The stoichiometry of carbon to nitrogen ratio (C:N) plays an important role in biogeochemical cycling in terrestrial ecosystems. As time goes by, the increase in atmospheric CO₂ levels is expected; however, the impact of elevated atmospheric CO₂ on the C:N stoichiometry of soils, plants, and microorganisms remains largely unclear. The results of the meta-analysis that included 174 studies with 1009 observations demonstrated that above- and below-ground C concentrations and C:N ratio increased under elevated CO₂ regimes, whereas N concentrations decreased. Importantly, these responses were more pronounced with rising CO₂ concentrations and longer experimental durations. Moreover, the responses of C, N, and C:N to elevated CO₂ were similar across croplands, forests, and grasslands ecosystems with varying climates. Our results revealed that the C:N stoichiometry of soils, plants, and microorganisms responded consistently to the rising global CO₂ levels, which indicated that terrestrial ecosystems might have the capacity to mitigate increased atmospheric CO₂ concentrations by increasing C sequestration in plants, soils, and microorganisms in future.

碳氮比（C：N）的化学计量在陆地生态系统的生物地球化学循环中起着重要作用。随着时间的流逝，预计大气中CO ₂含量会增加；然而，大气中CO ₂浓度升高对土壤，植物和微生物的C：N化学计量的影响尚不清楚。荟萃分析的结果包括174项研究和1009项观察结果，结果表明，在升高的CO ₂浓度下，地上和地下的C浓度和C：N比增加，而N浓度降低。重要的是，随着CO ₂浓度的升高和实验时间的延长，这些反应更加明显。此外，C，N和C：N对CO升高的响应在气候不同的农田，森林和草原生态系统中，有₂个相似。我们的结果表明，土壤，植物和微生物的C：N化学计量对不断上升的全球CO ₂水平做出了一致的响应，这表明陆地生态系统可能具有通过增加植物，土壤中C的固存来减轻大气中CO ₂浓度的能力以及将来的微生物。