What are Heatwaves?
When the period of high temperature, along with high humidity and low wind movement, occurs for a longer period, then it gives birth to heatwaves in that region. India’s parameters for declaring heatwaves are when temperatures go beyond.
(a) Forty degree Celsius in the plains.
(b) Thirty-seven degree Celsius in coastal areas.
(c) Thirty degree Celsius in hilly regions.
Causes
(a) Urban Heat Island Effect: Researchers noted that even in the 19th century, urban areas experienced higher temperatures than rural areas due to concrete structures, lack of vegetation, and human activities. This exacerbates heat stress in cities.
(b) Climate Change as a Driver: The rising temperatures and altered weather patterns are attributed to climate change, emphasizing its role in intensifying and prolonging heatwave events. Factors like El Niño can also contribute to higher temperatures.
The status of heat waves in India
India has been witnessing heat waves for many years. But, due to climate change effects, which have increased in the last few decades, the instances and intensity of heatwaves have also increased.
(A) States like Rajasthan, Gujarat, Uttar Pradesh, Delhi, Haryana, Punjab, and Madhya Pradesh are those states that experience the most heatwaves. (B) As per IMD, between 1981 and 1990, there were 413 heatwave days in India. However, the heatwave days have increased to 600 days between 2011 and 2020.
(C) People die from heat wave-related ailments increased from 5,457 between 1981 and 1990 to 11,555 between 2011 and 2020.
Factors behind the increase in Heatwaves in India
Natural causes
(i) High Atmospheric Pressure Systems- Heatwaves occur when high-pressure systems stall over a region. These systems trap hot air near the Earth’s surface and restrict the normal movement of air masses, resulting in prolonged periods of hot weather.
(ii) Climate Variability- Natural climate variations, such as El Nino and La Nina events, increase the likelihood of heatwaves. For ex- during El Nino events, warmer ocean waters in the tropical Pacific lead to changes in atmospheric circulation and weather patterns.
(iii) Drought and Dry Conditions- Prolonged periods of drought and lack of precipitation reduce the overall moisture of the soil, causing the land to heat up more quickly during heat waves.
(iv) Changes in Wind Patterns- Shifts in wind pattern transports hot air from one region to another. It intensifies heat waves in areas that are not typically prone to such extreme temperatures.
(v) Geography and Topography- Geographic features and topographical conditions also contribute to the development of heat waves. For ex-, Landlocked valleys and regions surrounded by mountains trap hot air and lead to temperature spikes.
Human-Induced Factors
(i) Global Warming- The long-term increase in Earth’s average temperature, primarily driven by human activities such as burning fossil fuels, deforestation, and industrial processes, contributes to the frequency and intensity of heat waves.
(ii) Urban Heat Island Effect- Urban areas with high population density, extensive concrete and asphalt surfaces, and limited vegetation tend to absorb and retain more heat, creating localized zones of higher temperatures. This phenomenon, known as the urban heat island effect, has intensified heat waves in cities.
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Impacts of Heatwaves
(i) Impact on Human Health- Rapid rises in heat compromise the body’s ability to regulate temperature, resulting in a cascade of illnesses, including heat cramps, heat exhaustion, heatstroke, and hyperthermia.
(ii) Impact on Energy- Increased demand for electricity for cooling purposes, leading to strain on power grids and potential blackouts.
(iii) Impact on the economy- Heatwaves disrupt economic activities, affecting the productivity of workers and labourers, who lack access to reliable electricity for cooling during heatwaves. According to an ILO study, at 34°C, workers can lose up to 50% of their work capacity.
(iv) Impact on Water Resources- Heatwaves exacerbate water scarcity issues in India due to drying up of water bodies and a decrease in the groundwater table. This exacerbates the interstate conflict over water. For the Cauvery water Dispute.
(v) Impact on food security- The rise in heat waves increases the probability of droughts. So, increasing the demand for irrigation water impacts agricultural production and increases food insecurity.
Way Forward
(i) Effective implementation of Heat Wave Action Plan- Effective implementation of the Heat Wave action plan with the State playing a leading role and sharing responsibility with other stakeholders is now the need of the hour.
(ii) Sustainable Cooling- Passive cooling technology, like the construction of ventilated buildings and the use of porotherm bricks, can be a vital alternative to address the urban heat island for residential and commercial buildings.
(iii) Heatwave Mitigation Plans- It includes access to drinking water, oral rehydration solutions (ORS), and shade at public places. Also, flexible working hours in workplaces must be effectively designed and implemented.
(iv) Creation of more Green Spaces- A US$ 100 million investment in street trees globally can bring 1°C temperature reduction (UN). India must scale up its reforestation and tree plantation efforts. For example, the Haritha Haram project of the Telangana Government aims to increase the green cover in Telangana.
(v) Adoption of energy-efficient solutions- Encouragement to the masses to adopt more energy-efficient solutions. For example, using desert coolers in place of air conditioners in dry areas.
Conclusion
In order to build resilience to extreme heat, strategies include identifying vulnerable populations and creating heat preparedness plans. It includes installing cool roofs and pavements, planting trees for shade, and promoting energy efficiency. Moreover, using climate mapping tools for planning and understanding climate risks.