Figure
3.2: Variations in atmospheric CO2 concentration on different
time-scales. (a) Direct measurements of atmospheric CO2 concentration
(Keeling and Whorf, 2000), and O2 from 1990 onwards (Battle et al.,
2000). O2 concentration is expressed as the change from an arbitrary
standard. (b) CO2 concentration in Antarctic ice cores for the past
millenium (Siegenthaler et al., 1988; Neftel et al., 1994; Barnola et al., 1995;
Etheridge et al., 1996). Recent atmospheric measurements at Mauna Loa (Keeling
and Whorf, 2000) are shown for comparison. (c) CO2 concentration in
the Taylor Dome Antarctic ice core (Indermühle et al., 1999). (d) CO2
concentration in the Vostok Antarctic ice core (Petit et al., 1999; Fischer et
al., 1999). (e) Geochemically inferred CO2 concentrations, from
Pagani et al. (1999a) and Pearson and Palmer (2000). (f) Geochemically inferred
CO2 concentrations: coloured bars represent different published
studies cited by Berner (1997). The data from Pearson and Palmer (2000) are
shown by a black line. (BP = before present.)
