Heat Waves in India 2024, Findings of Recent Study

Heat Waves in India 2024: A severe heatwave has hit northwest India, causing extreme temperatures. In southwest Delhi's Najafgarh, the temperature reached a blistering 47.4 degrees Celsius, the highest in India this season. According to a study in Science Advances, heatwaves are becoming longer and slower, especially in North America and Eurasia. The frequency of heatwaves has also risen, from around 75 events between 1979-1983 to about 98 between 2016-2020. This trend highlights the increasing intensity of heat waves in India 2024.

Heat Waves in India 2024

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Findings from Recent Heatwave Study

Research Approach:

• Heatwave Classification: The study classified heat waves by their temperature, area (over one million square kilometers), and duration (more than three days).
• Tracking: Researchers tracked the movement and speed of these heatwaves.

Heatwave Dynamics:

• Slower Movement: Heatwaves have slowed by nearly 8 km/day each decade.
• Longer Duration: They now last about four days longer.
• Increased Frequency: The number of heatwave events rose from approximately 75 (1979-1983) to around 98 (2016-2020).
• Regional Impact: North America and Eurasia are experiencing more pronounced effects.

Jet Stream Analysis:

• Weakened Jet Stream: The jet stream has weakened over the years, impacting heatwave movement.
• Influence on Surface Temperatures: Jet streams guide atmospheric waves, affecting surface temperatures. A weaker jet stream leads to more persistent and slow-moving weather events.

Human Activity:

• Impact of Greenhouse Gases: Simulations comparing scenarios with and without greenhouse gas emissions showed that human activity has significantly contributed to slower and longer-lasting heatwaves.

Future Research and Adaptation

Next Steps:

• Further Analysis: Researchers will continue to analyze atmospheric air circulation patterns.
• Country-Specific Changes: Exploring how heat waves change in specific countries.
• Climate Adaptation Strategies: Developing strategies to adapt to changing climate conditions.

Mitigation Strategies:

• Urban Areas: Increase green infrastructure by planting more trees.
• Education: Teach climate adaptation strategies through community projects.

What is a Heat Wave?

Impact on Life:

• Wildfires: Increased temperatures elevate the risk of wildfires.
• Crop Damage: Prolonged heat can damage crops, affecting food supply and agriculture.
• Health Problems: Heat waves pose significant health risks, including heat exhaustion, heatstroke, and other heat-related illnesses.

IMD Definition of a Heat Wave

Plains:

• Threshold: A heat wave is declared when the maximum temperature reaches or exceeds 40°C.
• Temperature Deviation: The temperature must exceed the normal by 4.5 to 6.4°C.

Hilly Regions:

• Threshold: A heat wave is declared when the maximum temperature reaches or exceeds 30°C.
• Temperature Deviation: The temperature must exceed the normal by 4.5 to 6.4°C.

Additional Criteria:

• Extreme Heat: A heat wave can also be declared if the maximum temperature reaches or exceeds 45°C.
• Severe Heat Wave: When the maximum temperature reaches or exceeds 47°C, it is classified as a severe heat wave.
• Health Hazard: Qualitatively, a heat wave is defined when air temperatures become hazardous to human health.

Criteria for Declaring a Heat Wave

Criteria Based on Maximum Temperature:

• Plains: The maximum temperature must reach at least 40°C.
• Hilly Regions: The maximum temperature must reach at least 30°C.

Criteria Based on Departure from Normal:

• Heat Wave: The temperature departure from normal must be between 4.5°C and 6.4°C.
• Severe Heat Wave: The temperature departure from normal must be more than 6.4°C.

Criteria Based on Actual Maximum Temperature:

• Heat Wave: The actual maximum temperature must be ≥ 45°C.
• Severe Heat Wave: The actual maximum temperature must be ≥ 47°C.

Declaration Criteria:

• Geographical Coverage: These conditions must be met in at least two stations within a Meteorological sub-division.
• Duration: The conditions must persist for at least two consecutive days.
• Timing: A heat wave is declared on the second day if the criteria are met.

Causes of Heat Waves

Atmospheric Conditions:

• High Atmospheric Pressure: When high atmospheric pressure dominates an area, it forces hot air downward and traps it close to the ground. This high-pressure system acts like a lock, preventing the hot air from rising and inhibiting the formation of rain. As a result, temperatures soar.
• Urban Heat Island Effect: Urban areas can feel 3 to 4 degrees warmer than surrounding rural areas due to the urban heat island effect, where concrete and asphalt absorb and retain heat.

Climate Change:

• Global Temperature Rise: Over the past century, global temperatures have increased by an average of 0.8 degrees Celsius. This warming trend has led to more frequent and intense heat waves.
• Nighttime Temperatures: Not only are daytime temperatures rising, but nighttime temperatures are also increasing, exacerbating the impact of heat waves.

