Heatwaves constitute a critical public health problem. Representative image showing a girl outlined against the sky drinking water out of a bottle.
Credit: iStock Photo
The World Meteorological Organization (WMO) in its recently released State of the Global Climate report sounded a ‘Red Alert’ and confirmed that not only was 2023 the hottest year recorded so far, but also that there was a high probability of 2024 witnessing new highs in heat records. The India Meteorological Department (IMD) in its seasonal outlook for the hot weather season (April to June) forecasted above-normal maximum temperatures over most parts of India, especially with a high probability over central India and western peninsular India.
Heatwaves constitute a critical public health problem. While on the one hand individuals and communities are adapted to their local climates, climate change leads to increase in the severity and frequency of extreme temperature conditions, and these in turn result in increases in temperature-related illness and death.
The body’s ability to regulate its internal temperature is affected by extreme heat events, and it could lead to heat cramps, heat exhaustion, heatstroke, and hyperthermia, among others. Heatwaves can acutely impact large populations for short periods leading to a public health emergency that is marked by excess mortality and cascading socio-economic impacts. The initial days of heatwaves can witness rapid (on the same day) deaths and hospitalisation or with a lagged effect (over several days). This phenomenon has led to an acute disaster framing of heat health.
Equally importantly, small differences from seasonal average temperatures can also be associated with increased illness and worsening of cardiovascular, respiratory, cerebrovascular disease, and diabetes-related conditions. Those at risk of exacerbated illness include the elderly, infants and children, pregnant women, outdoor and manual workers, athletes, and economically impoverished sections.
The understanding on gender differences on heat intolerance and heat illness is evolving; there is some evidence that a higher proportion of women were heat intolerant and being a female was associated with a greater risk of exertional heat illnesses. Governed by local cultural norms women may be expected to stay indoors with greater frequency, engage in heat-exposed outdoor or indoor labour (e.g., cooking near a hot stove) or wear heavy clothing.
Indian states that were not known to experience heat waves, such as Himachal Pradesh or Kerala, have increasingly come to experience such conditions. The number of states experiencing heat waves went up from 19 in 2018 to 23 in 2019. These states have formulated Heat Action Plans (HAPs) and around 100 districts currently have already kicked off campaigns on heatwave awareness generation.
The World Health Organization (WHO) reiterates that the adverse health effects of hot weather and heatwaves are largely preventable. A well-formulated heat-health action plan consists of a portfolio of co-ordinated and integrated actions at different levels. These include early warning systems for meteorological changes, timely public and medical advice, improvements to housing and urban planning and keeping healthcare and social systems in a state of preparedness.
Extreme heat, particularly in urban contexts, constitutes a resilience challenge. Urban settlements are marked by uneven development and hence disparity in terms of access to cooling benefits in the urban landscape. City HAPs, therefore, need to incorporate emergency response activities and long-term heat preparedness and cooling interventions across sectors. Importantly, the planning process should be co-led with community partners and be able to bring to the table actors across diverse sectors to increase co-ordination in preparation, response, and recovery stages of heat management.
The HAPs are tasked with identifying vulnerable populations and at the same time focus on urban planning to be able to reduce heat exposure, and real-time surveillance and evaluation. India’s National Programme on Climate Change and Human Health (NPCCHH) has initiated a process for reporting and collating data on heat-related illnesses. Some of India’s more sensitive city HAPs address community perspectives to include activities such as community-based surveillance for heat illness (there may not be appropriate local terms for standard clinical conditions in medical literature), incorporation and documentation of indigenous knowledge to develop protective measures, capacity building at community levels, and annual evaluation with community partners.
Local self governments are best suited to draw up action plans with an emphasis on identifying and addressing the needs of vulnerable communities and groups. The HAPs need to be integrated both with urban planning and health sector planning. Local initiatives, developed by grassroots groups, are key to managing resilience transitions.
(Rajib Dasgupta is Professor, Centre of Social Medicine & Community Health, Jawaharlal Nehru University, New Delhi, and is associated with a Wellcome Trust project on economic and health impact assessment of heat adaptation.)
Disclaimer: The views expressed above are the author's own. They do not necessarily reflect the views of DH.