Lately I’ve been listening to Prof. David Christian explain his “Big History” concept (courtesy of a CD course from the Teaching Company), and I’ve almost reached the end (i.e., the present). I’ve hung in there from the Big Bang and matter formation thru the first stars and star clusters leading to galaxies and solar system formation, then the condensation of the planets around those stars (using heavy elements sprayed into the void from the heart of supernova explosions). And then came the various coincidences that eventually allowed warm watery environments to evolve with slimy life forms somehow forming, eventually leading to intelligence, consciousness and society — at least on one tiny planet in an otherwise insignificant corner of the Milky Way (a generally insignificant galaxy in its own right).
In one of his final lectures in the course, Prof. Christian discusses the “Malthusian Crisis” or cycle, i.e. a situation where the human population of a large portion of the world (or sometimes the whole world itself) grows beyond its long-run carrying capacity in terms of nutrition, energy, shelter, and protection from disease. Under such conditions, the population starts decreasing, until things get back in balance a few generations later. Professor Christian offered two examples of an historical Malthusian Crisis — the first is in the 14th century, when people start intermingling from around the world, spreading nasty diseases and plagues (such as the Black Death) that started killing people off in large numbers. There were other basic factors, such as populations that were growing too fast for the agricultural capacity to keep up, along with climate changes that just made it worse. Experts estimated that world population levels dropped by perhaps one quarter (from 450 million to 350-375 million) in the 14th century, after a few hundred years of slow growth.
Then in the 17th century, things got bad once again, termed a “General Decline” by some scholars. A global cooling took place (called the Little Ice Age, possibly related » continue reading …