Understanding Historic Climate Events and Their Lessons
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Chapter 1: The Impacts of Climate Change on Society
Scientists have raised alarms regarding the devastating effects climate change may inflict on both human and ecological systems. In the publication “Atlas of the Anthropocene,” environmental geopolitics specialist François Gemenne forecasts a global temperature increase of 4 to 6 degrees Celsius by the year 2100. Climate researchers caution that this swift rise in average temperatures will likely lead to more frequent extreme weather occurrences, including hurricanes, floods, and droughts. Consequently, extensive areas of the planet might become uninhabitable, displacing millions of individuals.
In light of the imminent dangers posed by future environmental disasters, a number of archaeologists, climatologists, and natural scientists have turned their focus to historical patterns to investigate how climatic conditions influenced the development and decline of ancient societies. Timothy Beach, a geoscientist at Georgetown University, states, “We use that long past environment to look at scenarios for the future.” While it is improbable that climate events alone could bring about the downfall of civilizations, scholars contend that severe climatic phenomena can intensify pre-existing political, social, and economic challenges. Francis Ludlow, a geographer from Trinity College, asserts, “Abrupt climatic events place great stress on societies and can sometimes tip them over the edge.”
Here, we examine three pivotal historical climate events.
Section 1.1: The Agricultural Revolution and “Noah’s Flood”
Archaeological evidence indicates that around 8,000 years ago, Europe underwent a significant transformation. Communities that once relied on hunting and gathering began to settle and adopt agricultural practices, marking the onset of the Neolithic Revolution, also referred to as the Agricultural Revolution. Tribes in the region known as the Fertile Crescent, situated between the Tigris and Euphrates rivers, had already commenced farming. Although historians recognize the profound impact agriculture had on history, the precise trigger for this transition remains uncertain.
In recent years, some historians have posited that this agricultural shift was initiated by the migration of various groups from East to West, carrying their farming knowledge with them. This theory suggests that these early societies were forced to relocate due to a significant flood that submerged the fertile territories around the Black Sea, then a freshwater lake, circa 5600 BCE. Geological evidence points to the collapse of the Laurentide Ice Sheet as the cause of this deluge, which gradually increased global sea levels. As a result, water breached the Bosporus Strait, flooding the Black Sea region. Researchers estimate that approximately 145,000 individuals were displaced by this event. Chris Turney, a professor at Exeter University, emphasizes that this incident “illustrates how rising sea levels can instigate substantial social transformations.”
Furthermore, Turney proposes that this flood may have inspired the tale of Noah’s Ark. Translations of ancient cuneiform tablets discovered in the 19th century suggest that the flood narrative predates the biblical account, with its origins tracing back to the ancient civilizations of Mesopotamia. For instance, the “Epic of Gilgamesh” recounts the tale of Utnapishtim, who constructed a vessel to save his family and animals from an impending deluge. Some scholars believe that these early flood stories stem from the inundation of the Black Sea around 5600 BCE.
This video, titled "Climate Change: Past, Present, and Future," explores how historical climate events inform our understanding of current and future climate challenges.
Section 1.2: The Drought and the Fall of the Ancient Maya
The Maya civilization reached its zenith during the Classic Period, characterized by remarkable advancements such as sophisticated calendars, grand temples, and innovative agricultural methods. However, between 850 and 1000 CE, key cities within the empire were abandoned, eventually becoming engulfed by dense forests. Archaeologists have long sought to uncover the reasons behind this sophisticated civilization's decline.
In the 1990s, some researchers proposed that an extended drought prompted the ancient Maya to vacate their cities permanently. Recent studies have corroborated that a significant drought coincided with the civilization's decline. Nevertheless, this discovery has sparked new inquiries, as historical evidence indicates that the Maya had previously endured multiple droughts and continued to prosper. Scholars are investigating why they could not withstand this particular drought.
Billie Turner, a professor at the University of Arizona, suggests that the Maya's previous successes may have played a crucial role. Evidence shows that many cities were overpopulated at the time of the collapse. To meet the rising food demand amidst population growth, the ancient Maya resorted to deforestation and expanded agricultural practices into lowland wetlands, likely exacerbating the impacts of the last drought. Researchers agree that climate change, overpopulation, and environmental degradation contributed to the decline of the once-thriving Mayan cities.
However, more recent findings indicate that many cities in the northern lowlands survived the drought and even flourished during that time. In 2021, professors Charles Golden and Andrew Scherer discovered that the area around La Mar continued to yield abundant crops in the 8th and 9th centuries. Yale geology professor Mark Pagani supports this view, stating, “The north was already accustomed to fairly dry conditions and fared significantly better. There was actual expansion there after the collapse, but the southern cities never recovered.”
In this video, "Dan Britt - Orbits and Ice Ages: The History of Climate," the speaker discusses the historical climatic shifts and their implications for modern society.
Chapter 2: The Volcanic Winter of 536 CE and Its Consequences
In 536 CE, Syrian historian John of Ephesus described a phenomenon where “the sun became dark and its darkness lasted for 18 months. Each day, it shone for about four hours, and still the light was only a feeble shadow.” Ancient Chinese records also referenced a peculiar event where “yellow dust rained down like snow.” This event is commonly known as the “volcanic winter” of 536 CE, marking the beginning of a prolonged cooling phase in the Northern Hemisphere known as the Late Antique Little Ice Age, which persisted until the mid-7th century.
The “mystery dark cloud” noted by ancient writers was a result of sulfate aerosols released by significant volcanic eruptions. These aerosols reflect sunlight, consequently diminishing the solar radiation that reaches Earth. The cooling effects of such eruptions can last for several years.
Although researchers have yet to identify the specific volcanoes responsible for this cold spell, a multidisciplinary team led by Cambridge professor Ulf Büntgen has utilized tree ring data to confirm a temperature drop of up to 2 degrees Celsius (or 4 degrees Fahrenheit) during the summer of 536 CE. Büntgen emphasizes that this Late Antique extreme climate event coincided with widespread famines, social and political instability, and epidemics affecting regions from Europe to China.
While Büntgen cautions against assuming a direct correlation between environmental changes and political outcomes, it is evident that the Late Antique cooling period intensified social unrest across much of the Northern Hemisphere. Scholars speculate that this climatic shift may have contributed to the downfall of the Eastern Roman Empire and the Lombards’ incursion into Italy. Moreover, it likely exacerbated political turmoil in China and facilitated the spread of the Justinian Plague, a pandemic that claimed between 25 million and 100 million lives, many weakened by crop failures and famine.
Interestingly, Swedish archaeologist Bo Gräslund has proposed that the colder climate may have inspired legends such as the myth of Ragnarok. “First came the Fimbul winter,” recites the Edda (a collection of Old Norse poems), “that lasted three years. This was a warning of the coming of Ragnarok, when everything living on Earth came to an end.”
In his book “The Great Derangement: Climate Change and the Unthinkable,” acclaimed author Amitav Ghosh poses the question: “Will our future generations, standing in a rising pool of swirling waters, not beseech us with this question — ‘Why didn’t you do something?’” An examination of past climate change episodes illustrates the often catastrophic consequences of environmental disasters on societies. In this regard, they serve as cautionary lessons for both present and future generations. Anthropologist Ariane Burke asserts, “We can look to the past for inspiration and for practical solutions to make informed decisions for the future.”