Saturday, January 28, 2012


A desert is an area of land that is marked by very sparse vegetation due to extreme climatic conditions and extremely low levels of precipitation. There are hot deserts as well as cold deserts. The Antarctic desert which spans across the continent of Antarctica is the most prominent example of a cold desert! Due to extremely low temperatures, vegetation and plant life is very sparse in these regions and the soil is ill suited for farming and cultivation. In hot deserts, the complete lack of moisture coupled with the extremely high temperatures make normal vegetation and cultivation of food items an impossible task. Only about 20% of the Earth's deserts are covered by sand. Based upon topography and region, there are precisely four types of deserts - Mountain-Basin deserts, Plateau Deserts, Regs and Intermontane Basins.
  • About one-third of the earth's land area is arid and semiarid--in total size, this is roughly equal to the combined areas of North and South America.
  • Dry lands are found in over 60 of the world's nations. There are 30 nations, many in the Middle East and Africa, that are at least 75% dry lands.
  • The world's largest area of dry lands is the Saharan-Arabian-Iranian-Thar Desert, which stretches some 6,000 miles from North Africa through the Middle East to northwest India.
  • Dry lands occur in the tropics and the midlatitudes. Tropical drylands occur from 15-35 degrees latitude and extend from west coasts into continental interiors. Mid latitude drylands occur from 35-55 degrees latitude and are concentrated in continental interiors.
  • Although vast stretches of desert are devoid of human settlement, the world's dry lands have been occupied and utilized by humans for tens of thousands of years.
  • North America's Sonoran Desert has the richest diversity of plants and animals of all the world's deserts, with more than 3000 plant species, many thousands of invertebrates (1200 different bee species alone!), and more than 550 vertebrate species (fish, reptiles, amphibians, mammals and birds).
  • Some desert rodents, like the "Kangaroo rats" (Dipodomys spp), that live in many North American dry lands, never have to drink water--they can metabolize all the water they need from the seeds that they eat.
  • Surprisingly, bees are much more abundant in deserts and savannas, both in terms of individuals and of species, than in wetter climates. The desert regions of northern Sonora (Mexico) and southern Arizona (USA), are thought to have more bee species (between 1,000 and 1,200) than any other region in the world.
  • Because deserts are too dry for many wood-decaying fungi to exist, termites play a crucial ecological role by eating, breaking down, and recycling cellulose (wood, grasses, cactus skeletons, and dung). Without termites, the entire desert ecosystem would collapse.
  • There are some 2,500 species of cactus in the world. With one possible exception, all are found naturally only in the Americas (North, Central, and South America, and the Caribbean).
  • The largest cactus in the world is the Cardon (Pachyserius pringlei), which dominates the deserts of Baja California and coastal Sonora, Mexico; Cardons can be up to 20 meters high and live for 200 years. They are closely related to Saguaro cactus (Carnegeia gigantea).
  • Cities now house almost half of the world's population, and megacities with more than 10 million population are increasing. (per AAAS Atlas of Population and Environment, ). Roughly 800-900 million people in the world's dry lands live in cities. (per Philip Dobie, 2001, UNDP: Poverty and the Drylands).
  • Major dry land cities include Beijing (located in a dry subhumid zone of northern China); Mexico City, Mexico; Los Angeles, USA; Santiago, Chile; Madrid, Spain; Cairo, Egypt; Teheran, Iran.
  • The annual rainfall in deserts is less than 10 inches on an average.

Sahara Desert
Area:9, 400, 000 km2
Continent Located In:Africa
Countries It Covers:Algeria, Chad, Libya, Egypt, Eritrea, Morocco, Mauritania,
Mali, Niger, Sudan, Western Sahara and Tunisia
  • The Sahara is the world's largest hot desert, covering the maximum surface area among all other hot deserts! Antarctica is the world's largest cold desert
  • The Sahara desert covers the countries of Libya, Egypt, Algeria, Chad, Morocco, Mali, Sudan, Niger, Mauritania, Western Sahara and Tunisia.
  • Sahara desert plants include Welwitchsia, Peyote Cactus, date Palm, Thyme, etc. Sahara desert animals include, among others, sand vipers, monitor lizards, ostrich, death stalker scorpion, etc.
  • The Sahara started forming about 3 million years ago! The Sahara desert climate is pretty extreme with scorching hot days and chilly nights!
  • Prehistoric cave paintings in some Sahara desert regions depict it as a greener, more tropical region!
  • The Sahara desert is native to just about two million people, the reason of such low population being the extreme water scarcity as it receives just about 8 centimeters of rainfall each year!
  • Strange as it may sound, the peaks located in the Sahara get covered by snow in the winters!
  • The Sahara has a mostly rocky topography with different elevations at different places.
  • Some dunes in the Sahara are so high that they reach a height of about 180 meters!

Gobi Desert
Area:1, 295, 000 km2 km2
Continent Located In:Asia
Countries It Covers:China, Inner Mongolia and 7 Mongolian Provinces
(Govi-Altai, Sukhbaatar, Omnogovi, Dundgovi, Govisumber,
Dornogovi and Bayankhongor)
  • Gobi desert is a cold desert! Very often, frost and snow can be seen on its dunes!
  • Gobi is not a primarily sandy desert; it is rocky having salt marshes and shifting sands on the lower regions.
  • Due to its location to the north of the Himalayan range, the rain bearing clouds are blocked by mountain range and the Gobi desert receives as little as only about 8 inches of rainfall every year.
  • The most common Gobi desert plants are drought resistant shrubs such as saltwort, sagebrush and grass.
  • There are about 33 different species of animal lives that exists in the Gobi. Most common Gobi desert animals are jerboa, golden eagle, Gobi bear, Asiatic wild ass, Asiatic ibex, wild camel, Bactrian camel, etc.
  • The first dinosaur eggs and some of the first paleontological fossils were discovered in the Gobi desert regions!

Atacama Desert
Area:1, 295, 000 km2 km2
Continent Located In:South America
Countries It Covers:Argentina, Bolivia, Chile and Peru
  • The Atacama desert is located in the continent of South America. It is a 15 million years old cold desert!
  • The Atacama desert is flanked by the Andes Mountains on one side and the Chilean Coast Range on the other.
  • The Atacama desert witnesses quite a lot of human activities during the day as the pan American highway runs straight through it!
  • The Atacama is the world's largest reservoir of sodium nitrate!
Those were some brief but interesting desert facts. Despite being desolate and almost devoid of life and liveliness, deserts are some of the most interesting topographies to study. More so, because with the growing global warming due to increased ozone layer depletion, deserts are perhaps what the future of Earth has in store for the entire planet.

Courtesy: Ishani Chatterjee Shukla

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