The Arctic - a fragile system

The poles of the earth are a very special place – their location makes it a place of total darkness for half a year, and once the sun is on the sky it will not set anymore for the next half year. But even with the sun shining all day (and night) long for many month, it doesn’t get high enough on the horizon for providing enough power to heat very much. Therefore the poles are permanently covered in ice, the North Pole covered with sea ice while the South Pole lies underneath a thousands of meter thick ice sheet on the continent of Antarctica.

Sun Diagram for Longyearbyen, Spitsbergen (78° N). This diagram shows the amount of sun light at every day of the year: while in from November to Febrary it is dark all day (blue region), the sun is above the horizon all day from April to September. The transition takes place in a few month, causing the day to be “longer” by one quarter hour every day!