Example of Qualitative Criteria

International bunker fuels are fuels consumed for aviation or marine international transport activities, and emissions from these fuels are reported separately from totals in accordance with the IPCC guidelines. If these emissions were included in the totals, they would qualify as a key category according to the Tier 1 approach for most Parties. In addition, difficulties in collecting data on the use of bunker fuels and the use of varying definitions are a few of the uncertainties that could have a significant effect on total emission trends.

Fossil fuel feedstocks including naphthas, liquefied petroleum gases, and natural gas are used in the manufacture of a wide variety of man-made chemicals and products, in addition to their use as fuels.

Non-fuel feedstock uses of fossil fuels include manufacture of plastics, rubber, synthetic fibers, solvents, paints, fertilizers, pharmaceuticals, and food additives.

Subsequent use or disposal of these products may result in either carbon storage or carbon emissions. Industrial coking coal, petroleum coke, distillate and residual fuel oils, and other fossil fuels are also used for non-energy uses. Because non-fuel uses of these fuel types are diverse, the carbon storage and carbon emissions from these non-fuel uses are difficult to characterize.

Non-energy uses of fossil fuels represent a significant fraction of the total carbon in the fossil fuel combustion inventory estimates. Small changes in storage factors for these non-energy uses may result in significant changes in estimates of CO₂ emissions from fossil fuel combustion. Therefore, non-energy use of fossil fuels may be considered to be a key source from a qualitative standpoint.