Was the LIA a muted Heinrich Event?

[itsonlysteam]

The more I look into the evolution and history of humans and the climate in the last 100,000 years, the more I think the Milankovitch Cycle is still governing climate change.

We could argue about short term variations being driven by the Sun, the Oceans, or being lost in the muddle of various effects but they all seem mute compared to the big cycle.

From what I see we have been on a downward trend from the Holocene Optimum and right on schedule are into 2000 years of the Modern Glaciation for which the MWP and Modern Warming are blips and the Little Ice Age was a taste.

Just like previous glaciations the maximum ice extent will be close to the end of the 100,000 year glacial period and we will drift downward with sudden drastic cooling periods called Heinrich Events (for those who might not be into this).

So the question is on our drift downward in temperature when will the next Heinrich Event occur and bring the ice sheets suddenly South from the Arctic and North from the Antarctic? Was the LIA a muted Heinrich Event and we have a few millenia to worry about it or will it be sooner?

That is my new avenue of enquiry and I think the biggest concern outside asteroid impacts for Homo Sapiens. The slow brightening of the Sun is probably next but considering it has to get us out of this Ice Age first (1/2 to a billion years) ... who knows what we will be when that is of any consequence? My guess is we will have evolved into some kind of moderated Borg that has incorporated its technology into itself.

Had to throw the last bit in there for fun!

[sigurdur]

Look at the M11. We might be in a cycle very simliar to that one.

[sentient]

Gosh, where to start! I am going to do this from memory since I haven't the energy, after a long day doing field geology, to dig around for the most accurate data (too many papers!).

There were 24 Dansgaard-Oeschger oscillations between this interglacial, the Holocene, the interglacial in which all of human civilization has occurred, and the last one, the Eemian, in which the first fossils of Homo sapiens are to be found. D-O oscillations average 1,500 years, and have the same characteristic sawtooth temperature shape that the major ice-age/interglacials do, a sudden, dramatic, reliable, and seemingly unavoidable rise of between 8-10C on average, taking from only a few years to mere "decades, then a shaky period of warmth (less than interglacial warmth), followed by a steep descent back into ice age conditions. Each D-O oscillation is slightly colder than the previous one through about seven oscillations; then there is an especially long, cold interval, followed by an especially large, abrupt warming up to 16C (a Bond cycle). During the latter parts of the especially cold intervals, armadas of icebergs are rafted across the North Atlantic (Heinrich events), their passage recorded reliably by the deep ocean sediment cores which capture the telltale signature of these events in dropstones and detritus melted out of them.

Termination 1, or the end of the Wisconsin Ice Age involved several steps. Half of the warming that brought us out from the Last Glacial Maximum occurred in less than a decade. Termination 1 went into top-fuel, carbon-free overdrive with what is referred to as melt water pulse 1a (mwp-1a) centered at about 14,680 years ago which resulted in a 24 meter rise (about 78 feet) in sea level believed to have occurred at the rate of 4.5 cm (about 2 inches) a year. It was followed around 12,260 years ago by mwp-1b with a 28 meter (about 92 feet) rise nearer 5 cm per year.

We shot from the LGM up to the Older Dryascold spell, thence to the Bolling-Allerod Warm Period and into the Younger Dryas.

“Briefly, the data indicate that cooling into the Younger Dryas occurred in a few prominent decade(s)-long steps, whereas warming at the end of it occurred primarily in one especially large step of about 8°C in about 10 years and was accompanied by a doubling of snow accumulation in 3 years; most of the accumulation-rate change occurred in 1 year (National Research Council, 2002)”

Precisely matching a D-O oscillation in form, and within 200 years of the mean D-O age of 1,500 years.

A wealth of hypotheses exists relative to the YD, from THC switches, to the near instantaneous draining of paleo Lake Agassiz to the last in the 23 previous Dansgaard-Oeschger oscillations. There are MANY fascinating papers on these and more hypotheses available with cluey searching on scholar.google.com.

