Accurate constraining the ocean carbon sink is of utmost importance to improve our understanding of the fate of anthropogenic carbon and to better project anthropogenic carbon uptake in the coming decades. This study combines the outcomes of a suite of earth-system models with three well-documented observations (sea surface salinity in the Southern Ocean, strength of Atlantic Overturning and Revelle factor) to reduce bias and uncertainty in the global ocean carbon sink. The results suggest that the ocean carbon sink is about 10% larger than estimated before. This has implications for the global carbon budget.