Reservoirs are essential for human populations, but their global carbon footprint is substantial (0.73–2.41 PgCO₂-equivalent yr⁻¹). Yet the temporal evolution of reservoir carbon emissions and their contribution to anthropogenic radiative forcing remains unresolved. Here we quantify the long-term historical and future evolution (1900–2060) of cumulative global reservoir area, carbon dioxide and methane emissions and the resulting radiative forcing. We show that global reservoir carbon emissions peaked in 1987 (4.4 TmolC yr⁻¹) and have been declining since, due largely to decreasing carbon dioxide emissions as reservoirs age. However, reservoir-induced radiative forcing continues to rise due to ongoing increases in reservoir methane emissions, which accounted for 5.2% of global anthropogenic methane emissions in 2020. We estimate that, in the future, methane ebullition and degassing flux will make up >75% of the reservoir-induced radiative forcing, making these flux pathways key targets for improved understanding and mitigation.

水库对人类至关重要，但它们的全球碳足迹是巨大的（0.73–2.41 PgCO ₂ -当量 yr ^-1）。然而，水库碳排放的时间演变及其对人为辐射强迫的贡献仍未得到解决。在这里，我们量化了累积全球水库面积、二氧化碳和甲烷排放以及由此产生的辐射强迫的长期历史和未来演变（1900-2060 年）。我们表明，全球水库碳排放在 1987 年达到峰值（4.4 TmolC yr ^-1) 并且从那以后一直在下降，这主要是由于随着水库的老化而减少了二氧化碳排放。然而，由于水库甲烷排放量持续增加，水库引起的辐射强迫继续上升，占 2020 年全球人为甲烷排放量的 5.2%。我们估计，在未来，甲烷沸腾和脱气通量将占 >75 % 的储层引起的辐射强迫，使这些通量路径成为提高理解和缓解的关键目标。