Human Civilization: The Next Step Forward

The First Global Warming of Our Species

8,000 BC: Human civilization is just budding. Small settlements populate the Near East as a few thousand humans band together in farming villages. Food stocks are slowly filling up with excess grain as winter approaches. Each family has many kids due to the extra nutrition provided by animals and grains. Just as the remaining hunter gatherers considered switching over to farming, a sudden dry spell hit.

Thousands of miles away, a huge freshwater lake called Lake Agassiz dumped its fresh water into the Atlantic Ocean. This disrupted the global current cycle, resulting in radical weather

changes over a short period of time. Within 10 years, the once thriving Near East was becoming an arid landscape.

At this point, settled humans had already grown large families. They had two options: either return to hunting and gathering (resulting in a few starved children) or double down their farming efforts and give up foraging completely. While some humans did scatter, many chose the latter. This is important because the decision to stick to farming resulted in a society dedicated to that lifestyle.

As the agricultural revolution began to gain momentum, certain regions of the world got a head start on civilization, specifically Europe. The reasons for this are analyzed in depth in Jared Diamond’s Guns, Germs, and Steel but I will highlight a couple key points here:

1. Continental Axis: Climate differences on Earth are most significant over a north to south axis. The weather gets warmer as you approach the equator. However, when travelling east to west, average temperature is much less varied. Because of this, plants useful in agriculture can easily travel laterally (since they evolved to survive in that climate). The only inhabited continent that is wider than it is long is Eurasia. Thus, plants and animals had an easier time spreading there when compared to the Americas, for instance.
2. Immunity Development: In addition to the point above, more viable cereal grains and domesticable mammals were present on the Eurasian continent. As farmers came into close contact with these animals, many animal pathogens evolved to infect humans. This initiated biological warfare between humans and germs: humans would adapt with better immunity as microbes adapted to get past these defenses. This ongoing battle made human civilization in Europe and Asia better suited to fight disease, a point highlighted by the role of smallpox in the European conquest of the Americas.