What is Urban Heat-Island Effect, Leading to Scorching Heat in Metro Cities?

New Delhi: The higher temperature conditions are becoming more common in metro cities with Kolkata, Mumbai, Chennai and Bengaluru sizzling with heat. Such conditions are because of urban heat-island effect, in which metro areas are comparitively warmer than their surroundings.

The Bengaluru city on Sunday recorded a maximum temperature of 38.5 degrees Celsius, while the Indian Meteorological said that the heatwave will continue as the mercury is likely to be around 38 and 39 degrees celsius in Mumbai till Tuesday.

The urban heat islands occur when metro cities replace natural land cover with dense concentrations of buildings, pavement and other structures that absorv heat. The concerned effect also increases energy cost, heat-related illness and air pollution levels. 

Uraban areas mostly experience the urban heat island effect, leading to higher temperatur at night than during the day. The temperature difference becomes more evident in situation of weak wind, mostly in summer. 

The modification of natural land surfaces remain the main cause of urban heat island, with waste heat generated from energy usage being the secondary reason. 

Another major contributor to urban heat islands is the lack of evapotranspiration, like lack of vegetation in urban areas. Cities are increasingly losing trees in exchange of modern facilities. With decreased space of vegetation, cities also lose the evaporating cooling effect of trees, which can tackle urban heat islands. 

How to Reduce Urban Heat Islands Effect? 

Many governments, including that of the United States, have suggested building more green infrastructure and investment into capital improvement projects to continue heat-reducing practice. 

The space for planting trees and other vegetation in urban areas are usually less due to pre-occupied facilities like road infrastructure, housing societies and parking lots. However, small green practices into barren areas, vacant spaces, and street side-way can be easily integrated.