May 31, 2024
Urban Heat Island (UHI) effect
Urbanization has significantly impacted the climate in Indian cities, leading to nearly 60% more night-time warming compared to their surrounding non-urban areas. This was revealed in a study conducted by the Indian Institute of Technology Bhubaneswar, which analyzed over 140 prominent Indian cities. The research highlights that urban areas, with their concrete and asphalt surfaces, trap heat during the day and release it at night, causing higher night-time temperatures—a phenomenon known as the Urban Heat Island (UHI) effect.
Key Findings
1. Top Affected Cities: Ahmedabad, Jaipur, and Rajkot showed the highest urban effect, followed by Delhi-NCR and Pune.
2. Temperature Increase: The mean urban effect across all studied cities was found to be 0.2 degrees Celsius per decade, contributing to a 37.73% increase in urban warming due to urbanization. Overall, night-time surface temperatures in these cities increased by about 0.53 degrees Celsius every decade.
3. Regional Differences: Cities in northwestern, northeastern, and southern regions experienced a more pronounced increase in night-time temperatures. However, the contribution of urbanization to night-time warming was highest in eastern and central Indian cities, which are undergoing rapid development and expansion.
4. Comparative Warming Rates: Cities are warming at almost double the rate of the entire country. While most of India warmed by 0.26 degrees Celsius on average every decade, urban areas showed a more significant increase.
Implications
The study emphasizes the vulnerability of urban areas to the combined effects of urbanization and climate change. Residents and infrastructure in these regions are at the forefront of climate change consequences, such as heatwaves, extreme weather events, and flooding.
Recommendations
1. Mitigation Efforts: There is a pressing need for diverse mitigation strategies to reduce ongoing urban warming effectively. Increasing green cover can help moderate day-time heat but is less effective at reducing night-time temperatures.
2. Urban Planning: With India projected to become the fastest-growing economy and expected to witness substantial urban growth, these findings can assist urban planners and policymakers in allocating resources more effectively and building sustainable cities.
Future Projections
According to the World Resources Institute (WRI) India Ross Center, seven out of ten people globally will live in urban areas by 2050, with significant growth occurring in India. Currently, 36% of India’s population, approximately 40 crore people, is urban. This number is expected to double to 80 crore by 2050, highlighting the importance of sustainable urban development to manage the challenges of urbanization and climate change.
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