Education: hot deserts

Deserts make up one-third of Earth’s total landmass, and the hot ones form 20% of these CLIMATE LOCATION

ADESERT is a rocky, sandy area of land that’s dry and inhospitable. It’s usually not inhabited by people. The plant and animal life in deserts have adapted to survive with little water. There are four types of desert – hot, cold, semiarid and coastal. Let’s take a look at hot deserts, which include several of the most barren places on Earth. Hot deserts are aptly named because in these places the temperature can soar above 40°C in summer. At night the temperature can drop to below freezing point.

Hot deserts are also extremely dry, with less than 250mm of rainfall a year.

They have two distinct seasons – summer (with average daytime temperatures of 35-40°C) and winter (20-30°C during the day). Hot deserts are found close to the Tropics of Cancer and Capricorn. These two circular lines occur at the same latitude (23,5°) north and south of the equator. The equator is an imaginary line circling the middle of the globe (0°), and is the same distance from the North and South Poles.

In the intertropical zone between the Tropics of Cancer and Capricorn the sun is at its fiercest and the difference between the length of days and nights is the smallest. Hot deserts develop at these latitudes, where the air is generally calm and the atmosphere is stable.

The largest hot desert is the Sahara in North Africa. It’s located along the Tropic of Cancer and stretches all the way from west to east across the African continent.

Other hot deserts along this tropic include the Libyan and Nubian deserts in

North Africa; the Danakil and Grand Bara deserts in the Horn of Africa; the Dasht-e Lut and Dasht-e Kavir in Iran, as well as the Arabian and Syrian deserts in the Middle East; the Thar Desert across India and Pakistan; and the Mojave, Sonoran and Chihuahuan deserts in North America.

Along the Tropic of Capricorn in Southern Africa you find the Namib and Kalahari deserts while the Simpson and Great Victoria deserts are located in Australia.

PLANT AND ANIMAL LIFE

Deserts get little rain, and rainfall patterns are highly unpredictable. Rain storms are rare and long periods of drought often occur. Because of the low precipitation, animal life is quite sparse.

Although many people think desert soils are infertile this isn’t necessarily the case – after a good downpour, large parts of a desert can suddenly be covered in plants. But desert soil can’t retain water for long so vegetation quickly dies again. Desert plants and animals have adapted to cope with these cycles of abundance and scarcity.

The most extreme heat conditions on Earth (higher than 50°C) usually occur in hot deserts. The highest temperature ever recorded was 56,7°C, in Death Valley, California, on 10 July 1913. Phew!Valle de la Luna (Valley of the Moon) in Chile’s Atacama Desert is the world’s driest hot desert.

Bedouin people in the Sahara use modern technology but still rely on their camels. A San man in the Kalahari drinks water drawn from a bulb plant.

Cacti ward off animals with their sharp spines but the great horned owl (Bubo virginianus) has overcome these barriers and makes its nest in the saguaro cactus of the Sonoran desert in North America.The meerkats of the Kalahari Desert make underground burrows where they shelter from the heat.