Heatwaves and El Niño Threatening Bangladesh’s Food Security

The rising climatic instability is creating a grave crisis for the world’s food systems today. It is pushing Bangladesh, a country with dense population and rice-dependent agriculture, towards a quite vulnerable position. Even small shifts in temperature and rainfall now threaten national food security and rural livelihoods. According to the World Meteorological Organization, the past decade is the warmest on record, with global temperatures being about 1.5°C above pre-industrial levels, and 2025 is among the hottest years. At the same time, emerging El Niño conditions are disrupting global rainfall patterns, intensifying droughts and floods. In South Asia, especially Bangladesh, these global climate extremes translate into sharper and more immediate agricultural risks.
Bangladesh has recently experienced increasingly severe pre-monsoon heatwaves. In 2026, multiple districts recorded temperatures between 38°C and 40°C during critical agricultural periods. These extreme conditions have direct physiological impacts on crops. Rice, the country’s staple food, is particularly sensitive during flowering, where temperatures above 35°C can cause spikelet sterility and yield reduction. Scientific studies show that for every 1°C rise above optimal thresholds during sensitive growth stages, rice yields may decline by up to 10 per cent under field conditions. As rice provides more than 70 per cent of daily caloric intake in Bangladesh, such losses pose immediate and serious food security risks.
Heat stress in agriculture operates through multiple interconnected pathways. High temperatures increase plant respiration, reducing net photosynthetic efficiency and limiting biomass accumulation. Rapid soil moisture loss during heatwaves raises irrigation demand when surface and groundwater resources are already strained. In Bangladesh, dependence on groundwater for Boro rice intensifies pressure as aquifer levels decline and energy costs rise for pumping. Heat stress also reduces livestock productivity by lowering milk yield, fertility rates, and feed efficiency, thereby affecting the broader agricultural economy and rural livelihoods.
Vegetable and horticultural systems in Bangladesh are highly vulnerable to rising heat stress. Crops such as tomatoes, brinjal, chillies, and cucurbits experience flower drop and poor fruit set under high-temperature conditions. Mango, a key fruit crop, shows irregular flowering patterns under climatic stress, reducing yield and export quality. Litchi production in northern districts is increasingly affected during fruit development stages. Aquatic systems, including fisheries and aquaculture, critical for national protein supply, are also impacted by rising water temperatures, reduced dissolved oxygen levels, and increased disease incidence in fish stocks, threatening nutrition security and rural livelihoods.
Compounding these thermal stresses is the looming influence of El Niño, part of the El Niño-Southern Oscillation (ENSO), driven by abnormal warming of sea surface temperatures in the central and eastern Pacific Ocean. Although distant, its atmospheric teleconnections influence Asian monsoon systems. In Bangladesh, El Niño years often bring weak or erratic monsoon rainfall, delayed onset, prolonged dry spells, and irregular heavy rainfall events, disrupting the carefully timed agricultural calendar for Aus, Aman, and Boro rice cultivation and increasing production uncertainty.
During strong historical El Niño events, agricultural impacts have been severe across Asia and beyond. The 2015-2016 El Niño contributed to drought-induced rice production declines in Southeast Asia, water stress in India, and food insecurity in parts of Africa. Globally, the Food and Agriculture Organization estimates climate-related disasters have caused agricultural losses exceeding USD 3.8 trillion over the past five decades. In Bangladesh, even moderate monsoon deviations can delay Aman rice transplanting, reduce irrigation for Boro rice, and create yield instability across seasons.
The interaction of heatwaves and El Niño creates a compound risk. Heatwaves reduce soil moisture and stress crops in early stages, while altered monsoon patterns disrupt later development. This dual stress lowers cropping intensity, especially in irrigation- and rainfall-dependent systems. In Bangladesh’s northwestern drought-prone districts, impacts are particularly severe, while coastal regions face added pressure from saline water intrusion combined with heat stress, further constraining agricultural productivity and resilience.
Beyond staple crops, Bangladesh’s diversified agriculture is increasingly at risk. Wheat, already marginal due to rising temperatures, faces yield declines during grain filling, while maize, critical for poultry and livestock feed, shows high sensitivity to heat during pollination. Together, these stresses disrupt crop output, feed supply chains, and protein production systems, increasing food price volatility that disproportionately affects low-income households. Pest and disease pressure is also rising: warmer temperatures accelerate insect life cycles and geographic spread, with outbreaks such as brown planthopper in rice and fall armyworms in maize becoming more frequent. Fungal diseases like rice blast and vegetable blight intensify under warm, humid conditions. Studies indicate pest populations can increase by 10-25% per 1°C rise, compounding climate-driven yield losses.
The socioeconomic impacts of climate-driven agricultural disruption in Bangladesh are severe. Agriculture employs about 40% of the labour force and supports most rural livelihoods, so reduced productivity directly lowers farm income, increases indebtedness, and accelerates rural-urban migration. Food supply shocks contribute to inflation, disproportionately affecting urban poor households. The World Bank estimates that climate-induced agricultural losses could push millions into poverty, with South Asia among the most vulnerable regions. Despite these risks, Bangladesh has strengthened resilience through stress-tolerant rice varieties (flood, drought, and salinity resistant), improved irrigation, and crop diversification. Climate-smart practices and floating agriculture in southern wetlands further demonstrate adaptive innovation under increasing climate pressure.
Technological advancements are central to climate adaptation in Bangladesh. Seasonal climate forecasting, mobile-based weather advisory services, and early warning systems are improving farmer decision-making, while solar-powered irrigation is reducing diesel dependence and improving water efficiency by 30-40% in pilot areas. Research institutions are developing heat- and stress-tolerant crop varieties and advancing integrated pest management. However, climate risk is rising faster than adaptation capacity, requiring sustained investment in research, extension services, and rural infrastructure. Heatwaves are becoming frequent and intense, with El Niño events amplifying impacts under a warmer baseline. Bangladesh’s situation illustrates how climate vulnerability is greatest where population density, poverty, and climate-sensitive agriculture intersect.
Food security in Bangladesh depends on transforming agriculture into a climate-resilient system through integrated strategies combining scientific innovation, policy support, infrastructure development, and farmer empowerment. Improving irrigation efficiency, soil health, climate-resilient seed systems, and real-time climate information services are essential survival measures. Warning signs are visible in drying fields under intense heat, erratic monsoon arrival, and unstable crop yields. The challenge is no longer to increase production but to sustain it under growing climatic uncertainty. 
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The writer is Assistant Professor, Institute of Development Studies and Sustainability (IDSS), United International University (UIU)