Take the 2-minute tour ×
History Stack Exchange is a question and answer site for historians and history buffs. It's 100% free, no registration required.

Has science been able to determine from the geologic record how our current ice caps compare to those that existed before before the beginning of the last Ice Age? If so, how do they match up? (I tried to ask this on Physics.SE, but it was suggested it was more of a history question)

share|improve this question
    
Perhaps "Are there historical records to establish the size/extent of the polar icecaps? –  Mark C. Wallace Jan 25 '13 at 12:09
    
Would be good if you shared with us when this last ice age began and ended and a little bit about the extent of the glaciers at the time your talking about. –  john Jan 25 '13 at 12:12
1  
This is a geology question, not history. History is not simply "things that occurred in the past"; it is a discipline, and one whose methodologies cannot answer this question. –  choster Jan 25 '13 at 16:12
    
So. You're saying Earth's history isn't history? Archaeologists will be crushed. –  Major Stackings Jan 25 '13 at 16:54
    
No, Earth's history is not history, nor is it archaeology. It is paleontology, and this already loosey-goosey site doesn't need any more expansions of scope. –  choster Jan 25 '13 at 18:25

2 Answers 2

up vote 7 down vote accepted

Perhaps this is what you are looking for. In particular, look at the bottom graph in red, which is an estimate of global ice volume. The data was taken from oxygen measurements in Antarctic ice cores.

enter image description here

Assuming they have their data and estimates close to right, it looks like our current worldwide volume of ice is not a record low for the Pleistocene. However, its pretty close to it. The end of the Oxygen (green) graph looks a bit wierd too. Still, there's nothing on the end of that ice graph that draws the eye to say, "something different is going on here".

Yet.

share|improve this answer
    
Eureeka! That is exactly what I was hoping to learn. :) –  Major Stackings Jan 25 '13 at 21:31
    
Yet? There IS nothing weird going on, we're just in an interglacial (and nearing the end of it), which means climate patterns are inherently unstable and prone to large variations over relatively short time periods (decades). –  jwenting Jan 26 '13 at 5:30
    
@jwenting - Its quite possible you are right. Even if you aren't, I've heard it argued that HCGW is putting off the onset of the next Glacial cycle (IOW: A Good Thing). The truth is we really don't know yet. (There's that word again). –  T.E.D. Jan 26 '13 at 6:35
1  
It might be worth noting that with the x-axis scale in tens of thousands of years, the last few decades don't really show up on this graph. I don't know what the motivation is behind this question, but if it's specifically about man-made global warming, and not about natural cycles, then this graph doesn't really provide the relevant level of detail. –  mcv Mar 31 at 8:56
    
@mcv it shows enough detail to see that on a geological timescale we're right where you'd expect us to be, and a few degrees higher or lower temperatures over a scale of centuries are well within normal margins (and the AGW movement predicts just that, a few degrees over a timescale of centuries). –  jwenting Mar 31 at 9:51

WHICH icecaps? If you mean glaciers, WHICH glaciers? Some no doubt extend further, some less far, some didn't exist before the last ice age, for example.
As to the polar icecaps, the northern one sits entirely on top of water, if floats, so there's no way to know if it was larger or smaller in the past beyond where we have photographic record
The southern one covers pretty much the entire Antarctic continent, so has the same issue. If it were larger in the past, it would have been over open water and no historical record is left. If it were smaller, the evidence is hidden under miles of ice and rather hard to reach.
Most likely it will be the same with the polar caps as it is with the glaciers: in some places they extend further, in others they extend less, than in the past. But no worry, with the predicted global cooling (announced last week by the British Met Office through the BBC) it'll sopon get a lot larger :) (of course that was in part sarcasm (they did indeed announce "global cooling", just as they did in the 1970s, right before they announced "global warming" and no are making an about face once again), I believe in global cooling as much as I do in global warming, such things are cyclical and nothing we can influence anyway so why worry about them?).
And no, it's not a history question so much as a geology one. Doesn't belong under physics indeed, but afaik there's no geology SE you could ask.

share|improve this answer
    
I thought global cooling was something from the last 15 years. 15 years ago, global-warming skeptics predicted that the temperature rise of the 80s and 90s would be undone by a cooling cycle in the 2000s. Didn't happen of course; seems like the cooling effect of that cycle and the warming effect of the greenhouse effect cancelled each other out. So once the current cooling cycle is over, we'll probably see another rapid warming period. –  mcv Mar 31 at 9:01
1  
How would anyone think CO2 would cause cooling? The greenhouse effect has been understood for ages. It matters little now; the warming is evident, and any cooling effects at best slow down the warming a bit. –  mcv Mar 31 at 10:05
1  
All those different feedback mechanisms is what makes this so hard to predict accurately. Yes, it is definitely possible that changes in climate could cause a new ice age, but that's largely speculation. Meanwhile, we do know that CO2 causes warming, which causes climate change. The fact that it's hard to predict where climate is eventually going to end up, only emphasizes that we'd better reduce our unintentional impact on it. –  mcv Mar 31 at 10:58
1  
Zero scientific credibility? Are you kidding me? IPCC reports on very real scientific research. Even really stubborn global warming deniers who set out to prove that the IPCC reports were crap, ended up confirming that the scientific aspects were sound (though they tried to spin it differently by focusing on the political aspects). So far, the only people I've seen who deny the IPCC's credibility are people who lack any such credibility themselves. They ignore the science and listen just to the oil-funded propaganda. –  mcv Mar 31 at 12:04
1  
To match their agenda? Their agenda is to report on the existing science of the field. Yes, there have been some minor mistakes in the report (and it'd be odd if their hadn't, for a report that size), but nothing that even remotely undermines the conclusions. The science itself is sound. The only people denying that are oil industry shills and the people who rather believe them than science. –  mcv Mar 31 at 13:27

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.