Heatwaves, as termed by the Indian Meteorological Department (IMD), are prolonged periods of excessively hot weather that can have detrimental impacts on human health, environment, and the economy. These heat waves have been observed to increase in frequency and intensity over the past few years, a trend that is particularly concerning for tropical countries like India.
This concern was recently brought to light when casualties were reported from an apparent heat stroke during a government award function in Navi Mumbai. It was noted that factors such as long-distance travel, underlying health conditions, and lack of access to drinking water and medical attention in large gatherings can increase vulnerability to heat strokes.
Criterion for Declaring Heat Wave in India
According to IMD, a heat wave in the plains is declared when the maximum temperature at a station reaches at least 40°C or more, and 30°C or more for hilly regions. A heat wave turns severe when the departure from normal temperature is >6.40°C. If these criteria are met in at least 2 stations in a meteorological subdivision for at least two consecutive days, it is declared on the second day.
In coastal areas, a heat wave may be described when the actual maximum temperature is 37°C or more with a departure of 4.50°C or more from normal temperature. However, high temperature, combined with high humidity known as the wet bulb temperature, can make heatwaves deadly due to increased internal body temperature.
Causes of Heat Waves
Global Warming: One of the primary causes of heatwaves in India is global warming brought on by human activities like burning fossil fuels, deforestation, and industrial activities. This results in higher temperatures and changes in weather patterns, leading to heatwaves.
Urbanisation: The rapid growth of concrete jungles in cities leads to the “urban heat island effect.” Urban areas with high population density, buildings, and concrete surfaces absorb more heat, leading to higher temperatures.
El Nino Effect: The warming of the Pacific Ocean during an El Nino event can affect global weather patterns, causing temperature and wind changes. Predictions for the summer of 2023 suggest it could be excessively hot due to the end of the strong La Nina phase and an earlier-than-expected occurrence of El Nino.
Impacts of Heat Waves
Health Impact: Heatwaves can compromise the body’s ability to regulate temperature, resulting in illnesses like heat cramps, heat exhaustion, heatstroke, and hyperthermia. Deaths from heat can be rapid and hospitalizations often follow.
Water Resource Impact: Heatwaves can also exacerbate water scarcity issues in India; drying up water bodies and reducing water availability for agriculture and domestic use.
Energy Impact: Heatwaves can increase electricity demand for cooling purposes, leading to strain on power grids and potential blackouts, disrupting economic activities and affecting productivity.
Mitigating the Risks of Heatwaves
Implementing a long-term Heat Waves Action Plan is crucial to safeguard human lives, livestock, and wildlife from the adverse impacts of heatwaves. Disaster adaptation strategies and more robust disaster management policies are required in heatwave zones. Effective implementation of the Sendai Framework for Disaster Risk Reduction 2015-30 is now the need of the hour.
Implementing National Action Plan for Climate Change (NAPCC) is another step towards mitigating the risks. It promotes nature-based solutions for tackling climate change induced heat waves.
Passive cooling technology can be used to address the urban heat island effect for residential and commercial buildings. This technology, mentioned by the Intergovernmental Panel on Climate Change (IPCC), creates naturally ventilated buildings and can be an alternative strategy.
Effective measures such as access to water, oral rehydration solutions (ORS), and shade along with flexible working hours in workplaces, and special arrangements for outdoor workers can prevent heat-related fatalities. Proactive implementation by vigilant local administration monitored by higher authorities is also crucial.
Last Modified: February 20, 2024