When most people imagine Antarctica they think of a cold continent covered in ice. And they’re right. In fact, 90% of the world’s freshwater is locked up in Antarctica’s permanent ice sheet. By contrast, the idea of the desert usually conjures images of rippled sand dunes and the shimmering heat of the Sahara. So how is it possible that a cold, ice-covered continent like Antarctica is a desert?
Why is Antarctica a desert?
A desert is defined by the amount of precipitation (rain, snow, mist and fog) in an area. A region that receives very little precipitation (the exact amount depends on who you ask) is classified as a desert. There are many types of deserts, including subtropical, coastal and polar deserts. What they all have in common is a barren, windswept landscape, which makes it difficult for plants and animals alike to gain a foothold on land. This all certainly applies to Antarctica.
The average yearly rainfall at the South Pole over the past 30 years was a tiny 10 mm (0.4 in). Most of the continent is covered by ice fields carved by the wind, and craggy mountains covered in glaciers. While Antarctica is home to wonderful forests of low-lying mosses and lichens, there are only two flowering plants that can survive the harsh conditions. And most of the animals we encounter – penguins, seals, whales and seabirds – rely on seafood for sustenance.
Is there a desert in Antarctica, or is Antarctica a desert?
While most deserts only cover part of a continent, the Antarctic Polar Desert spans the whole of Antarctica. It snows and rains on the coastal Antarctic Peninsula, but in the McMurdo Dry Valleys in East Antarctica, it never rains. In fact, scientists believe that in some parts of the Dry Valleys it hasn’t snowed or rained for 14 million years! So although the coast sees some precipitation, the average across the continent is low enough to classify all of Antarctica as a polar desert.
How much of Antarctica is covered in ice?
Approximately 98% of the Antarctic continent is covered by a permanent ice sheet. This beautiful and wild expanse of ice covers an incredible 14 million km² (5.4 million square miles). That’s about the same area as the United States and Mexico combined!
At its deepest, Antarctica’s ice is 4.5km (2.7 miles) thick. If it melted, global sea levels would rise about 60 m (200 ft). That’s a lot of ice. And due to Antarctica’s desert conditions, it has taken an impressive 45 million years for it to grow to its current thickness.
How much precipitation does Antarctica receive annually?
The interior is very dry and rarely sees clouds. Here, the annual precipitation averages around 50 mm (1.9 in), and most of this falls as snow or ice crystals. This gives rise to some of the most ethereal weather conditions you can see on earth including frost flowers, solar haloes and polar stratospheric clouds.
By contrast, the coast has a maritime climate influenced by the ocean and it’s quite common to see low clouds and mist clinging to the craggy mountains. The Antarctic coastline can receive more than 200 mm (7.8 in) of precipitation each year.
On the Antarctic Peninsula, which travellers can visit in the summer months, it’s quite possible to see snow, rain and sunshine in one day. Some northern parts of the Antarctic Peninsula receive 500 mm (19.7 in) between October and March, and on nearby subantarctic islands this can double, with 1000 mm (39.4 in) each year! That’s why we make sure that everyone on our voyages has a top notch, complimentary polar expedition jacket. These jackets are water and wind-resistant, so you’ll be protected from the elements whatever the weather.
Which is bigger: Antarctica or the Sahara Desert?
Antarctica is the largest desert on earth, almost twice the size of the Sahara Desert. How does Antarctica compare to other deserts on earth?
The 5 largest deserts on earth
- Antarctic Polar Desert: 14 million km² (5.4 million square miles).
- Arctic Polar Desert: 13.7 million km² (5.3 million square miles).
- Sahara Desert: 9.2 million km² (3.5 million square miles).
- Arabian Desert: 2.3 million km² (800,000 square miles).
- Gobi Desert: 1.295 million km² (500,000 square miles).
Tundra or desert: What’s the difference?
Tundra and desert biomes share some features. They both:
- Receive very little rainfall
- Support limited vegetation
However, they differ in a few key ways. While deserts can be either hot or cold, tundra is characterised by cold temperatures between -40°C and 18°C (-40°F and 64°F). Tundra is often found in cool subarctic and subantarctic regions and alpine areas. Deserts, on the other hand, can be found at any latitude, from sea level to high altitudes.
The defining feature of tundra is permafrost, a thick layer of soil that stays frozen all year. In tundra biomes a thin, surface layer of soil thaws in the summer allowing lichens, mosses and small shrubs to grow, while the soil beneath never thaws.
While Antarctica is classified as a desert, many of the nearby islands are considered tundra, including the South Shetland Islands, South Georgia and the Falkland Islands.
Take the first step towards your Antarctic adventure today
Antarctica may be a desert, but it’s surrounded by iridescent blue icebergs, an endless expanse of ocean and a dome of polar sky. If you’d like to find out how you can join a small ship expedition cruise to Antarctica, please take a look at our upcoming voyages here. And if you’d like to keep learning about Antarctica, this article with 10 fun Antarctic facts is a good place to continue reading.
If you’re interested in learning more about Antarctica or seeing for yourself what it’s all about, contact our expedition experts today.
Words by Nina Gallo, Aurora Expeditions’ historian and certified PTGA polar guide.
Nina has been drawn to the polar regions since her first otherworldly experience of the midnight sun in 2002. Since then she has spent time in far northern Canada, the Himalayas, the Alps and deserts in America and Australia, always seeking out quiet, wild corners to explore. She feels immensely privileged to travel to these places and shares her passions for the natural world, human stories and adventure with all the wonderful people she meets. Nina is the author of Antarctica, published by Australian Geographic in September 2020.