Lifetime of Anthropogenic Climate Change: Millennial Time Scales of Potential CO2 and Surface Temperature Perturbations

TLDR

The study investigates the persistence of climatic impacts from anthropogenic CO₂ emissions using multimillennial simulations. Multimillennial simulations with a fully coupled climate–carbon cycle model are employed to evaluate the absorption of anthropogenic CO₂ and the resulting climate response. The simulations show that absorbing 50 % of anthropogenic CO₂ can take over 2000 years, the climate response is largely independent of emission rate, and the resulting temperature anomaly may last up to 60 % longer than the CO₂ itself, with two‑thirds of the peak warming persisting beyond 10 000 years, implying millennial‑scale consequences.

Abstract

Abstract Multimillennial simulations with a fully coupled climate–carbon cycle model are examined to assess the persistence of the climatic impacts of anthropogenic CO2 emissions. It is found that the time required to absorb anthropogenic CO2 strongly depends on the total amount of emissions; for emissions similar to known fossil fuel reserves, the time to absorb 50% of the CO2 is more than 2000 yr. The long-term climate response appears to be independent of the rate at which CO2 is emitted over the next few centuries. Results further suggest that the lifetime of the surface air temperature anomaly might be as much as 60% longer than the lifetime of anthropogenic CO2 and that two-thirds of the maximum temperature anomaly will persist for longer than 10 000 yr. This suggests that the consequences of anthropogenic CO2 emissions will persist for many millennia.