Published on: December 2, 2022

Heat wave

Heat wave

Why in news?

From 2030, 160 million to 200 million people can be exposed to lethal heatwaves in India every year, and nearly 34 million Indians will face job losses due to heat stress-related productivity decline, the World Bank has said in a report


  • According to the report, “Climate investment opportunities in India’s cooling sector” it is imperative for India to deploy alternative and innovative energy efficient technologies for keeping spaces cool.
  • Report also stated that this could open an investment opportunity of $1.6 trillion by 2040, besides reducing greenhouse gas emissions significantly and creating 3.7 million jobs.
  • The report proposes a road map to support New Delhi’s India Cooling Action Plan (ICAP), 2019, through new investments in three major sectors: building construction, cold chains and refrigerants.

the way ahead

  • Adopting climate-responsive cooling techniques as a norm in both private and government-funded constructions can ensure that those at the bottom of the economic ladder are not disproportionately affected by rising temperatures.
  • Ex: India’s affordable housing programme for the poor, the Pradhan Mantri Awas Yojana (PMAY), can adopt such changes on scale.
  • It proposed enacting a policy for “district cooling”, which could lead to the consumption of 20-30% less power than the most efficient conventional cooling solutions.
  • District cooling technologies generate chilled water in a central plant which is then distributed to buildings via underground insulated pipes. This brings down the cost for providing cooling to individual buildings.
  • Apart from this, guidelines for implementation of local and city-wide urban cooling measures such as cool-roofs should also be considered. India’s cooling strategy can help save lives and livelihoods and reduce carbon emissions.

About Heat waves

  • It is a period of excessively hot weather, which may be accompanied by high humidity,especially in oceanic climate countries.
  • Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, increased risk of wildfires in areas with drought, and widespread power outages due to increased use of air conditioning
  • The World Meteorological Organization, defines a heat wave as five or more consecutive days of prolonged heat in which the daily maximum temperature is higher than the average maximum temperature by 5 °C or more


  • When high pressure aloft (from 10,000–25,000 feet ) strengthens and remains over a region for several days up to several weeks.
  • This is common in summer (in both Northern and Southern Hemispheres) as the jet stream ‘follows the sun’. On the equator side of the jet stream, in the upper layers of the atmosphere, is the high pressure area.


  • Summertime weather patterns are generally slower to change than in winter as results in this upper level high pressure also moves slowly.
  • Under high pressure, the air subsides (sinks) toward the surface, warming and drying adiabatically, inhibiting convection and preventing the formation of clouds.
  • Reduction of clouds increases shortwave radiation reaching the surface.
  • A low pressure at the surface leads to surface wind from lower latitudes that brings warm air, enhancing the warming.
  • Alternatively, the surface winds could blow from the hot continental interior towards the coastal zone, leading to heat waves there, or from a high elevation towards low elevation, enhancing the subsidence and therefore the adiabatic warming.