Chennai is heating up — and not just during the scorching afternoons. A new climate study reveals that the city’s built-up area has grown from 48% to 74% in just 30 years. But experts warn that concrete alone isn’t the villain. The real danger lies in a web of ecological imbalances: shrinking greenery, vanishing wetlands, obstructed wind corridors, and escalating land surface temperatures.
The State Planning Commission’s latest decadal report, ‘Urban Growth and Thermal Stress’, warns of intensifying heat stress across Tamil Nadu, with Chennai and its suburbs among the worst-hit. The study presents a granular, block-level view of land use changes and their growing impact on local climate.
“There’s no direct evidence that concrete alone causes this. It’s an interplay of ecosystem disruptions — forest loss, altered wind patterns, and warming land surfaces,” explained Sudha Ramen, who led the research.
Since 2000, Tamil Nadu has lost over 3,000 sqkm of forest. Coastal belts like Nagapattinam and Thoothukudi — once shielded by sea breeze — are seeing warmer nights due to urban sprawl and diminishing greenery. Even cool hill zones like Kodaikanal and the Nilgiris are no longer safe havens, thanks to unchecked development.
In Chennai, nighttime land surface temperatures have jumped by nearly 4°C over two decades. Alarmingly, 94 blocks across Tamil Nadu have shown long-term warming since 1985, with 64 now facing above-average heat levels.
The study calls for urgent climate-smart planning — integrating heat stress into urban policies, reviving wetlands, enforcing green building norms, and incentivising rooftop gardens and urban water bodies.