"who knows what we will be when that is of any consequence?"

Welllll......

“An examination of the fossil record indicates that the key junctures in hominin evolution reported nowadays at 2.6, 1.8 and 1 Ma coincide with 400 kyr eccentricity maxima, which suggests that periods with enhanced speciation and extinction events coincided with periods of maximum climate variability on high moisture levels.”

state Trauth, et al (2009) in Quaternary Science Reviews. There is just nothing quite like having such a natural fly land in your climate change soup. As it turns out, periods of wet maximum climate variability (in modern lingo, global warming/global cooling correctly re-branded as climate change), cook-up the larger braincases. We went from 500-550cc braincases 2.8 mya to the average of about 2,500cc today in the most rapid encephalization of any mammal in the fossil record. So the answer to your question may be 200kyrs off just now. We are at an ecc. minimum now, and 200kyrs we will be at the next maxima (and 200kyrs on from there we will be at another minima, and so on...).

"My guess is we will have evolved into some kind of moderated Borg that has incorporated its technology into itself."

Well, you know, replacement parts, these days, just keep getting better and better. In 200,000 years? That's two more ice ages and one interglacial to possibly the next naturally enhanced encephalization.... And we are making some pretty good movies these days. At the very least, artists have been thinking about it for decades, if not centuries, now. I was listening to a braodcast about NASA on POTUS on the way home from work today. They discussed R2, the robot developed through GM, wihch is designed to work with humans on the space station. So, we are on the threshold at least.

[scpg02]

Apr 15, 2010 2:36:59 GMT sentient said:

after a long day doing field geology,

Oh now that is sexy.

[itsonlysteam]

WOW ... thanks. Just skimmed through it. I spent a bit of time looking for papers related to the Antarctic during the Holocene Optimum. I actually found a couple. Lot's of stuff to dig through but it sure does look like you could easily define our present state as being in the beginning of the next Glaciation and that the Holocene is not lingering ... but over.

Lot's of material to dig through and expand.

[scpg02]

Apr 15, 2010 10:52:23 GMT itsonlysteam said:

WOW ... thanks. Just skimmed through it. I spent a bit of time looking for papers related to the Antarctic during the Holocene Optimum. I actually found a couple. Lot's of stuff to dig through but it sure does look like you could easily define our present state as being in the beginning of the next Glaciation and that the Holocene is not lingering ... but over.

Lot's of material to dig through and expand.

Now isn't that a pleasant thought.

[itsonlysteam]

I've updated my 'climate model'. I decided to go with the Timo Norima Jose Cycle (Jupiter is everything) although the Milankovitch Cycle governs as a rule. Still need to incorporate some information and just hanging the flesh on the skeleton. The Heinrich Events look to be triggered by or fit in almost too neetly. Probably mistakes in there and am wondering at the format of graphic ... whatever ...

[jpowell]

The Bond events of the Holocene line up very well with major volcanic eruptions.

They also line up with close encounters from Comet Encke which is one of “my” pet theories.

Attachments:

[jpowell]

The Bond events of the Holocene line up very well with major volcanic eruptions.

Attachments:

[itsonlysteam]

I was thinking about Volcanism and whether it would help cement me in the ranks of 'cycle nut' extraordinaire ... thanks. Just as the weather is getting magnetic in the sub-Arctic ... I get a ton of hooks pulling me to the numerous digital devices in my climate sanctuary

I hope a switch from an El Nino to a La Nina means some moisture in the Boreal Forest just North of the semi-arid Northern Plains ... because its downright miserable if you have to watch every spark off the fire pit (ie: do without the fire pit). From what I can tell colder means drier in general but looking at my particular location it could go both ways.

By the way, Ancient Climate on History Channel Canada ( www.history.ca/video/ close to the bottom) is a wonderful series. The last of the 4 programs should be posted by next week.