Analysis of proposed CO₂ emission reductions in the context of stabilization of CO₂ concentration

Targets for reduction of CO₂ emissions have been proposed in response to concerns over future global climate change with a focus on a 2010 target date. We develop emission scenarios over the 1990 to 2010 time-frame from available emissions data, and which encompass the range of proposed emission reductions. Emission reductions over this time frame could be viewed as steps towards mitigating impacts of climate change as well as steps towards the objective of the Framework Convention on Climate Change which is, in part, the stabilization of greenhouse gas concentrations. Illustrative analyses of the stabilization of CO₂ concentration have defined pathways that lead to constant CO₂ concentrations over time ranges of greater than a century. While the prediction of specific impacts of climate change is highly uncertain, models have been developed to project changes in global-average temperature, sea level, and CO₂ concentration; these quantities are often used as indicators in place of specific impacts of climate change. In this study, we summarize projections made with our Integrated Science Assessment Model of these quantities for the range of emission scenarios, and find that the reductions considered are not expected to effect near-term (by 2010) impacts. We also find no obvious correspondence between CO₂ emissions reductions by 2010 and the stabilization levels eventually arrived at by previously defined pathways of CO₂ concentration.