Last week we spoke of sandy beaches along the vast seas… And today we take a look at a different kind of oceans, the endless expanse of dunes we know as desert.
Much like on the beach, in the desert sand due to erosion, inheriting the colour of the rocks and soil and varying in consistency according to the extent of weathering. Unlike our favourite summer destination, however, deserts are the last thing we want to spend our vacation in unless it’s to see the pyramids or the spring blooms.
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| Photo by Javier Rubilar |
Deserts can be cold or hot and equally unfriendly to the majority of living beings, but how do they form and conquer so much land?
A variety of conditions and reasons lead to the formation of deserts but by far the most important are distance from the ocean and the presence of natural barriers such as mountains. The further we get from the seas, the dryer the air becomes as moisture is absorbed by the land and plants along the way leading to little or no rainfall in the inner areas. Mountains, like the Andes or the Himalayas, are also excellent shields against moisture, trapping clouds to one side and leaving the other dry.
Desertification also depends on the winds, dryer, hotter winds in the equatorial zones can slowly erode the land into finer and finer sand. These winds prevent the formation of clouds and the dryer the area becomes, the fewer the plants keeping the soil together. The more sand is formed due to erosion, the stronger the wind erosion becomes as sand is carried on, grinding down hills and suffocating plant life.
Or at least that’s the simple version. Deserts may be hot or cold, covered in sand, pebbled stone or even ice, they can have little to no vegetation or a cover of low grasses, what they all have in common is the aridity. Whether no rain falls, or the land and air are unable to preserve moisture, the lack of surface water leads to scarcity of plants and large empty planes of sand or ice dunes.
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