mongoring won’t supply the money to pay for what you want accomplished. For the short term, we are going to have to rely on hydrocarbon fuels and an expanded nuclear power generation system.
In the long run, the wealth that is created by “capitalism” can be tapped to cure malaria, AIDs, poverty, lack of education, birth control, and pollution caused by the ineficient use of all carbon based fuels (that was a short list of our problems, I know there are more problems).
Scare tactics based on “feelings” and not based on sound science, history, geology, engineering, and physics won’t solve mankinds problems. In order to fund the above activities, a sound economy conducted by people endowed with freedom is required.
There are growing fresh water shortages,
There are growing local fresh water shortages. Due to the failure of mostly governments to invest in adequate infrastructure for at least the last 50 years and politicization of water ownership rights.
To imply this is somehow unsolvable and inevitable is ridiculous. You might as well argue your local KMart has a growing shortage of plasma TVs.
All economic activity is in response to a shortage of something, somewhere.
Treat water like any other tradeable commodity and local shortages will be solved in fairly short order.
@RobJM (22:27:21) :
“It should be noted that the same “flickering” conditions are not seen in antarctic record. My guess is that ocean circulation patterns drive the ice age cycle, since they only started a few million years ago when the americas joined. The southern hemisphere being the engine and the north hemisphere is the overdrive!”
Amen. I’m a true believer in your church. But the glacials and interglacials are still just weather when you consider the climate history of the earth.
“I also find it interesting that all glacial cycles have ended after a significant accumulation of dust in the antarctic ice, albedo reversal anyone?
cheers”
I wasn’t aware of that. Sources, please? I’d really like to know. I will either shout out another amen or consider joining another church, depending on what you provide ;o)
P.S. Are you a geologist?
But surely, 10ºC in 20 years; that’s not climate, it’s just weather, ha ha.
Could the Bishop of Geneva be persuaded to exorcise the AGW crowd?
@Fred (07:30:26) :
From the peanut gallery: I’ve pondered what you’ve written and you’ve nailed it.
Class? Class? Required reading, everyone. (Can I get an “Amen” from crosspatch and Smokey?)
ABRUPT CLIMATE AND SEA LEVEL CHANGES DURING THE LAST MILLENNIUM
There is an abundance of evidence of abrupt climate and sea level changes over the last millennium, additional to Jean Grove’s massive and thorough research.
Here’s another example, one only has to listen carefully to what the tube worms are trying to tell us, now read on….
BAKER et al (2005) used evidence of tubeworms to find evidence about sea level changes. The tubeworms attach themselves to coastal rocks at inter-tidal levels, as they have to be covered by seawater for about six hours each day. The careful study of tubeworm casings along coastlines in Australia, Brazil and South-east Asia has revealed that, even within the past thousand years, there have been several sudden changes in sea levels of up to two metres.
The UNE team has discovered that each of these large changes took less than 40 years from beginning to end. They have therefore found convincing evidence of large, rapid changes in sea levels around the world in the recent past.
‘Most of the climate-change modelling done in Australia and overseas assumes a basically stable natural system underlying the man-made variable of greenhouse gases,’ said one of the UNE researchers, Dr Robert Baker. ‘Our research indicates that the underlying system is anything but stable and that we would be well advised to take this into consideration in our planning. We’re adding a destabilising factor (greenhouse gases) to a system that is already subject to large, rapid changes.’ (See National Science Week article dated August 19 2005 Sea level changes give us an urgent message on the website of the University of New England: http://www.une.edu.au/news/archives/000327.html )
BAKER et al (2005) were collaborating on the project for the past eight years and have published nine papers in scientific journals in relation to it.
BAKER et al (2005) builds on research Professor Fairbridge conducted on Rottnest Island off Perth in the late 1940s and published in 1950. This research was the basis for his pioneering theory of the Fairbridge curve.
Reference:
BAKER, R. G. V., HAWORTH, J., FLOOD, P. G., (2005). An oscillating Holocene sea-level? Revisiting Rottnest Island, Western Australia, and the Fairbridge Eustatic Hypothesis. Journal of Coastal Research, SI42, 3-14
Rhodes Fairbridge was the first to document that the ocean levels rose and fell over long time scales. His first paper on this theme was published in 1950 (FAIRBRIDGE, 1950). The major paper that included what has become known as the Fairbridge Curve of the Holocene Eustatic Fluctuations was published in 1958 (FAIRBRIDGE, 1958, 1960, 1961a).
These are extracts from a paper of mine wherein you can find all the other references:
http://www.griffith.edu.au/conference/ics2007/pdf/ICS176.pdf
Richard Mackey (19:37:12)
BAKER, R. G. V., HAWORTH, J., FLOOD, P. G., (2005). An oscillating Holocene sea-level? Revisiting Rottnest Island, Western Australia, and the Fairbridge Eustatic Hypothesis. Journal of Coastal Research, SI42, 3-14
I can’t find this paper via the web, JSTOR, or from the Journal archive, although it’s often been cited.
