At 8am, a factory attendance sheet can show a full workforce. By 2pm, it still may. What the sheet cannot show is whether the same people are moving more slowly, taking longer to recover or producing less because the heat has turned an ordinary shift into a physiological test.

That gap between attendance and actual output is where Bangladesh’s heat-productivity crisis becomes hard to see.

A World Bank study released in September 2025, based partly on a 2024 survey of more than 16,000 people, estimated that heat-related physical and mental health conditions cost Bangladesh 250 million workdays in 2024 and between USD 1.3 billion and USD 1.78 billion, roughly 0.3-0.4% of GDP. Since 1980, the country’s maximum temperature has risen 1.1°C, while its “feels-like” temperature has climbed 4.5°C. On days above 37°C, productivity losses were 36% higher than on milder days, according to a January 2026 World Bank analysis.

The 2025 Lancet Countdown data for Bangladesh give an even larger estimate: 29 billion potential labour hours lost to heat in 2024, 92% more than the 1990s average, with potential lost income of USD 24 billion, or around 5% of GDP. Agriculture accounted for 64% of those lost hours and 55% of lost earnings. Bangladeshis were also exposed to an average 237 more hours of moderate-or-higher heat-stress risk during outdoor physical activity than in 1990-99.

The figures are not measuring the same thing. The World Bank estimates work and productivity lost through heat-related illness; the Lancet models the labour capacity that disappears as heat makes normal physical work harder or unsafe.

That distinction matters. Bangladesh may be losing far more productivity than companies can see on an absence register.

THE WORKER IS THERE, OUTPUT IS NOT

Heat does not need to send a worker home to cut production.

The World Health Organization and World Meteorological Organization say worker productivity falls by roughly 2-3% for every degree increase above 20°C in Wet-Bulb Globe Temperature, or WBGT, which combines temperature, humidity, wind and radiant heat. Among about 8,000 workers studied globally, 30% of those frequently exposed to workplace heat stress reported productivity losses. More than one-third of people frequently working in hot conditions experience physiological heat strain.

The mechanism is simple. As heat stress rises, heavy work becomes harder to sustain. Rest, hydration and a slower pace are necessary protections, but they also reduce productive minutes.

Bangladesh is unusually exposed because of the structure of its labour market. The Bangladesh Bureau of Statistics’ Labour Force Survey 2024 put the labour force at 69.1 million. Of them, 58.04 million – 84% – were in informal employment, according to CPD’s analysis of the BBS data. Agriculture alone accounted for 44.67% of employment, according to the survey figures reported by The Financial Express.

For millions in physical or outdoor jobs, the choice can be brutal: slow down and risk earning less, or keep working and absorb the health risk.

The danger is also expected to intensify. A July 2026 adelphi global report, reported by The Business Standard, projects that agriculture and construction workers in Bangladesh could lose the equivalent of 23.75 working days a year to heat stress by 2030. Working-hour losses in those sectors are projected to rise from 6.28% to 9.58%; across all sectors, from 4.24% to 4.84%.

These are projections, not observed 2026 losses, and build partly on earlier labour modelling. But they point in the same direction as the newer World Bank and Lancet evidence: heat is becoming a constraint on how much work can physically be done.

The mechanism is simple. As heat stress rises, heavy work becomes harder to sustain. Rest, hydration and a slower pace are necessary protections, but they also reduce productive minutes.

FACTORIES FACE A DIFFERENT TRAP

Air-conditioning an office is one thing. Cooling a dense production floor with hundreds of workers, heat-generating machinery and narrow margins is another.

A 2025 Bangladesh Labour Foundation study of 700 workers in RMG, leather and footwear factories in Savar, Ashulia, Gazipur and Hemayetpur found 82.1% reporting significant heat stress. The share reached 87% among RMG workers.

