Prolonged heat waves challenge sustainable development

Weather forecast for May indicates that heat wave, (the Department of Meteorology reveals that the very hot temperature and prolonged heat waves in the country broke 76 years record in last April 2024), depressions in the Bay of Bengal, thunderstorms and rain will prevail in the country.

There are concerns for sudden floods in the eastern and northern (Teesta flood plains) parts of the country, the other regions of the country have been praying for rains. In the meantime, water levels in the rivers (including the Padma and Gorai) and canals, surface water bodies have alarmingly dropped and the farmers have been struggling to irrigate their fields. The largest Ganges-Kobodak (G-K) project has been compelled to shut all its pumps to supply irrigation water for the project's command area. Boro rice producers express their concerns for saving their crops in the fields in Kushtia-Bheramara-Jessore area. Shallow irrigation pumps in other parts of the country often fail to pump water from underground water sources as the water tables have been lowered to the level below the shallow water pump's lifting capacity.  Experts anticipate that the Boro paddy cultivable lands may reduce and production may decline due to prolonged and record breaking heat waves during the season. Also, there are concerns that summer fruits (like litchi, plum, mango) productions will be low this year due to excessive heat in the atmosphere. Prolonged hot weather also affected negatively on poultry, dairy and fish farming in the country. Published reports further suggest that around Tk 2.0 billion has been lost in  poultry (chicken) production due to prolonged heat wave in the country for the last few weeks. The Department of Livestock estimated at least 10 per cent loss of dairy products due to changed weather and heat waves. The Dairy Farm Owners Association suggested a higher (up to 25 per cent) loss due to changed and extreme weather in the country. Extreme weather badly affected service industries, a major contributing sector in Bangladesh's GDP growth. The labour intensive sectors of economy have been suffering badly from very hot weather due to output and productivity losses. If the episodic 40°c and above days in April and May become the new normal of weather pattern in the country and in the region (due to global and man-made climate change), food security will be challenged, health and nutrition crisis will increase, accelerated climate migration and social unrests will intensify.

The extremely hot weather and low rain in April 2024 made the urban areas including Dhaka city very uncomfortable for living as the urban 'heat island effect' (Dhaka city's temperature exceeded compared to that in the surrounding countryside) become obvious here. Climate and environment experts, urban planners agree that the heat island effect increases rapidly as the city areas rapidly lose green and open area coverage, open water bodies. Recently published data  (from 2001-to 2023) from the Global Forest Watch says Bangladesh has lost approximately 246,000 hectares of forest area. In 2010, Bangladesh had more than 2 million hectares of natural forest (16 per cent of the total land area of the country) coverage. Bangladesh Government's Chief Conservator of Forests Mr. Amir Hossain Chowdhury said to media that every year the country has been losing about 10,000 hectares of forest, though there are some increase (of green covers) in new areas. He said 'if we consider carbon, our losses outweigh our gains, meaning there is a net loss'.

Unplanned urbanisation, illegal occupation of forestlands and resources, riverbank erosion are mainly responsible for decreasing forest covers in the country. The Institute of Remote Sensing and Geographical Information Systems at Jahangirnagar University found that Dhaka city had approximately 2 per cent tree coverage while 20 per cent tree coverage is considered as a requirement for a balanced city environment. Study reports further found that there were at least 2 degree celsius atmosphere temperature difference between Dhaka city's busy commercial areas compared to Dhaka University, Ramna Park areas.

Environmental experts also observe that the construction materials used and the infrastructure development planning deserve attention in Dhaka city and in other towns in the country. Use of glass structures and over dependency on artificial lighting and air conditioning in the new multi-storied buildings in urban areas have been contributing to increased 'heat island' affects. Prof. Adil Mohammed Khan, the executive director of the institute of Planning and Development considers that 'a class (of people) may be comfortable in air-conditioned environments by cutting down trees and filling in water bodies but the vast majority of people suffer the discomfort of using air-conditioning'.

The more we ignore the need for preserving green coverage, open spaces and water bodies and rely on artificial air conditioning and heat retaining infrastructures in urban development, the more we convert our cities and towns into 'heat islands'!

Mushfiqur Rahman is a mining engineer writes on energy and environment issues.

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