This question popped into my head because I am designing a fictional world map, and I was wondering what factors influence the amount of ice at poles.

I want to know why there is much more ice covering South Pole than North Pole.

An answer I found here states:

What makes the South Pole so much colder than the North Pole is that it sits on top of a very thick ice sheet, which itself sits on a continent.

Does that mean that if there was a continent at North Pole, there would also be much more ice there? Is impact of Gulf stream also a factor in this or no?

I think I am on the right track but someone more knowledgeable than me could really clear this up.

Thank you in advance!

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    $\begingroup$ The main reasons are elevation; there is more land at the S pole than the N pole; and the Antarctic Circumpolar Current. $\endgroup$ – bon Feb 19 '16 at 10:24
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    $\begingroup$ ISTVR that part of the reason is that the Arctic ocean under the ice can't get much below freezing point (more ice forms rather than the water getting colder), which limits how cold the Arctic can get. There is no such limit for the rock on which most of the Antarctic ice sits. Not sure how much of a factor this is compared to those given by @bon. I would have thought that if there were a continent covering the North pole, the Arctic would indeed be colder. $\endgroup$ – Dikran Marsupial Feb 19 '16 at 10:42
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    $\begingroup$ It only remains, then, for somebody with time and a thirst for rep to write a good answer containing those points :-) (I'm serious here, it's a reasonable question and we should answer it) $\endgroup$ – Semidiurnal Simon Feb 19 '16 at 12:08
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    $\begingroup$ I'll write up an answer later when I get back from the lab. $\endgroup$ – bon Feb 19 '16 at 13:31
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    $\begingroup$ A third factor is that the Southern Winter Solstice coincides with aphelion. The last so-called "ice age" in the northern hemisphere was when the Northern Winter Solstice ~coincided with aphelion. At the moment it coincides with perihelion, so they tend to cancel out in the northern hemisphere. $\endgroup$ – winwaed Feb 19 '16 at 13:33

The most obvious reason why the South pole is colder than the North pole is altitude. The Arctic is mostly covered by ocean and low lying land whereas the Antarctic continent is really quite high, with an average height of about 2,400m. The environmental lapse rate in the troposphere is about 6.5°C/km and so this corresponds to about a 15°C temperature difference between the Arctic and Antarctic based on altitude alone. Obviously the actual temperature difference is greater than this so there must be something else at work. Most of Antarctica is only this high because it has a couple of kilometres of ice sitting on top of it and so this doesn't explain why there is a huge, permanent (at least for the last ~35 million years) ice sheet sitting there in the first place.

There are two main reasons why a large ice sheet can persist at the South pole. First is that the southern polar region is currently covered by a large continental land mass (Antarctica). Land has a much lower heat capacity than water and so in the Arctic, the ocean acts as a large reservoir of heat, mainly transported there from lower latitudes and this limits the sea ice thickness. Conversely, in Antarctica snow can accumulate on the land and, if it does not melt in the summer, it will be buried next winter, leading to ice accumulation.

The second reason is the existence of the cold Antarctic Circumpolar Current which flows from west to east and is the largest ocean current in the world, with a mean transport of 100-150Sv. This cold current, transporting huge volumes of water, serves to thermally insulate Antarctica from the warmer subtropical waters to the north, cooling the continent. The openings of the Drake Passage and the Tasman Gateway, the exact timings of which are debated but are generally thought to have both happened by about 30 million years ago, allowed the formation of the ACC and are roughly coincident with the onset of permanent glaciation in Antarctica.

An additional factor in the present day, as mentioned @winwaed, is that southern hemisphere winter solstice currently coincides with aphelion (roughly), which produces colder winters in the southern hemisphere, allowing extreme temperatures of -94.7°C to be reached. The flip side of this is that summer solstice coincides with perihelion, which produces higher summer temperatures.

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    $\begingroup$ WRT what would happen if there was a continent at the North Pole, note the similarity between the Greenland ice cap and Antarctia. $\endgroup$ – jamesqf Feb 19 '16 at 18:23
  • $\begingroup$ there is also a difference between oceanic and continental temperatures (even with no mountains). Fundamentally, water acts as to regulate temperature extremes. Continents generally have colder temperatures since water isn't cycling. $\endgroup$ – farrenthorpe Feb 19 '16 at 23:04

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