Stratfor recently published an article entitled "The Dawn of a New Dark Age," in which the author lists 5 "horsemen of the Apocalypse" which he contends have been present in all major collapses of complex societies, including the fall of Rome and the Bronze Age collapse of the 18th Century B.C. They are:
The first, which is always prominent, is mass migration, on a scale that the societies of the time cannot control. Just how many immigrants it took to destabilize borderlands and spread violence across entire empires must have varied, although DNA seems to suggest that in the wrong circumstances even a group less than one-tenth the size of the host population could bring the roof crashing in.Take note that the first of the horsemen is "mass migration" into the affected nation or civilization. Since one of the basic functions of a state is to protect against invasion, I would suggest that uncontrolled mass immigration is a sign of state collapse. And it is interesting that in analyzing whether a civilization can reverse or stop a dark age, the author selected one where the key was reversing mass migration. He relates:
The second factor, often coming on the back of the first, is disease. Long-distance mass movements sometimes merged what had previously been separate disease pools, producing new infections to which hardly anyone was immune. Steppe nomads migrating across thousands of kilometers were probably the main vector for the Black Death, which killed perhaps a quarter of the world's population between 1350 and 1400.
The third force, regularly linked to the first two, is state failure. Collapsing borders and shrinking populations often bring down governments too, and as chaos spreads, even states that have not been directly hit by invasion and plague can be sucked into the whirlpool.
Fourth, and strongly linked to the first three forces, is the collapse of trade. When failing states can no longer protect merchants, long-distance exchange networks break down, bringing starvation and yet more rounds of migration, disease and violence. Many historians think that the tipping point in the fall of the Roman Empire came when the Vandals invaded North Africa and cut off grain shipments to Italy from what is now Tunisia in 439. The city of Rome lost three-quarters of its population across the next two decades, and in 476 the Western Empire was officially declared defunct.
The fifth factor, always present but never in a straightforward way, is climate change. Some great collapses, such as that in the Eastern Mediterranean after 1200 B.C., coincide with rising temperatures; others, such as the Roman and Han Chinese breakdowns in the early first millennium, coincide with global cooling. The direction of climate change seems to matter less than the fact that any big change puts stress on farming, which — when everything else is already going wrong — might be enough to push people over the edge.
One [example where the downward spiral was disrupted], in China after 600, is particularly informative. The empire had recently been reunited by the Sui dynasty after a dark age, but Turkic invasions from the steppes, new epidemics, civil war, trade breakdowns and global cooling threatened its recovery. In 614 the Sui government collapsed and the worst seemed about to happen; but through a clever combination of diplomacy and war, the first two emperors of a new Tang dynasty, Gaozu and Taizong, stopped the population movements completely by 650. Freed from external threats and with plagues abating, they restored law and order and revived trade. They could do nothing about climate change, but the absence of the other Horsemen reduced it to a mere nuisance. By 700 China had entered a golden age, its economy booming so much that a million people were living at Chang'an.It is also interesting to me that another example references was post-1945 Europe, which, while the author does not mention it, was marked by mass expulsion of foreign populations from many of the countries of Europe.
Germany--all of Europe, really--is facing uncontrolled mass immigration. The latest figures I can find is for 2010, at which time Germany had 4.8 million Muslims, or 5.8 percent of its population. Germany had 476,000 asylum applications in 2015 alone; but it is estimated that 1.1 million immigrants entered Germany last year. In short order, Germany will cross the 10 percent threshold. This pool of immigrants mean that Germany is already seeing the first and third horsemen. The second will likely come due to the influx of refugees bringing either new diseases or antibiotic resistant versions of older diseases. And the climate is expected to cool in the 2030s.
Time is running short.