Due to the lack of vegetation and wetlands, the temperature of Dhaka is high
Twenty percent of Dhaka should have trees, but only 2 percent have. A comparative figure shows that 50 percent of Jahangirnagar University’s area in Savar near Dhaka is covered with vegetation and 22 percent is wetland.
Due to this, the temperature there is 3 degrees Celsius lower than that of Dhaka at the same time. The temperature in Dhaka’s commercial area is 2 degrees higher than in Dhaka University and Ramna Park area.
However, due to the geographical location and geological structure, the temperature should be high in Jahangirnagar University. This university, located only 32 km from the capital, has a temperature that is typically less than 3 degrees during the summer.
There are 27,000 trees and wetlands cover half and one-fifth of the university’s area, helping to keep the temperature low. Most of the trees planted here are invasive species like Acacia and Akashmani.
This data is from a research study at the Institute of Remote Sensing and GIS of Jahangirnagar University, which was completed this month. The research was led by the director of the institute, Professor Sheikh Touhidul Islam.
A study by Jahangirnagar University and Bangladesh University of Professionals found that the number of plants in Dhaka city decreased by 56% from 1989 to 2020.
Now only 2 percent of the city has rich and eco-friendly species of plants and vines. And the total tree-covered area is only 8 percent.
Vegetation and wetlands in Dhaka have been decreasing quickly since 1989. At the same time, there has been an increase in high-rise concrete buildings and infrastructure. The temperature of Dhaka also started increasing rapidly from this time. Along with that, the heat discomfort also started to increase.
A city like Dhaka should cover 20 percent of its area with trees. In this case, the temperature of the city is normal. But the temperature in Dhaka is becoming unbearable day by day. Therefore, the survey has been done to understand the extent of tree fall in this city at that time.
Several researches and observations of the Department of Botany of Dhaka University have shown that the temperature of Motijheel and Farmgate area of Dhaka is always 2 to 3 degrees Celsius higher than that of this university, Ramna Park and Suhrawardy Udyan area.
Dhaka University, Ramana Park and Suhrawardy Udyan – tree-covered areas are also mainly invasive species trees. Still, the temperature in these areas is low because of the trees.
Mr Jasim Uddin, Professor of Botany Department of Dhaka University, said, ‘How many new residential areas are being built in Dhaka city, if only 20 percent of the areas are planted with trees, it is possible to keep the temperature bearable and provide shade for the local people. And if you plant environmentally friendly trees, this benefit is even more.’
The reason for the high temperature in Dhaka
According to the forest department, 14 percent of the country’s area is covered with trees. And in the case of Dhaka city, this number is 9 percent. Global Forest Watch, an international organization that monitors the world’s forest resources, has observed that there are 5.9 percent trees in Dhaka.
Professor Sheikh Touhidul Islam said, ‘There were not many plants in Jahangirnagar University when it was established. Later, tree saplings were planted in a planned manner.’
“The main reason why the temperature here is always 2 to 3 degrees Celsius lower than Dhaka is the trees. If we can only increase the planting of trees in Dhaka city, the temperature can be reduced. Trees also provide shade and food for city dwellers, including those who belong to the lower class,” he added.
The Institute of Remote Sensing and GIS measured the temperature difference between Jahangirnagar University area and Dhaka city for a month and a half during the summer from 2021 to 2024. Daily maximum temperature for the period from March 01, 2024 to April 20, 20214, has been taken into consideration.
It can be seen that the average temperature of Jahangirnagar in 2021 was 36.47 degrees. It was 39 degrees in Dhaka. In 2022, it was 34 degrees and 37.26 degrees respectively, in 2023 it was 37 degrees and 38 degrees and this year (2024) it was 33 degrees and 36 degrees.
In this regard, Dhaka North City Corporation Mayor Atiqul Islam said, “We have started planting trees in various slum areas and roadsides of Dhaka city. More trees will be planted gradually.”
But city dwellers should also plant trees on their rooftops, balconies and empty spaces next to their houses. We hope to be able to reduce the temperature in Dhaka with everyone’s collective efforts.
