The only thing that comes to our mind when we think of the deserts are the sand dunes, camels, the hot weather and scanty growth of flora. But out there in the world there are all kind of deserts from the hottest subtropical to the icy tundra of the uninhabitable Antarctica. Barren land with little or no rainfall and in hostile conditions for the varied flora and fauna is what we call a desert. Deserts, although cover 1/3 of the land surface are diverse in nature but that one common factor playing a vital role and classifying them as one is that they all are areas receiving less than 10 inches of rainfall a year, and the evaporation rate is twice as much as the rate of precipitation. In the succeeding paragraphs various types of deserts will be brought out and dwelled upon in detail in order to provide a clear perspective to the readers. The deserts of the world are put into four categories namely subtropical, cool coastal, cold desert and the polar region deserts. All of them have only one factor in common and that is they all receive less than 250mm of annual rainfall. The hottest are the subtropical deserts which have frequent evaporation , the cool coastal deserts although being on the same latitude as the former one records lesser temperature making it cooler because of the strong ocean currents. On the other hand, the cold winter deserts have extreme climates, with summers recording a temperature of upto 38 degrees C and the temperatures dropping to as low as -12 degrees C during winters. The polar region deserts are basically the deserts which remain too cold both during summer and winters. This region consists of the Antarctic and Arctic region deserts, where temperature goes to as low as -30 degrees C during winters and in summers it ranges from 0 to -1 degrees C making the living conditions there very harsh. These regions experience many months of darkness, during winters, at a stretch with no sunlight at all. On the contrary the summers are characterized by months of sunlight & high humidity. Antarctic and Arctic region deserts are mainly part of the polar desert region and they are the largest deserts in the world with Antarctic desert ranked first and arctic polar region ranked second. The flora and fauna found in these harsh climates have to be environment friendly and be able to adapt themselves to the dryness, the little precipitation and should be able to retain moisture for longer sustainability. The animals too have to be well adapted to the availability of very little water and horrid temperature differences.
Largest Deserts Of The World
These are the hottest which have dry terrain and a high rate of water evaporation. These are also characterized by low levels of moisture and precipitation , hot day time and equally cold nights. They exhibit extreme type of climate and constitute a significant portion of the land mass of earth. Flora and fauna are rare but those existing have evolved over centuries and have adapted to the harsh climate. The notable subtropical deserts of the world are as under.
Extending from Atlantic ocean in the west to the Mediterranean in the north and red sea in the east, it is the largest subtropical desert situated in continental Africa , there are at least ten countries having there national boundaries in this desert. The height of the sand dunes is phenomenal some of them are as high as approx 200 meters. The hottest temperature that has been recorded in this area is 58 degree C. The vast expanse boasts of a variety of rugged species who have adapted and made this desert there home.
Constituting of gravel planes and rocky hills, the Arabian desert gets its name from the Arabian peninsula and includes the countries of Qatar, Yemen, Oman, UAE and Saudi Arabia. Rub’al-Khali are planets largest unbroken sand lies in the centre of this desert. Some of its patches also show presence of the deadly quick sand in which even horses disappear without a trace. The nile river valley and the gulf of suez bound this desert from the west and east respectively making it essentially bounded by water on most sides, except the north eastern area which is linked to Asia.
Lying on the African continent, this desert has the uniqueness of receiving almost double the rainfall than what the above deserts receive and supporting a very diverse life than the Arabian and Sahara deserts. A point in case being that portions of Kalahari still meet the criteria of a desert in terms of level of precipitation. Its expanse is around 1609km by 966km within which is situated the famous central Kalahari game reserve which is the runner up in the wildlife protected areas of the world.
It is the home of death valley, which is famous for having the lowest point and driest location of the continent. It is situated in the south-western United States and encompasses certain areas of Nevada and California. Maximum temperatures on the North American continent are reached in this location. Having an extreme climate, temperatures range from 57 degrees C during summers to -10 degrees c during winters.
The sonoran desert is spread across United States and Mexico over an area of 259000 sq km. maximum temperatures persisting in the desert have been consistent at 48 degrees C. Besides Saguaro Cacti, another noteworthy fact of this area is the wide range of flora & fauna unique to it. The 65 species of mammals &2500 species of plants do make one wonder about the nature’s magic.
Spread over an area of 1,010,095 square km , this desert constitutes about 1.5% of the landmass of the North American continent . Spreading into US & Mexico, both countries have at least 4 states touching this arid expanse. It lies in the Rain Shadow area as the mountains skirting the desert severely limit the precipitation levels thus leaving the soil parched. The desert is home to over 200 species of cacti .
Situated in north western india, the Thar desert is often termed as the great Indian Desert. Though a sparsely populated region in India, it is one of the most densely populated deserts of the world. It has been the part of many an Indian folklore and continues to host several festivals round the year. It lies in Rajasthan state of India and is home to a diverse flora and fauna. Some of them which are peculiar only to this region. It spreads into Pakistan and is frequented by tourists visiting either of the countries.
The continent country of Australia has a wide range of desert areas . this is attributable to both its location and hence climate. A large portion of this continent is arid and it is the driest continent on the planet after Antarctica. As many as 10 different deserts can be witnessed on this continent. Some of them are co-located and not clearly demarcated. Being an isolated land mass the degree of evolution undergone by the native species even today baffles the scientists.
The Great Sandy Desert
Situated in north of western Australia, in the southern vicinity of the coastline is the great sandy desert. Ranked second in its expanse on the continent, the great sandy desert showcases Ayers, a heritage site. The Ayers rock, a huge sandstone feature extends mysteriously from desert to a mountain plateau of 350 meters upwards. The Australian authorities had tried to preserve the authentic flora and fauna of this area by means of building a fence which at that time was the longest in the world. However, invasive species especially rabbits and fox continue to be a threat to the deserts unique environment.
