Heat Wave & Climate Change Impact

Context:

A heatwave has led to 61 deaths from suspected heat stroke, including 23 poll workers in the Lok Sabha election.
Around 7 lakh people have been hospitalized in north India due to extreme heat, with rising temperatures and no rain forecasted.
Two weather stations in the capital New Delhi have reported temperatures of 49 C (120.2 F) and 49.1 C (120.38 F) for Wednesday 29th May.

1.What are Heat Waves?

Qualitatively- heat wave is a condition of air temperature which becomes fatal to the 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.
In certain countries it is defined in terms of the heat index based on temperature and humidity or based on extreme percentile of the temperatures.

2.How are Heat waves defined in India?

In India IMD defines heatwave based on the following criteria

Physiography of regions	Condition
Plain	The maximum temperature recorded at a station is 40 degrees Celsius or more.
Coast	The maximum temperature recorded at a station is 37 degrees Celsius or more.
Hills	The maximum temperature recorded at a station is 30 degrees Celsius or more.

Based on Departure from Normal Temperature

Heat Wave- Departure from normal is 4.5°C to 6.4°C
Severe Heat Wave- Departure from normal is >6.4°C

Based on Actual Maximum Temperature

Heat Wave- When actual maximum temperature ≥ 45°C
Severe Heat Wave- When actual maximum temperature ≥47°C

Heat Wave is declared if above criteria are met in at least 2 stations in a Meteorological subdivision for at least two consecutive days.

3. Which are the heat wave prone states in India?

Rajasthan, Punjab, Haryana, Chandigarh, Delhi, West Madhya Pradesh, Uttar Pradesh, Chhattisgarh, Odisha, Vidarbha in Maharashtra, parts of Gangetic West Bengal, coastal Andhra Pradesh, and Telangana are the most heat-wave-prone states or regions.

4. What is the status of Heatwaves in India?

India has observed a significant mean temperature increase of 0.15 degrees C per decade since 1950, according to a 2020 assessment by the Ministry of Earth Sciences.
According to IMD, between 1981 and 1990 there were 413 heatwave days in India.
The observed warming is not occurring evenly across India.
Warm days and warm nights have also increased at about seven and three days per decade, respectively, during the period 1951- 2015.
Currently, 23 States, mainly of plain and coastal regions, are considered more vulnerable to widespread heat impact.
However, that doesn’t mean hilly states are safe. Although their maximum temperatures do not reach heatwave threshold levels of 45 degrees C, the population is experiencing higher temperatures compared to previous decades.

5. What are Heatwave related Tolls in India?

Nearly 25,000 people have suffered suspected heat stroke and 61 died after several heat waves across India between March and May,2024 as per the government data.
When doing a comparison between the figures of 2000-2004 and 2017- 2021, The Lancet Countdown on Health and Climate Change: Health at the mercy of fossil fuels, found that there has been a 55 percent increase in heat related deaths in India.
India had reported 20,000 heat related deaths in adults over the age of 65 annually in 2000 to 2004, and the number grew to about 31,000 deaths in 2017 to 2021.

6.What are favorable conditions for Heat wave?

Condition	Analysis
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.

7. How does the India Meteorological Department (IMD) monitor the Heat wave?

IMD has a big network of surface observatories covering the entire country to measure various meteorological parameters like Temperature, Relative humidity, pressure, wind speed & direction etc.
Based on daily maximum temperature station data, climatology of maximum temperature is prepared for the period 1981-2010 to find out the normal maximum temperature of the day for a particular station.
Thereafter, IMD declared a heat wave over the region as per its definition.

8. What is impact based heat wave warning issue by India Meteorological Department (IMD)?

India Meteorological Department issues following color code impact based heat warning jointly with the National Disaster Management Authority.

9. What is the status of Heatwaves in other Countries?

United States

Heat Wave Characteristics in the United States by Decade, 1961–2021.

Europe:

Number of occurrences of heat waves in Europe from 1995 to 2015.

10. What are the factors behind the increase in Heatwaves in India?

There are multiple reasons why heat waves occur in India, and they are primarily caused by a combination of meteorological, geographical, and human factors.
Some of the significant contributors to heat waves in India include:

Factor	Description
Meteorological Factors:	Heat waves in India can be caused by meteorological factors include high-pressure systems over northwestern India, the Arabian Sea, and the Bay of Bengal. This creates a stagnant air mass that traps hot and dry air, leading to higher temperatures. The climate can also be affected by the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), which can contribute to the occurrence of heat waves.
Geographical Factors:	India's position near the equator results in high levels of solar radiation all year round, especially during the summer season. The country's terrain, which includes deserts, semi- arid areas, and high-altitude regions, can also worsen the conditions of heat waves.
Human Factors:	Human activities like urbanization, deforestation, and poverty can increase temperatures and create heat island effects, making vulnerable populations more susceptible to heat-related illnesses due to the lack of access to cooling and drinking water, and inadequate public health infrastructure. “Urbanization alone has led to an overall 60% enhancement in warming in Indian cities,” as per the study published in the journal Nature stated.
Urban heat island	The Intergovernmental Panel on Climate Change (IPCC) Working Group-II, which assesses impacts of, and vulnerabilities to climate change, has noted that the urban heat island effect leads to cities experiencing air temperatures that are several degrees warmer than surrounding areas, especially during the night, “reducing adaptive capacity”.

