Antarctica is the world’s largest desert by area, including its ice-covered interior.
A desert is defined by very low precipitation, not by heat or sand. Antarctica receives little precipitation because frigid air holds little moisture, and much of the continent gets less than 200 millimetres of water-equivalent precipitation annually. The vast Antarctic ice sheet therefore accumulates extremely slowly.
The Sahara is the world’s largest hot desert, but Antarctica is larger overall. Antarctica covers about 14 million square kilometres, while the Sahara covers roughly 9.2 million. Antarctica is also the coldest, windiest and driest continent, although coastal snowfall is higher than in the interior.
The ice sheet stores most of Earth’s fresh water. If it melted completely, global sea level would rise by around 58 metres, though such a change would take an extraordinarily long time.