package story | Chennai News – Times of India

Chennai is burning — and it’s not just the afternoon sun. While a climate assessment reveals the city’s built-up area surged from 48% to 74% over the past 30 years, researchers caution that concrete alone isn’t to blame. The study states that rising nighttime temperatures and growing heat stress are the result of a complex mix of factors –– shrinking green cover, depleted wetlands, disrupted wind flow, and changing land surface temperatures –– pointing to a deeper urban ecological crisis beyond just real estate growth.The decadal assessment by the State Planning Commission has raised red flags on the intensifying heat stress across Tamil Nadu, with the capital city and its sprawling suburbs identified among the most vulnerable zones. The study, titled ‘Urban Growth and Thermal Stress’, provides a block-level analysis of land use changes and their impact on local climate patterns, underscoring the growing influence of urban expansion on temperature spikes.“There is no scientific evidence to prove that built-up area alone is a direct cause. It is a complex system that has multiple parameters –– local ecosystem, overall land surface heat, green cover, wind flow, depleting water bodies –– are also contributors,” said Sudha Ramen, who led the study.As per the study, Chennai not only experienced a steep rise in surface and air temperatures over the past two decades but is also among the 25 blocks across the state facing both long-term and immediate heat stress. What makes the findings more concerning is the state-wide pattern: 94 blocks have undergone significant warming since 1985, while 64 blocks are currently experiencing above-average heat intensity, even if they didn’t show long-term trends. Eleven districts, including Karur, Ramanathapuram, Tiruppur, and Coimbatore, are now classified as highly heat-vulnerable.Interestingly, the report points out that coastal districts like Nagapattinam and Thoothukudi, traditionally buffered by sea breeze, are witnessing a rise in nighttime land surface temperatures (LST), possibly due to shrinking green cover and urban sprawl. “Increasing oceanic temperature is also contributing to the heat stress along coastal areas, added Sudha.Meanwhile, hill regions such as Kodaikanal and the Nilgiris, once considered climate refuges, are warming due to unregulated construction and loss of forest cover. Between 2000 and 2023, over 3,000 sqkm of forest area was lost in TN, the study noted. Blocks that saw more than 20% increase in construction footprint over three decades — including parts of Coimbatore, Salem, Madurai, and Trichy — witnessed some of the steepest spikes in surface heat. In Chennai’s case, LST rose by nearly 4°C during night hours compared to the early 2000s.Calling for urgent climate-sensitive urban planning, the report urges the state to integrate heat stress indicators into smart city missions, urban zoning laws, and infrastructure development. It recommends enforcing green building codes, restoring wetlands, and incentivising blue-green infrastructure such as rooftop gardens and urban ponds. “The report should serve as a climate alarm bell,” says an official with the environment department.