[Stephen V]

Stephen V asked the Naked Scientists:

If there were no land at the South Pole, would an ice pack form under ice age conditions?

What do you think?

[sarah cp]

I'm not sure but my guess would be 'yes'.

The Antarctic is much colder than the Arctic, and part of this is to do with the fact that it is a landmass, whereas the ice in the Arctic is mostly floating on water.

Even without this land though, I would expect an ice cap of some sort to form - if one can form at the North pole, then why not the South? Both poles are the furthest areas away from the equator and receive the least amount of energy from the sun. If anything, I would say it would be more likely for ice to form at the South than North pole, as it is so isolated from the warming effects of other landmasses, whereas the Arctic ocean is surrounded by land. Also the cold polar winds and ocean currents help to isolate the South pole further, although these could of course be different if there was no land there.

[stevewillie]

Thank you for the reply. I admit it's a purely theoretical question, but it might give some insight into global climate mechanisms if we knew the answer. The question is whether the Arctic icepack exists because of, or in spite of being mostly surrounded by land. The land masses tend to contain the ice pack and block warm water intrusions. In the absence of a landmass, the Antarctic would be much warmer and open to dispersion of any ice that might form as well as warm water intrusions. Imagine the poles shifted 90 degrees so that South Pole was in the middle of the Pacific (0 lat, 180 long)  and the North pole was in the Atlantic Ocean near Africa (0 lat, 0 long). Most likely, Africa would would be partially glaciated and an ice shelf would extend into the ocean supported in part by the landmass. However, the middle of the Pacific there would be nothing to keep an ice pack together and any ice that formed might tend to be dispersed. I wonder what computer simulations might show. In the past, the poles were in different positions relative to continents and we have some idea of land conditions at those times but not sea conditions. Is it likely that a polar core of ice covered sea might be cut off and stabilized by circumpolar currents and winds? I'm not an expert on this. What do you think?