Farmers fret as climate change upends onion farming

For more than two decades, Shamsul Alam of Khansama in Dinajpur cultivated onions on 10 bighas every year without worrying much about the weather. Thick winter fog rarely harmed his seedbeds and the farming calendar remained predictable. Not anymore.

Prolonged fog now destroys seedlings, while untimely heavy rain washes away seedbeds and damages standing crops. The repeated climate shocks have left the veteran farmer counting losses almost every season.

Weather has become completely unpredictable. Earlier we knew when to prepare seedbeds. Now heavy rain even in Agrahayan destroys everything, Shamsul said.

He has been forced to buy seeds again at much higher prices, raising production costs and delaying cultivation. Later, intense pre-harvest heat shrivelled plants, leaving behind undersized bulbs.

The story is much the same for Sohel Rana, an onion grower from Paba in Rajshahi.

After suffering repeated losses in winter onions, he switched to summer cultivation hoping to escape erratic weather. Instead, scorching heat cracked the soil during the growing period, while storms, hail and heavy rain battered the crop at harvest.

Although he managed to harvest onions from muddy fields, persistent humidity prevented proper drying. Much of the produce rotted within days in storage. Despite investing around Tk 350,000, he could not sell even one-fourth of the harvest and failed to pay his farm workers.

Farmers said onion cultivation costs have risen sharply over the past decade. Around 2016, producing onions on one bigha (33 decimals) of land cost between Tk 15,000 and Tk 25,000. By 2026, the cost has increased to around Tk 50,000 to Tk 70,000 because of higher prices of fertiliser, seeds, irrigation, labour and pesticides. Expenses are even higher for farmers cultivating leased land.

Agricultural experts warn that climate change is increasingly threatening onion production in Bangladesh, with rising temperatures, erratic rainfall, prolonged droughts, flash floods, cold waves, dense fog and increasing soil salinity reducing production, quality and storage capacity. They say the impacts extend beyond farmers, posing risks to food security, inflation and the national economy.

One of the world's most important spice and vegetable crops, onion (Allium cepa) is highly sensitive to climatic conditions. Its growth depends on specific temperature ranges, photoperiod and soil moisture, making it vulnerable even to slight weather changes.

Experts said the ideal temperature for the initial growth stage ranges between 12°C and 25°C, while bulb formation requires temperatures of 20°C to 30°C with sufficient sunlight. However, rising temperatures caused by global warming are disrupting normal plant development. In many cases, bulbs begin forming prematurely, producing undersized onions commonly known among farmers as marble-sized bulbs. Excessive heat also reduces photosynthesis, increases transpiration and weakens plants, resulting in lower yields. Sudden temperature fluctuations often produce double or split bulbs, which receive lower market prices.

According to the Bangladesh Bureau of Statistics (BBS), onion production increased from about 2.56 million tonnes in FY2019-20 to approximately 2.917 million tonnes in FY2023-24. Despite the increase in output, production costs have risen by around 30 to 35 percent over the past five years because of higher prices of fertiliser, diesel, seeds, pesticides and labour.

Changing rainfall patterns have become another major challenge. Rainfall is often absent when crops need moisture but arrives heavily during seedbed preparation or harvesting. As a result, seedbeds become submerged, seeds rot and germination declines. Waterlogging also encourages fungal diseases such as damping-off and root rot, which can destroy entire fields. Rain during harvesting prevents proper drying of onions, leading to heavy post-harvest losses from black mould and other fungal infections during storage.

Farmers' experiences suggest that climate uncertainty is now affecting the entire onion production chain-from seedbed preparation to storage. Untimely rainfall destroys seedbeds, irregular winters and sudden heatwaves reduce yields, while adverse weather during harvest and inadequate storage facilities cause significant post-harvest losses.

Distinguished Fellow at the Centre for Policy Dialogue (CPD), Dr Mustafizur Rahman, said climate-induced production losses are forcing Bangladesh to rely more heavily on imports. If exporting countries are also hit by climate shocks, international prices rise sharply, increasing import costs, putting pressure on foreign exchange reserves and fuelling domestic food inflation.

He stressed expanding climate-smart agricultural technologies, improving storage facilities and increasing domestic production to reduce future risks.

Meanwhile, rising sea levels are increasing soil salinity in coastal areas. Experts say onion is highly salt-sensitive, and higher salinity limits water absorption, causing leaf tips to dry and plant growth to stop. 

Consequently, many coastal lands are gradually becoming unsuitable for onion cultivation.

Sources said that Bangladesh's annual onion demand stands at around 3.0 to 3.5 million tonnes. However, excessive rainfall, irregular winters and intense heat during March and April are reducing production in both the Murikata and Hali seasons. Lower output creates supply shortages and pushes up market prices. In previous years, retail onion prices exceeded Tk 300 per kilogram, increasing household food expenses and contributing to inflation. Small and marginal farmers, many of whom rely on loans, suffer severe financial hardship when crops fail, while lower domestic production increases dependence on imports and puts additional pressure on foreign exchange reserves.

Agricultural economist Dr Jahangir Alam said climate-related losses in onion cultivation are no longer just a farmers' problem but a major shock to the rural economy. He recommended direct government procurement of onions at fair prices, establishment of modern storage facilities and stronger measures to curb the influence of middlemen, alongside wider adoption of climate-resilient farming practices.