What actually makes a place a desert, and why does Antarctica count?
A desert is defined by missing water, not by heat, which is why Antarctica, a continent of ice, counts as one.
▶ Start the storyA desert is a place that gets very little rain or snow, not a place that is hot. By the usual rule of thumb, a desert receives less than about 250 millimetres of a year. That rain, snow, mist or fog can fall on baking sand or on ice, so the world's largest cold desert, Antarctica, is a frozen one.
The word itself shows how our idea has shifted. Desert comes from a Latin word meaning an abandoned place, and for centuries English speakers used it for any empty, unpopulated land. When Shakespeare wrote about the deserts of Bohemia he did not necessarily mean sand or dryness. Only in the 20th century did it settle into its usual modern meaning of a place with low .
250 mm
Antarctica fits the modern meaning well. Its great ice cap is most of the continent, yet on the central plateau only about 50 millimetres of falls in a year. Scientists call it a , or a white desert. It is a desert where water is plentiful in one sense, because it is locked up as ice, but almost none is arriving from the sky.
So when you picture a desert, picture a rule about water, not a thermometer. About one third of the land on Earth is a desert, and many of those lands are cold, windswept and covered in snow or bare stone.
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Recap
A desert is a place short of water from the sky, not a place that is hot.
💡 A trick to remember it · Think of a desert as an empty cup, not a hot oven: it can be icy or sandy, but the cup is almost never filled.
Surprising fact · The world's largest cold desert is Antarctica, because so little snow falls on its interior.
Sources (2)
No source, no claim. Every fact in this lesson (13 claims) cites at least one of these.