environmental determinism

Favorable Climatic Conditions and the Flourishing of the Tibetan Empire, 618-842 CE

I have long been perplexed by the Tibetan Empire, which existed from 618 to roughly 842 CE. The Tibetan Plateau is a sparsely populated land with a challenging physical environment. Not surprisingly, for most of recorded history it has played a minor geopolitical role. Yet for more than 200 years, the Tibetan Empire was something of a superpower, fully competitive with the Tang Empire of China, the Muslim caliphates of the Middle East, and other great Eurasian states. As the maps posted below indicate, the Tibetan Empire’s territorial sway extended, at various time, well beyond the plateau itself. At its height it covered the Tarim Basin of northwestern China (Xinjiang), the Yunnan Plateau, and more.  

The most extensive depiction of the Tibetan Empire that I have found was published in a recent Science Direct article (Hou et al., 2023). On this map, posted below, the Tibetan Empire in 820 CE is shown (with a dashed yellow line) as having included most of what is today Afghanistan, Uzbekistan, Tajikistan, and Kyrgyzstan, as well as much of Bangladesh and lowland north India. Most maps of the empire show it as having exercised only indirect power over a much smaller part of northern South Asia. Animated maps, moreover, indicate that its power over this area was brief. The map posted in Hou et al. thus seems to be exaggerated, as is so often the case in the mapping of empires.

Regardless of cartographic hyperbole, the article in question does offer an intriguing and largely convincing explanation for the rise and fall of the Tibetan Empire. As the authors’ investigation shows, between 600 and 800 CE the Tibetan Plateau experienced both relatively warm and wet conditions, allowing both agriculture and pastoralism to thrive. Such circumstances, in turn, provided the economic basis for a strong and expansionistic state. Importantly, this period was the only time in the past several thousand years that saw both warmth and “exceptional” humidity on the lofty plateau. Significantly, the collapse of the Tibetan Empire coincided with a return to drier conditions. As the authors write:

A closer examination at the precipitation records revealed that periods when Tibetans actively invaded Tang territory mostly coincided with humid periods, while conversely, Tang invasions into Tibetan territory occurred during relatively dry periods on the TP [Tibetan Plateau].

The peak of the drought at approximately 840 AD coincided with the collapse of the Tibetan Empire. Cold and dry events would be expected to lead to a decline in crop production, breaking the balance between population and resource supply.

Other major episodes of imperial expansion in Central Eurasia also seem to have been linked to favorable climatic conditions. A 2014 article, for example, found something similar in regard to the Mongol Empire. As the authors summarized their findings:

A 1,112-y tree-ring record of moisture shows that in opposition to conventional wisdom, the climate during the rise of the 13th-century Mongol Empire was a period of persistent moisture, unprecedented in the last 1,000 y. This 15-y episode of persistent moisture likely led to a period of high grassland productivity, contributing fuel to the Mongol Empire.

A century ago, leading geographers argued that climate and other aspects of the physical environment determine the course of human history. Such overweening determinism weakened the discipline, contributing to its subsequent marginalization. Today, however, historians and physical scientists are reviving the study of the influence of climate – and of climate change – on the course of history, but are doing so in more modest, rigorous, and productive manner.

Environmental determinism reached its height in the early twentieth century in the works of Yale geographer Ellsworth Huntington. In 1907, Huntington argued in The Pulse of Asia that a long period of intensifying droughts beginning several thousand years ago forced Central Asian pastoral nomads out of their homelands, impelling them to conquer sedentary states located in more climatically favorable areas. As he put it (page 393-394):

If the rainfall fell from 20 inches to 10, the number of sheep would decrease from 60 to one. Manifestly, if such a change took place in the course of a few hundred years, most of the inhabitants would be obliged to migrate. As the nomads pressed outward from the dryer central regions of Asia, we can imagine how they were obliged to fight with the neighboring tribes whom they tried to dispossess. The older inhabitants and the newcomers could not all live together; new migrations would be a necessity; and the confusion would spread in every direction. Meanwhile, Europe, after this long period of blighting cold, was becoming warm and habitable, and the migrants pressed into it, horde after horde. No one tribe could stay long in its chosen abiding-place, for new bands of restless nomads pressed upon it. Rome fell before the wanderers. Nothing could stay their progress until the turn of the tide.

