For the purpose of an essay, what are some overarching lessons that could be taken from ancient societies to shape and guide our present society?

There are two very important lessons that we can draw from various ancient civilizations in order to improve or guard against the repetition of similar mistakes. First, from looking at the Mayan Civilization, and others like it, whose capital cities seemed to have grown very rapidly in population by expanding its agricultural production, we can see that the over-reliance on natural resources and a lack of planning for downside risks to resources (such as drought, famine, et cetera) can lead to catastrophic results. As far as archeologists can tell, the Mayans' population centers relied heavily on the farming of just core crops to feed their population. This practice of relying on just a few crops for the sustenance of many was quite common. But when the climate shifted just a bit, and became dryer and perhaps warmer, those crops failed en masse. As a result, historians today theorize that many Mayans fled the large cities of that empire, while others fought over food, and still others starved.

Today, our civilization is heavily dependent on a wider variety of crops and other resources, but catastrophic climate change seems to have begun, and while we are better equipped than the Mayans to adapt, we still are highly reliant on fossil fuels, cheap and abundant sources of clean drinking water, and crops that also require a great deal of water in order to produce. Like the Mayans, we have failed to plan for a worst case scenario, or at least, we have failed to plan adequately. Should the changes to our climate happen more rapidly than we have predicted, which seems to be the case, we could be caught very flat footed and many people could die as a result. Humans have never been very good at long term planning. Hopefully, we will become at it.

A somewhat similar analogy can be made from looking at the Roman cities of Pompeii and Herculaneum, which were both built right next to the long-dormant volcano, Vesuvius. The fertile ground that volcanic soil produces made those cities very wealthy and successful, and although some scholars from that time understood that Vesuvius was at one time an active volcano, they ignored the possible risks that the mountain might become active again. So in 79 AD, because the cities of Pompeii and Herculaneum had not planned for a worst case scenario, the majority of the inhabitants of both cities were wiped out.

Today, many Japanese live next to Mount Fuji, which is an active volcano. The land is very fertile but the risk is similar. Others around the globe live in tsunami zones, and still others (like the residents of Miami and New Orleans) live in hurricane zones. The risks they face are enormous and well known. Our government and private sector does a poor job of dis-incentivising people to live in such places, even though we know that a catastrophic weather is not a matter of if, but when.

We humans still have not learned to fully face up to the downside risks of how we live, even when the evidence tells us that we should.