Day 60 – Q.1 Evaluate the role of deserts and their geographical features, such as sand dunes and salt pans, on the climate and ecosystem of the regions they occupy and their impact on human settlement and trade.

Evaluate the role of deserts and their geographical features, such as sand dunes and salt pans, on the climate and ecosystem of the regions they occupy and their impact on human settlement and trade.

रेगिस्तानों की भूमिका और उनकी भौगोलिक विशेषताओं, जैसे रेत के टीले और नमक के ढेर, उनके कब्जे वाले क्षेत्रों की जलवायु और पारिस्थितिकी तंत्र पर और मानव बस्ती और व्यापार पर उनके प्रभाव का मूल्यांकन करें।

Approach – 

A simple straightforward question where candidates need to write about role of deserts and their features such as sand dunes salt pans on climate change and ecosystem of the regions .and impact they had on trade and human settlements .

Introduction –

A desert ecosystem is characterized by low precipitation and high temperatures, with a variety of plant and animal life adapted to these harsh conditions. Sand dunes can have an impact on climate change by trapping and preserving carbon in the sand. They can also help to reduce the amount of carbon in the atmosphere by acting as a sink, absorbing and storing carbon from the atmosphere.

Body –

• Dunes move when sand grains on one side are picked up by the wind and deposited on the other. But the speed of movement varies greatly depending on factors including the shape and size of the dunes, moisture content in the sand, and wind speed.
• Dune movement can be dramatically slowed or prevented by sparse vegetation. When vegetation cover drops below 14%, erosion speeds up significantly. The result is a self-perpetuating system in which the blown sand smothers remaining plants, destroying ecosystems and prompting further erosion.
• These shifting sands are likely to destroy local ecosystems, making any kind of farming or other use of nearby land even more difficult, they report in Nature.
• The model included seasonal variations in annual rainfall and the likely impact of an increase in atmospheric greenhouse gases on temperature. It did not, however, include the influence of higher carbon dioxide levels on plant productivity, nor human impacts such as increased agriculture in surrounding areas.
• Fighting the process of vegetation loss and dune movement would require major adaptations,” says Thomas. One possible solution would be to plant new vegetation. But dune ecosystems are very sensitive and differ greatly from region to region. It would take many years of careful tending to stop a moving dune from wandering around, he explains.

Salt pan

• Natural salt pans or salt flats are flat expanses of ground covered with salt and other minerals and are found in deserts.
• Large salt plains are common in the Sahara Desert, the Kalahari Desert, the Rann of Kutch, the western United States and the central deserts of Australia.
• These are natural formations which are formed by evaporation of a water pool such as a lake or pond.
• This happens in climates where the rate of water evaporation exceeds the rate of precipitation.
• If the water cannot drain into the ground, it remains on the surface until it evaporates, leaving behind minerals precipitated from the salt ions dissolved in the water.
• Over thousands of years, the minerals (usually salts) accumulate on the surface. These minerals reflect the sun’s rays (through radiation) and often appear as white areas.
• Ecological significance: Salt pans play a significant role in the ecology of the neighbouring areas. Salt pans have different species of birds and insects thriving on them. They have an enormous water-holding capacity that helps in flood control.
• Sand dunes in the Kalahari Desert in Africa, which have been immobile for thousands of years, will soon start to move again, researchers warn. The wandering dunes may affect hundred of thousands of people in southern Africa.
• Low precipitation: Deserts typically receive very little rainfall, which can contribute to a lack of vegetation and a high rate of evaporation. This can increase the amount of carbon dioxide in the atmosphere.
• High temperatures: Deserts are known for their high temperatures, which can accelerate the rate of evaporation and contribute to the formation of heat waves.
• Dust storms: Deserts are also known for their dust storms, which can transport large amounts of dust and other particles into the atmosphere. These particles can reflect sunlight and contribute to cooling the planet
• Researchers have long warned that some of the driest and poorest parts of the world are getting drier, causing deserts to grow. But researchers wondered whether the anticipated climate change might also affect the movement of dunes within deserts.

Impacts on human settlements –

• Human settlements in deserts are challenging due to the arid conditions and lack of water, which can limit the availability of resources such as food and fuel. Additionally, the harsh living conditions can make it difficult for people to survive in these regions.
• Deserts also act as a barrier to human expansion and help to preserve unique ecosystems and biodiversity.
• Researchers have long warned that some of the driest and poorest parts of the world are getting drier, causing deserts to grow.
• Dune movement can be dramatically slowed or prevented by sparse vegetation. When vegetation cover drops below 14%, erosion speeds up significantly.
• These shifting sands are likely to destroy local ecosystems, making any kind of farming or other use of nearby land even more difficult.
• The model included seasonal variations in annual rainfall and the likely impact of an increase in atmospheric greenhouse gases on temperature.
• It did not, however, include the influence of higher carbon dioxide levels on plant productivity, nor human impacts such as increased agriculture in surrounding areas.
• Local people are aware of the problem, , but often act to worsen it. Large-scale sheep farming in the northern part of South Africa, for example, reduces available ground water, because it requires extensive well digging.
• Fighting the process of vegetation loss and dune movement would require major adaptations,”. One possible solution would be to plant new vegetation. But dune ecosystems are very sensitive and differ greatly from region to region.
• It would take many years of careful tending to stop a moving dune from wandering around
• Additionally, deserts can also impact human settlement through their arid conditions and lack of resources. However, they also can act as barriers to human expansion and can help to preserve unique ecosystems and biodiversity.

Conclusion 

Deserts have played a significant role in human settlement and trade throughout history. Due to their harsh conditions, deserts have often been viewed as barriers to human migration and economic activity. However, many deserts have also served as important trade routes for caravans and merchants, connecting different regions and cultures.