Climate Change Impact on India and World – International Reports, Key Observations, etc.

Heatwaves in India: Increasing Frequency Needs Range of Measures to Mitigate


From UPSC perspective, the following things are important :

Prelims level: Heatwaves, Urban heat island effect

Mains level: Climate change induces weather variability, its impact and mitigating measures


Central Idea

  • India is facing an increasing heatwave due to climate change, leading to significant agricultural crop losses, urban unlivability and reduced labour productivity. India need to take range of measures to mitigate the problem, such as expanding green cover, upgrading urban building standards, embracing public transportation, and improving waste segregation and management.

What is Heat wave?

  • A heatwave is a prolonged period of abnormally hot weather.
  • Heatwaves usually last for several days or weeks and can occur in both dry and humid climates.
  • They are characterized by temperatures that are significantly higher than the average for a particular region during that time of year. This is because climate change is causing a rise in global temperatures. As the planet heats up, it leads to more extreme weather events, such as heat waves. Its geography makes India particularly vulnerable to these events.

Frequency of Heatwaves in India

  • Increase in frequency and intensity: India has been witnessing an increase in the frequency and intensity of heatwaves in recent years.
  • For instance: In April and May 2022, around 350 million Indians were exposed to strong heat stress. On an average, five-six heat wave events occur every year over the northern parts of the country.
  • Rise in summer temperatures as well as winter temperature: Summer temperatures have risen by an average of 0.5-0.9°C across districts in Punjab, Haryana, Uttar Pradesh, Bihar, and Rajasthan between 1990 and 2019. In addition, around 54% of India’s districts have seen a similar rise in winter temperatures.
  • Temperature rise projection: It is expected that between 2021 and 2050, the maximum temperature will rise by 2-3.5°C in 100 districts and by 1.5–2°C in around 455 districts. Winter temperatures will also rise between 1°C and 1.5°C in around 485 districts


Fact for prelims: Urban Heat Island Effect

  • High temperature in Urabn areas: The urban heat island effect is a phenomenon in which urban areas experience higher temperatures than the surrounding rural areas.
  • For instance: Cities in India are beset with the urban heat island effect, with temperatures 4-12°C higher than rural outlying areas.
  • Human activities are primary reason: This is primarily caused by human activities such as transportation, industrial processes, and energy consumption, which release heat and pollutants into the atmosphere.
  • Urab landscape made up of concrete absorbs more heat: The urban landscape, with its large amounts of concrete and asphalt, also absorbs and retains more heat than natural surfaces such as forests and grasslands.
  • Reduced vegetation is a contributing factor: Additionally, reduced vegetation and tree cover in urban areas contribute to the urban heat island effect, as plants help to cool the environment through evapotranspiration.
  • Negative impact: The urban heat island effect can have negative impacts on human health, as well as on energy consumption, air and water quality, and ecological systems.


The Socio-economic impact of heat waves

  • Health: Heatwaves can cause heat exhaustion, heat cramps, and heat stroke, leading to hospitalization and death. People working outdoors, such as farmers, construction workers, and street vendors, are particularly vulnerable. The elderly, children, and people with pre-existing health conditions are also at a higher risk of heat-related illnesses.
  • Labor productivity: High temperatures reduce work capacity and productivity, especially for outdoor workers. This can lead to income loss and lower economic growth.
  • For instance: For labourers doing heavy work, heat exposure leads to a loss of 162 hours per year, as per one study. A rise in temperatures directly impacts labour productivity. About 50% of India’s workforce is estimated to be exposed to heat during their working hours. This includes marginal farmers, labourers at construction sites and street vendors parlaying their produce on the streets; increasingly, even gig economy workers are affected.
  • Agriculture: Heatwaves can damage crops and livestock, leading to reduced yields and income loss for farmers. High temperatures and low soil moisture can also lead to drought and water scarcity, which can further exacerbate the agricultural impact.
  • For example: 90% of India’s cumin production is from Gujarat and Rajasthan. The recent weather variability has destroyed the majority of the cumin crop in Rajasthan. From agricultural crop losses, it is a short step towards drought and higher mortality.
  • Energy demand: During heatwaves, the demand for electricity and other forms of cooling increases, leading to power outages and blackouts. This can affect businesses, hospitals, and other critical infrastructure.
  • Migration: Heatwaves can lead to migration as people seek cooler areas or better living conditions. This can strain resources in the destination areas and lead to social tensions.


Ways to Mitigate the Problem

  • Greening could help mitigate part of the problem: Ideally, for every urban citizen in India should have at least seven trees in the urban landscape. However, many urban localities even in leafy Delhi fall short. Development plans for Tier 2 and Tier 3 cities can set up a mandate to increase urban surface area that is permeable, while pushing to increase the density and area of urban forests.
  • Expanding and restoring wetlands: Expanding wetlands and restoring dead and decaying ponds/lakes may also help ensure ecological functioning along with reducing urban heat.
  • Reducing the urban heat island effect: This requires a push for greater usage of permeable materials in civic infrastructure and residential construction and enhancing natural landscapes in urban areas. Urban layouts such as brick jalis for ventilation and terracotta tiles to allow hot air to escape, and curbs on anthropogenic heat emissions from vehicles, factories, etc. may be considered.
  • Avoiding usage of heat absorbent material: Urban building standards should be upgraded to avoid usage of heat-absorbent galvanized iron and metal roof sheets.
  • Using cleaner cooking fuels: Using cleaner cooking fuels will reduce indoor air pollution, which may also help reduce urban heat.
  • Increasing natural vegetation: Streets with low ventilation may need further expansion, or an increase in natural vegetation
  • Voluntary and other measures: Other measures can also be considered such as, from embracing public transportation, to reducing personal vehicle usage and, most importantly, reducing the size of landfills. A push for waste segregation, along with solid waste management at source, can help.
  • Improving our forecasting ability: India needs to improve our forecasting ability, including the potential impact of heat on food production.
  • Improving economic models: Current econometric models associated with food inflation primarily look at the variability in the monsoon, minimum support prices and vegetable prices. India needs to add local heat trends to the mix as well, given the impact of heat on food production, storage and sale.
  • Detailed management policies: We need detailed policies and guidelines on weather variability and urban heat management at the State, district, city and municipality ward levels.

Value addition box: The Chandigarh Model, a template to build climate-responsive architecture

  • Natural green belts: The city was set up by the foothills of the Shivaliks, between two river beds, while natural green belts were incorporated within the city’s master plan.
  • For instance: A large green belt of mango trees was also planted around the city to help reduce urban sprawl and to serve as a buffer between the residential city and the industrial suburbs.
  • Climate responsive architecture: Local architecture such as mud houses within the region was considered as a template to build climate-responsive architecture.
  • City cooling plans: A small rivulet was dammed to create the Sukhna lake, to help cool the city, while small water bodies were developed near large buildings.
  • Increased tree cover: Parks were planned out in every sector, along with tree plantations alongside all the major roads. Large forest areas were also reserved.


  • With climate change exacerbating local weather patterns, we are likely to see April-May temperatures reaching record highs every three years. Moreover, an El Niño-influenced monsoon bodes ill for marginal farmers and urban migrants. Policymakers must take mitigatory action early, while instituting structural infrastructure measures to help Indians adapt to these conditions.

Mains Question

Q. What do you understand by mean urban heat island effect? What measures can be taken to mitigate the impact of rising heatwaves and how can these efforts be integrated with broader climate change adaptation strategies?

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