11. What are the effects of Heatwaves?

Effects	Description
Health	Heatwaves can have significant impacts on health, depending on the timing, intensity, and duration of high temperatures. Exposure to excessive heat can lead to various illnesses, including heat cramps, heat exhaustion, heatstroke, and hyperthermia.
Economy	A 2020 McKinsey Global Institute paper estimated that “an increase in lost labour hours due to rising heat and humidity could put approximately 2.5-4.5 per cent of GDP at risk by 2030, equivalent to roughly $150-250 billion.”
Labour Productivity	According to an ILO study at 34°C, workers can lose up to 50% of their work capacity.
Social Impacts	Heat waves can have social impacts, such as increased crime rates, social unrest, and migration. Populations that are vulnerable are at a higher risk of being affected.
Environmental Impact	Extreme heat can increase the risk of other disasters like droughts and wildfires. They can also lead to the spread of disease-carrying insects, such as mosquitoes and ticks.
Effects on Air Quality	On hot days air quality can worsen due to ground- level ozone production and pollution from air conditioning.
Decreases Agriculture Output	High temperatures resulted in moisture stress, sunburn, flower drop and less fruit setting in horticultural crops such as kinnow, pomegranate, mango and lemon. Similarly, in the case of vegetables, significant impact was observed especially in tomato, cole crops and cucurbits. The heat wave coincided with grain filling and development stage of wheat, yellowing and shriveling of grain, forced maturity, resulting in reduction of yields up to 15-25%.
Power Breakdown	Heatwaves can cause power breakdowns due to excessive usage of air conditioners, leading to high electricity consumption and outages.

12. What are the initiatives taken by the government to address the issue of heatwaves?

Policy/Initiatives	Description
National Disaster Management Plan (NDMP)	Provides a framework for heatwave mitigation under disaster management, including early warnings, capacity building, and inter-agency coordination.
National Action Plan on Climate Change (NAPCC)	Addresses adaptation under its “National Mission on Sustainable Agriculture” including managing heat stress on crops/livestock.
National Action Plan on Human Health and Climate Change	It aims to facilitate capacity building, surveillance, preparedness and awareness generation for climate-sensitive health risks, including heat stress.
Heat Action Plans	City-level plans were initiated after the Ahmedabad model to issue early heatwave warnings, minimize exposure of at-risk groups and boost health system preparedness.
National Disaster Management Policy	Mandates development of disaster-specific action plans, including for heatwaves, outlining prevention, preparedness and risk reduction.

13. What You Can Do to Reduce impact of Heatwaves?

Increase shade around your home	Planting trees and other vegetation lowers surface and air temperatures by providing shade and cooling through evapotranspiration. Trees and vegetation that directly shade your home can decrease the need for air conditioning, making your home more comfortable and reducing your energy bill.
Install green roofs	A green roof, or rooftop garden, is a vegetative layer grown on a rooftop. Green roofs provide shade and remove heat from the air through evapotranspiration, reducing temperatures of the roof surface and the surrounding air.
Use energy- efficient appliances and equipment	Using efficient appliances and equipment in your home can help to lighten the load on the electric grid during heat waves, thus ensuring a more reliable supply of electricity to your community. Replacing your old appliances and equipment with ENERGY STAR-qualified products can also help save you money.

14. What are the measures one should take to minimize the impact during the heat wave?

Avoid going out in the sun, especially between 12.00 noon and 3.00 p.m.
Drink sufficient water and as often as possible, even if not thirsty
Wear lightweight, light-coloured, loose, and porous cotton clothes. Use protective goggles, umbrella/hat, shoes or chappals while going out in sun.
Avoid strenuous activities when the outside temperature is high. Avoid working outside between 12 noon and 3 p.m.
While travelling, carry water with you.
Avoid alcohol, tea, coffee and carbonated soft drinks, which dehydrates the body.
Avoid high-protein food and do not eat stale food.
If you work outside, use a hat or an umbrella and also use a damp cloth on your head, neck, face and limbs
Do not leave children or pets in parked vehicles
If you feel faint or ill, see a doctor immediately.
Use ORS, homemade drinks like lassi, torani (rice water), lemon water, buttermilk,etc. which helps to rehydrate the body

15. What can be possible way forward:

1. Urban greening

Urban greening – creating living walls, roofs and green corridors – can benefit cities in areas of high rainfall, including around the equator.
The World Economic Forum’s Global Commission on BiodiverCities and Adrienne Arsht-Rockefeller Foundation Resilience Center (Arsht-Rock) have developed the Heat Action Platform, an online resource that provides cities around the world with a roadmap and tools to address extreme heat.

2. Appointing Chief Heat Officers

Jane Gilbert became the world’s first Chief Heat Officer in May 2021, and as global temperatures rise it’s becoming an increasingly widespread and important role.

3. Passive cooling

A US study found strategies like shading and natural ventilation could reduce pressure on air conditioning by up to 80%.

16. What is the relevance of the topic for UPSC CSE?

For Prelims: Heat Waves, Indian Meteorological Department (IMD), global warming, urban heat island effect, El Nino , Sendai Framework for Disaster Risk Reduction 2015-30, Nature-based solutions, Intergovernmental Panel on Climate Change (IPCC), Passive cooling technology.

For Mains: Role of India Meteorological Department (IMD) in mitigating severe weather events, Concept of the Heat Index.

Some previous years prelims questions.

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)

Some previous years mains questions.

Q1. Bring out the causes for the formation of heat islands in the urban habitat of the world. (2013)

Some questions from this year and previous years interview transcripts.

Board Dinesh Dasa sir(2024)

Difference between CDRI and NDMA ?

Board Suman Sharma mam(2024)

What are man made disasters?
What to do as dm?
Major changes in NDMA after 2005?

Board Sanjay Verma sir(2024)

Global warming is going to affect both MP and Kerala in a similar way.
Analyze it for me.

Board Lt. Gen Raj Shukla sir(2023)

What is a heat wave ?
What steps should we take to deal with heat waves ?

Board BB Vyas sir(2023)

Your optional is geography, why are we facing so high temperatures and heat waves, etc (talked about the IPCC report)
What is the solution for this?
What are marine heat waves?