Kochi: Not including the impacts of heat waves as a climate risk factor while assessing climate vulnerability could threaten India’s progress on its Sustainable Development Goals, according to a new study.
The study, published on April 19 in the journal PLOS Climate, found that around 90% of the country is in the ‘Extreme Caution’ and ‘Danger’ categories – which signify high risk with regard to impacts caused by heat waves. Currently, India’s climate vulnerability assessments – used to quantify the progress on SDGs – do not incorporate impacts of heatwaves as a climate risk. The omission of heat wave impacts from the state action plan could be hampering urban sustainability in the national capital of New Delhi too, the study suggested.
With ongoing climate change increasing the occurrences of extreme weather events, current climate vulnerability assessments should be updated to include the impacts of all extreme weather events such as heat waves, floods and cyclones to be able to meaningfully assess risks and take necessary action, said climate scientists.
SDGs and heat
India has committed to achieving 17 Sustainable Development Goals (SDGs) put forward by the United Nations. These include good health and well being, gender equality, decent work and economic growth, life on land and so on.
The Indian government uses climate vulnerability assessments to quantify the progress made in these SDGs. Its Climate Vulnerability Index (CVI) – developed under the National Climate Vulnerability Assessment Framework by the Department of Science and Technology – takes into account state-level climate vulnerability indicators. These include water and vector-borne diseases, proportion of income from natural resources, women in the overall workforce, and more.
The CVI does not, however, does not take into account the impacts of extreme weather events such as heat waves. And with ongoing climate change, this could be a big gap.
Heat waves – unusually hot weather featuring above-normal temperatures that usually last for more than three days – are increasing in occurrence and intensity. As per one estimate, India recorded 280 days of heat waves across 16 states in 2022, the most ever in a decade. The year also witnessed India’s hottest April in 122 years. The impacts of heat waves are many: in addition to affecting human health and causing deaths, it also affects livelihoods and agriculture, among others.
Heat, a climate risk
To understand if incorporating the impacts of heat waves can change climate vulnerability, a team of researchers from institutes including the University of Cambridge in the UK used the 2022 heat wave conditions as a case study. They drew up a Heat Index (HI), which took into account the impact of temperature and relative humidity on the human body. Based on this, they categorised states into Low Risk, Caution, Extreme Caution, Danger and Extreme Danger. The team evaluated the HI with the climate vulnerability index, CVI.
Their results show that more than 90% of India is very vulnerable to heat wave impacts, falling under the Extreme Caution and Danger categories. This proportion is far higher than comparable CVI scores (around 45% of the country is at moderate CVI scores).
The study found that using CVI can underestimate the role of heatwaves in climate risk assessments, directly affecting India’s progress on its SDGs. For instance, Andhra Pradesh comes under the category of “Extreme Danger” when HI is considered, affecting SDG-3 and SDG-11 (Life on Land) but only in the moderate category under CVI. This can change the adaptive actions that are being proposed to address the issue (climate change adaptation measures such as providing not just cheap but also climate-friendly housing).
The team also evaluated India’s progress on its SDGs and the deaths due to extreme weather events between 2001 and 2021. They found that the effect of extreme weather events has intensified while SDG progress has slowed.
“As the heatwaves in India and the Indian subcontinent become recurrent and long-lasting, it is high time that climate experts and policymakers reevaluate the metrics for assessing the country’s climate vulnerability,” the study noted.
Delhi in ‘Danger’
Delhi was the first to develop a State Action Plan on Climate Change. Though authorities updated the Plan recently to include urban heat islands (pockets of higher temperatures within urban areas caused due to higher built up area) as a climate risk, it still does incorporate the impacts of heat waves.
When the research team evaluated Delhi’s heat index, they found that while south and northeast Delhi are most vulnerable to climate change impacts as per the Delhi government’s assessment, their assessment based on HI found that the entire city is in the ‘Danger’ category when it comes to being vulnerable to the impacts of heat waves.
“Delhi’s heat vulnerability will exaggerate indoor overheating especially for those people in affordable housing who have fewer resources to cool themselves,” said co-author of the study Ronita Bardhan, Associate Professor of Sustainable Built Environment at the University of Cambridge, in a press release. “Social cooling practices need to be understood to mitigate and adapt to heat-related health and energy burdens.”
The team found that Delhi’s current district-level climate change vulnerability assessments also do not take into account several factors that the national CVI considers. So apart from including heat risk in climate vulnerability assessments, the assessment method has to be standardised across federal, state and local levels, the paper also noted.
Both indices – the CVI and HI – are different, and the CVI includes many other parameters but excludes extreme cases such as the primary risks associated with heat waves or extreme weather events, said Jayanarayanan Kuttipurath, associate professor, Centre for Oceans, Rivers, Atmosphere and Land Sciences at IIT Kharagpur, who was not involved in the study.
Therefore, CVI may not show the high risk connected to heat waves that the HI does, he said. According to him, it is very important to incorporate the Heat Index in the CVI to evaluate SDG progress.
“In fact, in a climate change context, we expect more extreme weather events such as heat waves. Therefore, the indices like CVI should incorporate such events or related parameters to make a meaningful risk assessment,” said Jayanarayanan.
Moreover, the 90% risk shown here in the study is only for that pertaining to heat waves, said Jayanarayanan. “The CVI should be modified to include the primary risks with extreme cases such as heat waves, floods and cyclones,” he told The Wire.
“Indeed, we need a better vulnerability index and map for India, to prepare for imminent climate change and risks associated with it.”