Incredible as it sounds, it is but technically true.
Oceans occupy the majority of the Earth's surface — about 71% to be precise. That leaves about 29% for the land, which means it covers only about a third of Earth's area. But do you ever wonder how much of the available landmass is made up of deserts? It might surprise you to note that one-third of thirty-three percent of the total land is actually deserts!
Desert Definitions
True, that it might sound to be too large a portion, but if we go by the dictionary definition of a desert, it will seem to be just about right. Deserts are primarily defined by their dryness. The primary criteria for identifying a region as a desert is its aridity. As per technical terminology, any region on Earth that can build-up a moisture deficit over the course of one year can be classified as a desert. In layman's words, moisture deficit in geography means that an area gives off more moisture content via evaporation than it receives through any form of precipitation. In more quantifying terms, the desert is usually described as an area that receives less than 254 millimetres (10 inches) of any form of precipitation — be it rain or snow — in a given year.
Rethinking Deserts
Generally, when we think of deserts, we tend to associate it mostly with camels, sand stretching for miles & its dunes, oven-hot climatic conditions, and perhaps a few cacti as well. Going by the above definition, we find it to be a more widely inclusive geographic phenomenon. So, a desert can range between various types of lands, from arid canyons to frigid polar plains. Mountains which prevent cloud covers to empty on its leeward result in rain shadow deserts. Therefore, a diverse range of plants and animals can inhabit a desert region.
Blow Hot, Blow Cold
Also, interestingly, one habitually conceives of deserts to be very hot and arid ecosystems. Well, deserts can be cold too. And those cold deserts can be quite sizable. So much so that, the largest cold desert in the world is an entire continent. It is Antarctica, and with an area of 14.2 million square kilometres, it can steal a good bit of metric march over the Sahara Desert, the largest hot desert in the world which is located in northern Africa and covers 9.2 million square kilometres.
Antarctica, a polar desert, experiences less than 50 mm of snowfall annually which is about double of what Sahara Desert averages at less than 25 millimetres (1 inch).
