Mains Marathon

• Start introduction with the definition of desert in terms of rainfall.
• Elucidate the reason behind the distribution of the world’s cold and hot deserts.
• Conclude suitably.

Answer:

Desert is an area of land that receives less than 25 centimeters of precipitation a year. The amount of evaporation in a desert often greatly exceeds the annual rainfall. The world’s cold and hot deserts are distributed in different regions according to the causes of their dryness and the climatic conditions they experience.

The distribution of the world’s cold deserts and the reasons behind their formation are as follows:

• Distribution of Cold Deserts: Cold deserts are primarily found in the polar regions and high altitudes. The largest cold desert in the world is Antarctica. Other notable cold deserts include the Arctic region, parts of Central Asia (such as the Gobi Desert), and parts of North America (such as the Great Basin Desert).
  • These deserts experience extremely low temperatures, with freezing winters and short, cool summers.
• Formation of Cold Deserts: Cold deserts are formed due to specific climatic conditions and geographical features.
  • The primary factor is the rain shadow effect caused by mountain ranges. As moist air from the ocean moves towards the mountains, it rises and cools, resulting in precipitation on the windward side of the mountains. By the time the air reaches the leeward side, it has lost most of its moisture, creating arid conditions.
  • Additionally, cold desert formation is influenced by the distance from water bodies, prevailing wind patterns, and temperature fluctuations due to latitude and altitude.
• The impact of climate change on cold deserts includes the melting of polar ice caps in the Arctic region.
  • The reduction in sea ice cover has led to changes in the habitat and behavior of polar species.
  • Additionally, the retreating glaciers in cold desert regions like the Himalayas have had significant implications for water availability, impacting both local communities and downstream regions.

The distribution of the world’s hot desert and the reasons behind their formation are as follows:

• Distribution of Hot Deserts: Hot deserts are predominantly found in tropical and subtropical regions. The largest hot desert in the world is the Sahara Desert in Africa. Other notable hot deserts include the Arabian Desert, the Mojave Desert in North America, and the Australian Outback.
  • Hot deserts are characterized by scorching temperatures during the day and relatively cooler nights.
• Formation of Hot Deserts: Hot deserts are formed due to specific climatic and geographical factors.
  • These include high-pressure systems, global wind patterns, and the lack of moisture caused by cold ocean currents. The high-pressure systems in subtropical regions create stable atmospheric conditions, inhibiting the formation of clouds and rainfall.
  • Additionally, hot deserts are often located in rain shadows, like cold deserts, resulting in arid conditions.
• The impact of climate change on hot deserts includes the intensification of droughts and heatwaves in regions like the Sahel in Africa and the southwestern United States.
  • These phenomena have led to desertification, decreased agricultural productivity, and water scarcity, impacting local communities and ecosystems.
  • The expansion of the Sahara Desert into neighboring regions due to desertification is another concerning consequence of climate change.

The location and climate of cold and hot deserts are influenced by geographical and climatic factors. Cold deserts are mostly found in high altitudes and polar regions, while hot deserts are widespread in tropical and subtropical regions. Climate change affects desert ecosystems in various ways, such as reducing polar ice caps, melting glaciers, increasing droughts, and desertification.