Climate Change Through History

The Spirit of My Law

I want to open with a disclaimer. In my first post,  I promised to keep my blog as politically neutral as possible. However, some issues interplay with politics that aren’t in themselves inherently political. Religion is a great example of this throughout medieval Europe and even today in the Middle East and the Vatican. History can be politicized as well whether that’s downplaying the role slavery had in the American civil war or completely denying a genocide.

Today, I’m tackling another such issue that isn’t in itself political but has become so. That issue is climate change. This blog will keep its promise to remain politically neutral, but the facts of religion, history, and science are not political. The Lighthouse draws the line here: Science tells us what is happening around us and why. Politics is the discussion around what, if anything, to do about it.

A Little Summer Heat, A Little Icecream, and a Little Geopolitical Upheaval

Climate change has been diving in and out of the news for years in various forms, such as  the international signing of the Paris Climate accord, and the United States withdrawing just a few years later. Just recently, a report came out showing Canada is experiencing warming on a scale twice as quickly as the rest of the world. Ireland went as far as to declare climate change a national emergency.

This isn’t a science blog, but I think this concept warrants a quick explanation. Essentially, what regulates our planet’s temperature is a layer of ozone made up of a variety of molecules such as CO2. The sun’s heat hits earth and bounces off the surface. This layer of ozone reflects some of the heat back down to earth. This heat shield keeps the temperature from fluctuating too much between day and night. To get an idea of how effective this is consider that the moon, who has no such ozone, has a temperature that fluctuates between 260 and -280 degrees Fahrenheit on a daily basis (keeping in mind that a day on the moon is closer to 13 Earth days). These same molecules that regulate our heat by trapping and reflecting it back to the surface are released in most human industrialization efforts such as deforestation, manufacturing and burning fossil fuels, which heat our homes and power our cars.

There is little to no doubt the climate is indeed warming. NASA provides data from 6 separate institutions across 3 countries providing temperature data since 1880. This list also contains statements from dozens (possibly hundreds, I stopped counting) of scientific communities from around the globe stating the same. This is a global consensus. If you have further doubts or would like to read more, I highly suggest checking out NASA’s site here. It’s extremely informative in providing both data and explanations.

So let’s ask the million dollar question you all came here for. Has humanity ever had to face climate change before?

It turns out that climate change is one of the leading causes for several of the geopolitical upheavals throughout history. The fall of Rome, the fall of the Maya, the Bronze Age Collapse, the rise and fall of Vikings, the Andean civilization or the Khmer Empire’s fall have all been attributed to climate change. All over the world and all throughout history humanity has fought and lost to the climate.

From Bronze We Came, and to Dust We Returned

The Bronze Age started at different times in different civilizations and locations. We’re going to focus specifically on the near east: modern day Greece, Egypt, Turkey, and Syria. The main players affected were the Egyptian New Kingdom, Mycenaean Greece, the Hittite State, Assyria, Alashiya (ancient Cyprus) and the Minoans.

The Bronze Age started around 3300 BCE in the near east and ended in 1200 BCE in one of the greatest mysteries to historians. Several of the greatest kingdoms the world has ever seen collapsed within just a few years of each other – all of whom have records blaming a mysterious “sea people.” Who these sea people are is a matter of great debate. They may not have even been one homogeneous group. We know that these civilizations were attacked by people who came from the sea, but it’s not clear if these people were from the same country. The sea people that the Egyptians wrote about may have been different from those mentioned by the Hittites.

What exactly caused the collapse isn’t clear, so when I’m stating climate change is the cause, keep in mind that it’s one theory of many. However, it is one supported by compelling evidence. Some other theories include invaders who’d developed iron, while others mention earthquakes or volcanic eruptions, and still others mention internal rebellion or the breakdown of an interconnected trade system. While all of these things certainly happened, whether each of them were the cause or another symptom is difficult to determine.

Here’s what we know. In 1200 BCE, several empires existed with complex international trade agreements. They’d discovered metallurgy, employed administrators and wrote epic narratives. This is the world of Homer’s Odyssey, and when it ended, the world regressed so much that even writing was nearly absent for 400 years. It’s really hard to understate exactly how severe this collapse was. The strongest nations in the world were reduced to little more than rubble.

