Urban sprawl causing warmer temperature in peri-urban areas

Shrinking waterbodies, green cover in Chennai Metropolitan Area is causing higher land surface temperature

The Chennai Metropolitan Area, predominantly an agricultural area in 1988, has nearly 48.7% of built-up area. The decadal changes in land use and urban sprawl has led to warmer temperature and increasing urban heat island effect spreading to peri-urban landscape.

This was one of the key findings of a study titled “Monitoring spatio-temporal dynamics of urban and peri-urban land transitions - A case study of Chennai Metropolitan Area” by the Centre for Water Resources, Anna University.

According to the study that covered an area of 1,189 sq. km., including parts of Kancheepuram and Tiruvallur districts, the CMA had a vegetation cover of nearly 17,770 hectares, which was 14.9% of the area in 1988. It has drastically shrunk to 7,288 hectares, which was only 6.1% of the area in 2017.

Similarly, waterbodies that occupied nearly 8,023 hectares, which was 6.7% of the area in 1988, has decreased to an extent of 5,569 hectares, 4.6% of the CMA.

While the extent of agricultural lands had reduced from 42.2% in 1988 to 19.2% in 2017, it has been replaced by urban built-up area. The rapid urbanisation, particularly along East Coast Road and Rajiv Gandhi Salai and GST Road, led to increase in built-up area to 48.7% in 2017 from just 17.7% in 1988. The urban settlements has become denser from just 21,122 hectares in 1988 to 57,839 hectares now, according to the study.

As peri-urban areas are developed denser urban sprawl, particularly in the last three decades, they are experiencing a warmer temperature due to urban heat island effect, said M. Krishnaveni, Professor (Water Resources) and Director of Institute for Ocean Management, who co-authored the study.