Dhaka temperature 3 degrees higher due to lack of necessary trees, water bodies

Temperature of Dhaka is 3 degrees Celsius higher than Jahangirnagar University area which is only 32 kilometers away from the capital, according to a study by the Institute of Remote Sensing and GIS .

Dhaka should have 20 per cent green spaces, but the capital city has only 2 per cent while Jahangirnagar University area has 50 per cent green spaces and 22 per cent water bodies.

The temperature at the commercial areas is 2 degrees higher than Dhaka University and Ramna Park areas.

Temperature at Jahangirnagar areas is supposed to be higher due to the geographical location and geological formations.

The temperature at Jahangirnagar University areas remains 3 degrees lower than the capital Dhaka during the summer.

Temperature remains low as half of the university area is covered with 27,000 trees and about one-fifth of the area.

The study has been finalised this month by the Institute of Remote Sensing and GIS at Jahangirnagar University.

The institute's director Professor Sheikh Towhidul Islam led the study.
In a joint study by Jahangirnagar University and Bangladesh University of Professional, it is found that green spaces in Dhaka city have decreased by 56 per cent between 1989 and 2020. Only two per cent of the area has healthy green space. Dhaka only has 8 per cent of green space.

According to the study, greeneries and water bodies in the capital Dhaka mainly started to decrease fast since 1989 and high-rise building and infrastructure to increase. The temperature of Dhakha started to increase fast during the period. Discomfort due to the heat also started to increase. City like Dhaka requires at least 20 per cent of green space. If it happens, the temperature remains normal. But the temperature of Dhaka is becoming unbearable day by day.

In more than one study and observations by the Botany Department at Dhaka University, temperature in Motijheel and Farmgate areas is remaining 2 to 3 degrees higher than the university, Ramna Park and Suhrawardy area. There are invasive varieties of trees in these areas.
Science magazine 'Bangladesh Journal of Plant Taxonomy' publishes a study report titled 'tree diversity, abundance and dominance in the lakeside vegetation of Dhaka city'.

According to the study, there are 2,322 trees of 118 varieties on the lakeside of Dhanmondi, Hatirjheel and Gulshan. Of these, 39 are invasive.
When asked about the matter, botany department professor at Dhaka University, Md Jashim Uddin said, "New residential areas are developing in Dhaka city. If trees are planted in 20 per cent of the areas, temperature can be kept tolerable and shade can be provided to the people. if environment friendly trees are planted, the benefit will be more."

According to the forest department, 14 per cent of the country has green spaces. Dhaka city has 9 per cent. However, according to international organisation 'Global Forest Watch', Dhaka city has only 5.9 per cent of green spaces.

Speaking to Prothom Alo, Professor Towhidul Islam said, "When Jahangirnagar University was established, there were not so many trees. Later, trees are planted in a planned way. Temperature is 2 to 3 degrees lower here due to trees than Dhaka. If we increase planting trees in Dhaka city, the temperature can be lessened. Besides, shades and food can be provided from there to the low-income people.

The Institute of Remote Sensing and JIS measured differentiation of temperature in Jahangirnagar and Dhaka city area for one and half months from the summer between 2021 and 2024. The highest temperature of the day from 1 March to 20 April has been taken into consideration. It is found that the average temperature in Jahangirnagar was 36.47 degrees Celsicus in 2021 while the temperature in Dhaka was 39 degrees. Temperature was 34 degrees and 37.26 degrees respectively in 2022, 37 degrees and 38 degrees in 2023 and 33 degrees and 36 degrees in 2024.

When attention was drawn, Dhaka North City Corporation mayor Atiqul Islam said, "We started to plant trees in different slum areas and roadside. More trees will be planted. However, the city residents have to plant trees on the roofs, balconies and open spaces. We hope we will be able to bring down temperature with the concerted effort of all."

According to the study, of the 700 acres of land in Jahangirnagar University, half of the area is covered with greenery. Alongside trees, shades have been included. There are water bodies in 156 acres of land, 22 per cent. There are buildings on 7.17 per cent of land. In the remaining areas, there are other natural elements.

International science magazine 'Environmental Challenges' published an article titled, 'Present status and historical changes of urban green space in Dhaka city'. The article says a total 56 per cent of green space was seen to be lost between 1989 and 2020. Later, green spaces did not increase. There is a fear of losing.

It was found in the study that of the total land, 17 per cent was covered in healthy green spaces in 1989, which has now decreased to 2 per cent. This portion of land is limited to four areas. One area is the Botanical Garden, National Zoo and old airport. The second area is Sangsad Bhaban and Ganabhaban. The third area is Ramna Park, Suhrawardy Udyan, Hare Road, Gulistan Park, Osmani Udyan and Bangabhaban. The fourth area is Purbachal, a new city area.

Professor of the environment science department at Jahangirnagar University, Mostafizur Rahman said there are scopes to plant many trees in open space, around playground and water bodies and two sides of roads.
He also suggested planting local and fruit trees as these play a role to decrease temperature.

* This article, originally published in Prothom Alo print and online editions, has been rewritten in English by Rabiul Islam