201
Atmospheric Chemistry
in Figure 5.21. The present contributions of Asia are equivalent to the United States and
will be greater than the United States in the future. Although the United States has 5% of
the world’s population, we produce 20% of the fossil fuel CO 2 . This is shown more clearly
in Figure 5.22, where the per capita fossil fuel emissions are shown for various countries.
The United States produces 30% more per capita than the nearest country (Australia).
2000
1980
Annual mean
Five-year mean
1960
1940
1920
1900
1800
–0.6
–0.4
–0.2
0.0
0.2
0.4
0.6
0.8
Year
Figure 5.18
The temperature anomaly over the last 200 years.
Table 5.5
Trapping of IR Radiation by Trace Gases (ΔQ, W m –2 )
Gas
Present Level
Present ΔQ
Lifetime
CO 2
345 ppm
2.0
10–15 yr
CH 4
1.7 ppm
1.7
7–10
O 3
10 –100 ppb
1.3
0.5
N 2 O
340 ppb
1.3
100
CFC-11 a
0.22 ppb
0.06
75
CFC-12 b
0.38 ppb
0.12
100
6.5
a CCl 3 F.
b CCl 2 F 2 .
Table 5.6
Preindustrial Trapping of IR
Radiation of Trace Gases
Gas
Past Level
Past ΔQ
CO 2
275 ppm
1.3
CH 4
0.7 ppm
0.6
O 3
0–25% less
0–0.2
N 2 O
285 ppb
0.05
CFC-11
0
0
CFC-12
0
0
2.2