‘Urban heat island’ phenomenon behind Karachi’s recent heatwave
The urban heat island phenomenon derives its logic from simple physics. During the day, the city stores heat from the sun as well as traffic in its concrete and tarmac. During the night, when the weather should be comparatively cooler, the stored heat from the concrete and tarmac is released into the atmosphere. The nights are also not long enough to release all of the stored heat, which means that most of it also releases during the day, taking the temperature up a notch.
A heatwave that gripped Europe in 2003 killed more than 70,000 people, according to peer-reviewed research. Pollution and increasing urbanization contributes to the urban heat effect phenomenon. However, there are also multiple ways to contain the ‘urban heat island’ effect.
“The first thing that you can do is plant trees, to provide shade,” said Ingrid Coninx at Wageningen University and Research Centre in the Netherlands.
“But when you plant trees you have to do it in the right way. If you prevent downward breeze from reaching the street, you could make things warmer and trap pollution.
“So you have to have a better understanding of how your city interacts with the weather systems and about the kind of vegetation that works best.”
The most important and effective way to contain this heat is by planting as many trees as one can. Plantation of trees and construction of breeze channeled buildings have a positive effect on the atmosphere.