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Title: Carbon dioxide and the 'greenhouse effect': an unresolved problem

Journal Article · · Aware; (United States)
OSTI ID:6631348

The concentration of CO/sub 2/ in the atmosphere had risen to 330 ppmv in 1974 as compared to an assumed value of 290 ppmv from 1870 to 1900. Models predict a doubling of the concentration within the next century due to burning fossil fuel for all energy strategies, assuming that 50% of the CO/sub 2/ emitted actually remains in the atmosphere. Fossil-fuel combustion is not the only cause of the increasing amount of CO/sub 2/ in the atmosphere. In fact the contributions of CO/sub 2/ in the atmosphere from deforestation and other land modifications are estimated to be half or up to twice the amount due to fossil-fuel combustion. The effect of doubling the concentration of atmospheric CO/sub 2/ will be to reduce the net global heat loss, but the extent to which the earth's surface will be warmed as a result is still a matter for conjecture. At present concentrations, no global temperature rise has been detected above the noise level of natural variations. The most reliable estimates of temperature rise for a doubling of the concentration are 2/sup 0/C in the tropics and 10/sup 0/C at the poles, with an uncertainty factor of at least two either way. Four thousand to 8000 years ago, when the world was several degrees warmer than at present, the climate was more favorable to some areas than it is now. The question of a rise in sea level is equally unresolved. At present the only confirmed fact is that the concentration of CO/sub 2/ in the atmosphere is increasing. There is little evidence to support either a complacent or an alarmist attitude, so that it is most desirable that various aspects of the CO/sub 2/ cycle should be monitored to reduce uncertainties and give a firmer basis for energy policy during the next decade.

OSTI ID:
6631348
Journal Information:
Aware; (United States), Vol. 96; Other Information: Presents chapters 4, 5, 6 from the April 1978 report, London, the International Energy Agency (IEA) Coal Research
Country of Publication:
United States
Language:
English