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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The ideas of temperature change leading CO2, ideas of global cooling, and stating that other planet temperatures are changing therefore that explains the Earth temperature change (dramatic increases since 1850), all of those are efforts to avoid taking responsibility for the health of the planet. We (humans) have greatly changed the CO2 concentration, and that change explains over 1 C temperature increase. The previous rapid temp. change in 20 years, if that is what we are indeed leading up to, is of no comfort. In our current, crowded world (think Asia) or environment-stressed world (think Africa) such changes would lead to catastrophic collapse in human population through starvation, war, and the rest of what happens when a species goes through the bust part of a boom/bust cycle.
There are articles on the effect on just 1 C change in temperature – as others mentioned, major water current and wind shifts, amplifying the results. Shouldn’t we be reducing the risks of all this, even if it is not 100% sure? What is the cost? Fewer cars, more mass transit, focus on renewable energy sources, etc. My question is, why are some struggling so hard against making ANY change in their life habits, when there is at least a significant chance that the climate may change in very, very uncomfortable ways, and when there is the possibility we could take significant steps to reduce the risks. Last but not least: warming and climate change are not the only issue. There are growing fresh water shortages, greater difficulties getting oil, and other impending changes. These need to be considered with an objective and risk-reducing plan using the best minds available.
Steve Keohane (08:03:06)
You’re talking about something different there Steve. The see-saw transitions are rapid, transient asynchronous Nth/Sth cooling/warming events within glacials and on the glacial-interglacial transition. The global scale transitions from glacial-interglacial and back again are very, very slow processes which seem to be driven by very slow Earth orbital variations transmitted more extensively by ice sheet dynamics and greenhouse gas feedbacks. The “flickers” and the ice age periods are seperate issues (‘though there may be some overlap in mechanism..)
crosspatch:
Just for any of the readers who are unaware, this has actually been done:
http://www-argo.ucsd.edu/
We don’t hear so much about Argo, for the simple fact that the REALITY it reports doesn’t much line up with the catastrophic predictions that are much more newsworthy.
Younger Dryas was caused by a comet impact. Well documented in here and elsewhere. http://www.amazon.com/Cycle-Cosmic-Catastrophes-Stone-Age-Changed/dp/1591430615
Some believe a large comet plunged into the southern Indian Ocean off Madagascar a few thousand years ago. This would have cause massive tsunamis along the coasts and this may be the source of the flood stories.
“Climate Flicker” is a very decriptive term. It modifies “abrupt climate change” and takes it’s place in helping to describe the continuum of changes of climate during the current ice age (2.5 million yrs), periods of glaciation (so far about 20), a like number of shorter periods of interglacial warming, and evidently also helps describe the transitions between sub-glaciations such as the younger dryas. Because of the way it is described, it appears to not apply to periods like the recent mini ice age, unless that could be considered a flicker event in a yet to be fully experienced multi-century timeframe that includes the present periods.
Codetech
I am beginning to think that all of us here need to get a life after following your argo link and finding;
http://wo.jcommops.org/cgi-bin/WebObjects/Argo.woa/2/wo/fXSjOoYaIM6qbIhombOw0w/2.1.0.40.3.1.1.5.1.6.0
Which covers ‘float of the month’ for January. I’m going to go and have a lie down as the excitement has got too much for me…
tonyb
Potentially OT,
Is there room in this evidence line to consider signs of a large impact into a large ice formation related to the nano diamonds now identified in strata. Could the aftermath of such an event have caused a flicker?
Codetech
Ok I have now recovered a little… Having complained in the past about the deployment of so few weather stations to cover the earths land surface surely 3000 floats to cover the 70% of the earth that is water is not scientifically meaningful?
Can anyone point me to a summary of what has been found out to date about sea temperatures in the various oceans?
Tonyb
Frank Mosher (07:44:23) :
Very unlikely, SST are increasing along the equatorial Pacific http://www.bom.gov.au/climate/enso/indices.shtml
It hasx been a very strange year, the SOI has been around the 15 mark since September. http://www.bom.gov.au/climate/enso/soi30.png
Mary Hinge:”It has been a very strange year, the SOI has been around the 15 mark since September.”