Below we can see how many major cities were destroyed as well as the route the “sea people” likely took:

The Route of the Sea People
The Route of the Sea People

The most recent discovery of pollen samples (linked above) shows that the area experienced a drought for a 150 year period. This destabilized the region and its trade. The breakdown of international trade made it harder to create weapons. Creating bronze, which was used in weapons, relied on a mix of tin and copper. Tin is exceedingly rare naturally, and archaeological evidence hasn’t definitively defined where the Bronze age civilizations in the Near East even acquired it. We do know there was some in Mesopotamia, so it’s likely that it was traded to these empires. When these sea people arrived, likely seeking food that wasn’t there, they may have plundered trade routes robbing the empires of their tin and thus their ability to defend themselves. Once one empire fell, trade between these empires further fragmented, and it came crashing down like a Jenga tower. One clay tablet we found written by the old king Ammurapi reads:

My father, behold, the enemy’s ships came (here); my cities(?) were burned, and they did evil things in my country. Does not my father know that all my troops and chariots(?) are in the Land of Hatti, and all my ships are in the Land of Lycia?… Thus, the country is abandoned to itself. May my father know it: the seven ships of the enemy that came here inflicted much damage upon us.

I want to break this down a bit. This letter was intended to be a response to a plea from Alashiya (modern Cyprus) for help. This plea for aid’s response is basically, “I sent aid to Lycia and Hatti, and now my own city is defenseless against the invaders who are now here.

It is easy to see how widespread the invasions were and how overwhelmed each civilization was by them. Perhaps the most heartbreaking part of this is that the tablet was found in Ugarit, Ammurapi’s own city. That means it never even left the city before it was destroyed.

The parallels to our day and time are hard to miss. The reliance on international trade and a key good (bronze or petrol) are imperative to life as we know it. An interruption to such trade can have grave consequences and already has. Not to mention the parallel to blaming invaders such as the sea people for internal problems. Granted, the sea people truly wished to wage war rather than seek asylum, but the comparison still is worth consideration.

The Sea People We Know…or Don’t

The Vikings had nothing to do with the Bronze Age collapse, but their civilization was one that’s often postulated to have been affected by climate change. In fact, the common sentiment has been that they owe their existence to the medieval warm period and their collapse to the succeeding little ice age, but a recent study has called that sentiment into question. To be clear, that’s not to say that climate change didn’t affect the Norsemen, quite the opposite. Rather, the above study simply suggests that glaciers may have been larger than anticipated during the Medieval Warm Period, and thus climate alone may not have been the sole catalyst for their initial settlements or exodus.

Statue of Erik the Red
Statue of Erik the Red

Erik the Red is credited with establishing Greenland in the late 10th century. In 985 he convinced several hundred Icelanders to migrate to Greenland. For the following couple centuries, the Vikings would engage in trade with northern Europe. They were primarily farmers and ranchers, but hunted on occasion. However, when temperatures started to cool in the 12 and 1300s, partly due to Indonesian volcanic eruptions  spewing massive amounts of smoke into the air, Greenland became too inhospitable for cattle. They began hunting walrus more frequently, and eventually it became the backbone of their society. In fact, Walrus tusk became such a luxury good in Europe, it’s likely that Greenland began subsisting not on their own labor, but on trade.  However, as temperatures cooled, as the traditional theory goes, the arctic sea ice increased, which made ship travel more difficult and more dangerous. This bout of climate change is supposed to have occurred in two distinct phases. The first wrecked havoc on their agriculture, and so the Norsemen moved towards the coast to facilitate a greater focus on seal hunting and fishing. However, a second bout in 1425 increased storms in the region, and the recent migration to the coast would have left them extremely vulnerable to nature’s fury.

Things only got worse for the Vikings though. As the age of exploration advanced, elephant tusks from Africa began competing with the walrus tusks, which dampened trade. Not only that, but the black death began ravaging Europe, and though our viking friends were mostly unscathed, their trading partners on whom they relied for subsistence were devastated. The Vikings could simply not survive without trade. However, they may not have been totally extinguished as there’s a marriage record in Iceland of a couple who evacuated Greenland, though whether they came alone or as part of a larger exodus is lost to history. By the end of the 15th century, Norse Greenland was no more.