Increased Frequency and Intensity:

• Climate Change Impact: According to a study published in PLOS Climate (April 2023), heatwaves are becoming more frequent, intense, and deadly due to climate change. More than 90% of India could experience abnormal temperatures as a result.
• Longer Duration: Climate change is causing heat waves to last longer and become more severe globally.
• High UV Radiation: Regions with moderate to high heat are exposed to intense UV radiation, further increasing heat stress.

Specific Factors in India:

• Rural Vulnerability: India is particularly susceptible to heat waves due to its combination of extreme heat stress and a largely rural population, which is more vulnerable to the impacts.
• El Niño: This climate phenomenon contributes to higher temperatures and increases the occurrence of heat waves.

Consequences of Increased Heat Waves:

• Livelihoods: Heat waves can disrupt livelihoods, particularly in agriculture-dependent regions.
• Food Production: High temperatures can damage crops, affecting food security.
• Disease Spread: Increased heat can exacerbate the spread of diseases.
• Human Health: The World Health Organization (WHO) highlights that heat waves can cause severe health issues, including heat stress and death.

Impact of Heat Waves

1. Economic Effects

• Reduced Working Days: Frequent heat waves reduce working days, adversely affecting the livelihood of poor and marginal farmers. Daily wage workers experience reduced productivity, which negatively impacts the economy.
• Crop Yields: Higher-than-normal temperatures harm crop yields. Farmers in Haryana, Punjab, and Uttar Pradesh have reported losses in wheat crops during the previous rabi season. Nationally, wheat production could drop by 6-7% due to heat waves.

2. Impact on Humans

• Heat-Related Mortality: Rising temperatures, lack of public awareness, and inadequate long-term mitigation measures contribute to heat-related deaths. A 2019 analysis by the Tata Centre for Development and the University of Chicago predicts that climate change could cause over 1.5 million heat-related deaths annually by 2100.
• Health Issues: Higher temperatures increase the prevalence of illnesses such as diabetes, cardiovascular and respiratory problems, and mental health issues.

3. Impact on Livestock

• Milk Production: Researchers at Cornell University estimate that increased heat stress could reduce milk output in India's arid and semi-arid regions by 25% by 2100 compared to 2005 levels.
• Electricity Demand: The demand for electricity rises during heat waves. In North India, the average daily peak demand in April was 13% higher than in 2021, and it increased by 30% in May.

4. Impact on Food Security

• Tree Mortality and Crop Losses: These disasters lead to tree mortality and agricultural production losses, decreasing food production.
• Increased Food Costs: The resulting labor productivity losses will raise food costs, lower household incomes, and cause hunger and climate-related deaths, especially in tropical areas.

5. Impact on Workers

• Vulnerable Populations: A significant portion of India’s population relies on these sectors for their livelihood. By 2030, these workers will face severe impacts unless greenhouse gas and aerosol emissions are drastically reduced.
• Weaker Sections: Heat waves disproportionately affect vulnerable and underprivileged individuals who have contributed minimally to global warming.

Measures to Manage Heat Wave Impact

• Election Commission Advisory: For upcoming elections (April 19 – June 1), the Election Commission advised carrying water bottles, protecting oneself from sunlight, and monitoring the wet bulb temperature, a crucial indicator of heat stress and potential health risks.
• Wet Bulb Temperature: Deadly conditions can occur if the wet bulb temperature exceeds 30-35°C, even outside of a heat wave.

Mitigation Strategies for Heat Waves

1. Heat Waves Action Plan

• Long-term Planning: The government must prioritize creating a long-term action plan to safeguard people, animals, and wildlife. Heat-related deaths can be prevented with proper planning.
• Sendai Framework Implementation: Effective implementation of the Sendai Framework for Disaster Risk Reduction 2015–30 is essential. The State should take the lead, with other stakeholders sharing responsibility.

2. Implementing Climate Action Plans

• Nature-Based Solutions: These solutions should be considered to combat climate change in a way that is ethical and supports intergenerational fairness.

3. Early Warning Systems and Public Awareness

• Public Awareness Campaigns: Utilize print, electronic, and social media to raise awareness.
• Heat-Proof Shelters: Provide shelters in heatwave-prone areas.
• Accessible Drinking Water: Ensure easy access to public drinking water.
• Afforestation Programs: Implement these programs in urban and rural areas.
• Early Warning Systems: Establish systems to communicate heatwave hazards, suggest preventative measures, and limit disaster impacts.

4. Recognition of Heat Waves as a Natural Disaster

• Regional Action Plans: State and district governments should create regional heatwave action plans.
• Clear Guidelines: Establish guidelines for school closures and outdoor activities during heatwaves.

5. Sustainable Cooling

• Ancient Architectural Designs: Utilize ancient Indian architectural designs that incorporate passive cooling techniques, as suggested by the Intergovernmental Panel on Climate Change (IPCC) in its AR6 report.

6. Changing Dark Roofs

• Reflective Materials: Replace dark surfaces with lighter, more reflective materials to create a cooler environment.

7. Climate-Resilient Crops

• Crop Loss Insurance: Arrange for insurance to cover crop losses.
• Diversified Cropping: Encourage diversified cropping to enhance resilience against heatwaves.

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