Geoscience Reference
In-Depth Information
Table 2.3
Anthropogenically induced changes in concentration of atmospheric trace gases
Gas
Concentration
Annual increase (%)
Sources
1850*
2008
1990s
Carbon dioxide
280ppm
385ppm
0.4
Fossil fuels
Methane
800 ppbv
1775ppbv
0.3
Rice paddies, cows, wetlands
Nitrous oxide
280ppbv
320ppbv
0.25
Microbiological activity,
fertilizer, fossil fuel
CFC-11
0
0.27ppbv
≈
0
Freon†
HCFC-22
0
0.11ppbv
5
CFC substitute
Ozone
?
10-50ppbv
≈
0
Photochemical reactions
(troposphere)
Sources: Updated from Schimel et al. (1996), in Houghton et al. (1996).
Notes: *Pre-industrial levels are primarily derived from measurements in ice cores where air bubbles are trapped as
snow accumulates on polar ice sheets. †Production began in the 1930s.
ppm = parts per million; ppbv = parts per billion by volume
DEFORESTATION
ATMOSPHERE 750 +4/year
2
120
63
54
7
LAND BIOTA
550
LAND
USE
CHANGE
2
50
SURFACE OCEAN 1000 +1/year
FOSSIL
FUEL
BURNING
RIVERS
0.8
SOIL AND
DETRITUS
2000
34
BIOTA 3
45
11
33
42
RECOVERABLE
FOSSIL FUEL
1000
INTERMEDIATE AND DEEP WATERS
38000 +2/year
0.2
SEDIMENTATION 0.5
Figure 2.4
Global carbon reservoirs (gigatonnes of carbon (GtC): where 1 Gt = 10
9
metric tons = 10
12
kg)
and gross annual fluxes (GtC yr
-1
). Numbers italicized in the reservoirs suggest the net annual accumulation
due to anthropogenic causes.
Source: Based on Sundquist, Trabalka, Bolin and Siegenthaler; after IPCC (1990 and 2001).
