Figure 9.13: Simple model
results. (a) Estimated historical anthropogenic radiative forcing followed by
radiative forcing for the four illustrative SRES marker scenarios and for two
additional scenarios from the A1 family illustrating different energy technology
options. The blue shading shows the envelope of forcing that encompasses the full
set of thirty-five SRES scenarios. The method of calculation closely follows Chapter
6 except where explained in the text. The values are based on the radiative
forcing for a doubling of CO2 from seven AOGCMs as given in Appendix
9.1, Table 9.A1. The IS92a, IS92c and IS92e forcing
is also shown following the same method of calculation. (b) Historical anthropogenic
global mean temperature change and future changes for the six illustrative SRES
scenarios using a simple climate model tuned to seven AOGCMs. Also for comparison,
following the same method, results are shown for IS92a. The dark blue shading
represents the envelope of the full set of thirty-five SRES scenarios using the
simple model ensemble mean results. The light blue envelope is based on the GFDL_R15_a
and DOE PCM parameter settings. The bars show the range of simple model results
in 2100 for the seven AOGCM model tunings.