Could you post a PDF?
Thanks.
tty (11:52:05) 10 deg C in 20 years, as the article claims, is weather. I saw this information a year or two ago, and am glad to revisit it regarding the discernment of weather vs. climate. I had originally agreed with the line of thought that decades of weather=climate. However, in consideration of the multi-decadal ocean oscillations, I had come to think we need 120-150 years of consistant measurements to discern a trend in climate over weather. If, as the above article states that we can have 10 deg C increases in 20 years, this is the same magnitude of the whole temperature rise coming from glaciation to maximum temperatures in the interglacial, then weather has the same magnitude as climate, and we need 2-3 centuries of measurements to tell if it is indeed climate. Let me know c. 2230 AD, and we’ll look at the data to see if the climate has changed. As a side note, whatever can change the global temperature 10 deg C in 20 years makes CO2 look like a feather compared to an atom bomb, not scarey or anything to be concerned about.
I was in my 20s in the 70s and while there is no such thing as consensus in science, so Connolly is correct that there was not, the general thinking was that an ice age is coming.
Steve Keohane 061308
…”we need 2-3 centuries of measurements to tell if it is indeed climate.”
I concur. When can we get started with these measurements?
Along with gradual revision of atmospheric processes in GCM, feedbacks etc, I’d guess paleodata too will need to be revisited as to interpretation, role of CO2 etc – where else would such understanding come from?
That is also the lesson taught to us by the efforts to allocate stream flows based on 30 year average precipitation. Proper allocation of available historical stream flow over 30 years will leave some water claims unsatisfied in a subsequent 30 year cycle.
This is one of the reasons California is having water supply problems, she has been using more then her allocation of water for Colorado river water for some time. It was not a problem when Arizona and Nevada did not use their full claim, but as the upstream states begin to claim more of their allowed water usage California is getting left short. The Colorado River compact was drawn up in 1922 with water usage limits predicated on what they believed to be reasonably expected average flow of the river system. Over the years it has been found that the total flow in the river system has a wider swing than they anticipated, and growth has also exceeded expectations. Precipitation like temperature can vary over wide ranges over century time spans as the Anasazi found out.
http://wwa.colorado.edu/colorado_river/docs/CO%20River%20Compact.pdf
http://wwa.colorado.edu/colorado_river/docs/pontius%20colorado.pdf
We have already learned that short time span averages are inadequate for water management, it should not be surprising that similar short time spans do not get the job done when talking about temperature or sea level trends either.
Larry
MikeT (04:55:15) 28/02/09:
Re a pdf of the tube worm paper by Baker et al.
It’s Sunday evening down here in the land of Oz. I’ll be in the office during the week and will do my best. I have the journal so it shouldn’t be too hard!!
Richard
Regarding the point raised by Larry (hotrod (18:01:07) 28/02/09).
This is the general thesis about the appropriate means of statistical analysis to use, given the properties of the geophysical time series.
I refer readers to the homepage of Demetris Koutsoyiannis who has got across this problem probably better than anyone else in the world (see http://www.itia.ntua.gr/dk/).
There is a month of Sundays of hard work to understand properly the remarkable scholarship listed there.
Also Demetris’ pioneering breakthoughs have been recognised by his peers: he is awarded the Henry Darcy Medal for Hydrological Sciences at the forthcoming EGU2009 in Vienna.
Read the Abstract of his lecture here:
http://meetingorganizer.copernicus.org/EGU2009/EGU2009-14033.pdf
It promises some very exciting intellectual breakthroughs central to the issue under discussion here, indeed central to our understanding of geophysical time series (of which climate time series are a subset) and economic and finacial time series such as those that tried to tell us of the impending GFC but “we” (ie the government and financial sector orthodox econmetric analysts weren’t using the right tools so we couldn’t hear the screams of warning.
Richard
My pet theory is that the flickers are due to the asymmetry in the formation and melting of ice. The formation is gradual, the melting is catastrophic. So at the end of an ice age, warm currents gouge out oceans of frozen ice and move them round, causing rapid climate change. In the depths of an ice age, the formation is more gradual and the swings are much smaller.
******
Barry L. (10:29:11) :
Younger Dryas was NOT caused by a comet impact!!!!!!!
Select the PDF in the page.
http://starburstfound.org/YDextinct/p1.html
******
Well that’s a far-out theory. A supergalactic wave? Huge CMEs from the sun reaching the earth’s surface causing firestorms?
Very interesting at least. It does explain the lack of craters. Kinda scary to think that galactic “weather” could cause that kind of havoc so recently.
Richard Mackey (2:55 1/3) suggested reading the work of Demetris Koutsoyiannis (thanks), who writes: “Data also offer the only solid grounds to test any hypothesis about the dynamics, and failure of performing such testing against evidence from data renders the hypothesised dynamics worthless.” One of the most important purposes of WUWT is to make certain that the data used for hypothesizing about “climate change” is the most accurate possible.