More importantly, 60% believed climate change was reducing productivity. In RMG, the study reported 37% absenteeism linked to climate disruption, 23.5% production delays and 26.25% heat-related wage impacts. Only about half of workplaces were reported to have adequate – though often inefficient – cooling or ventilation.

Long hours deepen the exposure: 49.2% of surveyed workers worked nine to 11 hours a day and 25.5% exceeded 11 hours. More than half reported excessive heat stress or fatigue, 36% dizziness or dehydration, and 2.3% had experienced heatstroke.

These are worker-reported findings from selected industrial zones, not a national factory census. But they expose the business dilemma.

If heat requires more rest, slower line speeds or shorter shifts, output can fall. If factories maintain the same targets, workers absorb more physiological stress. Either way, someone pays.

What is largely missing is firm-level accounting of that cost. How much output is lost on high-WBGT days? Does overtime rise later? Do defects or absenteeism increase? How much more electricity goes into cooling?

Bangladesh has macro estimates of heat losses ranging from USD 1.78 billion to USD 24 billion depending on methodology, yet little public evidence that companies routinely measure heat as a separate operational cost.

A FAN IS NOT A STRATEGY

Businesses are adapting, but the quality of that adaptation matters.

A 2026 World Bank study of firms across South Asia found 63.38% had undertaken at least one weather-related adaptation measure. Once minor measures costing less than 1% of annual revenue were excluded, the share fell to 31.5%.

The most common response was buying fans, reported by 45.52% of firms. Another 29.73% bought air-conditioners. Only 21.64% had a heat contingency plan. These are regional, not Bangladesh-only, figures.

Still, the contrast is useful. Buying a fan treats heat mainly as a comfort problem. A contingency plan treats it as an operational risk.

That means knowing when WBGT becomes unsafe; shifting heavy tasks away from peak heat; guaranteeing water and paid rest; adjusting production targets; improving ventilation and building design; and having clear rules for when work should slow or stop.

Bangladesh’s regulations require workplaces to maintain a “reasonable temperature”, but there is no defined maximum workplace temperature or comprehensive mandatory heat-stress regime specifying paid heat breaks, cooling zones or work-suspension thresholds, according to a July 2026 review of the regulatory framework.

That leaves crucial decisions with employers precisely when commercial pressure is highest.

The cost also follows workers home. The World Bank found diarrhoea risk rose 47.7% on days above 35°C, heat exhaustion 26.5%, depression 23.8% and anxiety disorders 37.1%on very hot days.

WHO PAYS FOR ADAPTATION?

This is where the productivity debate becomes uncomfortable.

Protecting workers can reduce short-term output. Paid cooling breaks remove production time. Moving outdoor work away from midday can extend schedules. Lowering a factory line speed can affect delivery targets.

The question is who absorbs that cost.

Factories can invest in ventilation, insulation and cooling, but suppliers operating on narrow margins may resist expensive retrofits unless buyers share the burden. Daily-wage workers cannot reasonably finance adaptation through unpaid rest. And air-conditioning is no answer for farms, construction sites, rickshaw pullers or street workers.

The cost also follows workers home. The World Bank found diarrhoea risk rose 47.7% on days above 35°C, heat exhaustion 26.5%, depression 23.8% and anxiety disorders 37.1%on very hot days.

The July 2026 adelphi analysis adds another layer: households directly paid 79.3% of Bangladesh’s total health expenditure in 2023. For an informal worker, heat can therefore cut income at the same time it increases medical spending.

Part of the economic loss never reaches an employer’s balance sheet.

A flood can close a factory gate. A power cut stops a machine. Heat is less obvious. The gate stays open, the worker clocks in and production continues—only more slowly, with more strain and with some of the cost pushed onto workers and households.

Bangladesh’s productivity crisis is therefore not only that the country is getting hotter. It is that businesses and policymakers still do not fully measure where the lost work goes.

Until heat is treated as an input into production planning – measured alongside energy, labour hours and delivery time – the economy will continue counting attendance while missing the work that heat has already taken away.