The ocean

At Antarctica, there are deep crevasses formed by moving glaciers, in the Arctic the ice instead breaks up in open water leads. 

The leads are not deep, but the ocean in them is. Fall into one and feel up to 4000 meters of dark, cold water sucking you down. At Antarctica, there were fossils of Dinosaurs and original land below T&Ts steps, in the Arctic, there will be whales and nuclear submarines quietly cruising underneath.

The main obstacles will be moving ice floes, pressure ridges and open leads. 

Two major circulation patterns for Arctic sea ice are present: the Transpolar Drift and the Beaufort Gyre. The Transpolar drift carries ice westward from the Russian Arctic, the Beaufort Gyre is located north of the Alaskan and Canadian coast, and it rotates in a clockwise motion, exiting in the Farm Strait. This ice migration will carry the team backwards, away from the pole.