Extreme weather events exacerbate nitrous oxide emissions from soil (Extreme-N2O)

对农业温室气体排放量的准确估计是国家土地利用政策和后续目标的基础，例如英国最近提出的到2050年净零碳排放的目标。然而，使用大气浓度对一氧化二氮(N2O)的陆地来源进行建模表明，英国N2O排放的自下而上的温室气体清单要么缺少一个主要来源(S)，要么低估了一个来源(S)。日益频繁的极端天气，例如长期干旱和洪涝，扰乱了土壤的碳、氮和水文循环，影响了土壤在恢复其充气状态(洪灾后)和水分状态(旱后)时温室气体的产生和排放。在极端天气事件期间和之后，土壤中N2O排放量的增加可能是造成这种“缺失的”N2O的原因。虽然人们对土壤中N2O排放量的大小已经知道很多，但大多数用于得出改进的N2O排放系数的实验都是在没有极端天气的情况下进行的，以便在国家温室气体清单中使用。Extreme-N2O项目将检验以下假设：i)极端天气事件会加剧土壤中N2O的产生和排放，ii)极端天气事件会导致N2O的“丢失”。

Accurate estimates of agricultural greenhouse gas emissions underpin national land use policy and subsequent targets, e.g. the recent UK target for net zero carbon emissions by 2050. However, modelling of terrestrial sources of nitrous oxide (N2O) using atmospheric concentrations reveals that the bottom up greenhouse gas inventory for UK N2O emissions is either missing a major source(s) or underestimating a source(s). Increasing frequencies of extreme weather, e.g. prolonged drought and flooding, disrupt soil carbon, nitrogen and hydrological cycles, affecting the production and emission of greenhouse gases from soils as they recover their aeration status (post flooding) and moisture status (post drought). Increased N2O emission from soils during and post extreme weather events may be responsible for this 'missing' N2O. Whilst much is already known about the magnitude of N2O emissions from soil, most experiments used to derive improved N2O emission factors for use in in national greenhouse gas inventories have been conducted in the absence of extreme weather. The Extreme-N2O project will test the hypotheses that i) extreme weather events exacerbate N2O production and emission from soil, and ii) extreme weather events contribute to the 'missing' N2O.