Energy and Changes in the Environment - Hydrogen and Fuel Cells: Advances in Transportation and Power - page 43

Table 2-2. Emission of Greenhouse Gases
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Type and Source Unit 1990 1995 1997 1999
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Carbon dioxide
Carbon content, total Mil.

metric

tons 1,350.5 1,434.7 1,505.2 1,526.8

Energy sources “ 1,325.0 1,404.7 1,474.3 1,495.0

Methane
Gas total “ 31.74 31.18 30.11 28.77

Energy sources “ 11.94 11.38 11.03 10.58

Landfills “ 11.40 10.63 9.97 9.11

Agricultural sources “ 8.29 9.03 8.98 8.96

Nitrous oxide, total “ 1,168 1,257 1,226 1,224

Agriculture “ 844 859 865 870

Energy sources “ 211 269 269 279

Industrial sources “ 96 111 74 57

Chloroflurocarbons(CFCs) “ 202 102 51 41

CFC-11 “ 54 36 25 24

CFC-12 “ 113 52 23 14

CFC-113 “ 26 9 0.5 0.5

Other CFCs “ 9 5 0.5 0.5

Halons “ 2.8 2.9 3.0 3.0

Hydrofluorcarbons
HFC-23 “ 3.0 2.0 3.0 3.0
HFC-125 “ 0.5 0.5 0.9 1.3
HFC-134a “ 1.0 14.3 23.5 30.3
HFC-143a “ 0.1 0.3 0.7
Perfluocarbons “ 3 2 3 2
CFC-4 “ 3 2 2 2
CF-2 F-6 “ 1 2 2 2
C-4 F-10 “ .5 .5 .5 .5
Sulfur hexafluoride “ 1 2 2 1
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Other greenhouse gases, include nitrous oxide (laughing gas), carbon
tetrachloride, and several other minor gases. The collective greenhouse
effect of these gases is estimated to add 50-150% to the increase in
greenhouse effect expected from CO 2 alone.

The American Automobile Manufacturers Association, which