温室效应已成为重要的全球气候问题，而内陆水体是温室气体(CO2 和CH4)的重要排放源，更有研究发现筑坝蓄水可能引起河流水体CO2 和CH4 排放的增多。为积极响应国家"双碳"目标，使用水库温室气体净排放通量评估模型G-res Tool，利用流域基本信息及水库特征数据，对澜沧江干流已建成的10 座梯级水库温室气体(CO2 和CH4)进行模拟计算，10 座水库蓄水后温室气体(CO2 和CH4)年排放通量平均值为162。81 g CO2e/(m2∙a)，远低于全球水库平均水平，均表现为温室气体的"源"，从上游至下游整体呈增加趋势，且排放以CO2 为主，全年CO2 排放通量为CH4 的 36 倍。考虑了水库蓄水前的温室气体排放及其他非相关人类活动的影响后，得到澜沧江水库温室气体(CO2 和CH4)年净排放通量平均值为 225。70 g CO2e/(m2∙a)，表明筑坝增加了库区水体温室气体排放，但和火力发电相比，仍属于相对清洁能源。
Study on CO2 and CH4 emission fluxes from Lancang River cascade reservoirs
The greenhouse effect has become an important global climate issue,and inland waters are an important source of emissions of the greenhouse gases(GHG)CO2 and CH4.It has been found that hydropower energy,once considered clean,may cause an increase in CO2 and CH4 emissions from river waters as a result of damming and impounding water.In order to actively respond to the national"Dual-Carbon"goal and clarify the impact of damming and impounding on GHG emissions from water bodies,the G-res Tool,a model for evaluating the net flux of GHG emissions from reservoirs,was used to simulate the CO2 and CH4 emission fluxes before and after impoundment of 10 completed terrace reservoirs on the main stream of the Lancang River.The average annual GHG(CO2 and CH4)emission flux of the 10 reservoirs after impoundment is 162.81 g CO2e/(m2∙a),which is much lower than the global average level of reservoirs,but all of them behave as"sources"of GHGs,with an overall upward trend from upstream to downstream.Emissions are dominated by CO2,with an annual CO2 emission fluxes 36 times that of CH4,which is dominated by diffuse and off-gas emissions.After considering the GHG emissions prior to reservoir impoundment and the impacts of unrelated anthropogenic sources,the average annual net flux of GHG(CO2 and CH4)emissions from the reservoir is 225.70 g CO2e/(m2∙a),suggesting that damming increases the release of GHGs from the reservoir waters.However,hydropower is still a relatively clean energy compared to thermal power generation.
Lancang RiverTerraced power stationReservoir greenhouse gasModelNet emission flux
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