Figure 7-3: The mitigation costs
(1990 US$, present value discounted at 5% per year for the period 1990 to 2100)
of stabilizing CO2 concentrations at 450 to 750 ppmv are calculated
using three global models, based on different model-dependent baselines. Avoided
impacts of climate change are not included. In each instance, costs were calculated
based on two emission pathways for achieving the prescribed target: S (referred
as WGI emissions pathways in WGIII TAR) and WRE as described in response to Question
6. The bars show cumulative carbon emissions between the years 1990 and 2100.
Cumulative future emissions until carbon budget ceiling is reached are reported
above the bars in Gt C.