nope, cos its still there. If antarcticea had drifted enough this century to explain its deglaciation then the antarctic research stations would have noticed the shift in the stars by now. Also continental drift does not explain warming. If antarctica were drifting wouldnt you expect there to be an enlargement of the ice cap on the side nearset the pole as it drifts away? there isnt. Global temps are rising. Why is a good question, could be greenhouse effect, could be not, but moving the continents around doesnt explain the heating.
It could explain this particular incident though.
And yes antarctica used to be quite sunny. the himalayas used to be a seabed and africa was once part of siouth america.