Heat-baked Chennai can set an example for India

The year 2023 was the hottest ever, with global average temperatures reaching 1.45° C higher than pre-industrial levels. This has led to worsening climate impacts, including heatwaves sweeping through the Indian sub-continent. Cities like Chennai are particularly affected due to the Urban Heat Island (UHI) effect.

The Urban Heat Island Effect in Chennai

• Understanding the UHI Effect: The UHI effect refers to the phenomenon where temperatures in large, crowded urban settings are several degrees higher than in surrounding rural areas. Factors contributing to the UHI effect include concrete structures, tarmac roads, lack of green spaces, and waste heat from air conditioners and other machinery.
• Implications of the UHI Effect: In Chennai, the UHI effect adds between 2° to 4° C to temperatures in nearby rural areas. Under high humidity conditions, this can lead to debilitating heat stress, exhaustion, and even potentially fatal heat stroke.
• Heat Action Plans (HAP): India has national, state, and district-level HAPs to reduce morbidity and mortality from heatwaves. However, longer-term measures are needed to deal with UHI and reduce urban heat.

Proposed Measures to Combat the UHI Effect

• Increasing Green Cover: Green areas such as urban forests, parks, and trees release moisture which evaporates and cools the environment. Increasing green cover in the Chennai Metropolitan Area (CMA) to a well-distributed 25% could significantly reduce UHI by about 1.5° C or more.
• Energy-Efficient Air Conditioning: Moving towards more energy-efficient air conditioning could reduce UHI by as much as 1.5° C. Energy savings can also accrue from switching off air conditioners from the mains rather than by remote control.
• Green Building Codes and Public Transport: If buildings are better insulated and ventilated, and constructed using appropriate designs and materials according to “green” building codes, they would require less air-conditioning and generate less waste heat. A sharp reduction in personal vehicles through a rapid scaling-up of effective public transport with electric buses would be another major contribution.

Policy Recommendations and Future Prospects:

• Detailed Heat Maps and Localized Planning: The Chennai Metropolitan Development Authority (CMDA) is preparing detailed heat maps to aid in more localized planning and actions.
• Comprehensive Climate Action Plans: Chennai’s Climate Action Plan includes various measures to combat UHI and improve urban liveability. Increasing green cover to 25% and adopting energy-saving measures in air conditioning can significantly reduce UHI.
• Setting an Example for India: By implementing long-term policies and measures, Chennai can improve its liveability and set a model for other Indian cities in addressing climate change and urban heat challenges.

UPSC Mains Questions

Q. Discuss the impact of the Urban Heat Island (UHI) effect on health and urban liveability in Indian cities. What measures can be taken to mitigate this effect? Illustrate your answer with examples.