Global peatlands store more carbon than is naturally present in the atmosphere^1,2. However, many peatlands are under pressure from drainage-based agriculture, plantation development and fire, with the equivalent of around 3 per cent of all anthropogenic greenhouse gases emitted from drained peatland^3,4,5. Efforts to curb such emissions are intensifying through the conservation of undrained peatlands and re-wetting of drained systems⁶. Here we report eddy covariance data for carbon dioxide from 16 locations and static chamber measurements for methane from 41 locations in the UK and Ireland. We combine these with published data from sites across all major peatland biomes. We find that the mean annual effective water table depth (WTD_e; that is, the average depth of the aerated peat layer) overrides all other ecosystem- and management-related controls on greenhouse gas fluxes. We estimate that every 10 centimetres of reduction in WTD_e could reduce the net warming impact of CO₂ and CH₄ emissions (100-year global warming potentials) by the equivalent of at least 3 tonnes of CO₂ per hectare per year, until WTD_e is less than 30 centimetres. Raising water levels further would continue to have a net cooling effect until WTD_e is within 10 centimetres of the surface. Our results suggest that greenhouse gas emissions from peatlands drained for agriculture could be greatly reduced without necessarily halting their productive use. Halving WTD_e in all drained agricultural peatlands, for example, could reduce emissions by the equivalent of over 1 per cent of global anthropogenic emissions.

全球泥炭地储存的碳比大气中自然存在的碳还要多^1,2。然而，许多泥炭地正承受着排水农业、种植园开发和火灾的压力，相当于排水泥炭地排放的所有人为温室气体的 3% 左右^3,4,5。通过保护未排水的泥炭地和重新润湿排水系统⁶ ，遏制此类排放的努力正在加强。在这里，我们报告了来自英国和爱尔兰 16 个地点的二氧化碳的涡度协方差数据以及来自英国和爱尔兰 41 个地点的甲烷的静态室测量值。我们将这些与来自所有主要泥炭地生物群落站点的已发布数据相结合。我们发现年平均有效地下水位深度 (WTD _e; 也就是说，通气泥炭层的平均深度）优先于所有其他与生态系统和管理相关的温室气体通量控制。_{我们估计，WTD e}每减少 10 厘米， CO ₂和 CH ₄排放（100 年全球变暖潜能值）的净变暖影响减少相当于每年每公顷至少 3 吨 CO _{2 ，​​直到 WTD e}小于 30 厘米。进一步提高水位将继续产生净冷却效果，直到 WTD _e距离表面 10 厘米以内。我们的研究结果表明，为农业而排干的泥炭地的温室气体排放量可以大大减少，而不必停止其生产性使用。例如，将所有排干的农业泥炭地的WTD _e减半，可以减少相当于全球人为排放量 1% 以上的排放量。