Heat wave in India are becoming more frequent and severe due to climate change, with more than 90 percent of the country in the “extremely cautious” or “danger zone” of their effects, according to a new study.
The study, by Ramit Debnath and colleagues at the University of Cambridge, also revealed that Delhi is particularly vulnerable to the severe impacts of the heat, despite its recent state climate change action plan not reflecting this fact.
It suggests that heat waves are hindering India’s progress towards achieving the United Nations’ Sustainable Development Goals (SDGs) more significantly than previously thought, and that current assessment metrics may not fully capture the impacts of climate change-related heat waves on the country.
To assess India’s climate vulnerability and the potential impact of climate change on SDG progress, the researchers conducted an analytical assessment of the country’s heat index with the Climate Vulnerability Index.
The heat index (HI) is a measure of how hot the human body feels, taking into account both temperature and humidity. The Climate Vulnerability Index (CVI) is a composite index that uses different indicators to account for socio-economic, livelihood and biophysical factors.
The researchers accessed a publicly available dataset of state-level climate vulnerability indicators from the government’s National Data & Analytics Platform to classify severity categories. They then compared India’s progress on the SDGs over 20 years (2001-2021) with extreme weather-related mortality in 2001-2021.
90 percent of India in danger zone , heat wave
The study showed that more than 90 percent of India is in the “extremely cautious” or “dangerous” range of heat wave impacts through HI, otherwise considered “low” or “moderate” vulnerability through CVI.
States categorized as “low” in the CVI ranking were found in the HI “danger” categories, suggesting that heat waves are putting more people at extreme climate risk across India than the CVI estimates.
The authors concluded that the use of CVI may underestimate the true heat burden of climate change and suggested that India consider reassessing its climate vulnerability to meet the SDGs. They warned that if India fails to immediately address the impact of the heatwaves, it could slow progress towards achieving the Sustainable Development Goals.
The study also highlighted that the current heat action plans designed and implemented according to the Delhi government’s vulnerability assessment do not include HI estimates, which is a concern as even “low-lying” areas in Delhi are at high risk of heat waves.
The high intensity of development in central, eastern, western and northeastern districts may further increase HI risks through the formation of heat islands, he said.
Heat wave with high intensity causes high risk
The authors stated that some of the critical variables in Delhi that will exacerbate heat-related vulnerability include the concentration of slum dwellers and overcrowding in high HI areas, lack of access to basic amenities such as electricity, water and sanitation, inaccessibility of immediate health care and health .
The heat wave threshold is met when the station’s maximum temperature reaches at least 40 degrees Celsius in plains, at least 37 degrees Celsius in coastal areas and at least 30 degrees Celsius in hilly areas, and the deviation from normal is at least 4.5 degrees Celsius.
Earlier this month, the India Meteorological Department predicted above-normal maximum temperatures for most parts of the country from April to June, except parts of the northwest and peninsular regions. During this period, most parts of central, eastern and northwestern India are expected to experience above-normal heat days. In 2023, India experienced its warmest February since records began in 1901. However, above-normal rainfall in March kept temperatures under control.
March 2022 was the warmest ever and the third driest in the last 121 years. That year was also the country’s third warmest April since 1901. In India, about 75 percent of workers (about 380 million people) experience heat-related stress. A McKinsey Global Institute report warns that if this continues, the country could lose 2.5 to 4.5 percent of its gross domestic product (GDP) annually by 2030.
Written by: Vaishali verma