Emissions targets - what the numbers mean

摘要

The federal government has committed to reducing Australia's 2000 greenhouse gas emissions by 60% by 2050. It has also committed to setting a medium term (2020) emissions reduction target by the end of 2008. There has been vigorous public debate about the stringency of the prospective medium term target, particularly in the context of the Garnaut Review's release of its supplementary draft report on targets and trajectories. This article aims to explain Garnaut's proposal, how it relates to international negotiations leading towards an agreement on greenhouse gas reduction and how targets relate to atmospheric concentrations of carbon dioxide equivalent and global warming. The first issue is that the base year used to set the target and what is included in the greenhouse gas emissions count are important. The federal government's commitment sets 2000 as the base year, but many participants in the debate say that 1990, the base year for the Kyoto Protocol, should be used. The implication is that because emissions have grown between 1990 and 2000, using the former as the base takes this growth into account.