Deserts are usually considered to be hot, arid areas with vast stretches of sand and dry earth. While this is certainly the case for some regions, all do not fit this description. Precipitation, not sand and heat, determine what areas are deserts. Deserts are found in all continents of the world, but the nature and size of these deserts vary greatly. Since deserts are associated with difficult living conditions, they are often some of the world's most sparsely populated regions.
The Antarctic is classified as a polar desert, measuring 5.5 million square miles. It is the largest desert in the world. Unlike most global deserts, the Antarctic covers the entire continent. In fact, an amazing 98 percent is permanently covered by a sheet of ice. It is considered a desert because it rains on average less than half an inch every year. Some experts even believe that certain parts located away from the coast have not had rain in the past 14 million years.
The Arctic tundra is the only other polar desert in the world. It spans numerous northern countries, including Canada, Greenland, Russia, and Asia. It is second only to the Antarctic, measuring 5.4 million square miles It is also considered a desert due to the lack of precipitation; the frigid air is too cold to hold moisture. While it gets more rain than the Antarctic, it still only receives approximately six to ten inches a year.
The Sahara is the largest subtropical desert in the world of 3.5 million square miles. Spanning eleven countries, it covers nearly an entire third of Africa. It is most known for its scorching hot climate and mountainous sand dunes that reach as high as 600 feet. Despite these harsh conditions, it is home to numerous desert animals, including camels, lizards, and scorpions. Water sources are rare, but the Sahara does have two rivers and twenty seasonal lakes.
The Arabian is the world’s second largest subtropical desert. Spanning most of the Arabian Peninsula in Asia, it measures approximately 1.0 million square miles It is a barren and sandy landscape, but is surprisingly rich in natural resources, such as oil and sulfur. Summer temperatures can go as high as 120 degrees Fahrenheit during the day but drop drastically at night. Locust and dung beetles are native to this bleak region.
The Gobi Desert is the fifth largest desert in the world. Spanning parts of Mongolia and China, it measures 0.5 million square miles. Its terrain is mostly rocks and hard-packed earth, which made it a valuable trade route throughout history. Like all traditional semiarid deserts, the Gobi experiences extremely high temperatures during the summer and frigid temperatures during the winter. It is also considered a rain shadow desert because the Himalayas block out all rainy weather.
Located in Argentina, the Patagonian Desert—also known as the Patagonian Steppe—is the sixth largest desert in the world. It measures roughly 0.26 million square miles. To the west lie the Andes, the world’s longest mountain range, and to the east, the Atlantic Ocean. As a semiarid desert, it shares similar characteristics with the Gobi Desert. Frost covers the ground during the winter season, but snow is unusual due to the dryness of the region.
The Great Victoria is a subtropical desert located in Australia. It is the seventh largest desert in the world at 0.25 million square miles. It is a harsh environment of sand, rocks, hard packed-earth, and grassland. During the summer, temperatures rise up to one hundred degrees Fahrenheit. As with most subtropical deserts, it is cooler during the winter, but still fairly hot. The Great Victoria receives an average of eight to ten inches of rain every year.
The Kalahari is a subtropical desert located in southern Africa. Spanning parts of Namibia, Botswana, and South Africa, it is the eighth largest desert in the world at 0.22 million square miles. Interestingly, it is classified as a semi-desert as it receives four to eight inches of rain per year, but twenty during special wet years—ten more than what is generally accepted for a region to be considered a desert. Wild animals such as meerkat, hyena, kudu, and wildebeest call this region home.
At 0.19 million square miles, the Great Basin is one of the “big four” deserts in North America. It spans multiple states, covering most of Nevada and Utah. Located directly north of the Mojave Desert, it is a dry expanse of clay, silt, and sand; however, as a semiarid desert, it receives a fair amount of snow during the winter months. It is said that at 4,950 years old, a local Bristlecone Pine is the world’s oldest living thing.
The Syrian—also known as the Syrian or Jordanian Steppe—is the tenth largest desert in the world, measuring approximately 0.19 million square miles. It spans multiple Middle Eastern countries, including Syria, Jordan, Saudi Arabia, and Iraq. Despite its name, it covers more of Jordan than Syria. As a subtropical desert, it is a barren landscape of rock and gravel. What wildlife is able to thrive in such an environment is currently under threat from drought, over-grazing, and hunting.