Abstract

This report highlights the consequences of two policy scenarios of concern to the Climate Convention. In the first scenario CO2 would be stabilized in the atmosphere at 350 ppm by the year 2150 (367 ppm by 2100) ; in the second scenario it would be stabilized at 450 ppm in 2100. Among the main findings of this report are: - To achieve these stabilization targets, global emissions are not allowed to substantially increase at any time in the future, and eventually they must be significantly reduced. - Because of the current upward trend in global emissions, there is a large policy gap between the allowable emissions for stabilizing greenhouse gases, and the emissions that will occur if no action is taken. - Stabilization scenarios lead to much lower impacts on crop productivity, natural vegetation, and sea level rise as compared to the baseline case. - Although the stabilization scenarios show lower impacts than a baseline, they are not "risk-free". Some impacts do occur, and to further reduce these impacts would require more stringent stabilization targets.