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Mains Practice Questions

  • Q. Heat waves are among the most dangerous of natural hazards, the frequency and intensity of which will rise in the 21st century due to climate change. Discuss. (250 Words).

    06 Oct, 2021 GS Paper 3 Disaster Management


    • Start with writing about the heat waves and discuss the causes of increasing intensity and frequency of heat waves.
    • Discuss the impacts of heat waves.
    • Conclude by suggesting a way forward.


    A heat wave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer season in the North-Western and South Central parts of India.

    The India Meteorological Department requires that temperatures should reach at least 40°C in the plains and at least 30°C in the hilly regions, and should reflect an increase of at least 5°C-6°C above the normal temperature to be classified as a heatwave.


    Heat waves happen when a system of high atmospheric pressure moves into an area. This high-pressure system forms what is best described as a "cap" over the region — trapping heat that would otherwise escape into the atmosphere where it would otherwise cool off before coming back down to the surface. This environment of minimal heat circulation also reduces the chance of precipitation and rain, causing the heat to build up, which we experience as a heat wave.
    During summers, these buildups tend to change more slowly — the heat lingers on and on, and temperatures may not cool off enough at night to offer a sense of relief.

    Impact of Heat Waves

    • Heat Strokes: The very high temperatures or humid conditions pose an elevated risk of heat stroke or heat exhaustion.
      • Older people and people with chronic illness such as heart disease, respiratory disease, and diabetes are more susceptible to heatstroke, as the body’s ability to regulate heat deteriorates with age.
    • Increased Healthcare Costs: Effects from extreme heat are also associated with increased hospitalisations and emergency room visits, increased deaths from cardio-respiratory and other diseases, mental health issues, adverse pregnancy and birth outcomes, etc.
    • Lessens Workers’ Productivity: Extreme heat also lessens worker productivity, especially among the more than 1 billion workers who are exposed to high heat on a regular basis. These workers often report reduced work output due to heat stress.
    • Risk of Wildfires: The heat domes act as fuel to wildfires, which destroys a lot of land area every year in countries like the US.
    • Prevents Cloud Formation: The condition also prevents clouds from forming, allowing for more radiation from the sun to hit the ground.
    • Effect on Vegetation: The trapping of heat can also damage crops, dry out vegetation and result in droughts.
    • Increased Energy Demands: The sweltering heat wave also leads to rise in energy demand, especially electricity, leading to pushing up rates.
    • Power Related Issues: Heat waves are often high mortality disasters.
      • Avoiding heat-related disasters depends on the resilience of the electrical grid, which can fail if electricity demand due to air conditioning use exceeds supply.
      • As a result, there is the double risk of infrastructure failure and health impacts.


    • Cooling Measures: Effective and environmentally sustainable cooling measures can protect from the worst health impacts of heat.
      • These range from increasing green space in cities, wall coatings that reflect heat from buildings, and widespread use of electric fans and other widely available personal cooling techniques.
    • Climate Change Mitigation: Climate change mitigation to reduce carbon emissions and alter the further warming of the planet can also help.
    • Effective Prevention Measures: Identifying timely and effective prevention and response measures, particularly for low-resource settings can help in mitigating the problem


    In alignment with the Paris Agreement, the study calls for global warming to be limited to 1.5°C to avoid substantial heat-related mortality in the future. Reducing the health impacts of extreme heat is an urgent priority and should include immediate changes to infrastructure, urban environment, and individual behaviour to prevent heat-related deaths.

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