For Prelims: Heatwaves, Indian Meteorological Department (IMD), Global Warming, Urban heat island effect, National Disaster Management Authority, Greenhouse gases, Aerosols, Sendai Framework for Disaster Risk Reduction, National Action Plan for Climate Change, Nature-based solutions, Passive cooling technology

For Mains: Criteria for Heatwaves, Strategies to Mitigate the Impacts of Heat Waves in India

What are the Causes of Heatwaves?

• Prevalence of Hot and Dry Air: A large region of hot and dry air acts as a reservoir of heat. Prevailing winds then transport this hot air to other areas, further elevating temperatures.
• Absence of Moisture: Moisture in the air retains heat and prevents it from escaping while dry air allows solar radiation to reach the ground more readily and radiate back out at night with minimal trapping, resulting in a quicker increase in daytime temperatures.
• Cloudless Skies: Clouds act as a shield, reflecting sunlight back into space and preventing it from heating the Earth's surface. A clear, cloudless sky allows for maximum solar radiation to reach the ground, intensifying heating.
• Large Amplitude Anticyclonic Flow: Anti-cyclones are large-scale atmospheric circulation patterns characterized by sinking air.
  • This sinking air compresses and warms adiabatically (heats up without gaining heat), contributing to rising temperatures at the surface.
• Geographical Considerations: Heat waves are more frequent in regions with arid or semi-arid climates, such as Northwest India. Prevailing westerly winds during summer months can spread heat waves eastward and southward.
• Climate Change: Global warming is increasing the frequency and intensity of heat waves. Rising baseline temperatures create a more conducive environment for these events to occur.

What are the Impacts of Heatwaves?

• On Health: Heat waves can lead to dehydration, heat cramps, heat exhaustion, and heat stroke.
  • Symptoms include swelling, fainting, fever, fatigue, weakness, dizziness, and excessive sweating. Heat stroke can cause high body temperatures, delirium, seizures, or coma and can be fatal.
  • As per the data from the National Crime Records Bureau (NCRB), 730 deaths occurred due to heat-related causes in 2023.
• On Water Resources: These can exacerbate water scarcity issues in India by quickly drying up water bodies, reducing water availability for agriculture and domestic use, and increasing competition for water resources.
  • Example: Most of the major reservoirs in the southern States are filled to only 25% of their capacity or less.
• On Energy: Heatwaves can increase electricity demand for cooling purposes, leading to strain on power grids and potential blackouts.
  • This can disrupt economic activities, affect productivity, and impact vulnerable populations who may not have access to reliable electricity for cooling during heat waves.
• Crops and Livestock: Heat stress is a major problem for agriculture, negatively affecting both crops and livestock.
  • In crops, high temperatures hinder their ability to use sunlight for energy, reducing growth and overall yield.
  • For livestock, heat stress disrupts various physiological functions and behaviours, with the severity depending on the animal's breed and environment.
• Wild/Forest Fires: The Forest Survey of India has estimated that 21.4% area under forest is vulnerable to forest fires.

NDMA Guidelines for Heatwaves:

• Avoid going out in the sun, especially between 12.00 noon and 3.00 p.m.
• Drink sufficient water as often as possible.
• Wear lightweight, light-coloured, loose, and porous cotton clothes. Use protective goggles, an umbrella/hat, shoes or chappals while going out in sun.
• Avoid alcohol, tea, coffee and carbonated soft drinks, which dehydrate the body.
• Avoid high-protein food and do not eat stale food.
• Use ORS, homemade drinks like lassi, torani (rice water), lemon water, buttermilk, etc. which helps to rehydrate the body.
• Keep animals in the shade and give them plenty of water to drink.
• Keep your home cool, use curtains, shutters or sunshade and open windows at night.
• Use fans, damp clothing and take bath in cold water frequently.

What is a Heat Action Plan?

• A Heat Action Plan (HAP) is a comprehensive strategy developed by governments or organisations to mitigate the health risks associated with extreme heat events.
  • It includes measures to protect vulnerable populations, provide information and resources, and coordinate responses during heatwaves.
• They outline short-term measures, including alerts and inter-departmental coordination, to reduce human casualties. HAPs entail long-term strategies like infrastructure upgrades such as cool roofs and enhanced greenery to prepare for future heat waves based on data analysis.
• Odisha first developed a Heat Action Plan in 1999 following more than 2,000 Heat Wave deaths in 1998. Following this, the first city-level Action Plan was developed by Ahmedabad in 2013 following the severe Heat Wave in 2010.
• The NDMA and IMD are working with 23 States to develop HAPs. There is no centralised database on HAPs, but at least 23 HAPs exist at the State and city level, with a few States, such as Odisha and Maharashtra, laying out district-level HAPs.

UPSC Civil Services Examination, Previous Year Question (PYQ)

Q. What are the possible limitations of India in mitigating global warming at present and in the immediate future? (2010)

1. Appropriate alternate technologies are not sufficiently available.
2. India cannot invest huge funds in research and development.
3. Many developed countries have already set up their polluting industries in India.

Which of the statements given above is/are correct?

(a) 1 and 2 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3

Ans: (a)

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Mains

Q: Bring out the causes for the formation of heat islands in the urban habitat of the world.