Exposure to high temperature and humidity has made Dhaka a dangerous city for people to dwell in. Because of this high temperature and humidity, the productivity of people living in Dhaka has been decreasing and the loss in overall economy of the country increasing.
The annual loss of labour productivity in economic value is nearly US $6 billion (600 crore), which is more than 8 per cent of annual output of Dhaka.
These were the findings in a recent report ‘Hot Cities, Chilled Economies: Impacts of Extreme Heat on Global Cities’, published by the US-based Adrienne Arsht-Rockefeller Foundation Resilience Center (Arsht-Rock). The report evaluated social and economic impacts of extreme heat in 12 cities including Dhaka.
In Dhaka, heat stress impairs labour productivity more than any other city, with losses valued at 8 per cent of output under baseline conditions, rising to 10 per cent by 2050 without action to reduce emissions or adapt, the report said.
Speaking to Prothom Alo, professor Ashraf Dewan of School of Earth and Planetary Sciences at Curtin University, Australia said, “Several of our researches reveal the expansion of extreme heat islands alongside the rising temperature in Dhaka. There the heat is centralising and decreasing people’s performance. This loss will increase in the coming days if the waterbodies are not preserved, greenery not increased and urbanisation is not planned for air circulation to decrease the heat.”
Heat in Dhaka is concentrated in its urban core, including some informal settlements. Dhaka is subject to a strong urban heat island (UHI) effect due to its population density and lack of green space
The other 11 cities are – Athens (Greece), Bangkok (Thailand), Buenos Aires (Argentina), Freetown (Sierra Leone), London (the UK), Los Angeles (the USA), Miami (the USA), Monterey (Mexico), New Delhi (India), Santiago (Chile), and Sydney (Australia).
The average economic value of loss the 12 cities incur every year is around $44 billion. The loss could reach at $84 billion by 2050 if no measures are taken to decrease the heat.
According to the report, the high temperatures and humidity have already spread to about 60 and 80 per cent areas of Dhaka. “Climate change is set to make things substantially worse.”
The report said, “Heat in Dhaka is concentrated in its urban core, including some informal settlements. Dhaka is subject to a strong urban heat island (UHI) effect due to its population density and lack of green space. Large and widespread hotspots within the city are more than 10°C higher than the surrounding countryside.”
We have to decrease the amount of concrete in the buildings in our cities to control the situation. We have to have gardens and cultivate vegetables at roof
“For example, in Kamrangirchar, population density and the widespread use of corrugated iron sheet roofing in buildings means that outside temperatures are typically 12°C higher than the city’s surroundings, while temperatures experienced indoors are even hotter. These living conditions contribute to substantial health risks for Dhaka’s population,” the report added.
The report further said, “… while others such as Abu Dhabi and Bangkok are more exposed to heat stress, Dhaka is unusually vulnerable to its effects, due to its labour-intensive economy and low rate of active cooling …. Low-income workers are especially exposed to heat: in sectors such as garment manufacturing, transport, and retail trade, losses already amount to around 10 per cent of income.”
The Arsht-Rock report in its section on ‘Extreme heat threatens sidewalk vendors’ said there are as many as 400,000 informal street vendors (“hawkers”), who often are migrants seeking low-skilled employment in the city. The density of the built environment means hawkers rarely have permanent shops and instead set up shop on sidewalks, immediately beside roads whose surfaces can reach 60°C and where dense traffic continues to generate heat into the evening hours.”
It said 9 per cent of hawkers indicated they lost as much as 50 to 75 per cent of their earnings during heat waves, while more than 25 per cent hawkers lost between 25 and 50 per cent of their earnings.
Md. Akter Mahmud, professor of urban and regional planning department at Jahangirnagar University told Prothom Alo, “We have to decrease the amount of concrete in the buildings in our cities to control the situation. We have to have gardens and cultivate vegetables at roof. This will help reduce the temperature.”
Experts have been saying several buildings have used reflective roof paint, which has achieved significant cooling effects in schools, industrial buildings, and low-quality housing settlements to reduce indoor temperatures.
They have been stressing on increasing the green roofs of vehicles.
* The report has been rewritten in English by Shameem Reza