Heatwaves: A growing concern for Bangladesh

Global climate change is driving more frequent and severe weather extremes worldwide. While floods and cyclones cause immediate destruction to buildings, heat operates differently, gradually compromising human health and disrupting work patterns. 

Bangladesh is among the countries that are most susceptible as well as affected by extremes of climate change, including heatwaves due to global warming. 

Bangladesh Meteorological Department (BMD) has classified heatwaves into four categories based on maximum temperature: mild heatwave (temperature 36-38°C), moderate heatwave (temperature 38-40°C), severe heatwave (temperature 40-42 0C), and extreme heatwave (temperature > 42°C). 

In Bangladesh, the greatest risks occur during pre-monsoon periods. Climate and health studies identify March through June as the most hazardous months, with April regularly showing the highest temperatures. 

Bangladesh experienced its longest heatwaves in recorded history in April 2024. Research shows that since 1948, April 2024 has already seen a record number of heatwave days in a single year. 

In May 2025 alone, the heat index surged to 40°C, threatening health, livelihoods, and human dignity. This intense heat is now a recurring issue rather than a seasonal anomaly, and is caused by climate change, urban sprawl, and the continued loss of green infrastructure.

According to the World Health Organization (WHO), from 2000 to 2019, nearly 489,000 heat-related deaths occurred globally each year, with Asia bearing around 45% of that burden. 

The year 2024 is the warmest and longest heatwave year for Bangladesh in 75 years, leading to more than 700 heat-related deaths, one of the highest in the country's history. The neighboring country of Bangladesh, India, faces at least 219 reported deaths and more than 25,000 heatstroke cases in the 2024 heatwaves. 

The capital of Bangladesh, Dhaka, is experiencing rising temperatures, and in Bangladesh, the issue is no longer uncomfortable for the millions of people, but a real threat. 

Study revealed that Dhaka has experienced a temperature surge of nearly 3°C in the last 20 years, while the world is striving to limit the rise in global temperature to below 1.5°C. 

The future projection of climate in Dhaka city shows a continuous rise in temperature in the city and related extreme events, such as frequent outbreaks of tropical diseases and scarcity of water, will have the most immediate effects of climate change in Dhaka. 

The city with a population of over 30 million people, is the centre of Bangladesh's temperature crisis. 

Based on the data from the Bangladesh Meteorological Department, the highest temperature recorded in Dhaka was 40.6°C on 16 April 2023, which is the highest temperature in 58 years. 

Recent studies show that the overall city temperature has increased by around 0.57°C in the last decade. This temperature rise is different in various locations, larger in urban areas than in the surrounding rural areas. 

Increased exposure to heat raises the risk for dehydration, heat-related exhaustion, cardiovascular problems, and difficulty breathing. 

Extreme heat has been shown through epidemiological studies leading to a significant increase in mortality and hospital admissions, particularly in people over 80 years of age, young people, outdoor workers, and those with pre-existing health conditions.

Economic performance is affected by temperature extremes as well as by the impact on health. According to the World Bank analysis, Bangladesh lost around $1.78 billion due to heat-related illnesses and reduced productivity of workers in 2024. 

This equates to about 0.4% of the country's Gross Domestic Product (GDP). Studies on labour efficiency indicate that for every one degree higher or lower than the optimum working temperature, productivity is lost by 2%-4%. 

Outdoor workers are at particular risk. Studies commissioned by the World Bank show that people in the construction industry, farmers, and those in the informal sector are 3-4 times more likely to develop a health problem caused by high temperatures. 

The consequences affect income generation, exacerbate poverty, especially for those who are economically vulnerable and face limited income generating opportunities alongside rising living costs. 

The severe effect of extreme heat is also on the country's core export business, the Ready-Made Garment (RMG) business, where the country is a major exporter. 

Studies have shown that the heat stress experienced by the employees of the RMG industry is the worst during the period from 1pmto 4pm, particularly during April to June. 

Recent investigators report that heat sources such as warm equipment, physical exertion, lack of adequate air flow, and limited access to cooling technology are all reported causes of heat stress in workers. Water stations might be present, but often workers do not drink water or rest because they are required to remain on the job. Routine health research reveals typical symptoms, such as dizziness, headache, fatigue, thirst, and reduced concentration. 

Bangladesh is one of the most vulnerable countries in the world to the effects of climate change. The geographical position, high population density, and rapid urbanisation of the country contribute to increasing climate-related challenges. 

Heat stress is a structural crisis due to climate injustice, unregulated urbanisation, and systemic neglect. Adaptation measures, such as community cooling centres, heat action plans, or protection provided by employers, are scarce or absent in most informal sectors. 

Bangladesh lacks coordinated action to protect vulnerable groups from rising heat. It requires warning mechanisms, cooling facilities, skilled medical personnel, and focused community education programs, reflective roofing, workplace temperature regulations, and comprehensive alert networks. 

Long-term needs include increasing green spaces, implementing climate-responsive construction standards, and ensuring reliable funding integrated into routine city development plans. 

These measures are essential for achieving the Sustainable Development Goal (SDG) 8 (Decent Work and Economic Growth) SDG 11 (Sustainable Cities and Communities) and SDG 13 (Climate Action). 

Excessive heat stress not only threatens human health but also places additional pressure on environmental resources by increasing demand for water and energy. 

If immediate and effective measures are not taken, heatwaves may evolve into a major climate-related disaster, with profound consequences for the economy, society, and the environment.

Dr Wasim Akram is an assistant professor, Department of Economics at Southeast University.

Md Tanvir Ahmmed is a student of the Dhaka School of Economics.

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinions and views of The Business Standard.