Antarctica Is a Desert

While the word 'desert' often conjures images of scorching sand dunes, the defining characteristic is actually a profound lack of precipitation. By this measure, Antarctica is the largest desert on the planet. The frigid air over the continent is too cold to hold significant moisture, and a persistent high-pressure system over the interior pushes weather systems away. This creates incredibly arid conditions where the minimal precipitation that does fall is almost always in the form of fine ice crystals or light snow, not rain.

The continent's massive ice sheet, which holds about 90% of the world's fresh water, is the result of this light snowfall accumulating and compacting over millions of years, rather than heavy annual storms. The most extreme examples of this dryness are the McMurdo Dry Valleys. Shielded by the Transantarctic Mountains which block the flow of ice from the interior, these unique valleys are not only ice-free but are believed to have seen no rain for nearly two million years. This makes them one of the most lifeless, Mars-like environments on Earth and a key location for scientists studying the absolute limits of survival.