Intergovernmental panel on climate change's landfill methane protocol: Reviewing 20 years of application

Area of Science:

• Environmental Science
• Climate Change Research
• Waste Management

Background:

• The Intergovernmental Panel on Climate Change (IPCC) protocol for national methane emission inventories from landfills was established 22 years ago.
• A broad dataset now exists to evaluate the appropriateness of landfill parameters and reported values for various estimates.
• Existing data highlights potential inaccuracies in default values used in current landfill methane prediction models.

Purpose of the Study:

• To review and assess the appropriateness of landfill parameters and reported values used in the IPCC protocol.
• To identify uncertainties and limitations in the IPCC protocol for predicting national methane emission inventories.
• To compare experimental and field-validated data with IPCC default values for key parameters.

Main Methods:

• Literature review of existing datasets on landfill parameters.
• Analysis of reported values for degradable organic carbon (DOC), DOC fraction (DOC f), methane correction factor, methane fraction (F), methane generation rate constant (k), and methane oxidation (OX).
• Comparison of reviewed data with default values specified in the IPCC Revised Guidelines (1996).

Main Results:

• Degradable organic carbon (DOC) content in waste varies widely (0.0105 to 0.65 g C/g waste).
• Field validation of methane correction factors yielded substantially lower values than IPCC defaults.
• Methane generation rate constants (k) show wide variation (0.01 to 0.51 y⁻¹), and methane oxidation (OX) values can exceed reported defaults.

Conclusions:

• The IPCC protocol is a practical tool but possesses significant uncertainties and limitations.
• The default values in the IPCC protocol may not accurately represent real-world landfill conditions.
• The protocol's application for purposes beyond national inventory development requires careful consideration of its limitations.