Temperature projections and heatwave attribution scenarios over India: A systematic review

FOCUS

This paper was published in the open-access scientific journal Heliyon, on February 18, 2024. It was written by Khaiwal Ravindra from Post Graduate Institute of Medical Education and Research, Chandigarh; Sanjeev Bhardwaj, Chhotu Ram, Akshi Goyal and Suman Gor from Panjab University, Chandigarh; Vikas Singh from National Atmospheric Research Laboratory, Gadanki; Chandra Venkataraman from IIT Bombay; Subhash C. Bhan from Ministry of Earth Sciences, New Delhi; and Ranjeet S. Sokhi from University of Hertfordshire, United Kingdom.

Examining the projected impacts of increasing global temperature, the paper examines their connection to heatwaves in India and comments on the various mitigation and adaptation measures available and possible in the country.

Heat stress caused by global temperature increase has already affected around 68 million people across the world and if temperatures rise 2°C over pre-industrial levels, a billion people will face effects of heat stress. In India, the years 2016 and 2020 were recorded to be the hottest years in the previous century. The paper adds that between 1901 and 2018, India witnessed its average annual temperature increase by around 0.7°C and if the present rate of emissions continue, the country could face an almost 5°C increase by 2100.

The paper examines existing scientific research and climate data to evaluate various projected scenarios relating to temperature rise and heatwave days in the country. It takes a brief look at initiatives undertaken by the Indian government to address climate change and also recommends some adaptive strategies imperative to achieving mitigation goals.

    FACTOIDS

  1. With every 1°C rise in average temperature, mortality risks rise by 0.2 to 5.5 per cent, the paper notes. Estimates say, between 2000 and 2016, 125 million people were exposed to heatwaves worldwide.

  2. Heatwaves across India have seen a considerable increase since the year 2000. States like Himachal Pradesh and Kerala, which had not experienced heatwaves in the past are also experiencing extreme temperatures more frequently.

  3. The National Disaster Management Authority attributed 24,223 deaths occurring between 1992 and 2015, as heatwave-related deaths. The risks only increase as seen in 2022 when several Indian cities recorded temperatures above 40°C.

  4. Heatwaves in India are also affected by the warm sea surface temperatures in the Bay of Bengal and the Arabian Sea. This can worsen the effects of heatwaves by adding high humidity to the mix leading to an increase in the overall heat index.

  5. Rainfall across several regions in the country was also noted to have been affected by extreme temperatures. The paper notes that 11 meteorological divisions in the country recorded a considerable decline in monsoon rainfall.

  6. The paper also considers the Urban Heat Island Effect (UHI) which causes urban areas to experience higher temperatures due to several reasons including anthropogenic heat, less presence of greenery, land use dynamics as well as higher population density. It recommends better urban planning, implementation of energy consumption policies, green building codes and air pollution mitigation measures to address UHI effects.

  7. For rural areas, it suggests adoption of ‘high heat capacity construction’ like thatched roofs and shaded exterior living spaces. It also calls for the restoration of village water bodies and irrigation facilities to relieve heat strain on agrarian activities. The paper also recommends expanding tree cover and green spaces to aid in evaporative cooling and providing shade from radiation.


    Focus and Factoids by Anusha Madhumitha Sendil Velavan.

AUTHOR

Khaiwal Ravindra, Sanjeev Bhardwaj, Chhotu Ram, Akshi Goyal, Vikas Singh, Chandra Venkataraman, Subhash C. Bhan, Ranjeet S. Sokhi and Suman Mor

COPYRIGHT

Heliyon

PUBLICATION DATE

18 Feb, 2024

TAGS

#environment #heatwaves #climate-change

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