Warming from Tropical Deforestation Linked to 28,000 Excess Deaths per Year.
Published by Carbon Brief on 27 August 2025, a landmark study in Nature Climate Change reveals that warming driven specifically by tropical deforestation contributed to an average of 28,300 excess heat-related deaths annually across Africa, South America, and Asia between 2001 and 2020 (Carbon Brief).
Deforestation’s Hidden Toll on Heat and Health
The study pioneers an analysis that isolates the warming caused by deforestation—separate from broader fossil fuel–driven climate change. Key findings include:
Tropical deforestation alone caused 0.45 °C of warming in affected regions, representing 64% of the local warming in areas with forest loss (Carbon Brief).
345 million people were exposed to additional local warming in that period (Carbon Brief).
On average, six deaths per 100,000 residents in deforested areas were attributable to this excess warming (Carbon Brief).
In specific hot spots, such as Vietnam, this figure reached 29 deaths per 100,000 people (Carbon Brief).
Mechanisms and Geography: Heat, Forest Loss, and Exposure
Deforestation disrupts evapotranspiration—the cooling process where trees draw water from soil to leaves then into the atmosphere—thus reducing local cooling and driving temperature increases (Carbon Brief).
Satellite data reveals substantial warming:
Central and South America: ~0.34 °C rise
Tropical Africa: ~0.10 °C rise
Southeast Asia: ~0.72 °C rise (Carbon Brief)
Comparing deforested regions to forested neighbors, the study estimates an average 0.7 °C warming in deforested zones vs. 0.2 °C in intact forests, solidifying the 0.45 °C attribution to deforestation (Carbon Brief).
Quantifying Human Impact
Using population density data and mortality risk models from the Global Burden of Disease, researchers estimated non-accidental deaths linked to the elevated heat. Combining these models with local warming data revealed the staggering toll: 28,300 extra deaths per year across the tropics, accounting for 39% of heat-related mortality in deforested areas (Carbon Brief).
Highlights, Caveats, and Voices
Several experts described the study as “sobering,” reframing deforestation not just as an environmental or carbon concern, but as a public health emergency (Carbon Brief).
Methodological caveats include:
Reliance on models (not direct measurements)
Use of South American heat-vulnerability data to estimate African impacts, due to data limitations in Africa (Carbon Brief)
Acknowledgment that warming effects can extend up to 100 km from deforested zones (Carbon Brief)
The study also stresses that vulnerable and Indigenous communities, often living near deforested areas with limited resources, bear the brunt of these impacts (Carbon Brief).
Beyond Heat: Wider Implications
Deforestation’s consequences are mounting:
It undermines biodiversity, degrades critical ecosystem services, and exacerbates carbon emissions (Carbon Brief).
It potentially facilitates the spread of zoonotic diseases like malaria (Carbon Brief).
The study underscores that planting more trees and halting deforestation are essential strategies to reduce extreme heat and safeguard public health (Carbon Brief).
Why It Matters
Quantifies a clear link between tropical deforestation and human mortality.
Elevates deforestation as a pressing public health concern, not just an environmental one.
Emphasizes action, urging forest conservation and reforestation to curb not only climate change but direct human suffering.
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