The problems associated with the impact of single projects on emissions in the commitment period were first raised by the delegation of Iceland during the negotiations on the Kyoto Protocol. Iceland expressed concern that, for Parties with very low emissions baselines, a single project (e.g. construction of an aluminium smelter) could lead to a disproportionate percentage increase in emissions. Iceland's concerns were reflected through paragraph 5(d) of decision 1/CP.3, which called for this issue to be further considered at COP 4.
At COP4, Iceland proposed a draft decision on the impact of single projects. According to this proposal, single projects that have a significant proportional impact on emissions in the commitment period should be reported separately, and not included in national totals, to the extent that they would cause a Party to exceed its assigned amount. The proposal explicitly limited this provision to:

• Parties that account for less than 0.05% of total Annex I emissions in 1990;
• Single projects involving industrial processes that account for more than 5% of the total greenhouse gas emissions of a Party in 1990;
• Single projects where renewable energy is used, resulting in a reduction in greenhouse gas emissions per unit of production; and
• Single projects where best environmental practice is used to minimize process emissions.