Possible effects of rising CO2 on climate.

Two factors will determine the rate at which CO[sub2] levels in the atmosphere increase in the future: the rate of input to the atmosphere, primarily from fossil fuel burning, and the way in which this CO[sub2] is partitioned between atmosphere, ocean and biosphere. A brief review is given of the current state of knowledge of these aspects of the CO[sub2] issue prior to a discussion of the changes in climate that might be expected from increased levels of CO[sub2], whenever these might occur. The basis of climate modelling upon which our expectations rest is explained, indicating the nature of the uncertainty that currently exists in the model results. While some of the gross features of the likely climatic change seem reasonably well established qualitatively, considerable model development will be needed before reliable information on the likely regional effects is forthcoming. Observations have yet to confirm the occurrence of temperature change attributable to CO[sub2] increases. Nevertheless, the possibility exists of a change in climate during the coming century that may be substantial relative to past experience. Although direct measures to control CO[sub2] emissions would certainly be premature, long-term planning of infrastructures, closely tuned to present climatic conditions, should ensure their robustness in the face of the uncertain climatic changes that may lie ahead. [ABSTRACT FROM AUTHOR]