Civilization and the environment

In a world where the map of global climate change is always shifting, the conditions that once made a civilization flourish can never be taken for granted. There is a constant ebb and flow of migration and return-migration, as changes in weather patterns modify a people’s environment and sources of sustenance. These changes have often proven so drastic as to contribute to the demise of previously stable civilizations.

Background

The extent to which climatic change has affected the genesis, development, location, nature, and the rise and fall of civilizations throughout history has been a matter of long-standing debate. The issue has gained a sharper edge and assumed a greater urgency, however, in an era of increasing environmental awareness. Any agreement among scholars seems to be on a broad scale rather than on specifics. The wider view is that the globe has been in a predominantly warming trend for the last seventeen thousand years. This thaw in the wake of the last major ice age has been proposed as the main factor that started, propelled, and sustained the spectacular advance of human civilization, notably from around 3000 b.c.e. to the present. However, when historians attempt to determine causal factors contributing to the success and failure of particular cultures, multiple factors other than climate have to be taken into account.

Indus River Valley Culture

A long-standing debate has raged over what might have caused the demise of the Indus River Valley culture. Sprawled along the alluvial plain of the Indus River in what later became Pakistan, this culture was the largest in terms of the land area of the four earliest cradles of civilization. Dependent on the agricultural productivity of the fertile soil along the riverbanks, it was highly urbanized and had strong trade links with Mesopotamia. The cities were painstakingly planned; buildings were constructed of oven-baked brick; spacious streets were almost perfectly laid out in modern grid fashion; and the cities employed advanced drainage and sewage disposal mechanisms.

The Indus culture flourished beginning around 2500 b.c.e. then declined and became depopulated by no later than 1200 to 1100 b.c.e. Several theories attempt to explain its downfall, but none are conclusive. However, research continually indicates that climatic and environmental factors brought about the downturn in the culture’s fortunes rather than attacks by Aryan invaders. According to one scenario, a climatic change seems to have triggered increased rainfall, leading to massive flooding. The demand for wood to fire the kilns used to produce bricks had denuded the forests, and this deforestation eroded the soil, rendering it vulnerable to flooding. Another climate change theory has it that drought, warmer temperatures, and anthropogenicdeforestation resulted in desertification, which caused the large-scale abandonment of the Indus cities.

Egypt, Mesopotamia, and Greece

The Old Kingdom civilization of Egypt, 3100-2200 b.c.e., was renowned as the era of pyramid construction and exemplary of strength and prosperity. However, there is some evidence that global climate change possibly caused the disruption of the annual flooding of the Nile River—perhaps augmented by El Niño-Southern Oscillation (ENSO) effects—and thus might have brought about a devastating drought cycle that led to the termination of the Old Kingdom. The kingdom’s demise was followed by a chaotic 150 years known as the First Intermediate Period.

The climatic vulnerability of Mesopotamia has been amply attested to in the cuneiform texts of its various civilizations and evidenced by the archaeological record. The Akkadian Empire (2400-2200 b.c.e.), which encompassed Mesopotamia and the Fertile Crescent up to the Levantine Coast, was apparently brought low by a series of very severe winters, drought conditions, and perhaps occasioned by volcanic eruptions. Another such massive drought cycle around 1200 b.c.e. is also believed to have contributed to the ending of the Hittite Empire and Mycenaean Greece.

The Americas: Anasazi and Maya

Lack of documentation makes it exceptionally difficult to gauge the scale of the impact that climate may have had on pre-Columbian Native American cultures. The Maya of Mexico and Central America, whose civilization was the most advanced and probably the best documented, suffered the nearly wholesale destruction of their books by Spanish missionaries. The Anasazi, who dwelled in present-day portions of the southwestern United States from around 700 to 1150 c.e., had no such documentation to begin with, so their abrupt collapse has proven even more puzzling.

The Navajo term Anasazi, or “ancient ones,” has been used to denote the Pueblo cultures known variously in different regions as the Hohokam, Mogollon, and Patayan. These peoples inhabited the area around the modern Four Corners—where Utah, Colorado, Arizona, and New Mexico converge—and southward into the greater part of the modern state of Chihuahua, Mexico. They constructed the spectacular cliff dwellings that still dot the regions they once inhabited, including Mesa Verde, Chaco Canyon, and Canyon de Chelly. Around 1150 c.e., a particularly severe and prolonged period of drought drove the Anasazi to nearby areas where water was slightly more accessible, and the descendents of the Anasazi can be found among the present-day Pueblo.

Deriving, most likely, from the more ancient cultures of the Olmec and Teotihuacan in southern Mexico, the people known as the Maya flourished in the region of the Mexican Yucatán Peninsula and the modern countries of Guatemala, Belize, El Salvador, and Honduras around 200 to 900 c.e. Massive and sophisticated in their architectural designs and elaborate pyramids, Mayan city-states burgeoned into mini-empires under autocratic kings who claimed to serve as conduits to the gods to ensure their people’s prosperity. The once-baffling collapse of these city-states is thought to have been caused by a series of droughts; the resulting crop failures drove the Maya to abandon both their faith in these kings and the city-states themselves, which became isolated ruins.

The Andes and Oceania

The enigmatic Moche culture of the Andes lasted from about 100 to 750 c.e. along the northern coastline of Peru and coincided with the Nazca culture to the south. Both ended abruptly, leaving little more than their major artifacts (Moche pottery and the Nazca lines in the Nazca Desert). There is some disputed evidence that extensive ENSO episodes set off alternating patterns of flooding and drought, causing both civilizations to crumble. The more extensive Tiahuanaco culture, centered around an urban site in Bolivia, flourished from about 700 to 1150 c.e., left giant stonework ruins, and seems to have perished from the effects of the same massive drought period that destroyed the Anasazi.

