Deserts

Intro

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- [Narrator] Wind whips over a barren wasteland.

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Vast nothingness as far as the eye can see,

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or so it may seem.

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Creatures peek out of burrows,

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scurry across the sand,

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and soar through the sky,

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revealing a landscape not as lifeless

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as it might first appear.

Definition

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Deserts are often defined as areas of land

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that receive less than 10 inches of rainfall each year.

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These regions are low in humidity

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and can even be moisture-deficient,

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evaporating water faster than it is received.

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While most deserts are found in the mid-latitudes,

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these diverse ecosystems occur on all seven continents

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and make up nearly one-third of Earth's total land mass.

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Deserts are sometimes classified into four major types:

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subtropical, semiarid, coastal, and polar.

Types

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Subtropical deserts are found along the equator,

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and the Tropic of Cancer, and the Tropic of Capricorn.

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They are the hottest deserts on Earth,

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with daytime temperatures

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that can reach up to 120 degrees Fahrenheit.

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Semiarid deserts are located in Asia,

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Europe, and North America.

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These cold-winter deserts often form

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when tall mountain ranges block moisture

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through a process called the rain-shadow effect.

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Coastal deserts form alongside the tropical western edges

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of certain continents.

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Despite their proximity to water,

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coastal deserts remain dry.

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Polar deserts are found in the Arctic and Antarctic.

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The other end of the extreme,

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winter temperatures in the Antarctic Desert

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average around minus 50 degrees Fahrenheit.

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While deserts experience extreme temperatures

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and receive very little precipitation,

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they are still important habitats for plants and animals.

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Desert animals, such as the coyote,

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have evolved to withstand harsh desert conditions

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by burrowing into the cool ground

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and emerging at night, when desert temperatures drop.

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Many desert plants, including the saguaro cactus,

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have established long and shallow root systems

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to better absorb what minimal moisture might be present

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in the ground.

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Highly specialized to survive in such a harsh environment,

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desert wildlife is particularly vulnerable

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to ecological changes.

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Existing deserts have become less habitable

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because of rising temperatures

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that dry up scarce water resources

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and increase the risk of wildfires.

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Additionally, new desert areas are beginning to form

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through desertification.

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This phenomenon occurs when factors such as deforestation,

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climate change, and resource mismanagement

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degrade the biological productivity of a region,

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thereby creating a desert.

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For instance, in Central Asia,

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poor irrigation practices and excessive water usage

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dried up the Aral Sea

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and formed the youngest desert on the planet.

Desertification

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But by practicing responsible agriculture,

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better management of limited water resources,

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and limiting further development,

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it may be possible to curb desertification

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while protecting our surprisingly rich desert ecosystems.