Heat Waves, Meaning, Criteria, Causes, Impact, Mitigation

Context: The India Meteorological Department (IMD) reported an expected increase in days experiencing heat waves across India, affecting the southern, central, eastern, and northwestern areas.

You can read about the Heat waves, Impact and mitigation mentioned in this article to prepare for this important topic for the UPSC CSE Exam.

What is Heat Wave?

Heat Waves is a period of unusually high temperatures. They often occur in India from May through June, and in a few rare instances, they can even last into July. The India Meteorological Department (IMD) divides the country into different temperature zones to categorise heat waves. According to IMD, there were 413 heatwave days in India between 1981 and 1990, whereas there were 600 days between 2011 and 2020. The rising effects of climate change are to blame for this substantial increase in the number of heatwave days.

IMD definition of Heat Wave

• Plains: Maximum temperature ≥ 40°C, exceeding normal by 4.5-6.4°C.
• Hilly regions: Maximum temperature ≥ 30°C, exceeding normal by 4.5-6.4°C.
• Additionally, a heatwave can be declared if:
  • Maximum temperature ≥ 45°C
  • Maximum temperature ≥ 47°C (severe heatwave)
• Qualitatively: When air temperature becomes hazardous to human health.

Criteria for Declaring a Heatwave

• When a station’s maximum temperature reaches at least 40°C for plains regions and at least 30°C for hilly regions, it is referred to as a heatwave.
• Heatwave conditions are defined as increases of 5 to 6°C above the station’s typical maximum temperature, which is less than or equal to 40°C.
• Furthermore, a severe heat wave condition is defined as a temperature increase of 7°C or more over the average.
• Heatwave conditions are defined as increases of 4 to 5°C from the normal temperature at a station when the maximum average temperature is greater than 40°C. Furthermore, a severe heat wave condition is defined as an increase of 6°C or greater.
• In addition, a heat wave is proclaimed if the actual highest temperature stays at 45°C or higher regardless of the typical maximum temperature.
• The National Disaster Management Authority (NDMA) published thorough guidelines in 2016 to help develop important national-level initiatives for reducing the effects of heat waves.

Heat Waves Causes

• When there is high atmospheric pressure, hot air is forced downward and trapped close to the ground, resulting in heat waves. The hot air is kept from rising thanks to this high-pressure system, which functions like a lock. As a result, rain cannot form, and the air temperature rises.
• Ambient temperatures may feel 3 to 4 degrees warmer than they actually are due to urban heat island effects.
• As global temperatures have increased by an average of 0.8 degrees over the previous century, more heat waves were anticipated. Temperatures at night are increasing as well.
• Globally, heat waves that last longer and are more powerful are becoming more often as a result of climate change.
• High UV radiation intensity in areas of moderate to high heat. India is susceptible to heat waves due to a combination of extreme heat stress and a largely rural population.

Causes of Increased Heat Wave Days

• Climate change: A study in PLOS Climate (April 2023) shows heatwaves are becoming more frequent, intense, and lethal globally.
  • Over 90% of India could be impacted by abnormal temperatures due to climate change.
• Increased heat waves have severe consequences:
  • Livelihoods
  • Food production
  • Disease spread
  • Human health (heat stress, death) according to WHO
• El Niño contributes to higher temperatures and increased heat wave occurrence.

Heat Waves Impact

1. Economic Effects

The frequent occurrence of heat waves hurts numerous economic sectors. For instance, the reduction in working days hurts the livelihood of poor and marginal farmers. The productivity of daily wage workers is negatively impacted by heat waves, which affects the economy.

Crop yields are impacted negatively when temperatures are higher than they should be in the agriculture sector. Wheat crop losses during the previous rabi season have been reported by farmers in Haryana, Punjab, and Uttar Pradesh. Due to heat waves, wheat production could be down 6-7% throughout India.

2. Impact on Humans

Rising temperatures, a lack of public awareness campaigns, and insufficient long-term mitigation measures all contribute to heat-related mortality. A 2019 analysis from the Tata Centre for Development and the University of Chicago predicts that by 2100, more than 1.5 million people per year may pass away from heat-related deaths brought on by climate change.

As the temperature rises, more people will contract illnesses like diabetes, cardiovascular and respiratory problems, and mental health issues. As the temperature rises, more people will contract illnesses like diabetes, cardiovascular and respiratory problems, and mental health issues.

3. Impact on Livestock

According to Cornell University researchers, increased heat stress could cause milk outputs in India’s arid and semi-arid dairy farming to decline by 25% by 2100 (compared to 2005 levels).

Heatwaves unavoidably increase the electricity demand. The average daily peak demand in North India was 13% greater in April than it was in 2021, and it was 30% higher in May.

4. Impact on Food Security

Tree mortality and agricultural production losses are being brought on by the simultaneous occurrence of heat and drought disasters. The rapid decreases in food production caused by heat-related labour productivity losses will increase the dangers to human health and food production.

In particular, in tropical areas, these interrelated effects will raise food costs, lower household incomes, and cause hunger and climate-related fatalities.

