There have been popular predictions of global freezing [ http://en.wikipedia.org/wiki/Global_cooling ]which were almost as well accepted as current predictions of global warming [ http://en.wikipedia.org/wiki/Global_warming. ]

Perhaps the big freeze was averted as aerosols were thought to be the dominant cause of mid-twentieth century cooling? So I suppose the logic is if we address the carbon cycle perhaps we will avert global warming?

Under [ http://en.wikipedia.org/wiki/Population_decline ] and over [ http://en.wikipedia.org/wiki/Overpopulation ]population predictions seem also to alternate.

The key factor in debates on underpopulation seem to be economics while the key factor in the debates on overpopulation seem to be environmental.

‘The garden city was the utopian brain-child of a humble British clerk, Ebenezer Howard, who imagined a new kind of settlement that would fuse the best of town and country, creating not just decent living places for ordinary people, but a new social harmony.’