Global importance of methane emissions from drainage ditches and canals
Global importance of methane emissions from drainage ditches and canals
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DOI：
10.1088/1748-9326/abeb36
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发表时间：
2021-04-01
影响因子：
6.7
通讯作者：
Evans, C. D.
中科院分区：
文献类型：
--
作者：
Peacock, M.;Audet, J.;Evans, C. D.
在全球范围内，有数百万公里的排水沟有可能排放强大的温室气体甲烷（CH 4），但这些排放量没有在内陆沃茨或排水土地的预算中报告。在这里，我们综合数据表明，跨越全球纬度梯度和不同的土地利用沟渠排放大量的甲烷到大气中。特定区域的排放量与湖泊、溪流、水库和湿地的排放量相当。虽然人们普遍认为，排水否定陆地甲烷排放量，我们发现，甲烷排放量从沟渠，平均而言，抵消类似于10%的这种减少。使用全球排水土地面积，我们表明，沟渠贡献3.5 Tg CH 4年（-1）（0.6-10.5 Tg CH 4年（-1））;相当于全球人为CH 4排放量的0.2%-3%。CH 4排放量与温度呈正相关关系，富营养化沟渠的排放量最高。我们主张将沟渠排放纳入国家温室气体清单，因为忽视它们可能导致关于基于排水的土地管理对CH 4预算影响的错误结论。
Globally, there are millions of kilometres of drainage ditches which have the potential to emit the powerful greenhouse gas methane (CH4), but these emissions are not reported in budgets of inland waters or drained lands. Here, we synthesise data to show that ditches spanning a global latitudinal gradient and across different land uses emit large quantities of CH4 to the atmosphere. Area-specific emissions are comparable to those from lakes, streams, reservoirs, and wetlands. While it is generally assumed that drainage negates terrestrial CH4 emissions, we find that CH4 emissions from ditches can, on average, offset similar to 10% of this reduction. Using global areas of drained land we show that ditches contribute 3.5 Tg CH4 yr(-1) (0.6-10.5 Tg CH4 yr(-1)); equivalent to 0.2%-3% of global anthropogenic CH4 emissions. A positive relationship between CH4 emissions and temperature was found, and emissions were highest from eutrophic ditches. We advocate the inclusion of ditch emissions in national GHG inventories, as neglecting them can lead to incorrect conclusions concerning the impact of drainage-based land management on CH4 budgets.