A Heat Wave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer season in the North-Western parts of India. Heat Waves typically occur between March and June, and in some rare cases even extend till July. The extreme temperatures and resultant atmospheric conditions adversely affect people living in these regions as they cause physiological stress, sometimes resulting in death.

Criteria for Heat Wave

IMD has given the following criteria for Heat Waves:

• Heat Wave need not be considered till maximum temperature of a station reaches atleast 40oC for Plains and atleast 30oC for Hilly regions
• When normal maximum temperature of a station is less than or equal to 40oC Heat Wave Departure from normal is 5oC to 6oC Severe Heat Wave Departure from normal is 7*C or more
• When normal maximum temperature of a station is more than 40oC Heat Wave Departure from normal is 4oC to 5oC Severe Heat Wave Departure from normal is 6oC or more
• When actual maximum temperature remains 45oC or more irrespective of normal maximum temperature, heat waves should be declared. Higher daily peak temperatures and longer, more intense heat waves are becomingly increasingly frequent globally due to climate change. India too is feeling the impact of climate change in terms of increased instances of heat waves which are more intense in nature with each passing year, and have a devastating impact on human health thereby increasing the number of heat wave casualties.
• Higher daily peak temperatures and longer, more intense heat waves are becomingly increasingly frequent globally due to climate change. India too is feeling the impact of climate change in terms of increased instances of heat waves which are more intense in nature with each passing year, and have a devastating impact on human health thereby increasing the number of heat wave casualties.

Impact

• Heatwaves can burden health and emergency services and also increase strain on water, energy and transportation resulting in power shortages or even blackouts. Food and livelihood security may also be strained if people lose their crops or livestock due to extreme heat.
• Social impacts: Extreme heat can lead to heat-related illness and death, particularly in elderly populations, the poor, outdoor workers, and in urban areas
• Economic impacts: Multiple areas of the economic sector experience reduced worker productivity during heatwaves, especially agriculture and construction
• In parts of India, changes to weather patterns and the resulting impacts on agriculture and other sectors are expected to translate into a 9% decrease in standards of living by 2050 assuming no adaption
• Ecological impacts: Heatwaves, without concomitant increases in precipitation, can lead to water shortages and increased stress for plants, particularly in arid regions. This has the effect of reducing plant growth, the basis of energy production and the food chain, with an overall drying-out of the landscape.

The most effective way to avoid the negative impacts of heatwaves is to mitigate climate change by reducing greenhouse gas emissions (GHG) and minimize the rise in global mean temperatures. In particular, shifts towards cleaner energies will not only reduce GHG emissions, but will also reduce localized air pollution and heat island effects within cities. Secondly, new initiatives to create early warning and response systems and improved communication approaches  can help to save lives and build resilience to heatwaves. Thirdly during a heatwave, decision-makers can employ a range of strategies and policies to modify social behaviour and reduce exposure to heat by closing schools or offices which lack adequate air conditioning, ensuring availability of water, health care and first aid, and extending access to pools, parks and public cooling centers.  Finally, improved urban design and sustainable planning that increases the amount of and access to green space and other cool environments (pools, air-conditioned spaces) and encourages white roofs, will play an important role in avoiding heat-related illness, in reducing surface temperatures, and in providing a wealth of other nature-related benefits.

https://www.thehindu.com/sci-tech/energy-and-environment/explained-what-is-causing-the-intense-heat-in-north-west-central-and-east-india/article65369867.ece

How to structure:

1. Give an intro about heat waves
2. Discuss the reasons for its causes, and its increase
3. Explain the impacts of heat waves
4. Mention way forward
5. Conclude