Bhutan rice heartland faces climate strain as heat and water drop

Warming temperatures, erratic rainfall, and drying water sources are straining Punakha’s rice farming, reducing productivity and livelihoods while exposing the growing vulnerability of Bhutan’s key agricultural valley.

Rising temperatures and dwindling water supplies are putting increasing pressure on rice farming in Punakha, Bhutan’s most productive agricultural valley, as farmers report falling yields and growing uncertainty over their future.

Often described as the country’s rice bowl, Punakha is warming at a rate that is straining large stretches of paddy land. Irrigation channels that once sustained crops are running low, while heat and erratic rainfall are reshaping farming conditions in the valley.

“The water is not like before,” said Aum Gyem, a 65-year-old farmer in Changyel. She said the irrigation flow weakens at critical times and added that the heat “feels different”.

These experiences are supported by scientific findings. A study by Karma Tempa, Assistant Professor at the College of Science and Technology, documents a sharp rise in land surface temperatures in Punakha over the past three decades.

The research, titled “Emerging heat stress and local prospects in Punakha, Bhutan: Opportunities and challenges of satellite-based observation”, points to an escalating climate threat to the valley’s long-standing farming traditions.

According to the study, pre-monsoon maximum temperatures have increased by about 2.8°C per decade, while average maximum temperatures have risen by roughly 3.55°C per decade. Post-monsoon temperatures have also climbed by around 2.5°C per decade.

Punakha’s location makes it particularly vulnerable. As a low-altitude valley and a key rice-growing region, it has always been warmer than much of Bhutan. That baseline warmth is now intensifying.

Climate data from 1996 to 2025 show hotter summers and heavier monsoon rainfall. August 2024 recorded a peak temperature of 33.6°C, while the lowest minimum temperature was 4.0°C in January 2013. Rainfall extremes have become more pronounced, with 257 mm recorded in August 2002 and 204 mm in August 2023, even as winter months grow increasingly dry.

Tempa combined satellite observations with community surveys to assess local impacts. The findings show widespread concern among farmers.

Nearly 93 percent of respondents reported declining water resources linked to rising temperatures. More than half said farm productivity had decreased, while about 44 percent reported direct impacts on their livelihoods. Almost all respondents, 98.2 percent, said rising heat poses a serious threat to their future.

The study did not identify significant negative health effects so far, suggesting the main impacts remain environmental and economic.

Farmers across the valley say the changes are already evident.

“Now, rains are unpredictable and water sources have dried up,” said Aum Mindu, 61, from Talo. “If it keeps getting hotter, we don’t know how long this will work.”

In Yebesa in Chubu Gewog, Namgay Bidha, 37, said yields have declined and more land is being left uncultivated each year.

Older farmers also report reduced physical endurance. “Before, we could work for hours,” said Dorji, 69, from Sirigang. “Now it is not possible.”

Agricultural data reflect these concerns. The Integrated Agriculture and Livestock Survey 2025 shows total rice production fell slightly from 8,059.45 metric tonnes in 2022 to 7,760.55 metric tonnes in 2023 before recovering to 8,027.35 metric tonnes in 2025. However, yield per harvested acre declined steadily from 2.28 metric tonnes per acre in 2022 to 2.07 metric tonnes per acre in 2025, indicating falling productivity despite expanded cultivation.

Water scarcity remains a central challenge. Farmers depend heavily on rivers and catchment streams, many of which are under strain.

Nationwide, 0.9 percent of 7,399 identified water sources have already dried up, while another 1,856 sources, or 25.1 percent, are drying. Punakha is among the affected areas, with some villages reporting no reliable water supply.

The impact is visible in rising fallow land. In 2023, more than 1,455 acres across Punakha’s 11 gewogs were left uncultivated, including over 900 acres of wetland. Lingmukha, Shengana and Talo recorded some of the highest levels, with 134.205 acres, 132.5 acres and 122 acres of uncultivated wetland respectively.

Climate stress is also increasing pest risks. In 2023, hopper infestations damaged paddy fields in Shengana, with officials linking the outbreak to temperature fluctuations and intense afternoon heat, conditions that favour pests and diseases.

Despite these challenges, Punakha’s agriculture remains diverse. Farmers cultivate several rice varieties, including Nab-Ja, Tan-Tshering and the high-value scented Bondey. Prices have risen, but often not enough to offset declining yields and rising risks.

The study also highlights broader vulnerabilities across Himalayan valleys. Punakha spans subtropical, temperate and alpine zones, exposing it to multiple climate hazards. Rising temperatures could accelerate glacial retreat upstream, increasing the risk of glacial lake outburst floods, while also disrupting hydrological cycles and reducing water availability for irrigation.

Tempa called for urgent localised climate risk assessments and the adoption of climate-smart farming practices. Recommended measures include improved irrigation systems, drought-resistant crop varieties and stronger water management, aligned with Bhutan’s National Adaptation Plan and the UN Sustainable Development Goal 13 on climate action.

He stressed the need for long-term, sector-specific adaptation programmes supported by strong financial backing.

“Rising temperatures are inevitable and require place-based responses,” Tempa said, adding that data-driven research, risk-informed governance, better institutional coordination and early warning systems are key to effective action.

For farmers, however, the concern is immediate survival.

In Changyel, Aum Gyem said a neighbour left land uncultivated last year due to water shortages. Such decisions, repeated across the valley, are gradually reshaping the agricultural landscape.

Punakha’s situation reflects a slower, less visible form of climate change. Unlike sudden disasters, rising heat and shrinking water supplies unfold gradually, often escaping urgent attention. Yet their cumulative impact can be severe, particularly in regions where livelihoods depend on natural cycles.

Farmers continue to adapt with limited resources. The challenge now is whether broader and coordinated action will come in time to sustain the productivity of Bhutan’s most fertile fields.

This post is republished from ASIA NEWS NETWORK.