Ice ages vague questions

[Poto]

I was trying to look up some material on ice ages. I found this chart: http://www.geo.sunysb.edu/cei542/Workgroups/atmosphere/vaughn/figure1.htm
but the scale is hard to read.
Similarly: http://tvl1.geo.uc.edu/warm/topics/deeptime/deeppart1/sld012.htm

I’d like to see the last 100 000 years in better detail
General info:
Periodic Ice Ages —> Glacial-Interglacial Periods
 Major Period: —> 100,000 years; 9 degree F decrease
 Minor Period: —> 12,000 years; 5 degree F decrease
 Smaller Periods??: —> 1,000 years; 3 degree F decrease
We currently are nearing the end end of a small, minor interglacial period
Major Ice Ages: Most of the Planet is Covered Minor Ice Ages: 40 Latitude and Above Little Ice Age: (1000-1850 AD; Irish Potato Famine; Nisqually Glacier)

Here’s some theory: http://www.tgx.com/rockymountains/Iceages.html

Volcano connection? http://www.iitap.iastate.edu/gcp/influ/volcano.html
Are those numbers right?
http://museum.state.il.us/exhibits/ice_ages/why_4_cool_periods.html
(more theory)

There was some recent news item as well, some conference.

Is there anything missing? Any further crackpot theories?

Comments?

I gotta go…

[mr_john]

Sun, at the International Conference on…whooo it’s gettin cold in here, I’ll have to get back to you.

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“Pardon me while I have a strange interlude.”-Marx

[Poto]

OK, then, the volcano thing:
¨

Gregory Zelinsky et al (1996) report recent analysis of the
Greenland ice core that lends new insight on this issue. The
volcano Toba that erupted in the Indonesian island of Sumatra
71,000 years ago put about 100 times as much sulfuric acid into
the atmosphere (1 to 10 billion tons) as did Mt. Pinatubo.
Although conclusive evidence has not been presented, it is now
estimated that such an event might cause a 3 - 5 degree C cooling
for a few years but would not likely plunge the planet into a
prolonged cold period.

How did mammals survive the cold and perhaps dark or clouded period?

[mr_john]

So the tem. drops 3-5 cel. so instead of a balmy 80* F we now gota freezing 71* F. As to how the mammals could survive these bone chilling temps. i guess we’ll have to ask a passing polar bear or muskox. As for the light perhaps a few plants might be affected,marigolds replaced by oxalis maybe.How the poor mammals could stumble around in this Stigian environment perhaps a raccoon made a flashlight which he sold to the Tiger. If Al had one of those lights he woulda seen that tiger and wouldn’t a got et.

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“Pardon me while I have a strange interlude.”-Marx

[Jois]

Are you asking this because of Learning Channel (TLC) program(s) about early man? I wish I’d paid more attention but hope it will just run again in a couple of weeks. I’d like to hear more about volcano TUBA and what it did to early man.

[Jois]

Well, TOba

[Poto]

Well, Toba is in some books about early man, but there’s no concensus I guess on the effects. I suppose the effect would have been great, because we were wimps compared to other mammals at the time.

[_Df]

So the tem. drops 3-5 cel. so instead of a balmy 80* F we now gota freezing 71* F.

Okay, it doesn’t sound like much put that way, but apparently it’s a lot more complicated. (And in regards the OP, the danger isn’t darkness (probably no noticeable difference) as much as starvation, I believe.)

It’s not only summer days that get cooler - and not only winter nights, for that matter. It apparently isn’t even a case of a given climate range getting evenly cooler; when the climate changes, the average temperature changes, but you can get a situation with, say, slightly warmer summers but MUCH colder winters, or little noticeable daily change but unseasonal cold snaps, etc. Also, precipitation patterns can change, in theory.

I think the real danger with prolonged warming or cooling involves changes in the schedule of the growing seasons. Plants sprout, or flower, or seed, at the “wrong” time (still too much rain, too little time left until the snows, etc.). Or there are “cold snaps” that kill off plant generations that thought they were starting life off properly. Or the plants wait until a certain temperature to flower, and maybe it’s the bees or butterflies that die off - with big consequences the next year. …Eventually, with enough dislocations, year after year, the whole ecosystem degrades or starts to fail.

Anyway, the point I remember from college (big caveat, there) was that a “permanent” 5 degree © change in a given environment pretty much requires a replacement of the majority of the flora. If the climate ‘bands’ migrate faster than the flora can (for example, faster than the edge of a forest can advance) such that the flora gets overtaken by climate for which it is not adapted, it just sickens and dies. Multiply that all over the world, it could be a big deal.

[Rich_Hall]

Come check it out at The Restaurant at the End of the Universe.