Ozone from fires and rising heat threaten Amazon's carbon sink
New research shows that smoke-generated ozone and increasingly frequent heat-drought events are cutting the Amazon’s ability to absorb CO₂, turning parts of the forest into net emitters.
Scientists have documented that ozone formed from smoke of Amazon fires, agricultural burning and forest clearing harms tree foliage far beyond the blaze itself, lowering the forest’s CO₂ absorption by roughly 24 % of the fire’s carbon release. A separate analysis links the severe heat and drought of 2023-2024, driven by El Niño, to a future where such extremes occur almost yearly within the next 20-30 years, disrupting the forest-atmosphere moisture feedback.
Together, these stressors have already pushed large swaths of tropical forest to emit more CO₂ than they capture during droughts. Measurements from controlled growth chambers, satellite reflectivity data and canopy flux towers underpin the findings. While rising CO₂ can slightly reduce ozone uptake, the net impact of more frequent fires, heat, and drought outweighs this benefit. Researchers stress that curbing agricultural burning and halting deforestation are essential to prevent a tipping point for the Amazon.
Why it matters
The Amazon’s declining carbon sink accelerates global warming and threatens climate stability worldwide.
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