5. Impact on Workers

Given that a big portion of India’s population depends on industries like agriculture and construction for a living, these workers will be badly impacted in 2030. Weaker Sections to Be Affected in Particular: Unless greenhouse gas and aerosol emissions are drastically reduced globally, the climate science community has documented overwhelming evidence that severe events like heatwaves are projected to grow more intense, more frequent, and of longer length in the future.

It is crucial to keep in mind that heatwaves in India, like the one that is currently occurring, have the potential to affect thousands of weak and underprivileged individuals who made minimal contributions to the global warming catastrophe.

Measures to Manage Heat Wave Impact

• The Election Commission (EC) issued an advisory for upcoming elections (April 19 – June 1) coinciding with summer and potential heatwaves:
  • Carrying water bottles
  • Protecting oneself from sunlight
• Wet bulb temperature: Crucial indicator for heat stress and potential health risks.
  • Deadly conditions can occur even outside a heatwave if the wet bulb temperature exceeds 30-35°C.

Heat Waves Mitigation

1. Heat Waves Action Plan

A Heat Waves Action Plan is necessary for heatwave zones to decrease the impact of heatwaves due to the negative effects of heat waves and the need for effective disaster adaption techniques and more robust disaster management regulations.

The government must prioritise creating a long-term action plan to protect people, animals, and wildlife because heat-related deaths can be avoided.

The Sendai Framework for Disaster Risk Reduction 2015–30 needs to be implemented effectively, with the State taking the lead and other stakeholders sharing responsibility.

2. Implementing Climate Action Plans

To promote equitable growth and ecological sustainability, the National Action Plan for Climate Change (NAPCC) should be implemented in its true spirit.

Not only should nature-based solutions be considered to combat climate change, but also to do it in a way that is moral and supports intergenerational fairness.

3. Early Warning Systems and Public Awareness

To reduce the number of fatalities caused by heat waves, it is important to raise public awareness through print, electronic, and social media, provide heat-proof shelters in summer in areas that are prone to them, make public drinking water easier to access, and implement afforestation programmes in both urban and rural areas.

By putting in place effective early warning systems that communicate heatwave hazards, suggest various preventative measures and limit disaster repercussions, heat wave fatalities can be avoided.

4. Recognition of Heat Waves as a Natural Disaster

Recognizing heat waves as a form of natural disaster It is past time to acknowledge heat waves as a serious catastrophe. India still has a ways to go in raising general understanding, especially about how people and small communities may look after themselves.

The state and district governments could create a regional heatwave action plan with the aid of a declaration of heat waves as a natural disaster. Clear rules must also be established governing when to close schools and how long people must spend outside if it cannot be helped.

5. Sustainable Cooling

For both residential and commercial buildings, passive cooling technology, a popular technique for designing naturally ventilated structures, can be a critical alternative to combat the urban heat island.

In the third section of its AR6 report, the Intergovernmental Panel on Climate Change (IPCC) suggested that in the context of global warming, ancient Indian architectural designs that have utilised this technique can be applied to modern structures.

6. Change of Dark Roofs

Cities have darker roadways, parking lots, and roofs than rural regions, which absorb and hold heat. This is a major factor in cities being hotter than rural places. Replace the dark surfaces with lighter, more reflecting materials as one of the long-term remedies; this will produce a noticeably cooler environment.

7. Climate-Resilient Crops

To determine if the crops we have relied on in the past will continue to supply food and nutrition security in the future, it is necessary to have a dynamic understanding of hazards. It will be necessary to make arrangements for crop loss insurance, and diversified cropping should be encouraged.

Heat Waves Europe

The frequency and severity of heat waves are rising faster in Europe than almost anywhere else on the planet, including the Western United States. Because temperatures now are generally around 1.1 degrees Celsius higher than they were in the late 19th century, when emissions of carbon dioxide and other heat-trapping gases became common, global warming plays a part in heat waves around the world. Therefore, intense heat begins at a higher altitude. However, there are additional causes that could turn Europe into a hot zone for heat waves, some of which involve the circulation of the atmosphere and water.

One factor could be the Arctic’s rapid warming, which is happening far quicker than in other regions of the planet. The difference in temperature between the Arctic and the equator narrows as it heats more quickly. This results in a reduction in midsummer winds, which has the effect of prolonging weather systems.

Additionally, there are hints that the Atlantic Meridional Overturning Circulation, one of the world’s largest ocean currents, may have an impact on Europe’s temperature. As the planet warmed, the current would diminish, changing the atmospheric circulation and resulting in drier summers in Europe.

Heat Waves UPSC

Enhancing the capacity of local healthcare personnel to recognise and manage diseases brought on by extreme heat. These training programmes should concentrate on medical officers, paramedical staff, and community health professionals to properly prevent and manage heat-related medical disorders and reduce mortality and morbidity.

Public education and community involvement – Public awareness messages on how to protect against the extreme heat wave are disseminated through print, electronic, and social media, as well as IEC tools like pamphlets, posters, and advertisements, as well as television commercials (TVCs) on dos and don’ts and treatment options for illnesses related to heat exposure.

Collaboration with civic society and non-governmental groups. Non-governmental and civil society organisations have collaborated to improve bus stops, build temporary shelters where necessary, and develop improved water distribution systems in public spaces to mitigate heatwave conditions.

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