Heatwave increasing in India

India is now entering a new phase, where climate change induced heatwaves are getting more frequent.

 Heatwave increasing in India

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• The story: New research has found a spatial shift of heatwaves in India, with this weather event now occurring in new regions in the country. It was done by the Mahamana Centre of Excellence in Climate Change Research (MCECCR) at Banaras Hindu University (BHU), in collaboration with the Department of Science and Technology and the Ministry of Earth Sciences.
• What are heatwaves: Heatwaves are defined as prolonged episodes of extreme temperature over any region. Apart from temperature, humidity is an important parameter considered for declaring heat-related stress.

1. The study looked at temperature data of pre-monsoon (March-May) and early summer monsoon (June-July) seasons from the India Meteorological Department, spanning 65 years from 1951-2016, to assess the monthly, seasonal, decadal and long-term trends in heatwaves in the country.
2. It found a warming pattern over northwestern and southern India, while a progressive cooling phase over northeastern and southwest regions of the country.
3. The study revealed a “spatio-temporal shift” in the occurrence of heatwave events, with a significantly increasing trend in three prominent heat wave prone regions — northwestern, central, and south-central India, with the highest being in west Madhya Pradesh (0.80 events/year).

• What changed: Heatwaves have been generally associated with UP, Bihar, Delhi and northern parts of Madhya Pradesh. For the study, analysis was done of the daily temperature on a 0.25 square kilometre grid over the past seven decades.

1. Both heatwaves and severe heatwaves are increasing — and new locations are seen where these events are taking place, especially in the last two decades.
2. Heatwaves were seen in southern Madhya Pradesh, Andhra Pradesh, Karnataka and Tamil Nadu, where they would traditionally not take place.
3. An increase in heatwaves in Karnataka and Tamil Nadu are particularly significant, and point to increased events in the future. The study found a significant decrease in heatwaves over the eastern region, that is Gangetic West Bengal (−0.13events/year).

• Moving south: Especially severe heatwave events have shown a “southward expansion and a spatial surge during the decades of 2001–2010 and 2010–2016”.
• More details: During the period 1961–2010, from March-July, the highest number of heatwave days were experienced over the northwestern, northern, central, and eastern coastal regions, with an average of eight heatwave days and 1-3 severe heatwave days during the season.

1. Two elements that have worsened the heatwave conditions in India are the increase in night time temperatures, which disallows heat discharge at night, and increasing humidity levels.
2. An increasing trend of heatwave days and severe heatwave days was observed in the decade of 2001–2010 as compared to previous decades.
3. The eastern and western coasts, which are currently unaffected by heatwaves, will be severely impacted in the future.
4. There also was jump in heat-related deaths, from 5,330 deaths reported during 1978–1999 to extreme cases of 3,054 and 2,248 deaths in 2003 and 2015, respectively.

• EXAM QUESTIONS: (1) Explain the nature and problems arising out of heatwaves in India. (2) Climate change is here, and climate change is now. Explain the governance challenges that will arrive due to this.

Read more on - Polity | Economy | Schemes | S&T | Environment

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