Urbanisation alone accounts for overall 60% increase in temperature across India: Study

Bhubaneswar: Indian cities are at risk these days from compounded effects of ongoing urbanisation and climate change. Urbanisation largely causes local warming and Tier-II cities in eastern part of the country take the lead, revealed a recent study.

Urbanisation alone causes an overall 60 percent increase in local warming in Indian cities, claimed a panel of researchers in their article published in the journal ‘Nature Communications’.

Projections on a global scale suggest that by 2050, proportion of the population residing in urban areas will surge to nearly 68 percent.

The varying levels of urban-induced warming in cities across India necessitate a tailored approach to effectively address urban warming, the researchers opined.

Urbanisation represents a profound and unalterable human influence on land use and cover, catalysing significant socio-economic transformations. Despite encompassing just around 1 percent of the Earth’s landmass, cities serve as homes for over half of the world’s population.

Altered urban landscape no longer benefits from the cooling properties of evaporation. It absorbs heat instead due to factors such as surfaces with higher thermal mass (like concrete and asphalt), changes in airflow efficiency, variation in surface reflectivity, and increased human activity.

This phenomenon, known as the urban heat island (UHI) effect, impacts other climate parameters such as rainfall patterns and pollution levels. The process of urbanisation, coupled with growing energy needs, simultaneously generates greenhouse gases and their emissions, thereby worsening climate change.

According to the Global Climate Risk Index 2021, India ranks as the seventh most severely impacted nation by climate-related extreme weather phenomena.

Differentiating between the warming effects of urbanization and those of climate change is a complex task. Urbanisation was found to significantly impact local warming and, to a lesser extent, regional warming in highly urbanised areas.

However, its contribution to global warming was assessed to be quite minimal, accounting for less than 1 percent, the researchers expressed.

“We assume that the observed annual warming trend over the surrounding non-urban/rural region is primarily due to large-scale regional climate change, and the same for the urban region is due to the combined effect of warming driven by both regional climate change and local-scale changes due to urbanisation,” a member of the panel V. Vinoj stated.

Notably, a total of 141 major cities across the country were selected for this study.

[This story is a part of ‘Punascha Pruthibi – One Earth. Unite for It’, an awareness campaign by Sambad Digital.]