I am becoming concerned about the data for hypothesizing about “abrupt climate change” or even “flickers”. (I have been reading abstracts of a number of recent studies.) How is the data being gathered and for what purposes? Is this topic coming more to the forefront today in order to scare us further about “tipping points” due to the combination (now it’s usually a combination) of forcing elements that always include CO2?
Will the 2009 International Conference on Climate Change March 8-10 begin a list of vetted data gatherers (in addition to the presenters), and scientists whose research is based on valid data, and organizations who only work with valid data or who rush to correct theirs when problems are found? Our universities can no longer be trusted nor can our government scientists. IMO this is an important function for the only independent and investigative center in our society — serious bloggers.
Pyromancer
These are not tipping point, per se. All systems are inherently unstable unless they have some stabilisers built in (feedback). You will have heard sound systems that suddenly scream a very loud monotonic sound normally due to positive feedback from microphone to speaker and back again and so on. This is positive feedback. You may have seen someone adjust the volume so as to eliminate this whistle, that is reducing the positive feedback. Thge point at which it begins to screech could be termed a tipping point. In all large systems this is usually the end game and the system runs away to destruction. Chenobyl was a classic example. The carbon rods were designed to block the neutrons which were the positive feedback to the nuclear reaction but they failed to bring enough blocking to restrain the neutrons and voilà disaster ensued.
There is little evidence for these dramatically rapid tipping points in our climate system, not because they don’t exist because they almost certainly do, but because in 3000,000,000 years climate change had been within nomminally reasonable bounds in spite of some massive changes caused by asteroids etc. That is, we have much the same climate now as we probably had some 10,000,000 yrs ago. The climate has swung between ice ages and period of greater warmth than now and the climate of now is not the climate that can be said to be NORMAL but never the less you have to admit that it is fairly stable +/- 0.5 °C in 150 yrs considerable humankind’ nasty habits.
Ergo, somewhere in this massive system there has to be a good balance between negative and positive feedback which cannot be easily tipped either way very easily. Remember, in the last 250 yrs there have been some pretty big volcanic eruptions which temporarily modified the climate but the climate always returned to it’s previous state. This in itself is good evidence for some sizeable negative feedback(s).
Along with gradual revision of atmospheric processes in GCM, feedbacks etc, I’d guess paleodata too will need to be revisited as to interpretation, role of CO2 etc – where else would such understanding come from? yes
MikeT (04:55:15) 28/02/09: Re a pdf of the tube worm paper by Baker et al.
I now have a pdf made from scanning the journal article
I can’t work out how to attach it here.
I’ve emailed it to Anthony to either post on WUWT or to email you directly.
Richard
The simple explanation is here from NASA
http://earthobservatory.nasa.gov/Features/Milankovitch/milankovitch_2.php
Richard Mackey (19:33:51) :
Thanks Richard, that’s very kind of you. Much appreciated.
And if Anthony finds the time to send it through/post it up, also much appreciated!
The use of invertebrates/invertebrate structures for this kind of analysis is fascinating (to me, at least!).
Many thanks
Mike
Steve Keohane (08:03:06) : We need to be figuring out how to survive without crops north of 30 degrees, short growing seasons, and if we can influence climate forcings that we don’t understand to prolong the point of termination of this interglacial which is imminent in climatic scales.
Well, I’ve got some good news and I’ve got some bad news 😉
There will be crops north of 30, just mostly on the West Coast. Short growing seasons are not so hard. There are many short season varieties developed specifically for cold northern climates. For any given latitude, you can also just grow a slightly more cold tolerant crop (i.e. Kale instead of Chard or Potato instead of Wheat). And if you are willing to put together cloches or greenhouses, there is no limit.
Per the “imminent” ice ages: WHEN it starts (that could be up to 10,000s of years in the future, but also could have been back in the LIA) it will proceed slowly. I figured it out at about an 800 foot per year rate of ice advance… It will be very hard to know when it has happened because we are about 3 or 4 orders of magnitude off in our sense of time vs glacial time.
Mitigation? Probably not so hard. One solution I saw proposed was to just widen the Panama canal to a few miles with “Atoms for Peace” excavation and restore the current that used to keep them away. Another would be to just make lots and lots of Freon again… and there are always the space mirror concepts. Personally, I’d just by a Polaris snowmobile…
Bottom line is that if a brand new Ice Age Glacial Period had started 200 years ago, we would know for sure in about 2000 years. Nuclear power is effectively unlimited, and with that you can have unlimited greenhouse foods and heat. So we might all end up living in Brazil in condo’s. I’m good with that 😉
Anthony: if you’re still tuned in to this thread, I’ve made contact with Richard Mackey and have the PDF he sent to you.
Thanks!
The Younger Dryas lasted about 800 years, thats pretty long for “weather”. And Foinavon: glacial/interglacial shifts are not “very slow”. They occur stepwise and are quite abrupt, at least on a geological time-scale.