Figure 4.14: Atmospheric
composition and properties predicted using the six SRES Marker-Illustrative scenarios
for anthropogenic emissions: A1B (green dashed line), A1T (yellow dash-dotted),
A1FI (orange dash-dot-dotted), A2 (red solid), B1 (cyan dashed), B2 (solid dark
blue). Abundances prior to year 2000 are taken from observations, and the IS92a
scenario computed with current methodology is shown for reference (thin black
line). Results are shown for CH4 (ppb), N2O (ppb), tropospheric
O3 (DU), HFC-134a (ppt), CF4 (ppt), SF6 (ppt),
the lifetime of CH4 (yr), and the global annual mean abundance of tropospheric
OH (scaled to year 2000 value). All SRES A1-type scenarios have the same emissions
for HFCs, PFCs, and SF6 (appearing a A1B), but the HFC-134a abundances
vary because the tropospheric OH values differ affecting its lifetime. The IS92a
scenario did not include emissions of PFCs and SF6. For details, see
chapter text and tables in Appendix II.
