Non-hazardous engineered landfills (ISDND) are a recognised source of methane emissions — a short-lived but highly potent climate pollutant. According to the national inventory, landfills account for 75 to 81% of GHG emissions from the waste sector (around 12 MtCO₂e/year), compared to roughly 6 MtCO₂e according to industry estimates.

This information paper, produced with Citepa, examines the main methodological limitations behind these discrepancies — landfilled waste composition, the IPCC decomposition model, and methane capture data — and presents ongoing work to improve knowledge of sorting-refuse composition, led by Citepa in partnership with ADEME, FNADE and the French Ministry for Ecological Transition.

The FSWP is working to raise awareness of the importance of improving practices at landfills worldwide as a climate action. Indeed, in addition to reducing the volumes of landfilled waste with high methane-generating potential, design and operational management practices can contribute to reduce methane emissions into the atmosphere. These practices include:

• Biogas capture from the very first months of landfill operation,
• Operating in bioreactor mode
• The installation of an impermeable cover as soon as a cell is closed, and the addition of a layer of soil promoting the oxidation of methane escaping from older cells

French know-how in controlling methane emissions and capturing biogas is an asset that can be leveraged abroad, particularly in the context of international tenders.