There are seasonal variations at the Poles, but these are much more noticeable in the Arctic than in the Antarctic. During the Arctic summer the sea ice begins to melt and break away in large icebergs. Although the area around the North Pole is always covered by ice, the snow melts around the edges of the Arctic Circle so that Arctic animals can browse on the sparse vegetation. One result of this is that some Arctic mammals, which need camouflage to keep them safe from predators, change the colour of their coats from white in the winter to brown in the summer months.
The Arctic region contains a wide range of landscapes; plains, mountains, some very large significant rivers and lakes, rolling hills, huge stretches of tundra and the edge of the largest biome in the world, the taiga. The ice in the Arctic Ocean is largely formed from the frozen sea and contained by the surrounding land masses. It contains a large proportion of multiyear sea-ice that is 3-4m (10-13 feet) thick with some much thicker ridges. Greenland has the largest ice cap in the Arctic (and second largest in the world after the Antarctic ice cap) other than this permanent ice is quite rare and relatively small in extent. Ice bergs form when the edges of the Greenland ice sheet reach the sea, most of the ice in the Arctic even in the summer is frozen sea ice.
The ice you are standing on is 1m to 3m (3-10ft) thick floating on the Arctic Ocean, it is made of frozen sea water with some snow on top, sea level is usually no more than 1m below your feet and the sea bed another 4,260m below that. The ice may be flat and smooth or rough, having been broken up and refrozen together again. The ice is moving at anywhere from a snails’ pace to walking pace. You are about 730km from the nearest land at the northern tip of Greenland. Temperatures here are estimated from those measured elsewhere in the Arctic, as there are no structures or a settlement out on the ocean, the ice is too unreliable and unstable.
Antarctica is 98% covered in ice which means that away from coastal regions (and even including many coastal regions) the landscape is icy mountains, glaciers or smooth ice-sheet. There are no significant rivers and none that flow year round, lakes are small, rare and often permanently frozen over, there is very little land vegetation, and no grassland, shrubs or trees. There are small areas of tundra on the Antarctic Peninsula and larger expanses on a number of Antarctic and sub Antarctic islands (though nothing like the huge areas found in the Arctic).
The total surface area of Antarctica approximately doubles each winter as sea-ice forms around the coasts, in the summer this ice breaks up and drifts north mainly melting as it does so, Antarctic sea-ice is therefore mainly first year ice. The great ice sheets of Antarctica calve enormous ice bergs into the sea that are measured in square miles (sometimes hundreds or thousands of them), much of the ice in Antarctic waters especially in the summer is freshwater ice from glaciers and ice sheets.
The South Pole has the opposite to this with the sun at its highest around the 21st of December, midsummer to the North Poles midwinter. You are standing at an altitude of about 2,835m (9,300ft) on ice that is 2,700m (9,000ft) thick, it reaches down to rock which rises to just over 100m above sea level, this rock is pushed into the earth’s mantle by the weight of the ice. Altitude sickness is a risk at the South Pole for new arrivals arriving by plane. The ice is made from accumulated snowfall that has built up because it never melts. The ice is moving towards the Weddell Sea in the west at about 10m (33ft) per year. You are about 1,300km from the nearest sea at the Bay of Whales. Temperatures have been measured at the South Pole since 1956 as there is a large research station there.
