The Amazon is often treated as a single forest, yet the risks its people face from extreme weather vary sharply across borders. A new analysis by researchers from Brazil, Ecuador, Bolivia, Colombia and the United States suggests those risks are also widely undercounted. The team compiled more than 12,500 reports of storms, floods, landslides, droughts and wildfires between 2013 and 2023, covering five countries. Even with major gaps, the picture is grim. In a single year, more than 3 million people were affected and more than 100,000 pieces of public infrastructure damaged.
The authors show that disasters cluster along two flanks of the basin: the Andean foothills, where steep terrain and intense rain drive landslides, and the Orinoco–Amazon transition zone, where fires linked to agriculture and land grabbing are increasingly common. Ecuador dominates the list of municipalities with the highest reported events. Brazilian cities, by contrast, appear less frequently—not because the country is spared, but because reporting systems differ. Four Amazonian countries offered no municipal data, despite clear evidence of impacts.
Heatwaves and droughts show the starkest reporting failure. Almost all recorded incidents came from Brazil, even though both hazards occur throughout the region. The authors argue these events are “likely underreported across the Amazon,” a conclusion echoed by satellite evidence of warming and drying trends.
Remote-sensing data helped validate parts of the record. In Bolivia, peaks in satellite-detected “hot pixels” matched wildfire reports. Floods increased during years with more days of heavy rain, and landslides were concentrated in higher-elevation municipalities along deforested slopes. Still, the correlations cannot compensate for missing or inconsistent government records.
The broader concern is mounting vulnerability. Many affected communities depend on forests, rivers and small-scale farming. When drought exposes riverbeds, food security collapses. When floods overwhelm sanitation systems in river cities like Manaus, tens of thousands are exposed to untreated wastewater. And wildfire smoke now reaches major urban centers, driving respiratory illness far beyond the fire zones.
The study concludes that the region lacks the shared data, coordination and long-term planning required to cope with worsening climate risks. As the authors write, countries must “envision the Amazon as a single system” and design transboundary strategies accordingly.
CITATION: Rayane Pacheco et al (2025). Weather Disasters and their Underreported Transboundary Impacts on Amazonian Communities. Environmental Research Letters. In press https://doi.org/10.1088/1748-9326/ae20a7
