Frequently Asked Questions
The most-asked questions about deserts and drylands.
What exactly counts as a desert?
A desert is any region that receives roughly 250 mm or less of precipitation per year, making water scarcity — not heat — the defining trait. This single rule covers blazing hot basins, frozen polar plateaus, and fog-fed coastal strips alike.
What are the main types or 'characters' of deserts?
Deserts are usually grouped into four families: hot (Sahara, Arabian), cold (Gobi, Antarctic), semi-arid steppe, and coastal (Atacama, Namib). Each family has its own signature climate, geology, and cast of specialist organisms.
How much of Earth's surface is desert or dryland?
About one-fifth of all land on the planet falls into the arid-to-dry-sub-humid range. That translates to roughly 50 million square kilometres of genuinely arid desert plus a much wider band of semi-arid steppe.
What's the difference between a 'desert' and a 'dryland'?
'Dryland' is the broader umbrella term used by the UN and FAO, covering arid, semi-arid, and dry sub-humid zones. 'Desert' usually points to the most extreme, driest end of that spectrum.
Which deserts are the largest?
The Antarctic Desert tops the list at roughly 14 million km², followed by the Arctic Desert, the Sahara, and the Australian Outback. The Atacama in Chile, while smaller, holds the record for the driest non-polar spot on Earth.
What are the most iconic landmarks or 'notable moments'?
Fans often point to the 300-metre-tall dunes at Sossusvlei (Namibia), the mirror-like Salar de Uyuni in Bolivia, and the hyper-arid core of the Atacama as the quintessential set-pieces. Each one showcases a different desert process — wind sculpting, evaporation, and extreme aridity.
Who are the emblematic animals and plants?
The fennec fox, the saguaro cactus, the addax antelope, and the resurrection plant are frequently treated as the 'main cast' of desert life. Each has evolved a distinct strategy — water storage, metabolic dormancy, or nocturnal foraging — to survive with almost no rainfall.
Are deserts only hot and sandy?
Not at all. Sand covers only a small fraction of most desert floors; many are rocky, gravelly, or salt-crusted. Cold deserts like the Gobi and polar deserts like Antarctica prove that freezing temperatures and sparse moisture define the category just as well as heat does.
Where should a newcomer start exploring?
A good entry point is the UNCCD's working definition of drylands, followed by a deep dive into one hot desert (the Sahara) and one cold desert (the Gobi). Comparing the two side by side quickly reveals how much variety hides behind a single word.
What is desertification and why does it matter?
Desertification is the slow, human- and climate-driven degradation of dryland soils through overgrazing, deforestation, and shifting rainfall patterns. It now threatens the food and water security of roughly 1.3 billion people across 100-plus countries.