Amid the relentless rise of urban temperatures, the battle against urban heat phenomenon has never been more critical. Cities across the globe, especially in developing nations like India, are grappling with the alarming consequences of climate change, where each heatwave brings forth escalating challenges that threaten livelihoods, ecosystems, and public health.

Recent Heat Incidents and Trends

Since 2023, combined with the impacts of El Niño, urban heat has become an alarming phenomenon in South Asia, especially in India. According to a study by the World Weather Attribution Initiative, extreme heat in pre-monsoon India has been exacerbated by climate change, with 2024's mean temperatures showing extreme heat to be 45 times more likely and 0.85°C hotter than before. Heat in India is not just rising but steadily escalating due to human actions (Mitali Mukherjee, 2024). In 2024, India experienced 24 days of heatwaves across various regions, marking the longest heatwave spell recorded, resulting in significant socio-economic consequences and health risks (Indian Meteorological Department). A study by Saudamini Das and E. Somanathan (2024), involving nearly 400 workers in Delhi's slums, shows a clear correlation between rising temperatures and reduced earnings, increased sickness, and a decrease in workers' attendance.

In May 2024, ten of India's 65 cities with over one million people experienced more than 100 hours of 'heat stress'—a dangerous combination of heat and humidity. Nearly 85 per cent of these cities experienced increased levels of heat stress as compared to the previous year (Mint, May 29, 2024). Heat stress is classified into two categories: humid heat stress (when relative humidity exceeds 50 per cent) and dry heat stress (when humidity is below 50 per cent). Humid heat stress was particularly high in coastal cities.

Urban Heat Island Effect and the Need for Urban Planning

The lack of effective urban planning and the reduction of green spaces in cities have led to a significant rise in temperatures as compared to surrounding non-urban areas. Rapid urbanization, changes in land use, and the depletion of vegetation contribute to the Urban Heat Island (UHI) effect. Heavily built-up areas, concrete structures, and increased air conditioning loads make cities warmer than non-urban surroundings (Prasad, 2017; Şekertekin et al., 2016; Burak et al., 2004). Urban growth and sprawl lead to thermal changes, further exacerbating the heat burden on cities. The intensity of UHI risk is higher in cities with a single, continuous urban structure, increasing greenhouse gas emissions.

Adaptation Effortsunder the Global Climate Regime

The UNFCCC has played a key role in creating frameworks to support countries in implementing effective climate adaptation strategies, including measures for heatwaves. Article 7 of the Paris Agreement focuses on global climate resilience, aiming to enhance adaptive capacity, strengthen resilience, and reduce vulnerability to climate change. This international commitment requires countries to present formal plans detailing their adaptation strategies, with National Adaptation Plans (NAPs) serving as a critical tool for achieving these objectives.

The urgency of adaptation planning has been highlighted in the Global Goal on Adaptation (GGA) under the Paris Agreement and the UAE Framework for Global Climate Resilience, adopted at COP28 in December 2023. This framework emphasizes science-based approaches to enhancing adaptive capacity and reducing vulnerabilities. Additionally, the outcome of the first global stock take at COP28 urged countries to implement NAPs by 2025 and progress in their execution by 2030. India is actively working on developing a comprehensive adaptation framework through its NAP.

Domestic Adaptation Efforts on Heatwaves

Even before the Paris Agreement in 2015, India had already taken steps to mainstream adaptation actions. The National Action Plan on Climate Change (NAPCC) was launched in 2008, followed by State Action Plans on Climate Change (SAPCC), that proactively pursued adaptation strategies. India's Nationally Determined Contributions (NDCs) in 2015 and its updated version in 2022 also emphasized the importance of adaptation measures.

In 2019, India introduced the India Cooling Action Plan (ICAP), which provided an integrated vision for cooling across sectors. The ICAP's recommendations focused on reducing cooling demand, transitioning refrigerants, enhancing energy efficiency, and improving technology options, aiming for a 20-year time period. It also provided an implementation framework, linking various government programmes aimed at ensuring sustainable cooling and thermal comfort.

Managing Urban Heat Stress

The extensive spatial diversity of urban areas calls for targeted actions to manage the heatwave phenomenon. Addressing heat stress requires focused planning that considers city-specific vulnerabilities, engages local stakeholders, and implements tailored adaptation measures.

Buildings contribute significantly to India's cooling demand, driven by rapid urban growth. However, with the low penetration of air conditioners, many households rely on fans, air coolers, or passive cooling techniques. A significant portion of the population may not be able to afford air conditioning in the near future. Therefore, designing thermally comfortable buildings is not only vital for reducing cooling demand but also crucial for building climate resilience.

Urban areas, due to their lack of passive cooling, thermally comfortable housing, and common cooling services, are especially vulnerable to heat impacts. In 2024, there were 32 fire incidents caused by air conditioner malfunctions during extreme heat events, underlining the need for climate-resilient urban infrastructure.

A Systematic Approach to Combat Urban Heat

To address urban heat challenges, some instrumental steps must be adopted. These include, but are not limited to, assessment of vulnerabilities, stakeholder engagement, mitigation and adaptation measures, community adaptation, etc.Heat mapping using satellite data, temperature sensors, and GIS to identify heat islands and hotspots. Engaging with communities and stakeholders through public consultations, multi-stakeholder committees, and awareness campaigns. Implementing resilient urban design through green infrastructure, urban forestry, radiant cooling technologies, and heat-resilient building codes. Drawing from experiences of the Covid-19 pandemic, effective dissemination of heat-related health warnings (e.g., through SMS/WhatsApp) should be implemented. Local municipal and district authorities must play a crucial role. Developing cross-sectoral and interdepartmental coordination to streamline health services and emergency responses. Enhancing community adaptability and optimizing social-institutional networks to support vulnerable groups, as highlighted by Tandra Mandal et al. (2024).

Need for Immediate Action

As urban heat intensifies, the urgency for innovative and resilient adaptation strategies cannot be overstated. Communities must come together to adopt sustainable urban planning and health measures to ensure cities can thrive in the face of rising temperatures. Prioritizing sustainable urban design and community-based initiatives will not only mitigate the effects of increasing heat but also lay the groundwork for resilience and liveability. The time to act is now—cities' sustainability depends on it. #