“Uncovering the Impact of Urbanization and Climate Change on India’s Cities: A Call to Action”
Delhi recently experienced record-breaking daytime temperatures above 50 degrees Celsius for two consecutive days, marking the highest ever recorded in the city. This extreme heatwave is not an isolated incident but rather a reflection of the ongoing climate change and rapid urbanization that is reshaping our cities and making urban populations more vulnerable to the compounding impacts of these phenomena.
The phenomenon of urban heat islands (UHIs) is well-known in the scientific community, where cities tend to trap more heat due to altered thermodynamic and aerodynamic properties compared to rural and suburban areas. Climate change is exacerbating this effect, leading to a significant increase in record-breaking temperatures and prolonged heatwaves. As a result, cities are experiencing complex warming patterns influenced by both urbanization and global warming, which in turn affect micro-climates, rainfall distribution, air pollution dispersion, and public health.
A recent study published sought to quantify the relative contributions of local-scale urbanization and regional-scale climate change to the warming trends observed in 141 major cities in India. Using high-resolution night-time land surface temperature data from NASA’s MODIS sensor, researchers were able to estimate the urbanization-driven warming in each city after removing regional climate change signals. The results showed that cities are warming at a rate nearly twice that of rural areas, with local-scale urbanization accounting for approximately 60% of the additional warming.
Interestingly, the study found that tier-II cities in the eastern part of the country exhibited stronger urbanization-driven warming compared to larger metros and mega cities. This highlights the importance of tailored city-specific action plans for sustainable urban growth, especially in rapidly urbanizing areas where proper urban planning can make a significant difference.
India has been proactive in addressing the challenges posed by urban heat islands and climate change, with initiatives such as state-level heat action plans, early warning systems for heatwaves, and a shift towards non-fossil fuel-based energy sources outlined in the updated nationally determined contribution (NDC). Mitigation efforts must take into account the dominant contributor to warming in each city, whether it be urbanization or climate change, to effectively allocate resources and implement targeted interventions such as cool roofs, green infrastructure, emission reduction strategies, and afforestation.
In conclusion, the study underscores the need for differential approaches to urban heat management based on the unique characteristics of each city. By understanding the underlying drivers of warming and implementing tailored mitigation strategies, cities can better adapt to the challenges of climate change and urbanization while promoting sustainable and resilient urban growth.