Great Victoria Desert
The number one ranking in being large rests with this huge arid expanse on the continent. On the world stage it ranks third after the deserts of Sahara and Arabia. Great Victoria Desert is a sparsely populated area in south west Australia and is surrounded by Gibson, Little Sandy, Simpson and Sturt Stony Desert to the north, north west and east respectively. Hardly resembling a desert, it is devoid of numerous sand dunes or barren areas, scarce rainfall being the only factor of it qualifying as a desert. The wide spectrum of flora and fauna in this desert makes it a frequently visited place by tourists.
The keeper of the famous Tanami track, this desert lies eastwards of Great Sandy Desert and is the third largest on the continent. The 1000 kilometers road stretch(Tanami track) attracts four wheel drive adventurers from all around the globe. This road is also frequented by miners and their resources as the desert is a bowl of natural resources. Endangered flora and fauna including mulgara are found in this rugged area.
Essentially a gibber desert, characterized by surface covered with crowded stones having shiny tops. It is situated in the north east of south Australia. The Simpson Strzelecki and Tirari Desert are situated on its periphery. The shiny surface of the stones are a result of constant erosion of the stones by sand carrying wind. It is a long drawn natural process systematic & back breaking.
Another scantily populated location in Australia is the Simpson Desert. The limited precipitation of only 5 inches has resulted in this desert being amongst the driest on the continent. Its topography and terrain ensure adequate water to support wildlife when flooding occurs in nearby areas. This desert is home to many endangered species like marsupial mouse. The wind patterns in this region has resulted in formation of long sand dunes running parallel to each other unlike anywhere else on the planet.
The Atacama desert located in Chile is an example of coastal desert. Such deserts are located in moderately cool to warm places like US, Greenland, Mexico, South America etc. these deserts have cool winters succeeded by long summer months. 13 to 24 degrees C is the average temperature range during summers whereas winters witness 5 degree C or even less. 35 degrees C and -4 degree C are the maximum and minimum annual temperatures in these areas. Specifically in Chile, July has temperature range of -2 to 5 degree C and January 21 to 25 degree C. average precipitation measures around 8-13 centimeters in most areas. Since a long time, the maximum yearly precipitation has been 37 centimeters while 5 centimeter has been minimum. Fine textured soil with a balanced soil content being pores and having good drainage is readily available in such areas. Some plants of the flora existing in such deserts have extensive system of roots near the surface which makes it easy for making the best of any rains. Plants here have thick leaves and stems and can store huge volumes of water when readily available for the hot and arid days. Groove and longitudinal ridges corrugate the surface of some plants from a unique mechanism to ensure survival of the plant during adverse weather conditions. Salt bush and buck wheat bush are some of the common flora available in these areas. Evolution and adaptation is also visible amongst animals to deal with desert heat and water scarcity. Some species if toads show inactiveness for 8 to 9 months till heavy rains occur by ceiling themselves under the ground and secreting gelatinous matter. Accelerated life loops are seen in case of amphibians that go through larval periods hence improving their scope of survival before evaporation of water takes place. Insects display adaptation by laying eggs that remain in an unchanged state till the atmospheric vagaries are best suited for hatching. Insects, badgers, coyote, toads, great hound owl, bald eagle, snakes and lizards are various mammals, birds and reptiles that are frequently spotted in such deserts.
Frigid winters supported with snowfall and high overall precipitation all through the winters and one odd during the summer characterize the cold desert. Areas of occurrence are generally Antarctic, Greenland, US etc. moderately warm, short and moist summers followed by substantially cold long winters are unique to such deserts. -2 to 4 degree c and 21 to 26 degree C are the mean winter and summer temperatures respectively. Large volumes of snow are received during winters and annual mean precipitation ranges from 15 to 26 centimeter. 46 centimeter has been the annual precipitation recorded so far and the minimum being 9 centimeter. The months of april and may witness the spring seasons heaviest rainfall. Not with standing some locations can have heavy rainfall during autumn also. The heavy, silty and salty soil is relatively porous in the alluvial fans and salt gets leached out due to good drainage. The wildly scattered plants consist of shad scale covering about ten percent of the ground whereas in some area of sage bush it touches 85%. Heights of plants range from 15 centimeter to 102 centimeter. Deciduous plants with spiny leaves are wildly found in this region. Jack rabbits, kangaroo mice, pocket mice, ground squirrel etc are some of the wildly dispersed animals which one can spot in these deserts. The jack rabbits found herein are not burrowers unlike the other species of animal kingdom residing here. Even carnivores like coyote, badger etc are also in the burrowing habit. Deer can be spotted during winters. The Gobi desert in nestled beyond the Himalayas and spreading from the territories of Mongolia to China is perhaps one of the finest examples of a Cold Desert. Its Ibex & double hump camels are nowhere else to be seen in the world. The snow leopards of this desert are a highly endangered species. The desert boasts of linkages to the traditional Silk Route.
The Taklamakan desert spread over an area of 337,000 square km is another prominent illustration of a cold desert. Lying in the watershed area of the Himalayas it receives very limited precipitation and was covered with 4 cm of snow in the year 2008 due to a winter storm. Its oasis though scanty lay astride the famed silk route and were always a conquerors prized possession. Ancient cities like Almaty boast of a rich heritage.
In today’s wired and informative age, it is essential that the fact of deserts not only being dry and very hot be clearly understood. There are deserts, which are very cold and have large quantum of water, all be it frozen. More often that not large quantities of natural resources have been found in these dry and arid regions contributing directly to the economic growth of the nation. Deserts form a vital part of our ecological system and where on one hand there spreading should be checked, on the other it must be ensured that the bio diversity unique to these regions be preserved, lest the same becomes extinct or endangered.