Global Warming

32 The greenhousegases

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12500 10000 7500 5000 2500 0

Age (yr BP)

(a) Taylor Dome

CO

concentration (ppm) 2

Year

CO

concentration (ppm) 2

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Law Dome

Adelie Land

Siple

South Pole

Mauna Loa

(b)

(c)

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1960 1970 1980 1990 2000

fossil fuel emissions

monthly atmospheric increase (filtered)

ppm (yr)

Year

Figure 3.2Atmospheric
carbon dioxide concentration,
(a) over the last 10 000 years
from the Taylor Dome
Antarctic ice core; (b) from
Antarctic ice cores for the past
millennium; recent
atmospheric measurements
from the Mauna Loa
observatory in Hawaii are also
shown; (c) monthly changes
in atmospheric carbon dioxide
concentration, filtered so as to
remove seasonal cycle; vertical
arrows denote El Ni ̃no events;
note the small rate of growth
from 1991 to 1994 which
may be connected with events
such as the Pinatubo volcanic
eruption in 1991 or the
unusual extended El Nino of ̃
1991–4 (denoted by
horizontal line).

fossil fuel burning, cement manufacture and land-use change amounted

to about 7.1 Gt; over three-quarters of these resulted from fossil fuel

burning. Since the annual net increase in the atmosphere was about

3.3 Gt, about forty-five per cent of the 7.1 Gt of new carbon remained to

increase the atmospheric concentration. The other fifty-five per cent was

taken up between the other two reservoirs: the oceans and the land biota.