This dataset is a synthesis of published nitrous oxide (N2O) fluxes from permafrost-affected soils in Arctic, Antarctic, and Alpine permafrost regions. The data includes mean N2O flux rates measured under field (in situ) conditions and in intact plant-soil systems (mesocosms) under near-field conditions. The dataset further includes explanatory environmental parameters such as meteorological data, soil physical-chemical properties, as well as site and experimental information. Data has been synthesized from published studies (see 'Further details'), and in some cases the authors of published studies have been contacted for additional site-level information. The dataset includes studies published until 2019. We encourage linking additional N2O flux data from unpublished and future studies with similar metadata structure to this dataset, to produce a comprehensive, findable database for N2O fluxes from permafrost regions.

If not reported, water-filled pore space (WFPS) was calculated as follows: WFPS (%) = VWC/(1-BD/PD)100, where VWC is the volumetric water content, BD is the bulk density, and PD is the particle density. If BD was not reported, BD was estimated from the SOM content using functions developed for Arctic soils (Hossain et al, 2015) as follows: 0.075+1.301EXP(-0.06SOM) for mineral soils, and 0.0430+4.258EXP(-0.047SOM) for organic soils. If not reported, SOM via loss on ignition was derived from the soil carbon content as follows: SOM (%) = C content2. If the resulting SOM value was >100%, SOM (%) = C content1.724. PD can be derived as follows (Okruszko, 1971): PD = 0.011*(100-SOM)+1.451 (see references Okruszko, 1971 and Hossain et al, 2015). The term "topsoil" depends on the exact depths the soil characteristics are reported in the individual publications, but generally the soil layer of 0–10cm was used. Column "SOC" includes mostly total soil C content (reported in the majority of studies), and on some occasions total organic C.