The contribution of artificial reservoirs to greenhouse gas (GHG) emissions has been emphasized in previous studies. In the present study, we collected and updated data on GHG emission rates from reservoirs at the global scale, and applied a new classification method based on the hydrobelt concept. Our results showed that CH4 and CO2 emissions were significantly different in the hydrobelt groups (p < 0.01), while no significant difference was found for N2O emissions, possibly due to their limited measurements. We found that annual GHG emissions (calculated as C or N) from global reservoirs amounted to 12.9 Tg CH4-C, 50.8 Tg CO2-C, and 0.04 Tg N2O-N. Furthermore, GHG emissions (calculated as CO2 equivalents) were also estimated for the 1950–2017 period based on the cumulative number and surface area of global reservoirs in the different hydrobelts. The highest increase rate in both the number of reservoirs and their surface area, which occurred from 1950 to the 1980s, led to an increase in GHG emissions from reservoirs. Since then, the increase rate of reservoir construction, and hence GHG emissions, has slowed down. Moreover, we also examined the potential impact of reservoir eutrophication on GHG emissions and found that GHG emissions from reservoirs could increase by 40% under conditions in which total phosphorus would double. In addition, we showed that the characteristics of reservoirs (e.g., geographical location) and their catchments (e.g., surrounding terrestrial net primary production, and precipitation) may influence GHG emissions. Overall, a major finding of our study was to provide an estimate of the impact of large reservoirs during the 1950–2017 period, in terms of GHG emissions. This should help anticipate future GHG emissions from reservoirs considering all reservoirs being planned worldwide. Besides using the classification per hydrobelt and thus reconnecting reservoirs to their watersheds, our study further emphasized the efforts to be made regarding the measurement of GHG emissions in some hydrobelts and in considering the growing number of reservoirs.

中文翻译：

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全球水库温室气体排放的长期演变

先前的研究强调了人工水库对温室气体 (GHG) 排放的贡献。在本研究中，我们收集并更新了全球范围内水库温室气体排放率的数据，并应用了基于水带概念的新分类方法。我们的结果表明，水力输送带组的 CH4 和 CO2 排放量显着不同（p < 0.01），而 N2O 排放量没有发现显着差异，可能是由于它们的测量有限。我们发现全球水库的年温室气体排放量（以 C 或 N 计算）为 12.9 Tg CH4-C、50.8 Tg CO2-C 和 0.04 Tg N2O-N。此外，1950 年至 2017 年期间的温室气体排放量（按二氧化碳当量计算）也根据不同水利带中全球水库的累积数量和表面积进行了估算。1950 年至 1980 年代水库数量及其表面积的最高增长率导致水库温室气体排放量增加。从那时起，水库建设的增长速度以及温室气体排放量的增长速度已经放缓。此外，我们还研究了水库富营养化对温室气体排放的潜在影响，发现在总磷翻倍的情况下，水库的温室气体排放量可能增加 40%。此外，我们还展示了水库的特征（例如，地理位置）及其集水区（例如，周围陆地净初级生产、和降水）可能会影响温室气体排放。总体而言，我们研究的一个主要发现是对 1950 年至 2017 年期间大型水库在温室气体排放方面的影响进行估计。考虑到全世界正在规划的所有水库，这应该有助于预测水库未来的温室气体排放。除了使用每个水带的分类，从而将水库重新连接到其流域之外，我们的研究进一步强调了在测量某些水带中的温室气体排放和考虑水库数量不断增加方面所做的努力。考虑到全世界正在规划的所有水库，这应该有助于预测水库未来的温室气体排放。除了使用每个水带的分类，从而将水库重新连接到其流域之外，我们的研究进一步强调了在测量某些水带中的温室气体排放和考虑水库数量不断增加方面所做的努力。考虑到全世界正在规划的所有水库，这应该有助于预测水库未来的温室气体排放。除了使用每个水带的分类，从而将水库重新连接到其流域之外，我们的研究进一步强调了在测量某些水带中的温室气体排放和考虑水库数量不断增加方面所做的努力。