The recent enhancement of CO2 uptake by the terrestrial biosphere is slowing down an acceleration of the atmospheric CO2 increase. A stimulating effect of rising atmospheric CO2 on plant photosynthesis (CO2 fertilization) provides the most pronounced impact on the enhanced CO2 uptake. However, the question remains on how much of the enhanced uptake CO2 fertilization accounts for and a possible contribution from past land use change. Here using multiple terrestrial biosphere models, we demonstrate that despite a large contribution from CO2 fertilization, the enhanced CO2 uptake in the 2000s cannot be fully explained without an increasing uptake by land use change, in particular, plant regrowth. The regrowth effect is most pronounced in North America, Europe, and temperate Eurasia, and they account for 94% of the global total CO2 uptake enhancement by plant regrowth. The strengthening trends in both CO2 fertilization and plant regrowth suggest that the deceleration of the atmospheric CO2 increase continues in the future.