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3rd April 2024 (14 Topics)

Heatwaves Conditions across India


Anthropogenic climate change is turning ambient heat into an inevitable environmental hazard. India is poised to encounter an increased number of heat-wave days than usual from April to June and this expansion of the realm of extreme heat is potentially the gravest consequence of climate change for India. 

1: Dimension: Impact of Heat Waves over different sectors

  • Health impact:
    • Heat Stress: Exposure to severe or continuous heat leads to heat stress. Illnesses range from superficial/mild and manageable (e.g. prickly heat, heat-related swelling, heat cramps, heat exhaustion) to a medical emergency (i.e. heat stroke).
    • Heat stroke is the most severe of heat-related illnesses. It presents with impaired brain function (i.e. stroke) due to uncontrolled body heating. It is a time-critical condition that often turns fatal if there is a delay or failure in reducing body temperature by rapid, active cooling. Besides neurological impairment, high core body temperature (at least 40 degrees C), or hot, dry skin are other heat stroke symptoms. Someone in perfect health and participating in what seem to be normal activities may die from heat stroke within an hour. 
  • Environmental impact: Heatwaves also have compound and cascading environmental impacts like concurrent drought, glacial lake outbursts causing flash floods, urban/wildfires, and increased air pollution from ground-level ozone and dust storms.
  • Economic Impact:
  • Impact on crops: There are concerns about the potential adverse effects on wheat, rapeseed, and chickpea production. India, being the world’s second-largest wheat producer, could face significant repercussions.
  • Power demand: There are possibility of surpassing power demand over supply during the summer season.

Fact Box

Heat Wave

  • Heat wave is a condition of air temperature which becomes fatal to human body when exposed.
  • Quantitatively, it is defined based on the temperature thresholds over a region in terms of actual temperature or its departure from normal.
  • For declaring a heat wave, the temperature should be 4.5 °C above normal for that time in a region.
  • The criteria for the coastal station maximum temperature should be greater than or equal to 37 °C.

Favourable conditions of heat wave formation

  • Transportation / Prevalence of hot dry air over a region: There should be a region of warm dry air and appropriate flow pattern for transporting hot air over the region.
  • Absence of moisture in the upper atmosphere: As the presence of moisture restricts the temperature rise.
  • The sky should be practically cloudless: To allow maximum insulation over the region.
  • Large amplitude anti-cyclonic flow over the area.

Practice Question

Q: Heatwave is the gravest consequence of climate change for India. Discuss the impact of heatwave as a disaster. (250 words)


Q: Discuss the consequences of climate change on the food security in tropical countries. (UPSC 2023)


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