Table 1: Trace gas characteristics and their estimated future impacts on atmospheric warming.
| Characteristics | H2O | CO2 | CH4 | N2O | CFC-11 | CFC-12 | O3 |
| Concentration (ppmv) Pre-1850 1985 A.D. 2030 A.D. | Variable Variable Variable |
275 345 450 |
0.7 1.7 2.3 |
0.28 0.30 0.38 |
0 0.22 1.1 |
0 0.38 1.8 |
Upto 25% less than now 0.1-1.0 Upto 12.5% more than now |
| Main IR absorption wavelength (m) | 6.3-8.0 >15 | 4.3 15
| 3.3 7.6 | 4.5, 7.6 8.6 | 9.22 11.22 | 8.68-9.13 10.93
| 4.75 9.6 |
| Observed (%) increase 1975-1985 | Variable | 4.6 | 11.0 | 3.5 | 103.0 | 101.0 | Variable |
| Approximate lifetime in atmosphere in years | Variable | 2 | 5-10 | 120 | 65 | 110 | 0.1-0.3 |
| IR trapping (W m-2) 1985 2050 |
Variable Variable |
50 53 |
1.7 2.5 |
1.3 1.5 |
0.06 0.3 |
0.12 0.6 |
1.3 1.7 |
| Estimated temperate increase (oK) | Variable | 0.71 | 0.2-0.25 | 0.10 | 0.24 | 0.12 | 0.06 |
Table 2. Effects of differences in potential climatic changes from doubling of carbon dioxide concentrations in three global GCMs compared to present-day control.
(Data: Schlesinger and Mitchell, 1987)
Parameter | Season | Model NCAR | Model GISS | Model DFDL |
| MAXIMUM SURFACE WARMING Latitude average (0C) Northern Hemisphere Southern Hemisphere Geographical LocationNorthern Hemisphere Southern Hemisphere |
DJF JJA
DJF JJA |
7 13
16 18 |
7 7
10 18 |
14 7
18 14 |
| LATITUDE OF MAXIMUM SURFACE WARMING Northern Hemisphere (0N) Southern Hemisphere (0S) |
DJF JJA |
65 65 |
80 80 |
80 80 |
| Tropospheric min. Maritime warming (0C) |
Both |
2 |
4 |
4 |
| Stratospheric max. cooling (0C) |
Both |
-6 |
-3 |
-8 |
| Precipitation, 300N-300S | Both | More to S Less to N | More to N Less to S | More to S Less to N |
| Indian summer monsoon strength Tropical rain rate increase (mm/day) |
JJA
Both |
Same
0.75 |
Lesser
1.25 |
Much more
0 |
| SOIL MOISTURE CHANGE Australia Africa |
DJF JJA |
Drier Drier except N |
Wetter Wetter except N |
Wetter Dry in E wetter in W |
DJF = December, January, February (Winter in Northern Hemisphere); JJA = June, July, August (Winter in Southern Hemisphere)
Table 3. Estimated average growth and yield changes in C3 species assuming a doubling of CO2 concentration. (SCOPE, 1986)
| C3-group | Species | Immature crop | Mature crop | ||
| No. of records | % increase in biomass | No. of records | % increase in biomass | ||
| Fiber crop
Fruit crop
Grain crop
Leaf crop
Pulses
Root crops
C3 weeds
Trees | Cotton
Cucumber, eggplant, okra, pepper, tomato
Barley, rice, wheat, sunflower
Cabbage, white clover, fescue, lettuce, chard
Pea, bean, soybean
Sugar beet, radish
Jimson weed, pigweed, ragweed, sicklepod, other weeds
Cottonwood
| 5
15
6
5
18
10
10
14 | 124
40
20
37
43
49
34
26 | 2
12
15
9
13
Nil
Nil
Nil | 104
21
36
19
17
?
?
? |
| Mean of all C3 plants | 83 | 40+7 | 51 | 26+9* | |
* = 95% confidence limits.
Note: C3 plants have the highest rate of photosynthesis and can assimilate carbon dioxide better than lower plants.
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