Abstract
Nitrous oxide (N2O) is approximately 265 times more potent than carbon dioxide (CO2) in atmospheric warming. Degraded peatlands are important sources of N2O. The more a peat soil is degraded, the higher the N2O-N emissions from peat. In this study, soil bulk density was used as a proxy for peat degradation to predict N2O-N emissions. Here we report that the annual N2O-N emissions from European managed peatlands (EU-28) sum up to approximately 145 Gg N year−1. From the viewpoint of greenhouse gas emissions, highly degraded agriculturally used peatlands should be rewetted first to optimally reduce cumulative N2O-N emissions. Compared to a business-as-usual scenario (no peatland rewetting), rewetting of all drained European peatlands until 2050 using the suggested strategy reduces the cumulative N2O-N emissions by 70%. In conclusion, the status of peat degradation should be made a pivotal criterion in prioritising peatlands for restoration.
Highlights
Nitrous oxide (N2O) is approximately 265 times more potent than carbon dioxide (CO2) in atmospheric warming
The managed European peatlands are characterized by a wide range of topsoil (0–30 cm) bulk density (BD) from 0.1 to 0.9 g cm−3 (Supplemental Fig. 1)
The estimated average N2O-N emission factors using BD for cropland, grassland, and forest were 19.3, 17.4, and 3.4 kg N ha−1 year−1, respectively (Table 1), which are greater than the default values from IPCC (Supplemental Table 1)
Summary
Nitrous oxide (N2O) is approximately 265 times more potent than carbon dioxide (CO2) in atmospheric warming. Nitrous oxide (N2O) is classified as a long-lived GHG and has a global warming potential of ~265 times[3] that of carbon dioxide (CO2). Peatland drainage causes land subsidence and carbon mineralization leading to soil degradation, GHG emissions (e.g., CO2, N2O), and dissolved organic carbon (DOC) leaching into downstream water bodies[12,13]. It has been reported that the well-drained and nitrogen-rich tropical peatlands are global N2O emission hotspots[16]. The N2O emissions from drained peatlands vary greatly because of nutrient content variations and land management. Several studies[19,21,22] found that N2O emissions from cropland and grassland are generally higher than those from the forest (natural peatlands drained for forestry). In the national GHG inventories, the published IPCC default emission factors (Tier 1)
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