The Antarctic desert is the largest and arguably most famous of these polar deserts, and is also the largest of any of the deserts on the planet. Surprisingly, the number two desert by size is also a polar desert—it's the Arctic desert that covers the North Pole and much of the Arctic Circle.
Deserts, both hot and cold, play a very important role in regulating the temperature of the earth. This is because they have a much higher albedo, or reflectiveness, than other parts of the world. With a higher albedo, they reflect some of the sun's rays back into space and keep Earth cooler than it would have been if there were no deserts at all!