I’ve been using Norse and Viking somewhat interchangeably, but if you’re familiar with Vikings, you may be confused by that last statement since the Viking Age ended in the 1066 with the defeat of the Vikings in their conquest of England. To clear a few things up, the term Viking, as it’s used today, refers to a type of Norsemen in a specific time period. Not unlike how “Yankee” could be somewhat interchangeable with “American,” but more specifically refers refers to a Union solider in the Civil War period. Viking refers to a person from Scandinavia who went “a viking”  between 800 and 1066. While going viking did often entail violent raids the people have become known for, it was just as often used to establish trade or be hired as a foreign mercenary. After 1066, Viking raids were far less common and the typical Norse pantheon began being replaced by Christianity in pace with the rest of Europe. While the Norse would still exist for a few centuries, they wouldn’t be characterized by the barbarism of the Viking age, and the extent to which they raided and pillaged is often overplayed in modern culture.

The important takeaway from the rise and fall of the Norse as it relates to climate is that even in the absence of invaders, in relative peace time, your trading partner’s demise can mean your own. Climate, disease, and other areas of mother nature can cause a civilization’s downfall from afar. It need not be invaded by hungry interlopers. It can be starved by arid land and a lack of trade. As the climate continues to change, violent storms such as the ones likely experienced by the vikings in 1425 will become more common, and in fact, already are. Lastly, the Norsemen’s demise was a slow burn. The civilization declined over the course of a century. That’s 3-4 generations. The climate becoming inhospitable doesn’t necessarily mean a war for remaining resources. It may happen too slowly to notice the change, with not a bang, but a whimper.

Maya Have a Glass of Water?

When Americans think of the native Americans in Mexico and South America, they mostly think of the Spaniards that all but wiped them off the face of the continent. This is true for the Aztecs and the Inca civilizations. The Maya, however, were far past their peak by the time the Spanish arrived, but when they did arrive in addition to waging war against them, the Spanish destroyed nearly all their records and history. Specifically, a bishop burned every Mayan codex he found to prevent them from practicing their religion.

It may be important to provide a brief distinction between pre-Columbian civilizations in the region. The big ones you’ll always hear about are the Olmec, the Aztec, the Maya, and the Inca. The latter 3 coexisted to some extent. The Olmec, however, rose and fall millennia beforehand. The former 3 all shared neighboring land as you can see in the map below.

Location of Mesoamerican civilizations

The Inca were in South America and had a vast and strong empire when the Spanish arrived. The Aztec and Maya also coexisted, but the Maya were far older and were far past their height as an empire by the time the Spanish arrived. Even so, it still took the Spanish 170 years from their first attempts to conquer them, far longer than the other pre-Columbian civilizations. The Mayan Civilization comprised several city-states, and at its height a population of about 2 million. That may not sound like a lot today, but consider that the population of England in 1085 (about 100 years after the Mayan’s height) was about 3.5 million.

What caused the Maya’s demise is perhaps the most relevant to our case of human caused climate changed as several studies suggest that the Maya’s decline from prominence was due to a drought that was severely exacerbated on by their own logging activities. There’s a wide range of studies on this claim some of which question this assumption, but none I found provided an alternate solution. There are several articles that support it.

The Maya’s incessant deforestation was due to both their rising population numbers and their practice of slash and burn agriculture. While the Maya also practiced much more advanced methods of irrigation, their methods of agriculture could not scale with their population. Slash and burn agriculture is a relatively ineffective way to make infertile land fertile. It consists of chopping down and uprooting any plants in a given area and setting them on fire. The resulting ash will fertilize the soil well enough for farmers to use it for about two years before the nutrients are used up, and they must repeat the process on a new patch of land.

This process works reasonably well for small populations, but it’s easy to see how it would never scale. The ecological problems are vast. Aside from the likelihood of accidental fires, it also releases CO2 in the atmosphere, results in habitat loss for any native species, and can even make the land less fertile and more subject to desertification and water loss.

The Maya’s treatment of their environment may not have been the sole cause of their decline before their encounters with the Spanish, but it certainly exacerbated it. In addition, the scholastic disagreement on exactly how much responsibility the Maya had in contributing to their drought directly mirrors political discourse today. In the end, you may consider that regardless of the role humans have in changing their environment, any action that be taken to help prevent its change may prevent a societal collapse, and I think we can all agree that is something worth avoiding.

Further Reading:

When we almost stopped climate change

On the Fall of Troy’s pertinence today

On the role of climate in the fall of the Western Roman Empire

2 thoughts on “Climate Change Through History

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