If the world depends on fossil fuels for its energy needs over the next two centuries, the U.S. National Academy of Sciences/National Research Council report Energy and Climate foresees the possibility of a peak atmospheric concentration of carbon dioxide of between 4 and 8 times the preindustrial level as occurring in A.D. 2150 to 2200. Climatic models of the general circulation of the atmosphere predict a 2–3°C rise in average temperature of the atmosphere for each doubling of the carbon dioxide content. Thus, a mean value of about 6°C increase in average atmospheric temperature would be anticipated if the models prove to be accurate and if the growth scenario used in the report were to be realized.

It is characteristic of our time that its most profound problems are global, involving all men, yet the nations into which men have divided themselves have never been as numerous nor as sharply diverse. A hundred years ago poverty was the common lot of most human beings; today we find two sets of nations staring at each other across the oceans, one rich and one poor, with a growing gap between them. The technological revolution has continuously improved the levels of living in the rich countries; in the poor ones its principal effect has been to multiply human misery by causing a rise in human numbers at rates higher than ever before experienced.