Figure 4.2: Change in N2O
abundance for the last 1,000 years as determined from ice cores, firn, and whole
air samples. Data sets are from: Machida et al. (1995); Battle et al. (1996);
Langenfelds et al. (1996); Steele et al. (1996); Flückiger et al. (1999).
Radiative forcing, approximated by a linear scale, is plotted on the right axis.
Deseasonalised global averages are plotted in the inset (Butler et al., 1998b).