This study simulates long-term future climate scenarios to assess the persistence of CO₂ emissions in the atmosphere. Results show that the land stores 4 %–13 % of emissions after 100 kyr and that the removal timescale of CO₂ for silicate weathering is shorter than previously expected. Our study highlights the importance of adding model complexity to the global carbon cycle in Earth system models for improved predictions of long-term atmospheric CO₂ concentration.