Effective CO₂ lifetime and future CO₂ levels based on fit function

Abstract. The estimated global CO₂ emission rates and the measured atmospheric CO₂ concentrations show that only a certain share of the emitted CO₂ accumulates in the atmosphere. For given atmospheric emissions of CO₂, the effective lifetime determines its accumulation in the atmosphere and, consequently, its impact on the future global warming. We found that on average the inferred effective lifetime of CO₂ decreases as its atmospheric concentration increases, reducing the rate of its accumulation in the atmosphere. We derived a power function that fits the varying lifetimes. Based on this fitting function, we calculated the increase of CO₂ for different scenarios of future global emission rates.