Deserts are located across our planet along two border parallel to the equator at around 25-350 latitude in both the southern and northern hemispheres. Deserts are dry or arid regions that receive less than 10 inches of rain annually. Biologically, they contain animals and plants adapted to live in arid environments. Physically, they are vast areas with little vegetation cover and lots of bare soil. The world’s deserts occupy nearly one-quarter of the earth’s land surface. That is almost 20.9 million square miles.
Lack of vegetation generally exposes the bare surface of the ground to the denudation processes. Approximately 1/3 of the land surface throughout the world is either semi-arid or arid. This includes the large part of Polar Regions where low precipitation happens and which are sometimes known as polar deserts or ‘cold deserts.’ Deserts can be classified based on the quantity of rain which falls, causes of desertification, a temperature which prevails, or by their geographical position.
Mars is the only planet in the entire Solar System where deserts have been recognized. Despite its little atmospheric pressure at the surface (just 1/100 of that of Earth), the atmospheric circulation patterns on Mars have created a sea of circumpolar sand over 1.9 million square miles (5 million km²) in the area, much bigger than deserts on Earth. The Martian deserts mainly comprise of dunes in the form of half-moons in the flat region close to the permanent polar ice caps found in the north of the planet. The smaller dune fields inhabit the bottom of most of the craters located in the Martian polar areas. Examination of the rocks’ surface by laser beamed from the Mars Exploration Rover have revealed a surface film which looks like the desert varnish situated on Earth even though it might only be surface dust. The surface of Titan, Saturn’s moon, also has a desert-like surface with the dune seas.
People have really struggled to live in various deserts and the adjacent semi-arid lands for millennia. Nomads have also moved their herds and flocks to any place where grazing is available and oases have offered them opportunities for a more stable way of life. The cultivation of semi-arid areas encourages soil erosion and is one of the top causes of rising desertification. Desert farming, on the other hand, is possible with the help of irrigation and the Imperial Valley in California gives an example of how formerly barren land can be easily made productive by the supplying water of from an external source. Several trade routes have been formed across deserts particularly across the Sahara Desert, and historically were used by camels’ caravans carrying ivory, gold, salt and other goods. Huge numbers of slaves were also transported northwards across the Sahara. Some high mineral extraction also occurred in deserts and the constant sunlight provides a potential for the capture of sufficient quantities of solar energy.
Deserts often receive little rainfall, but when rain does fall, they experience a short period of high abundance. Plants and animals have developed some specific adaptations to take advantage of these short irregular periods of high abundance.
Interesting Desert Facts:
1. Antarctica is the largest desert in the world.
2. In 1979, it snowed once in the Sahara Desert.
3. Deserts usually contain vast mineral deposits.
4. The Sahara Desert is considered the largest desert in the desert biome. It covers over 300 million square miles.
5. Several desert animals seem to be nocturnal. They sleep during the day and coming out at night when the environmental temperatures are very favorable.
6. The desert biome can be found on every continent except Europe.
7. The wind often blows sand from the Sahara all the way to the Amazon, eventually recharging its minerals content. The desert typically fertilizes the rainforest.
8. One-third of Earth’s land surface is totally or partially desert.
9. Rain has never been recorded in parts of Atacama Desert of Chile. It is considered the driest place on Earth.
10. One time, camels were roaming in the deserts of Arizona.