Published on 23 Feb 2025
A heatwave is an extended stretch of abnormally warm weather that typically lasts longer than two days. There can be heat waves with or without a lot of humidity. They have the potential to cover a wide area, putting many individuals in danger of being overheated.
Causes of Heatwaves
Subcontinental Location: India's geographical location, covering a large part of the Indian subcontinent, exposes it to extreme weather conditions. During certain times of the year, India experiences intense heating due to its position.
Clear Skies and Solar Radiation: Heatwaves are often associated with clear skies and abundant solar radiation. When high-pressure systems dominate the region, they suppress cloud formation, allowing the sun's rays to heat the surface intensely.
Seasonal Changes: Heatwaves in India are more common during the pre-monsoon and summer months. Before the arrival of the monsoon rains, the land heats up significantly, leading to soaring temperatures.
Delayed Monsoon: A delayed or weak monsoon can contribute to the prolongation of hot and dry conditions, exacerbating heatwaves. Monsoons play a crucial role in cooling the Indian subcontinent.
Low Humidity: Heatwaves are often characterized by low humidity levels, making the air feel even hotter. Dry air heats up quickly, leading to increased discomfort and health risks.
Westerly Winds: The flow of hot, dry air from the west, particularly from the Thar Desert and surrounding arid regions, can intensify heatwave conditions in northwest India.
Urban Heat Island Effect: Rapid urbanization and the expansion of cities can create localized hotspots known as urban heat islands. These areas experience higher temperatures due to the heat-absorbing properties of concrete and asphalt, as well as reduced vegetation.
Climate Change: Global climate change has contributed to the increased frequency and intensity of heatwaves in India and worldwide. Rising temperatures caused by greenhouse gas emissions exacerbate heatwave conditions.
Low Wind Speeds: Reduced wind speeds during heatwaves limit the dispersal of heat, allowing hot air to accumulate and persist over a region.
Impacts of Heatwaves
Health impacts
Heat-related Illnesses: Heatwaves can lead to heat-related illnesses, including heatstroke, heat exhaustion, and dehydration.
Example: During a severe heatwave in 2015, thousands of people across India suffered from heatstroke, resulting in numerous fatalities.
Increased Mortality: High temperatures during heatwaves can lead to a spike in mortality rates, particularly among vulnerable populations.
Example: In 2019, a heatwave in Bihar resulted in over 100 deaths as temperatures soared above 45°C (113°F).
Healthcare Overload: Hospitals and healthcare facilities can be overwhelmed with patients seeking treatment for heat-related illnesses during heatwaves.
Example: Healthcare systems in cities like Delhi and Hyderabad have faced challenges during severe heatwaves.
Environmental Impacts
Ecosystem Stress: Heatwaves can stress ecosystems, leading to decreased biodiversity, wildfires, and disruption of ecological balances.
Water Scarcity: Elevated temperatures can accelerate evaporation and lead to reduced water levels in rivers, lakes, and reservoirs.
Socio-Economic Impacts
Agricultural Losses: Heatwaves can cause crop failures, reduced yields, and economic losses for farmers.
Example: In 2020, heatwaves in states like Maharashtra and Telangana led to significant losses in the agricultural sector.
Energy Demands and Disruptions: Increased energy demands for cooling during heatwaves can strain the power grid, leading to power outages.
Example: Cities like Chennai have experienced power disruptions during extreme heatwaves.
Migration and Displacement: Vulnerable communities, especially in rural areas, may be forced to migrate in search of relief from extreme heat and water scarcity.
Social Inequities: Heatwaves can exacerbate social inequities as marginalized populations often lack access to cooling and healthcare.
India’s Preparedness
Early Warning and communication: IMD provides real-time data and weather prediction of maximum temperature, heat-wave warning, heat-alert, etc.
Example: The Ministry of Earth Sciences (MoES) had set up an improved forecast system for early heatwave warnings as part of the National Monsoon Mission.
