资源环境科技发展态势分析平台

The El Niño Southern Oscillation (ENSO) is the largest driver of atmospheric CO₂ interannual variability. The equatorial Pacific Ocean, which is a natural source of CO₂ to the atmosphere, acts as a buffer of the terrestrial variations by releasing less CO₂ during El Niño events and releasing more CO₂ during La Niña events. Here, we examine how this ocean carbon buffer will respond to high anthropogenic emissions using Earth system models from CMIP6. Models project weaker ocean CO₂ flux anomalies in the future due to two main factors: a stronger compensation between thermal and non-thermal changes in ocean biogeochemistry (55% of signal) and a weaker influence of ENSO on the CO₂ transfer across the air-sea interface (10-25% of signal). The ocean would no longer buffer the land response to ENSO, and could even reinforce its impact on atmospheric CO₂, amplifying the atmospheric carbon variability on interannual timescales.