Tamil Nadu's Heat Crisis: Either Build Sustainably Or Burn

S Tamil Nadu continues its breakneck urbanisation, a new decadal study commissioned by the State Planning Commission (SPC) has sounded alarm bells over rising land surface temperatures (LST) and worsening heat stress across the state.

- SV KRISHNA CHAITANYA @ Chennai

Titled "Urban Growth and Thermal Stress: A Decadal Assessment of Built-Up Area and Climate Interactions in Tamil Nadu," the report reveals how unregulated urban expansion has created dangerous heat islands, strained infrastructure, and intensified ecological degradation in the last two decades.

The study, which integrates high-resolution spatial data from MODIS LST, ERA5 air temperature records, and building footprint changes from 1985 to 2015, maps heat exposure at the block-level for all 389 blocks across Tamil Nadu. The results show 94 blocks have witnessed a steep rise in heat over the past 40 years, while 64 blocks currently suffer from temperatures well above the state average. Particularly vulnerable are 25 blocks—including those in Chennai, Karur, and Ramanathapuram—which fall into both categories, making them high-risk zones for future climate and health.

The heat driver The report places rapid urbanisation at the heart of the problem. Between 1985 and 2015, Tamil Nadu witnessed unprecedented expansion in built-up areas, particularly in districts like Chennai, Coimbatore, Tiruppur, and Chengalpattu.