27 Feb 2023: UPSC Exam Comprehensive News Analysis

C. GS 3 Related

Category: DISASTER MANAGEMENT

1. The sophisticated anatomy of heat waves

Syllabus: Disaster and disaster management.

Prelims: About heat waves

Mains: Occurrence of heat waves in India – its causes, factors responsible, impact, and important recommendations

Context

• The India Meteorological Department (IMD) recently warned that maximum temperatures would be 3-5°C higher than the long-term average over the northwest, west, and central parts of the country.
• Against this backdrop, Delhi recorded its third hottest February day (33.6° C) in more than five decades on 21st of February 2023.

What are heat waves?

• A heatwave is qualitatively a condition of air temperature which becomes fatal to the human body under exposure. 
• According to the World Meteorological Organization (WMO) a heatwave refers to five or more consecutive days during which the daily maximum temperature exceeds the average maximum temperature by five degrees Celsius.
• As per the IMD, a region is considered to be experiencing a heat wave if its ambient temperature deviates by at least 4.5-6.4°C from the long-term average. 
  • Further, the prevalence of a heat wave can also be confirmed if the maximum temperature crosses 45°C or 37°C at a hill-station).

Occurrence of heat waves

Image Source: BBC

• Heat waves are formed mainly on account of the warmer air flowing in from other locations or being produced locally. 
• Heat wave is basically a phenomenon wherein the air in the local areas is warmed by higher land surface temperature or due to the air sinking down from above is compressed along the way which produces hot air.
• According to a study published in Nature Geoscience in 2023:
  • During the spring season in India, the air usually flows in from the west-northwest and since West Asia is warming at a rate faster than other regions in latitudes close to the equator, it acts as a source of the warm air that blows into India. 
  • Additionally, the air incoming from the northwestern areas flows through the mountains of Afghanistan and Pakistan, and due to the compression that takes place on the leeward side of these mountains, thereby heating up the air entering India.
  • Further, the air flowing over the oceans is usually expected to bring in cooler air. However, the Arabian Sea is warming up faster than most other ocean regions which negate the cooling effect.
  • Finally, the lapse rate. which is the rate at which temperatures cool from the surface to the upper atmosphere, is declining significantly due to global warming thus producing heat waves.

Other factors that influence heat waves

• The other key factors that influence the formation of heat waves are the age of the air mass and the total distance covered by such air masses.
• The north-northwestern regions in India usually experience heat waves that are formed due to air masses that come from 800-1,600 km away and are around two days old. 
  • Heat waves witnessed over peninsular India however arrive from the oceans (around 200-400 km) and are barely a day old. Therefore, the heat waves over southern parts of India are relatively less intense.

Concerns associated with heat waves

• Heat waves are expected to become longer, more intense and frequent over the Indian subcontinent in the coming years and also extend further towards the southern parts of India on account of three consecutive years of La Niña. 
• Furthermore, the equatorial Pacific Ocean which experienced an extended phase of La Niña (triple dip La Niña) is gearing up for an El Niño year, in which warmer water spreads west-east across the equatorial Pacific Ocean.
  • Heat waves are expected to be more intense and be confined to the northern and northwestern parts of the country during El Niño years.
• Health issues: India faces the largest heat exposure impacts in South Asia. 
  • As per available reports, close to 1,40,000 lives have been lost due to extreme weather conditions in India between 1971 and 2019, out of which the loss of 17,362 lives was linked to extreme heat.
• Impact on livelihood: India’s labour-intensive agriculture and construction work would be significantly impacted due to the heatwaves.
  • As about 33% of South Asia’s population depends on outdoor work, heatwaves severely affect the livelihood of the people.
• Economic consequences: Worldwide economic losses are expected to reach ₹1.6 lakh crores annually if global warming exceeds 2°C.  

Key recommendations:

• The consequences associated and the impact of heat waves depend upon how well we can predict them. 
  • Early-warning systems must be equipped to take advantage of the information that we have on the modes of formation, processes involved, location, and age of the air mass which can better the quality of warnings.
• Investments must be made in improving the forecasting skills of human and computational resources in India.
• Along with improving the warning and forecast mechanisms, policymakers must focus on formulating city-wide graded heat action plans in order to safeguard those individuals who are vulnerable to instances of heat waves.
• Furthermore, insurance schemes can help transfer the risks of heatwaves by the industrial, construction and agricultural workers to insurers.
• Water-intensive agriculture in heat wave-prone areas is also not feasible and hence there is a need to promote better agricultural practices.
• The intervening measures of the government to promote climate-resilient policies such as reducing the carbon footprint by adopting renewable sources of energy must speed up its process of implementation to mitigate the harmful consequences of climate change. 

To know more about – Heatwaves and its mitigation

Nut graf: In the coming years, the heat waves are expected to become longer and more intense and more frequent over the Indian subcontinent which poses a threat of increased instances of wildfires, drought, and various heat-related illnesses. This looming climate emergency calls for collective actions from the government, academia, earth Sciences and climate change experts.