Data from: Greenhouse gas emissions from reservoir water surfaces: a new global synthesis

Collectively, reservoirs created by dams are thought to be an important source of greenhouse gases (GHGs) to the atmosphere. So far, efforts to quantify, model, and manage these emissions have been limited by data availability and inconsistencies in methodological approach. Here, we synthesize reservoir CH4, CO2, and N2O emission data with three main objectives: (1) to generate a global estimate of GHG emissions from reservoirs, (2) to identify the best predictors of these emissions, and (3) to consider the effect of methodology on emission estimates. We estimate that GHG emissions from reservoir water surfaces account for 0.8 (0.5–1.2) Pg CO2 equivalents per year, with the majority of this forcing due to CH4. We then discuss the potential for several alternative pathways such as dam degassing and downstream emissions to contribute significantly to overall emissions. Although prior studies have linked reservoir GHG emissions to reservoir age and latitude, we find that factors related to reservoir productivity are better predictors of emission.

学界普遍认为，大坝构筑的水库是大气温室气体（Greenhouse Gases, GHGs）的重要排放源。迄今为止，针对此类排放的量化、建模与管控工作，均因数据可获得性不足及研究方法不统一而受到限制。本研究整合了水库甲烷（CH4）、二氧化碳（CO2）与一氧化二氮（N2O）的排放数据，设定三大核心目标：一是估算全球水库温室气体排放总量，二是明确此类排放的最优预测因子，三是探讨方法学对排放估算结果的影响。本研究估算显示，水库水面温室气体排放量年均达0.8（0.5~1.2）拍克（Petagram，Pg）二氧化碳当量，其中甲烷（CH4）是主要的辐射强迫贡献来源。随后，本研究探讨了大坝脱气、下游排放等若干替代路径对总排放量的显著贡献潜力。尽管既往研究曾将水库温室气体排放与水库寿命、纬度挂钩，但本研究发现，与水库生产力相关的因子才是更优的排放预测因子。