The more isolated islands of Pacific Oceania could be expected to offer more examples of vulnerability. Because of their remoteness, the scarcity of land and resources, and the potential capriciousness of nature, they have been home to some of the most frail of human societies. These societies, however, experienced different outcomes. For example, the native culture of Easter Island seems to have come to an end in part through a murderous civil war brought on by deforestation and social unrest. It is possible that an ENSO episode exacerbated conditions of drought and scarcity, bringing about the culture’s final destruction.

Norse Greenland

The fate of the Norse settlements in Greenland offers the most readily documented example of the negative impact of climate change. In 968 c.e., the Viking warlord Eric the Red sailed from Iceland to establish a Scandinavian colony in Greenland. During the Medieval Warm Period, the colony thrived and expanded, concentrating into two major settlements. An eastern settlement was located on the island’s extreme southern coast, and a less significant settlement was founded 320 kilometers up the western coast. In its heyday, each settlement may have had a population of five thousand. Their economic mainstays were cattle and sheep grazing, as well as trade, mainly with the Icelanders and Norwegians.

Around 1250 c.e., as the Medieval Warm Period gave way to the Little Ice Age, glaciers advanced dramatically across Greenland. (The term “Little Ice Age” is used differently by different writers. Many use it to refer to the climate cooling from about 1300 to 1850 c.e., while others use it for the latter half of that interval, when cooling was greatest, beginning around 1550 or 1600 c.e.) Growing seasons shortened; temperatures plummeted; and hunting, grazing, and agricultural land became scarce. The Greenlanders, always in an isolated position, became even more cut off as ice packs began blocking the passage routes to and from Iceland and Norway. Increasingly harsh conditions also drove the Inuit (Eskimos) south and west, and almost immediately, armed clashes broke out between them and the Norse, as both groups competed for dwindling sources of sustenance. The Inuit proved to be the more readily adaptable to change, while the Norse were reluctant to alter their ways. Thus, by 1400 c.e., the western and eastern settlements lay abandoned as the Vikings either starved, died at the hands of the Inuit, or fled.

Context

Though there exists little doubt that climate change and environmental factors have affected the course of civilization, there remains an element of debate over their relationship to other causal factors, such as outside encroachment and internal dissension. It may well be different in each case. The ability of climate to influence history may affect contemporary politics and public policydecision making. If the correlation between climatic or environmental events and the decline of civilizations could be conclusively established, then it would logically follow that governments should work to prevent or to alleviate the effects of such events in the interests of self-preservation.

Key Concepts

• deforestation: the process by which areas are stripped of forests and tree cover, exposing the underlying soil to erosive forces
• desertification: the process by which once semi-arable lands are converted into desert
• El Niño-Southern Oscillation: a climatic phenomenon wherein the normally cold ocean currents off the Pacific Coast of South America reverse, affecting global weather patterns
• Little Ice Age: time period from around 1250 to 1850 c.e. characterized by cooling global temperatures
• Medieval Warm Period: time period from around 800 to 1250 c.e. when European and possibly global temperatures were generally warming

Bibliography

Avari, Burjor. India—The Ancient Past: A History of the Indian Subcontinent from c. 7000 B.C. to A.D. 1200. Routledge, 2007. ocd.lcwu.edu.pk/cfiles/History/Maj/Hist-302/AncientIndia4majoreras-BurjorAvari.pdf. Accessed 19 Jan. 2023. Evenhanded account that examines both major theories for the collapse of the Indus Valley culture, with the logical preponderance of evidence supporting environmental or climatic calamity, rather than outside invasion.

Diamond, Jared. Collapse: How Societies Choose to Fail or Succeed. Penguin Books, 2006. cpor.org/ce/Diamond%282005%29Collapse-HowSocietiesChooseFailureSuccess.pdf. Accessed 19 Jan 2023.Though the author concedes that climatic change is a significant factor in the demise of several civilizations, he emphasizes the impact of ill-advised decisions by the leaders and populaces as necessary contributing elements.

Fagan, Brian. The Long Summer: How Climate Changed Civilization. New York: Basic Books, 2005. Advances the theory that all the major developments of human civilization may be seen as coinciding with the lengthy warming period that followed the last global ice age.

Henderson, John S. The World of the Ancient Maya. Ithaca, N.Y.: Cornell University Press, 1997. Sets out unhesitatingly the probable role of climate-related subsistence crisis in triggering the abandonment of Mayan city-states.

Jones, Gwyn. A History of the Vikings. New York: Oxford University Press, 1969. Seminal study that establishes the pivotal role of Greenland’s isolation and the onset of extreme global cooling to the subsistence crisis that overtook the westernmost Viking outposts.

Pike, Donald G. Anasazi: Ancient People of the Rock. Illustrated by David Muench. Palo Alto, Calif.: American West, 1974. Blames the Anasazi’s decline in part on drought, but asserts that the depredations of nomads were a more significant factor.

Schele, Linda, and David Freidel. A Forest of Kings: The Untold Story of the Ancient Maya. New York: William Morrow, 1990. Extremely detailed description of the complexity of Mayan culture, including its language and religion. Scant and inconclusive discussion of the culture’s decline.

Wheeler, Sir Mortimer. The Indus Civilization. 3d ed. Cambridge University Press, 1968. www.rarebooksocietyofindia.org/book‗archive/196174216674‗10153812320006675.pdf. Accessed 19 Jan. 2023. Downplays the idea of climate change and human environmental blunders as causes for the decline of the Indus culture; strongly advocates the view that Aryan aggression was more decisive.