Per chance, though this is only vague conjecture, the legends of King Arthur and his Knights bear a hint of what might have occurred all over central Europe if it had not been for the influx of Barbarians. England, in its remote corner of Europe, far from the dry plains of Asia, responded at first to the influence of improved climatic conditions, until it, too, was reached by the migrating hordes of invaders. Meanwhile, in the most densely populated part of Asia, another movement of nations had begun, presumably because of the distress due to rapid desiccation. The Arab migrants carried with them the fanatical faith of Mohammed, and were by it inspired to remoter conquest.

Such conclusions are directly opposite of those now being advanced by scientifically informed historical studies. One could not, of course, expect Ellsworth Huntington to have had a modern conception of environmental and historical processes and conditions in 1907. Still, to have argued, if only as “vague conjecture,” that the mythical glories of Camelot might have been replicated over central Europe in the early Middle Ages, had it not been for the drought-driven barbarian invasions, is more than a stretch. Unfortunately, the excesses of Huntington’s determinism led geographers to largely abandon the idea that the physical environment has any significant influence on human history, much to their detriment. Today, scientific studies of the changing physical environment are clarifying our conception of the human past are helping to solve historical mysteries.

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The Political Regions of Europe and the Fallacy of Environmental Determinism

Europe Political Orientation MapGeoCurrents reader Rafael Ferrero-Aprato recently brought to my attention an interesting map of political divisions in Europe made by the Dutch electoral geographer Josse de Voogd and reproduced by The Economist in 2014. Josse de Voogd notes the difficulties and limitations in making a map of this sort: “Some countries [are covered] in much greater detail than others and there are lots of political parties that are difficult to place ideologically. The information comes from a wide range of resources over a long time-span.” In general terms, the map seems reasonably accurate. But at the more local scale, the situation often gets too complex to be easily captured in a map of this sort. As Rafael Ferrero-Aprato notes in regard to his own country, Portugal:

Speaking for Portugal though, the red corresponds to the strongly leftists regions of Alentejo/South Ribatejo (because of the latifundium agricultural system) and Setúbal Peninsula (an industrial region). It includes also the moderately leftist areas of the north Algarve, lower Beira Interior and Lisbon. So far, so good.

But after giving it more attention, the borders are not perfect: they include south Algarve (moderately right-wing) and the city of Porto, despite it being considered right-wing. Some leftist “enclaves” are missing too, such as the peninsula of Peniche (industrial fishing) and the city of Marinha Grande (industrial).

The Alentejo, Setúbal Peninsula, Peniche and Marinha Grande were also areas of strong influence of the Portuguese Communist Party during the 1926-74 dictatorships, the only force that remained organized in the face of strong repression by the regime. As such, these regions saw numerous revolts during that time.

Germany Electoral Maps 1The only country that seems to be misconstrued on the map—at least for recent elections—is Germany. As the set of maps from Electoral Geography 2.0 indicates, German elections have recently been structured largely Germany Electoral Maps 2around a north/south division, especially those of 1998, 2002, and 2005. The 1994 and 1987 (West Germany only) maps fit better with de Voogd’s depiction, although it does seem that he unduly minimizes the left-wing Ruhr industrial area.

European right-wing populism mapUnfortunately, the interpretation of de Voogd’s cartography by The Economist is not particularly enlightening. Much of the attention here focuses on environmental determinism, referring both to the map discussed above and to another map made by de Voogd, posted here to the left. As the noted in The Economist article:

Flat areas are more right wing The flat pains of southern Sweden, East Anglia, north-eastern France, Flanders and Padania vote for right-wing populists. Hilly regions like Cumbria, south-west France and most of the Alps tend to stick with the mainstream parties. This observation is not as facetious as it may seem. According to Garry Tregidga, an historian at Exeter University, hilly pastoral areas are generally characterised by left-leaning politics. One debatable explanation is that flat crop-growing areas benefit most from economies of scale, so fathers traditionally passed on their land to the first born, reinforcing differences in wealth and creating a more hierarchical political culture. In hilly, pastoral areas inheritances were more commonly split equally, which over the generations created a more egalitarian social structure and political tradition. Another (equally debatable) explanation is that arable farms need cheap vegetable-pickers and that the consequent foreign immigration into otherwise homogeneous rural areas stokes right-wing sentiment.

