The urban community and natural resources: Climatic change and atmospheric pollution.

Increased atmospheric carbon dioxide content was concluded to have had an ambiguous climatic influence and may be less important than sometimes considered. Several studies have suggested increased turbidity has produced a recent global cooling trend. An examination of some climatic effects of volcanic eruption was made in relation to the prediction that the effect of 500 supersonic transport aircraft would be comparable over the North Atlantic to the amount of stratospheric injection from the 1963 Mount Agung eruption. World glacial advance over the past three centuries was shown to be synchronous with volcanic eruption (p <0.01) and with poor harvests (p <0.001) and lower world temperatures were significantly related to volcanism (p < 0.01). These relationships support the results of a previous study and suggest that the effects of 500 supersonic transport aircraft may lead to reduced surface temperatures and possibly an intensification of alpine glaciation.