24 
Studies have shown that an increase in global mean temperature of 
no more than 0.5° C has resulted over the last century from the man- 
made carbon dioxide injected into the atmosphere.*? Distribution 
over the globe is not uniform. Most of this change has occurred in 
regions adjacent to the Arctic Ocean. Although these trends have not 
reached disturbing levels to date, the much greater increase in carbon 
dioxide production projected to come in the next 50 years must be 
seriously considered. It is time to make a concerted effort to under- 
stand more fully what has been termed man’s greatest geophysical 
experiment.” 
30 Mitchell, J. M. On the world-wide pattern of secular temperature changes. Changes of climate, Arid 
Zone Monograph, v. 20, 1963. UNESCO, Paris. p. 161-181. 
31 Broecker et al, op. cit., p. 322. 
