Plant uptake of CO2outpaces losses from permafrost and plant respiration on the Tibetan Plateau

Significance Cold regions contain vast stores of permafrost carbon. Rapid warming will cause permafrost to thaw and plant respiration to accelerate, with a resultant loss of CO 2 , but could also increase the fixation of CO 2 by plants. A network of 32 eddy covariance sites on the Tibetan Plateau, which has the largest store of alpine permafrost carbon on Earth, shows that this region functions as a net CO 2 sink. Our sensitivity analyses, experiments, and model simulations consistently showed that the fixation of CO 2 by plants outpaces the loss of CO 2 from permafrost and accelerates plant respiration. This indicates a plant-dominated CO 2 balance on the Tibetan Plateau, which could provide a negative feedback to climate warming.