Methane (CH₄) is a potent greenhouse gas and its concentrations have tripled in the atmosphere since the industrial revolution. There is evidence that global warming has increased CH₄ emissions from freshwater ecosystems^1,2, providing positive feedback to the global climate. Yet for rivers and streams, the controls and the magnitude of CH₄ emissions remain highly uncertain^3,4. Here we report a spatially explicit global estimate of CH₄ emissions from running waters, accounting for 27.9 (16.7–39.7) Tg CH₄ per year and roughly equal in magnitude to those of other freshwater systems^5,6. Riverine CH₄ emissions are not strongly temperature dependent, with low average activation energy (E_M = 0.14 eV) compared with that of lakes and wetlands (E_M = 0.96 eV)¹. By contrast, global patterns of emissions are characterized by large fluxes in high- and low-latitude settings as well as in human-dominated environments. These patterns are explained by edaphic and climate features that are linked to anoxia in and near fluvial habitats, including a high supply of organic matter and water saturation in hydrologically connected soils. Our results highlight the importance of land–water connections in regulating CH₄ supply to running waters, which is vulnerable not only to direct human modifications but also to several climate change responses on land.

甲烷 (CH ₄ ) 是一种强效温室气体，自工业革命以来，其在大气中的浓度增加了两倍。有证据表明，全球变暖增加了淡水生态系统的CH _4排放量^1,2，为全球气候提供了正反馈。_{然而，对于河流和溪流来说，CH 4}排放的控制和规模仍然高度不确定^3,4。_{在此，我们报告了对自来水 CH 4}排放量的空间明确的全球估计， 每年占 27.9 (16.7–39.7) Tg CH _{4 ，其数量与其他淡水系统的排放量大致相等}^5,6。河流 CH _{4排放对温度的依赖性不强，与湖泊和湿地的平均活化能 (EM = 0.14 eV) 相比 (EM} = 0.96  eV )  1^较低。相比之下，全球排放模式的特点是高纬度和低纬度地区以及人类主导的环境中存在大通量。这些模式可以通过土壤和气候特征来解释，这些特征与河流栖息地及其附近的缺氧有关，包括与水文相关的土壤中有机质的大量供应和水饱和度。_{我们的研究结果强调了土地与水的联系在调节流水 CH 4}供应方面的重要性，流水不仅容易受到人类直接改变的影响，而且还容易受到陆地上几种气候变化反应的影响。