Heat Action Plans (HAPs): HAPs include components such as early warning systems, public awareness campaigns, and measures to provide relief during extreme heat events.
Example: Several Indian cities, including Ahmedabad, Nagpur, and Bhubaneswar, have developed Heat Action Plans (HAPs) to combat heatwaves.
Public Awareness Campaigns: Conducted by state governments and local authorities to educate people about the risks associated with heatwaves and the precautions they should take.
Cooling Centres: They are established, particularly in densely populated regions, to provide relief to residents during heatwaves. They offer access to air-conditioning, water, and shelter for those in need.
Challenges in mitigation
Limited Access to Cooling: Many vulnerable populations, particularly in urban slums and rural areas, lack access to cooling facilities like air conditioning or fans.
Urban Heat Island Effect: In cities like Delhi, the urban heat island effect can raise temperatures during heatwaves, exacerbating heat-related risks for residents.
Vulnerable Populations: Vulnerable groups, including the elderly, children, and those with pre-existing health conditions, are more susceptible to heat-related illnesses during extreme heat events.
Lack of Public Awareness: Limited public awareness about heatwave risks and protective measures can hinder individuals from taking appropriate precautions.
Energy Poverty: High energy costs and unreliable power supply in certain regions make it challenging for low-income households to afford cooling options during heatwaves.
Infrastructure Challenges: Inadequate infrastructure for water supply and sanitation can compound the effects of heatwaves, as residents may struggle to access clean drinking water and maintain hygiene.
Climate Change Amplification: Climate change is increasing the frequency and intensity of heat waves, making mitigation efforts more challenging.
Way Forward
Urban Planning and Design: Adopt urban planning strategies that incorporate green spaces, parks, and tree planting to mitigate the urban heat island effect in cities. Promote sustainable urban development to reduce heat-related risks.
Climate-Resilient Infrastructure: Invest in climate-resilient infrastructure, including building designs that provide natural cooling and insulation. Encourage the use of reflective roofing materials to reduce heat absorption.
Water Resource Management: Implement comprehensive water resource management plans to address water scarcity during heatwaves. Promote rainwater harvesting and efficient water use.
Climate Change Mitigation: Take proactive measures to mitigate climate change by reducing greenhouse gas emissions. Transition to cleaner and more sustainable energy sources to curb global temperature rise.
Community Engagement: Foster community-based initiatives that empower local residents to prepare for and respond to heatwaves. Encourage communities to check on vulnerable neighbours during extreme heat events.
Research and Data Analysis: Invest in research to study heatwave patterns and impacts in different regions of India. Use data-driven approaches to develop effective mitigation strategies.
Intersectoral Coordination: Strengthen coordination among government departments and agencies, including health, disaster management, and urban planning, to ensure a unified response to heatwaves.
Best Practices
France's Heat Action Plan: France has a national heat action plan that includes early warning systems, public awareness campaigns, and measures to support vulnerable populations, such as the elderly. During heatwaves, "cool rooms" are set up in public places, and transportation is made free to encourage people to stay in air-conditioned areas.
Australia's Cool Roofs Initiative: Several Australian cities have adopted cool roofs and cool pavements to reduce urban heat island effects. These surfaces reflect more sunlight and absorb less heat, helping to lower temperatures in cities.
United States' Cool Cities Initiative: Various U.S. cities have joined the Cool Cities Initiative, which promotes urban planning strategies to reduce heat, such as increasing green spaces, planting trees, and using reflective building materials.
Japan's Greening Urban Spaces: Japanese cities like Tokyo have focused on increasing green spaces within urban areas. These green spaces provide shade, reduce heat, and improve overall urban livability.
Disaster Management
HEAT WAVES
Criterion for declaring heat wave
Causes of Heatwaves
Impacts of Heatwaves
India’s Preparedness
Challenges in mitigation
General Studies Paper 3
Disaster and Disaster Management
Related Articles