Why is Antarctica so cold?
During winter, the average temperature in the South Pole is -60°C, but in the North Pole it is -30°C.
Why is there such a difference?
Three factors come together, resulting in the cold world we know as Antarctica, the icy ecosystem:
- Height above sea level
- Land masses
Height above sea level
The South Pole (Antarctica) is around 2,800m above sea level, unlike the North Pole (the Arctic), which is sea ice laying on the surface of the Arctic Ocean. For every kilometre (thousand metres) that Antarctica rises up from the sea, it gets colder by around -6°C. As well as the difference in height, the North Pole is lying on top of the Arctic Ocean, and heat is conducted through the ice and in the narrow gaps of open water (called leads), which makes the North Pole warmer.
The atmosphere above Antarctica is much thinner. Without clouds to cover it, the bright surfaces of snow and ice reflect a large percentage of sunlight. The percentage of sunlight reflected from the surface is called albedo. In contrast, more cloud cover in the North Pole traps the heat and increases the temperature.
If you look at a map of Antarctica, you will see that there is an ocean that circulates around it and the nearest land is some distance away. Water flows around Antarctica, getting colder and colder.
The size of land in each hemisphere also plays a role.
- In the Northern hemisphere, there are big pieces of land (like America and Europe). Land traps heat and then transfers heat into ocean currents, which, in turn, bring warmer water up to the Arctic.
- The Southern hemisphere has relatively little land – just small countries that can not trap as much heat.