How can environmental texts from antiquity help us to rethink our changing relationship to the natural world?
When we talk about climate change we tend to talk about the future: How much will global temperatures rise? How quickly will such changes occur? What sort of impact will this shift have on ecosystems around the world? Already, countless hours and resources have been spent attempting to predict how exactly the global climate will change in coming years and what we can do to mitigate any adverse effects on flora, fauna, and human communities. But at the same time, an interest in climate change in the past has steadily been growing.
For well over a century, scientists have been charting the fluctuations of climate across vast timescales; only recently, however, have concerted efforts been made to try to understand how the climate of the historical past (about the last 5,000 years) has changed. Naturally, this effort has been linked to the question of how human communities have adapted to those changes.
In the fall of 2015, I began working with Cam Grey of the Ancient History department at Penn to engage with this discussion in one particular part of the world (Greece) in one circumscribed period (the 4th century BCE). Those restrictions might seem oddly arbitrary, but thanks to the voluminous testimony of Aristotle and his pupil Theophrastus in works such as the Meteorologica, Enquiry into Plants, and On Winds, we have a considerable amount of evidence pertaining to the natural world of that region at that time.
Theophrastus’s works in particular reveal an intimate understanding of the impact that meteorological fluctuations could have on plant life, in addition to more far-reaching theories about climatic shifts:
If it is true what the Cretans among others say, that nowadays the winters are more severe and more snow falls, adducing as evidence that the mountains were settled in olden times and supported both cereal and tree crop as the land was planted and tilled (for there are extensive plains among the mountains of Ida and in the other mountains, none of which are worked now because they do not bear, whereas in those days, as we have said, they were settled, as a result of which the island was populous, because then the rains were generous, while snowfalls and wintery weather did not often occur), if then this is true, as we say, the Etesian winds must be more numerous today (De Ventis 13; my translation).
Historians of the ancient world have dabbled for some time in discussions of climate change, but have often done so with little concern for scientific rigor. A classic example of this is the work done on the so-called Bronze Age collapse of the 12th and 11th centuries BCE, during which complex societies throughout the Eastern Mediterranean rapidly disappeared. Already in the 1950s, a number of scholars proposed climate change as a possible culprit, though with little scientific evidence available and little consideration of how exactly a complex society would come to collapse because of a shift to more inclement weather.
Such hypothesizing may have been acceptable when palaeoclimatology (the study of past climates) was still rudimentary, but today, with the publication of a continuous stream of increasingly detailed historical climate research, this lack of rigor is no longer tenable. My main goal in approaching this topic has been to address how exactly an ancient historian like myself might begin to study past climate change and how societies have responded to such shifts.
This project is divided into three parts. The first is an historiographical survey of how ancient historians have addressed climate change. I want to highlight what I have called the “myth of the static climate,” the basic belief, still touted by many scholars, that the climate of the ancient Mediterranean has effectively remained unchanged since the beginning of the first millennium BCE, and thus that we may safely assume that temperatures and precipitation and wind patterns were the same in, say, Pericles’ day. Despite the widespread recognition of climate change throughout human history, this myth has had a persistent and insidious effect on discussions of climate in the ancient Greek world. My results have shown that many of the pieces of evidence used to suggest that the climate of later 1st millennium BCE Greece was very similar to that of today have in fact been misinterpreted, and that historians of the ancient world have too often allowed their desire to be able to use comparative climatological data from the recent past to cloud their judgment.
In the second part, I survey of how ancient historians should approach climate science data; in the vast body of palaeoclimatological material, what can we use now, what can we expect to find in the future, and how exactly can we use, say, speleothem evidence (geological formations such as stalagmites and stalactites whose growth is determined by the regular seepage of groundwater), varve records (the annual layering of sediments in a lakebed), or dendrochronological sequences (the measurement of tree-ring widths in order to assess annual precipitation and temperature fluctuations) to address events on a human timescale?
Finally, the third section addresses the issue of how, in practical terms, the ancient Greeks engaged with climate change. Were they aware of climate change? (Sort of.) Was there one particular class or group that determined how the community responded to changes in weather patterns? (No.) Did they have institutional means of buffering against food shortage? (Yes.) Theophrastus, for instance, describes the flexible responses of communities living on the shores of Lake Kopais, in central Greece in the 4th century BCE: when the lake was full during particularly rainy years, the resources of the coastal marsh were exploited for hunting, fishing, grazing livestock, and foraging for plants used to create products as varied as perfume and musical instruments. He also adds the surprising observation that when the lake was full, it acted as a heat sink, causing the surrounding area to experience fewer cold snaps in winter; as a result, tree crops sensitive to frost tended to fare better. When during dry spells the lake was empty, on the other hand, the exposed rich lakebed was instead planted with drought-resistant crops.
These are the sorts of questions that all too often go unasked by historians who want to get to the juicy stuff which supposedly ensued from climatic shifts—devastating droughts, mass migrations, and ultimately societal collapse—but that must be addressed before we can truly understand the impact that such changes had on past societies. My hope is that, through this research, I can contribute to the steadily growing debate about what we can learn today from responses to climate change in the past. By studying past climate change and how societies throughout history have responded to climate change, we can, firstly, better understand the varied impacts that climatic shifts can have on the natural world, and, secondly, analyze why certain societies were more resilient than others. Such information is invaluable for those interested in predicting where we are headed in the years to come and how we can prepare for an increasingly uncertain future.
Theophrastus. De Ventis. Ed. Victor Carlisle Barr Coutant and Val L. Eichenlaub. Notre Dame, IN: University of Notre Dame Press, 1975.