Human factors worsened deadly Assam floods, says global collaborative study

GUWAHATI Human factors, and not necessarily climate change, worsened the floods in a part of eastern Assam that killed at least 103 people, a global collaborative study has said.

According to the World Weather Attribution (WWA), an international scientific collaboration, heavy monsoonal rainfall in northeastern India has remained within historical norms, but land-use changes have increased the impacts and risks to the people and their livelihoods.

Between late June and early August, eastern Assam—particularly Sivasagar, Charaideo, and Jorhat districts—alongside hill catchments in Nagaland and Arunachal Pradesh, experienced intense monsoonal downpours.

The resulting deluge breached critical infrastructure, washed away agricultural land, and forced hundreds of thousands into relief camps. Thousands of livestock and other domesticated animals were also affected.

Scientists from India, Sweden, the Netherlands, the United Kingdom, and the United States analysed historical weather records and climate models, finding that the rainfall totals were not exceptional and are expected at least every two years.

“Although limited datasets for the region mean there is some uncertainty, the analysis showed no clear evidence that climate change was altering the trend in the intensity or likelihood of the rainfall. Instead, they found that the scale of the disaster stems largely from other human factors including colonial-era land regulations, displacement, land degradation, and a lack of sufficient flood mitigation,” the WWA study said on Friday (August 14, 2026).

The study found that unplanned urbanisation, rapid deforestation, wetland destruction, and riverbank erosion degraded Assam’s natural drainage capacity, increasing flood height and downstream impacts.

The scientists said reliance on concrete engineering and hard embankments trapped silt, artificially raising riverbeds and blocking natural runoff. “Embankments frequently exacerbate flooding and increase the risk of catastrophic breaches,” they noted, observing that combining infrastructure with social and nature-based approaches could be more effective in mitigating floods.

Future warming

The study also flagged historical vulnerability. “Historical land reallocation contributed to some indigenous communities living on marginal, flood-prone riverbanks, and sandbars (chars). These historical patterns continue to trap low-income agricultural populations in cycles of repeated displacement,” it said.

“Adaptation efforts must broaden to include floodplain restoration, wetland conservation, and expanded anticipatory disaster risk management using localised early warnings,” the study suggested.

“To understand whether climate change played a role in the rainfall in the Upper (eastern) Assam region and the surrounding hill catchments that led to the landslides and flooding, we analysed short, high-intensity downpours, and longer rainfall accumulations,” Mariam Zachariah, a research associate in extreme weather and climate change at the Centre for Environmental Policy, Imperial College London, said.

“Low station coverage and climate models struggling to capture processes in hilly regions create high uncertainties in the results. Therefore, overall findings suggest no discernible role of climate change. However, a lack of a clear trend today does not make the region immune to future warming. As global temperatures continue to climb, monsoon dynamics across South Asia will keep shifting, making proactive land and river management even more urgent,” she said.

“Hundreds of thousands of people have been affected, with low-income agricultural families and displaced communities paying the highest price. Marginalised populations living on flood-prone sandbars and reliance on rigid concrete embankments can be a recipe for disaster,” Emmanuel Raju, director of Copenhagen Centre for Disaster Research, said.

“True adaptation requires moving towards living with rivers through wetland restoration and proactive early action before floodwaters strike,” he added.

“While climate change is making life harder for most Indians, not every disaster is a climate change disaster. The devastating flooding in Assam was instead driven by extreme human exposure, environmental degradation, and infrastructure limitations,” Friederike Otto, professor of climate science at the Centre for Environmental Policy, said.

“This report is a crucial reminder that building climate resilience is not only about cutting emissions. It is also about sustainable land management, protecting ecosystems, and managing the exposure to disaster risk on the ground,” he said.

Published – August 14, 2026 12:40 pm IST