In a groundbreaking study published today in Nature Climate Change, researchers have revealed that deforestation across tropical regions has resulted in more than 500,000 heat-related deaths between 2001 and 2020. The loss of forest canopy in rainforests such as those in the Amazon, the Congo Basin, and Southeast Asia has diminished shade, reduced rainfall, and heightened fire risk. These changes have produced significant localized warming, with temperature increases in cleared areas contributing to over one-third of the warming experienced by about 345 million people in these regions.
Of particular concern is the finding that approximately 2.6 million individuals endured an additional 3 °C of heat due to deforestation — a drastic increase that correlates with a consistent annual toll of around 28,330 fatalities from heat-related causes over the 20-year period. The study further highlights regional disparities: Southeast Asia endured the highest share of deaths, owing to its dense population and increased vulnerability to heat stress; tropical Africa accounted for roughly one-third of the fatalities; and Central and South America comprised the remainder.
The research was conducted by a collaborative team across Brazil, Ghana, and the UK, who cross-examined non-accidental mortality data with local temperatures in areas subjected to forest clearing. While previous research had linked deforestation to long-term warming, this study is the first to quantify the resulting human death toll at a global scale.
Professor Dominick Spracklen of the University of Leeds, one of the lead authors, emphasized the urgency and gravity of the findings: “Deforestation kills,” he said. He warned that such lethal, local consequences are often overshadowed by the broader global climate debate and the drive toward market-led agricultural expansion.
To illustrate the real-world implications, Spracklen cited Brazil’s Mato Grosso—a region undergoing widespread deforestation to make way for soybean plantations. He argued that preserving forest canopy in such areas could alleviate heat stress, improve agricultural outcomes, and directly benefit local communities. “These forests aren’t idle—they’re working really hard and doing something really important for us,” he remarked.
This study’s findings underscore the urgent need to confront deforestation not solely as an environmental or climate issue, but as a significant public health crisis with tangible, immediate human costs.