Europe physical mapThe Economist author simply gets the physical geography of Europe wrong. Upper Saxony in Germany and Provence in France are correctly depicted as right-wing populist strongholds, yet they are hardly flat areas. And as the “dominant political force” map indicates, many “flat” areas generally vote for the left. Examples here include southwestern France (Aquitaine is not “hilly,” despite what The Economist claims), the lowlands of Scotland, the Brandenburg region of Germany, the plains of Andalucía, and the lower Danube Valley. And what of upland area such as the Alps, the Carpathians, the Pindus, and the Cantabrian Mountains that are accurately depicted as more “rightist” in their voting patterns? As a comparison of de Voogd’s basic political map with a physical map of Europe shows, there is simply no pan-European correlation between topography and political viewpoints.

Like most geographers, I am often perplexed by the hold that environmental determinism retains on the public imagination. Actual evidence is rarely able to dislodge such fallacies. Evidently there is something deep comfortable about the idea that landforms and climate determine how we think.

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Ellen Churchill Semple and Paths Not Taken


When I was studying geography as a graduate student in the 1980s, little attention was paid to the history of geographic thought. When the works of early 20th century geographers did come up in seminar, they typically served as sign-posts for discredited approaches. Ellen Churchill Semple was a favorite target; passages like this one, from her Influences of Geographic Environment, suggest why.

The dry, pure air stimulates the faculties of the desert-dweller, but the featureless, monotonous surroundings furnish them with little to work with. The mind, finding scant material for sustained logical deduction, falls back upon contemplation. … First and last, these shepherd folk receive from the immense monotony of their environment the impression of unity. Therefore all of them, upon outgrowing their primitive fetish and nature worship, gravitate inevitably toward monotheism (The Influences of Geographic Environment, 1911, p. 512).

Histories of geographic thought tend to pass lightly over “Miss Semple,” as she was once called. In the standard narrative, she performed a valuable service by introducing the “anthropogeography” of Friedrich Ratzel to an English-speaking audience, but she over-emphasized her mentor’s geographical determinism. Progress in human geography required that her approach be superseded, as it was in due time. End of story.

The 100th anniversary of Ellen Churchill Semple’s Influences of Geographic Environment makes this year an appropriate moment to revisit her scholarship. Yes, many passages are overblown and some are galling. But Semple, like the rest of us, was a creature of her time. Despite its flaws, Influences of Geographic Environment is a treasure trove of geohistorical information, reflecting the remarkable erudition of its author. While it is probably fitting that most geographers of her period are read mainly to grasp their manner of thinking, we can still read Semple to learn about the world. Her knowledge of places and times was nothing less than awe-inspiring.

Semple’s take on the world was more nuanced than excerpts like the one above would suggest; in fact, a number of her ideas were ahead of their time. For instance, over the past several decades, scholars have “discovered” ocean basins as coherent frames for historical investigation. Such fields as Atlantic studies, Mediterranean studies, and Indian Ocean studies are all relatively new, and thriving. All this was anticipated by Semple:

[The Indian Ocean] has linked together the history of Asia and Africa: and by the Red Sea and Persian Gulf, it has drawn Europe and the Mediterranean into its sphere of influence. At the western corner of the Indian Ocean, a Semitic people, the Arabs of Oman and Yemen, here first developed brilliant maritime activity, like their Phoenician kinsmen of the Lebanon seaboard. …

