Evaluating uncertainty in Sweden’s national methane inventory for landfills: A UAV-based case study at Filborna

Sammanfattning

Methane (CH₄) emissions from landfills are a key uncertainty in Sweden’s national greenhouse gas inventory. This thesis evaluates whether UAV-based CH₄ measurements can complement inventory-based estimates, using Filborna landfill in southern Sweden as a case study. UAV-derived emissions from 2022–2024 were compared with an IPCC Tier 2 First Order Decay model, reproduced from Sweden’s national inventory methodology and applied to the Filborna Waste Facility. For the UAV-derived emissions, uncertainty was assessed for wind speed, wind direction, kriging interpolation, sensor precision, and background estimation. Wind direction was the dominant source of uncertainty in the UAV-based flux estimates. The reproduced First Order Decay model showed good agreement with Sweden’s national inventory estimates at the national scale, while UAV measurements revealed short-term, site-specific variability that the model cannot capture directly. UAV methods cannot replace inventory modelling, but can provide independent observations to evaluate assumptions, identify variability, and improve confidence in landfill CH₄ emission estimates.