Estimates of soil nutrient limitation on the CO2 fertilization effect for tropical vegetation

Abstract

The CO₂ fertilization effect in tropical forests is a key factor for the global land carbon sink. We show that the normalized CO₂ effect on tropical vegetation carbon was c. 70% lower in seedling CO₂ experiments without nutrient fertilizers and c. 50% and 70% lower in models that consider nitrogen and phosphorus cycles, based on two model ensembles. The inadequate representation or lack of nutrient cycles in Earth System models likely leads to overestimating future tropical carbon gains.