Figure 16-6: Observed and
modeled variation of annual averages of Arctic sea-ice extent, based on Vinnikov
et al. (1999). Observed data are from Chapman and Walsh (1993) and Parkinson et
al. (1999). Sea-ice curves are produced by GFDL low-resolution R15 climate model
and by HADCM2 climate model, both forced by CO2 and aerosols.