An accelerated release of carbon dioxide into the atmosphere appears to have stimulated melting of the ice after an increase in global temperature at the end of the last ice age. After a relatively lengthy period of stable temperatures, the earth has warmed further owing to an additional 40% increase in carbon dioxide since the advent of the industrial revolution. This leaves us on the edge of potentially significant additional global warming even if we immediately abandon fossil-fuel induced release of additional carbon dioxide and other greenhouse gases into the atmosphere. Several issues unique to the presence of human activity on the planet are relevant to what may happen over the next half century and beyond.
First, since 2007 there are now more people living and working in cities than there are working the land. City dwellers work for higher salaries than those who remain in the countryside, and thus contribute more to economic expansion. But city dwellers depend more on the economy and are reliant on commerce, trade and technology than are their compatriots in the countryside. So, while we became more urban, we lost touch with the natural world and trusted that it would continue to feed us and provide for many of our other needs.
Barring major catastrophic events urban populations world wide may exceed a two-fold increase by mid century. While many urban populations in poor underdeveloped countries may not fare that well, many in Asia, the Americas and Europe should achieve a significant upward trajectory.
At the same time, at the current rate of population expansion we could be near 11-12 billion by mid century. But for the predominant increases in urban populations to occur an increasingly relatively smaller contingent in the rural areas would, with very little additional people and resources, somehow have to produce about twice the amount of food to support the urban population increase at a time which is most likely to witness a historic movement of economic power from west to east.
However, with improving health care and declines of death rates the median age of those living in cities and nations will generally increase. In the end, populations will decline owing to declining fertility rates; i.e, as populations age fewer and fewer babies are born.
Who will care for these urban, aging elite? Who will feed them? These are not easy questions to answer–but these problems will nevertheless occupy our thoughts more and more in the years ahead. Increasingly sophisticated robotic devices can help, but it is hard to see how they can be the whole answer. Are we coming upon too sophisticated a set of problems too quickly? Can there be answers?
And what then if global warming goes badly or at least as badly as we can presently foresee? Can we solve the difficult social problems of an expanding, graying urban population and the possible relocation and resettlement of significant numbers of them in the face of climate difficulties more major in scope than we had anticipated?