In accordance with the Revised 1996 IPCC Guidelines, which are used by Parties to prepare their greenhouse gas inventories, emissions from fuel sold to ships or aircraft engaged in international transport (known as "bunker fuels") should not be included in national emission totals, but reported separately.

Under this item, the SBSTA has undertaken methodological work to increase the accuracy of reporting on bunker fuel emissions in national inventories, and has also explored options for including these emissions in the overall greenhouse gas inventories of Parties; decision 2/CP.3, adopted by COP 3 together with the Kyoto Protocol, urged the SBSTA to "further elaborate" on this issue. The Kyoto Protocol itself calls on Annex I Parties to limit or reduce their greenhouse gas emissions from bunker fuels, working through the International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO) (Article 2.2).

At SBSTA 10 (May/June 1999), Parties considered a Special Report on Aviation and the Global Atmosphere prepared by the IPCC on request of ICAO. At SBSTA 11 (meeting together with COP 5 in Bonn, October/November 1999), Parties stressed the importance of cooperation with ICAO and IMO. The SBSTA also affirmed that the quality of reporting by Annex I Parties on bunker fuel emissions needs to be improved, and that the new reporting guidelines on annual inventories would contribute to such improvement. COP 5 itself adopted a decision requesting the secretariat to develop its cooperation with the secretariats of ICAO and IMO, and the SBSTA to continue its current work on methodological issues related to reporting on bunker fuel emissions.

At SBSTA 12 (June 2000), Parties were provided with copies of the IPCC Report on Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, which contains information on methods to estimate bunker fuel emissions.