The second largest desert in the world is the Arctic Polar Desert, a vast, frigid expanse covering the northernmost regions of the planet. This often surprises people, as the common image of a desert involves scorching heat and endless sand dunes. By area, the Arctic Desert is second only to the Antarctic Polar Desert, which is the largest on Earth. This classification highlights that a desert’s definition is based on its lack of moisture, not temperature.
How Deserts Are Classified
The scientific definition of a desert centers on aridity, meaning a region must receive very little precipitation to qualify. A widely accepted standard for a desert is an area that receives less than 250 millimeters (about 10 inches) of precipitation annually. This criterion focuses on the scarcity of water, which limits plant and animal life.
Deserts are broadly categorized into two main types: hot and dry deserts and cold deserts. Hot deserts, like the Sahara, are typically found in subtropical zones and are defined by high temperatures and low rainfall. Cold deserts include polar regions and high-altitude areas where precipitation falls mainly as snow, but the overall water input is minimal. The air in these frigid environments is too cold to hold much moisture, leading to arid conditions similar to those found in hot climates.
Identifying the World’s Second Largest Desert
The Arctic Polar Desert stretches across approximately 5.4 million square miles (13.9 million square kilometers). This immense region encircles the North Pole, spanning the northern parts of continents and islands across North America, Europe, and Asia. Its boundaries encompass parts of countries such as Canada, Greenland, and Russia, generally located above 75 degrees north latitude.
The landscape is defined by permafrost, soil that remains permanently frozen throughout the year, which restricts deep-rooted plant life. Though a cold desert, the Arctic receives slightly more precipitation than the driest parts of Antarctica, yet it remains intensely arid. The environment is characterized by ice-covered seas, glaciers, and tundra, with low biodiversity and sparse vegetation like mosses and lichens. The minimal precipitation and sheer size of this northern region solidify its ranking as the planet’s second most extensive desert.
Why Polar Regions Dominate the Global Rankings
The Arctic holds the number two spot because the largest desert is the Antarctic Polar Desert, which covers the entire continent of Antarctica. At roughly 5.5 million square miles (14.2 million square kilometers), it is only marginally larger than the Arctic. Antarctica is a desert because its interior receives an average of only about 50 millimeters (2 inches) of precipitation per year, primarily as snow.
This minimal moisture input, combined with extreme cold, makes Antarctica the world’s driest continent, qualifying it as a hyper-arid polar desert. The immense scale of both the Arctic and Antarctic deserts is a direct result of atmospheric moisture dynamics. Cold air holds significantly less water vapor than warm air, preventing precipitation and ensuring these two regions occupy the top two positions globally.
Ranking the Largest Hot Deserts
The common perception of the largest desert usually points to the Sahara, which is correct when considering only hot deserts. The Sahara Desert in North Africa is the largest hot desert on the planet, but it ranks third overall after the two polar deserts. Covering approximately 3.6 million square miles (9.2 million square kilometers), the Sahara is significantly smaller than the Arctic or Antarctica.
The world’s other major non-polar deserts are far down the list by comparison. The Arabian Desert is the largest hot desert after the Sahara, followed by the Gobi Desert, which is a cold winter desert. While these deserts are vast, none approach the sheer scale of the Arctic and Antarctic.