资源环境科技发展态势分析平台

A positive marine chemistry‐climate feedback was originally proposed by Revelle and Suess (1957), whereby the invasion flux of anthropogenic carbon into the ocean serves to inhibit future marine CO₂ uptake through reductions to the buffering capacity of surface seawater. Here we use an ocean‐circulation‐carbon‐cycle model to identify an upper limit on the impact of re‐emergence of anthropogenic carbon into the ocean’s mixed layer on the cumulative airborne fraction of CO₂ in the atmosphere. We find under an RCP8.5 emissions pathway (with steady circulation) that the cumulative airborne fraction of CO₂ has a seven‐fold reduction by 2100 when the CO₂ buffering capacity of surface seawater is maintained at pre‐industrial levels. Our results indicate that the effect of re‐emergence of anthropogenic carbon into the mixed layer on the buffering capacity of CO₂ amplifies the transient climate sensitivity of the Earth system.