During the warm period before the most recent ice age, 120,000 years ago, roughly half of the Greenland ice sheet melted.This is thought to have been the cause of the last ice age.

Question: If this occurred 120,000 years ago without human intervention what caused Greenland's glacial melting?

I would appreciate Reading the credible provided links before voting, commenting or answering:

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    $\begingroup$ "If this occurred 120,000 years ago and seems to be taking place again, Man is not the cause behind Greenland's glacial melting." is a logical fallacy. It does not follow. $\endgroup$
    – casey
    Jan 21 '16 at 18:27
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    $\begingroup$ @The Void how you formulate the context for your question is not clear. I understand that you are suggesting that the sudden influx of freshwater in the North Atlantic (120 ky ago) stopped the conveyor belt effect and triggered a cooling ? $\endgroup$
    – marsisalie
    Jan 21 '16 at 18:35
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    $\begingroup$ @TheVoid The link are credible no doubt. It is just that you loaded your question when specifying that the man have no role into the equation $\endgroup$
    – marsisalie
    Jan 21 '16 at 22:01
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    $\begingroup$ The "question" given at the end seems to bear little relationship to the title or the preceding text. One is about the cause of warming, while the other is about its possible results. $\endgroup$ Jan 22 '16 at 7:59
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    $\begingroup$ I think you're misinterpreting the meaning of the 2nd link and drawing a false conclusion about the cause. The article pretty clearly says that the melting leads to warming not cooling. Likely orbital changes lead to the cooling, not melted ice. I also think that saying anything definitive about what caused an ice age is a little tricky because there are still some uncertainties around ocean current changes. $\endgroup$
    – userLTK
    Jan 25 '16 at 9:42

This question (if you can call it like this) is not even wrong. Let's ignore the fact that the title has little to do with the actual content of the question.

Let's discuss your statement:

If this occurred 120,000 years ago and seems to be taking place again, Man is not the cause behind Greenland's glacial melting.

There is no logical part between the first part of the sentence to the second part. Let's change it a bit:

Forest fires occurred 120,000 years ago and seems to be taking place again, Man is not the cause behind forest fires.

Yes, forest fires happened 120000 years ago. Also a million years ago. Also 100 million years ago. And now. But now, forest fires are started by people throwing away cigarettes and not putting out their campfires properly. Does that mean that all modern forest fires are because of natural causes? No. I hope this analogy helps you understand the logical fallacy in what you wrote.

Now, to your question:

If global warming by man is not causing Greenland's ice sheets to melt, What natural source could be?

But global warming by humanity is causing ice sheets to melt. Therefore your question is invalid. I will not try to answer the hypothetical case that it is natural, because that will just be taken out of context and used as ammunition by climate change deniers, as always happens.

  • $\begingroup$ @MichaelI-instead of a attempt to answer a simply stated question you rather edit the structure and modify its content? This is not a grammar building site.What caused 50 percent of Greenland's ice sheets to melt 120,000 years ago? $\endgroup$ Jan 22 '16 at 17:09
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    $\begingroup$ Except that it was not your question. $\endgroup$
    – Gimelist
    Jan 22 '16 at 20:23
  • $\begingroup$ @TheVoid is this your question? "What caused 50 percent of Greenland's ice sheets to melt 120,000 years ago? " cause it's a little confusing the way you ask it, implying that the ice melt was the cause of the ice age that followed. $\endgroup$
    – userLTK
    Jan 25 '16 at 9:48

The changes of climate in the past you're talking about occurred mainly because of the periodic change of earth's movements relatively to the sun. For example the swinging rotational axis of the earth and the changing orbit (sometimes a very flat ellipsoid, then again more like a circle) around the sun. This leads to the periodic change you were talking about.

Though big ice shields will lower earth's temperature because the higher reflection of the sunlight..

But also changing weathering rates on earth or events of many or big volcanic eruptions can change the climate, since the composition of atmosphere's gases can change drastically.

I have to admit that I'm not sure about how the water circulation affects the whole process, but I think if even the pole shields melt there is a low chance it'll start to get frosty somewhere else.. if you open the refrigerator it will get colder around it, but never as cold as it was in it.

But for the current climate change it seems pretty obvious that it's our fault. Compare some pollutionew and temperature diagrams compared to temperature diagrams from long ago.. you'll see the connection.

  • $\begingroup$ I can't believe how the majority of people refer to records Temperatures that span 150 years in history as an accurate guideline.Record another 150 without human pollutants and then determine if man effects anything or not. A million years is a day to the earth.Record 100 million years of temperatures then analyze and chart the data.Maybe then a News Meteorologist won't feel like a failure 4 days out of the week.There's just not enough data collect as of now to predict or figure the source of cause "Realistically common". $\endgroup$ Jan 22 '16 at 22:36
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    $\begingroup$ 1. I never said you could collect viable data within 150 years.. still the collected data points to what I said in my last sentence.. that's two different things. 2. All i said before are facts and the effect of various aerosols in the atmosphere are proven, just not as to which extend.. but that has nothing to do with your question.. read the first half of my post again, there i explained the MAIN reason for climate change. $\endgroup$
    – Lew Pérez
    Jan 22 '16 at 22:41

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