– [Narrator] Wind whips
over a barren wasteland. Vast nothingness as
far as the eye can see, or so it may seem. Creatures peek out of burrows, scurry across the sand, and soar through the sky, revealing a landscape not as lifeless as it might first appear. Deserts are often defined as areas of land that receive less than 10
inches of rainfall each year. These regions are low in humidity and can even be moisture-deficient, evaporating water faster
than it is received. While most deserts are
found in the mid-latitudes, these diverse ecosystems
occur on all seven continents and make up nearly one-third
of Earth’s total land mass. Deserts are sometimes classified
into four major types: subtropical, semiarid, coastal, and polar. Subtropical deserts are
found along the equator, and the Tropic of Cancer,
and the Tropic of Capricorn. They are the hottest deserts on Earth, with daytime temperatures that can reach up to
120 degrees Fahrenheit. Semiarid deserts are located in Asia, Europe, and North America. These cold-winter deserts often form when tall mountain ranges block moisture through a process called
the rain-shadow effect. Coastal deserts form alongside
the tropical western edges of certain continents. Despite their proximity to water, coastal deserts remain dry. Polar deserts are found in
the Arctic and Antarctic. The other end of the extreme, winter temperatures in
the Antarctic Desert average around minus
50 degrees Fahrenheit. While deserts experience
extreme temperatures and receive very little precipitation, they are still important
habitats for plants and animals. Desert animals, such as the coyote, have evolved to withstand
harsh desert conditions by burrowing into the cool ground and emerging at night, when
desert temperatures drop. Many desert plants,
including the saguaro cactus, have established long
and shallow root systems to better absorb what minimal
moisture might be present in the ground. Highly specialized to survive
in such a harsh environment, desert wildlife is particularly vulnerable to ecological changes. Existing deserts have
become less habitable because of rising temperatures that dry up scarce water resources and increase the risk of wildfires. Additionally, new desert
areas are beginning to form through desertification. This phenomenon occurs when
factors such as deforestation, climate change, and resource mismanagement degrade the biological
productivity of a region, thereby creating a desert. For instance, in Central Asia, poor irrigation practices
and excessive water usage dried up the Aral Sea and formed the youngest
desert on the planet. But by practicing responsible agriculture, better management of
limited water resources, and limiting further development, it may be possible to curb desertification while protecting our surprisingly
rich desert ecosystems.