Weather conditions: Normal as expected …considering the recent Sun’s flicker- it flickers every 179,7 years- according to SIM enthusiasts: It changes from “trefoil pattern to quasi-trefoil pattern”, see: http://www.giurfa.com/charvatova.pdf
jack mosevich (07:57:10)
Jack that paper relates to the onset of the entire glacial period at the Eocene-Oligocene 34 million years ago. The idea is that weathering/mountain building over millions of years gradually reduced the CO2 concentrations below the thresholds that kept the Antarctic continent ice-free. The finding is that the gradual reduction in greenhouse gases determined elsewhere are associated with a drop in global temperature and the drop in temperature is associated eventually with the build up of Antarctic ice…
So it’s a bit of a different circumstance than the glacial-interglacial-glacial transitions within the post Eocene-Oligocene transition glacial period in which we currently residue…
here’s the abstract:
http://www.sciencemag.org/cgi/content/abstract/323/5918/1187
I am finding that the tree ring data for my area of the Earth (Pacific Northwest) was far more climactically stable during the Dalton Minimum than it is now.
The Dalton made it look like an anchor.
I’m all for another one.
I give GWrs a better idea: Why not provoke a “NUCLEAR WINTER” to counter CO2 effects?
Actually that theory about a slow reduction of CO2 in the atmosphere causing the rather abrupt cooling in the early Oligocene (with the first continental ice-sheet in East Antarctica) is pretty shaky. Among other things it can’t explain why temperatures rose again after a fairly brief glaciation. As a matter of fact by the Late Oligocene temperatures were pretty much back to what they were before the Oi-1 glaciation.
Mary. Soi has spiked up recently, and NINO 4 has been persistently negative. Add in the warm pool at 150m depth at 160-180e, and a “classic”, La Nina is evident.http://www.bom.gov.au/climate/enso/indices.shtml
Younger Dryas was NOT caused by a comet impact!!!!!!!
Here is a paper that not only explains the climate shift, but also explains the megafauna extinction event that happened at the same time.
Select the PDF in the page.
http://starburstfound.org/YDextinct/p1.html
foinavon (08:45:37) I stand corrected, didn’t read closely enough, not enough coffee yet. These abrupt changes, since they are short term, must be defined as weather. It is interesting these short term changes are the same magnitude as the whole warming from glacial to inter-glacial. Goes to show how little we know about climate beyond WAGs.
David / PlanetThoughts.org (08:39:04) : Shouldn’t we be reducing the risks of all this, even if it is not 100% sure?
————-
So, really, what we need to do is embrace a world government system that will solve this problem only because of the seriousness of the imagined problems? What if I make up a different problem, throw some science in for good measure, and define problems that are 10x worse than a 6C rise in temp? Would you then be willing to do whatever I prescribe? You know – it’s all about the seriousness of the imagined concequences after all.
No, these are efforts to understand what is actually occurring.
Somewhat true, not demonstrably true, not all that rapid (certainly not unprecedented) and what is the reason to worry?
Very unlikely. By studying past climate change, we know that most species, along with human civilization, adapted. Starvation, war, famine, plagues are prevalent during global cooling whereas global warming usually leads to milder weather and more food. Please look into the Little Ice Age and the Medieval Warm Period. In regards to climate, which would you rather have lived in?
Let’s not overlook a very obvious implication of these paleo-data.
Yes, the climate has changed (a lot) in the past and some of those changes have been very abrupt.
But the system has ALWAYS reverted to a long-term general trend. NO TIPPING POINTS, NO RUNAWAY CALAMITIES.
Once you realize that, the squabbling over cause vs effect is just that.
The only thing unprecedented about climate change today is that 6.5 Bn people are watching it.
John Galt “This is all the more reason to focus on real problems instead of attempting to control a necessary trace gas” Wise words. All the rest is plainly insanity.
Steve Kehane:
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.
RE: Richard Mackey (02:17:30) :
Fascinating thought, about the use of weather/climate by the authorities to manipulate the ignorant. From the beginning of civilization and beyond, people have tirelessly watched the stars, moon and sun, meticulously recording their positions in the sky. What if some ancient government was able to deduce vague correlatations, say, between the number of sunspots in a given year, and the local temperatures and weather patterns that follow. As long as you can somewhat predict the weather, you could trick the ignorant into believing that you can control the weather. That makes you a god to the gullible (or Gore-ible)
Bill Green (04:28:31)
You wrote: “It will be interesting to see if someone can identify ecological effects of these historical rapid fluctuations.”
Usually under the heading of “refuge areas” or some such title.
Here are two: http://www.jstor.org/pss/2413377
http://www3.interscience.wiley.com/journal/119411457/abstract
I don’t have the reference but the Great Smoky Mountains were reported to be a refuge for more northern species during the last ice age.
Also, try this: http://co2science.org/subject/i/summaries/butterflies.php