Tropical forests use CO₂ as fertilizer but are limited by phosphorus availability

Tropical forests store approximately 72% of the global forest biomass carbon and contribute about one-third of the global net primary productivity (NPP). The CO2 fertilization effect, which enhances CO2 concentrations in leaves and boosts plants' carbon fixation capacity, has been a key mechanism for maintaining and increasing tropical forest productivity. However, the future of this CO2 fertilization effect is uncertain, partly due to nutrient limitations.