From the dawn of history the northern Indian Ocean was a thoroughfare. Alexander the Great’s rediscovery of the old sea route to the Orient sounds like a modern event in relation to the gray ages behind it. Along this thoroughfare Indian colonists, traders, and priests carried the elements of Indian civilization to the easternmost Sunda Isles; and oriental wares, science and religion moved westward to the margin of Europe and Africa. The Indian Ocean produced a civilization of its own, with which it colored a vast semi-circle of land reaching from Java to Abyssinia… (Influences of Geographic Environment, 1911, p. 309)

Like other scholars of her day, Semple had to consider race. That she used racial categories uncritically strikes a discordant tone with modern readers, but she never really bought into racial ideology. Her maps were “ethnographic,” not “racial” (and were far more accurate than those of Fleure in 1962, as can be seen above). More important, she decided to confront the idea of racial superiority directly through research. Her question was simple: if public opinion proclaimed the progressive virtues of the Anglo-Saxon race, how then to explain the lack of progress in the backwoods of eastern Kentucky? Little information on the region was available, so Semple set out to obtain it.

Field research was new to human geography in the late 1800s, and Semple was one of its pioneers.* She undertook a 350-mile horseback trek through the most remote districts of the eastern United States. During her entire trip she reported seeing only a few wheeled vehicles. Blood-feuds still characterized the area, which remained largely beyond the reach of modern economy as well as that of state authority. She conducted interviews over a wide area, collecting information on the economy, crafts, agriculture, music, language, folklore, and so on. Semple was impressed by the resourcefulness of the inhabitants and by their cultural practices, reporting that the “accuracy of their memories for … long poems was suggestive of Homeric days” (p. 34). If the region was nonetheless beset by persistent stagnation, that could be attributed squarely to the topography. “The whole civilization of the Kentucky mountains,” she concluded, “is eloquent to the anthropogeographer of the influence of physical environment.” Race, in short, was not the key to human progress.

Deterministic and judgmental though they may have been, Semple’s conclusions about the mountaineers were not without merit. As she showed, the Kentucky hill-folk in the 1890s could barely participate in wider economic and social circles due to transportation constraints. The mountains here are not particularly high, but the land is steep almost everywhere, and the reach of the state did not extend to road-building in such inhospitable terrain. Given the primitive infrastructure, the only salable products that that would bear the costs of porting to market were ginseng and moonshine; even hogs, which could walk themselves to distant markets, would lose too much weight en route to make the trip worthwhile. Social travel was also highly constrained, enforcing isolation. The geographic environment, in other words, was a major influence. Rugged and remote mountains are indeed difficult for states to control and markets to penetrate. Harlan County Kentucky today has plenty of paved roads, of course, but Semple could hardly have been expected to have foreseen that. And even to this day, rugged lands often remain distinctive. Cultural diversity is typically concentrated in such regions, and insurgencies tend to be more numerous and successful in rough uplands than in adjacent lowlands.

Semple’s achievements are all the more impressive when one takes into account the obstacles that she faced as a woman. Having traveled to Leipzig Germany to study with Ratzel, she was not allowed to enroll in the university or even to sit in the lecture hall. To learn from the famous professor, she was forced instead to listen from the hallway. Yet student and scholar did work together, and Ratzel was sufficiently impressed with her that he picked Semple to translate his major work into English. This she refused to do, preferring instead to write a book of her own—albeit one dedicated to his memory.

By all rights, Semple should have been a star professor at a top university, building her own school of anthropogeography and training a cohort of strong graduate students. But while she lectured at a number of universities, Semple did not gain a regular faculty position until hired by Clark University at the age of 57 (at a significantly lower salary than that of her male peers). Her classroom prowess was legendary; while illustrating her lectures with glass-slide projections, she allegedly never turned to look back at the images, as she always knew exactly what was being shown on the screen behind her. She held seminars with graduate students while visiting other schools, and is said to have been inspiring. In 1921, Semple’s contributions to the profession were recognized when she was elected president of the Association of American Geographers. Needless to say, she was the first woman to hold that position. Until 1985, she was also the last.

* See “The Anglo-Saxons of the Kentucky Mountains: A Study in Anthropogeography.” Journal of Geography, June, 1901.

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