Heat wave In current scenario

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A heat wave is a spell of unusually high temperatures.

The following standards have been established by IMD for heatwaves:

A station's maximum temperature in the plains is 40 °C, in coastal locations it is 37 °C, and in mountainous terrain it is 30 °C.

When a station's maximum temperature is normally 40 °C or less, a heat wave deviates from the norm by 5 to 6 °C, and a severe heat wave deviates from the usual by 7 °C or more.

If the station's highest temperature is normally higher than 40 °C, then a heat wave deviates from the norm by 4 to 5 °C, and a severe heat wave deviates from the usual by 6 °C or more.

Heat waves should be declared when the actual highest temperature stays 45 °C or higher regardless of the typical maximum temperature.

While cities do not entirely prevent the effects of heatwaves, they do exacerbate the phenomena (Urban Heat Island).

Context:

Over the past three decades, India has experienced a dramatic increase in both the frequency and severity of heatwaves, according to data from the Indian Meteorological Department and the Indian Institute of Tropical Meteorology (Pune).

India will be more severely affected by global warming than the rest of the world if emissions keep rising.

India's average temperature increase over the same period has already surpassed 2 °C, although the global average temperature increase since 1900 is only about 1.3 °C.

Consequences of a heatwave

• Sunstroke, which causes a body temperature to rise above 40 °C, and failure of key organs: There were reportedly around 2,300 deaths in 2015 due to heatwaves.
• decreased productivity because of negative impacts on mental health (the body functions best within a specific temperature range, 36-37.5).

Economic cost:

• Higher costs for air conditioning equipment.
• Decreased carbon sequestration and biological activity are examples of ecological harm.
• flames in the forest.

Reasons for a Heat Wave

• Global warming and urban heat islands are examples of anthropogenic causes.
• Changing jet streams as a natural climatic phenomenon
• 2010 had an extremely severe heat wave that destroyed the South-Western strip of Russia.
• The subtropical Jet Stream, which is meandering, was redirected farther north than usual by a strong upper-atmospheric high over European Russia.
• Heat from the desert started to move into Russia from central Asia, the Arabian Peninsula, and North Africa.

La Nina, El Nino

• They change the jet stream's location, wind patterns, cloud cover, rainfall, and so on.

Warm local breezes, such as Loo

• In the afternoons of May and June, a scorching wind known as the "loo" blows eastward onto the Indian plain from its origins in the desert regions of Pakistan, Iran, and the Thar Desert.
• Its constant temperature fluctuates between 45°C and 50°C, resulting in extreme heat waves in the plain area.

Actions needed

• Boost the cities' general ventilation system. For instance, Stuttgart, which is situated in an area with poor wind flow, has been gradually enacting measures to enhance ventilation since the 1980s.
• Create a plan for integrating the green belt idea into urban planning and put in place building rules that require passive cooling techniques (dissipating heat using energy from the surroundings).
• expanding the amount of greenery and trees in cities
• Think of a heat wave as an act of nature.