Question

Explain the causes of drought.

Answer 1

A drought is characterized by prolonged period with less-than-average amounts of rain or snow i.e., the lack of precipitation. Their severity often depends on the amount of time that a region receives below-average precipitation.

Complete answer:
Drought is an extensive period of absence of rainfall and the shortage of available water. Droughts occur naturally but human activity (water management) can increase the chances of dry conditions. Droughts are caused by a combination of factors.

1)Meteorological: Meteorological factors can cause an area to get less rainfall than average. Changes in global atmospheric circulation affect rainfall patterns.
2)Hydrological: Lack of water in rivers, lakes, reservoirs may often lead to drought. Areas which largely rely on rainfall and surface water have high chances of going through drought. Surface water evaporates in warm, dry conditions which lead to an increased risk of drought.
3)Human causes: Various human activities such as deforestation lead to disturbance in the water cycle of the atmosphere and this further affects the rainfall timings. Deforestation also affects the moisture releasing ability of trees (transpiration). Decrease in the number of trees makes the atmosphere dry thus acts as a cause of drought. Intensive agriculture activities utilizes large amounts of water.
4)Droughts are also triggered by weather patterns, amount of moisture and heat in the air, land, and sea.
5)Fluctuating ocean and land temperatures: Temperatures of ocean also affect global weather patterns, including dry and wet conditions on land. Small fluctuation in temperature can have huge ripple effects on climate systems and also hotter surface temperatures on land lead to greater evaporation of moisture from the ground, which can increase the impact of drought.
6)Climate change: Climate change and global warming impacts drought by increasing temperatures which make wet regions wetter and dry regions drier. For wetter regions, warm air absorbs more water, leading to larger rain events. In arid regions, warmer temperatures mean water evaporates more quickly.
7)Excess water demand: Drought often reflects an imbalance in water supply and demand. Increase in the population puts strain on water resources thus acts as a threat of drought. 8)Demand for water supplied by upstream lakes and rivers, can lead to drying out of downstream water sources which contribute to drought.

Note: Rain can help during a drought, but it doesn’t make the drought go away. A light rain shower might cause the grass and plants to green up. But if water quickly evaporates into the air or is soaked up by plants, the drought relief doesn’t last long. Thunderstorms often bring rain in large quantities but the water drains into sewers instead of soaking into soil. A thunderstorm might also cause flash floods.
Rains soak into soil and can replenish groundwater. Groundwater provides water to plants and refills streams during non-rainy periods. Soaking of rain water may improve drought conditions.