A third of the Earth is desert.
Scientists define a desert as a region that receives less than 10 inches of precipitation per year. Including both warm and cold climates, deserts are subtropical, coastal, rain shadow and polar. About a third of the Earth is desert; the four largest are the Antarctic, Arctic, Sahara and Arabian deserts. Despite their similarity in precipitation, these deserts all have unique landscapes, vegetation, wildlife and human activity.
The Antarctic Desert
The Antarctic Desert is not only the largest desert on Earth, but is one of the coldest areas in the world. It is a 5.5 million-square-mile polar desert that has a record temperature of minus 129 degrees. The flora consists of moss, lichen, algae and fungi growing on rocks and soil. The extreme cold and wind prevent trees or shrubs from growing. Antarctic wildlife includes penguins, seals and birds, such as petrels and the southern fulmar. No people live in the Antarctic permanently, but several countries send scientists to conduct research in the area.
The Arctic Desert
The Arctic Desert, the world's second largest, covers approximately 5.4 million square miles overlapping sections of the United States, Canada, Greenland, Iceland, Norway, Sweden, Finland and Russia. As a polar desert, the temperature ranges from minus 22 degrees in winter to 33 degrees in summer. The combination of low temperatures and low precipitation limits the vegetation to moss, lichen and grass. The Arctic's wildlife includes a variety of birds and mammals, such as the Atlantic puffin, hares, caribou, walruses, polar bears and Kodiak bears. There is minimal human activity in the Arctic Desert.
The Sahara Desert
Although the Sahara Desert is the third-largest desert on earth, it is the largest hot desert. It is a 3.5 million-square-mile, subtropical desert located in North Africa. It overlaps Algeria, Chad, Egypt, Libya, Mali, Niger, Mauritania, Morocco, Sudan and Tunisia. Most of the vegetation in the Sahara has adapted to limited water supply with short life cycles and the ability to store water. Wildlife includes rodents, gazelles, baboons, hyenas, foxes and more than 300 species of birds. More than 4 million people live, permanently and nomadically, in the Sahara Desert.
The Arabian Desert
The Arabian Desert is a 1 million-square-mile subtropical region in the Arabian Peninsula. Overlapping Saudi Arabia, Jordan, Iraq, Kuwait, Qatar, Oman, Yemen and the United Arab Emirates, it is an important source for oil and gas exploration. The Arabian Desert landscape is diverse, ranging from sand dunes and canyons to limestone cliffs. Some of the dunes contain iron oxide, which gives them a brilliant orange color. The area's vegetation includes sparse trees, grass and periodic blooms of wildflower. Wildlife includes gazelles, rodents, hyenas, wolves, flamingos, bustards and dromedary camels.
Tags: Arabian Desert, Arctic Desert, Sahara Desert, Antarctic Desert, Desert Arabian, Desert Arabian Desert, Earth desert
