Effect of Rainforest Deforestation on Atmospheric Oxygen

Cutting down rainforests reduces global oxygen production, but the effect on atmospheric O₂ concentration is negligible on human timescales. Here's why:

Oxygen Production vs. Reservoir

• Rainforests produce ~28% of terrestrial photosynthesis (~16% of global O₂ production including oceans).
• However, the atmosphere contains ~1.2 × 10¹⁸ kg of O₂—a massive reservoir.
• Even total tropical deforestation would lower O₂ by <0.01%—undetectable against the 20.95% baseline.

Real Concerns

The critical impacts of deforestation are:

• Carbon release – Forests store ~250 Gt C; clearing emits CO₂, accelerating climate change.
• Biodiversity loss – Rainforests harbor >50% of terrestrial species.
• Hydrological disruption – Reduced evapotranspiration alters regional rainfall.
• Indigenous displacement – Loss of homeland and culture.

Oxygen depletion is a myth; carbon and biodiversity are the real crises.