Why urban greenery is vital to Bangladesh's sustainability

Due to rapid urbanisation, Bangladesh struggles to combine growth with environmental sustainability. Cities across are rising at unprecedented rates. 

Due to economic growth, population growth, and infrastructure improvements cities have lost green spaces as they grow. 

These spaces balance the environment, improve air quality, and improve living. Green urban plants are crucial for Bangladesh's long-term growth. Parks, gardens, street trees, and green roofs help mitigate urbanization's harmful consequences. One of the biggest benefits of urban vegetation is air purification. Bangladesh has some of the worst air in the world, notably in Dhaka. Dirty air kills 28% of Bangladeshis, according to the WHO. City green plants remove carbon dioxide, sulphur dioxide, and nitrogen oxides and release oxygen. In 2023, the Department of Environment (DoE) found that adding 10% more green cover to Dhaka might reduce PM2.5 levels by 20%. This would improve air quality and reduce lung and heart disease risks.

In addition to enhancing air quality, urban green vegetation helps minimise the urban heat island (UHI) effect, which makes cities hotter than rural areas. People are largely responsible for this temperature rise because they use heat-absorbing materials like concrete and asphalt.

The UHI impact worsens high temperatures in Dhaka and Chattogram. This uses more energy to cool and makes more people sick from heat. The Bangladesh Centre for Advanced Studies (BCAS) found that city green spaces can cool things by 5°C. Trees and other plants chill the air through evaporation-transpiration. Roots absorb water and release it as water vapour through leaves, cooling the air around the plant. This natural cooling impact helps mitigate climate change and reduce city energy needs. Urban greenery provides homes for birds, insects, and tiny animals, protecting biodiversity. As towns grow, natural ecosystems are eliminated, reducing biodiversity. Urban green spaces can protect wildlife if maintained effectively. Dhaka's Gulshan Lake Park, a green corridor in a densely crowded area, has over 50 bird species. Maintaining and expanding these green spaces protects biodiversity and ensures urban ecosystems can support themselves.

Urban greenery can also improve water control. Bangladesh has frequent floods and water shortages. City water is limited in the dry season and sufficient in the monsoon season. Green spaces, especially those in integrated urban water management systems, help reduce these issues. Plants increase soil permeability, allowing rainwater to restock groundwater instead of flowing off into storm drains and increasing flooding. The Institute of Architects, Bangladesh (IAB) and the Institute of Planners (BIP) promote green infrastructure in urban development. They claim vegetated swales, permeable pavements and green roofs reduce surface runoff by 40%. These procedures strengthen urban sewage systems and refill depleted reservoirs, ensuring long-term water security.

Another benefit of urban greenery is helping people. Green spaces allow individuals to relax, have fun, and socialise in densely populated areas, improving their physical and mental health. Studies show that green spaces reduce stress, anxiety, and sadness. In 2022, BRAC University discovered that Dhaka residents near parks were 15% happier with their quality of life than those in areas without green space. These facilities also encourage exercise, which helps fight lifestyle disorders like diabetes, obesity, and high blood pressure that are growing more widespread in Bangladesh cities.

Urban greenery may also improve towns and bring people together. Well-kept parks and gardens attract individuals from different backgrounds and help them build a shared identity. This is crucial in Bangladesh, where cities are increasing rapidly, where people lose touch with each other and their communities. Green spaces may draw people together for cultural events, festivals, and daily socialising. Green spaces help the economy by increasing property values and tourism. Dhaka's real estate market values residences near parks and other green spaces 10-15% higher than those in more congested regions. This benefits homeowners and raises property taxes, which may be used to develop communities and maintain green spaces. As Dhaka's Ramna Park and Hatirjheel demonstrate, well-planned green spaces can boost tourism and attract international visitors.

Bangladesh needs a more coordinated and planned urban planning approach to maximise city green spaces. This includes creating and maintaining green spaces, especially in rapidly developing areas. Legally required green spaces in new urban developments should specify plant types and quantities. Community members should also be encouraged to maintain green places. This will ensure they are well-maintained and satisfy residents' needs. Education and awareness efforts are crucial to promoting urban green spaces. Schools, neighbourhood groups, and local governments should advocate for green flora and encourage people to grow trees, farm, and do other green things. In summary, green plants in cities are crucial for Bangladesh's urban growth and not just for aesthetics. Its environmental, social, and economic benefits are vital to city and resident health. To make Bangladesh's cities livable, strong, and long-lasting for future generations, green spaces must be protected and expanded. Act now before the man-made jungle overtakes the natural one.

Dr Sajal Chowdhury is an architect, educator at the Department of Architecture, CUET and researcher focusing on Environmental Experience Design, Architectural Science and Well-being.