• Emissions from road vehicles are expected to have an uncertainty of ±40 percent for CH₄ and ±50 percent for N₂O.
  Paragraph 2.3.1.6. Uncertainty Assessment, CH4 and N2O Emissions
  
• Emissions from water-borne navigation are expected to have an uncertainty of a factor of two for CH₄ and an order of magnitude for N₂O.
  Paragraph 2.4.1.6. Uncertainty Assessment, Water-Borne Navigation
  
• Emissions from civil aviation are expected to have an uncertainty of a factor of two for CH₄ and several orders of magnitude for N₂O.
  Paragraph 2.5.1.6. Uncertainty Assessment, Aircraft

There are other uncertainties associated with carbon content and calorific values for fuels. These are primarily related to the variability in fuel composition within the country and the frequency and scope of actual measurements. The IPCC Good Practice Guidance does not expand on uncertainty ranges for carbon content and calorific values for fuels.