Dwindling green coverage responsible for warmer summers in Dhaka

Alongside several regions in Bangladesh, a heatwave has been sweeping over Dhaka, breaking 58 years' record with 40.6 degrees Celsius temperature on Sunday. The trend of increasing temperature has prevailed for the last couple of years.

The reasons behind the extreme weather can be summarised to three: global, regional, and local.

Climate change-induced global warming contributes to 2-3 degrees Celsius additional temperature in Dhaka during summer time.

Regionally, the countries under the Himalayas – Nepal, India, Bangladesh, and Pakistan – are experiencing hotter summers because of depleting glaciers and top hills that naturally absorb heat from the atmosphere.

However, I would emphasise the local reasons, particularly the dwindling green coverage, for the warmer summers in Dhaka and other urbanised parts of Bangladesh.

Usually in the past, some government-owned green parks were considered oxygen factories. Unfortunately, the parks are losing canopies over the years. For example, the Suhrawardy Uddyan lost at least 40% of its green coverage in the last 40 years. Of the damage, 30% happened in the last 20 years. This trend is also replicated in other green parks.

According to a study done in 2017-18, the atmospheric temperature was felt intolerable in the areas where green coverage is degraded extensively. That means the more trees we have around us, the less heat we feel in that environment.

The extreme summer and severe but short winter in Dhaka and cities alike is an indication of desertification. We are very much concerned about it.

The government should have accelerated the conservation of green coverage instead of promoting occasional tree plantation.

Recently we have seen how government agencies indiscriminately cut down the years-old trees on the Dhanmondi road medians in the name of development. The authorities often say that they are planting more trees than fell-down trees. Actually, hundreds of young trees cannot compensate for the loss of a decades-old tree.  

The reality is one-tenth of the trees fell due to development projects in Dhaka that have not even reached maturity to date.

Ahmad Kamruzzaman Majumder is a professor of Environmental Science at Stamford University Bangladesh

TBS Senior Staff Feature Writer Sadiqur Rahman interviewed Prof Ahmad Kamruzzaman Majumder over the phone.