High altitude may create barrier to ethnic diversity
PRINCETON (US) — Altitude sickness may be an obstacle to ethnic integration in some of the world’s steepest terrains.
People who are native to low-lying areas can be naturally barred from regions such as the Tibetan Plateau, the Andes, or the Himalayas by altitude sickness, which is caused by low oxygen concentration in the air and can be life-threatening.
As a result, as elevation increases so can the homogeny of the local population. In nations shared by people of high- and lowland extractions, this separation can potentially increase ethnic tension.
“Rather than saying there is merely a correlation between settlement patterns and altitude, our research takes it one step further and suggests that altitude can directly determine the settlement patterns we see today. There’s a causal story here,” says Christopher Paik. (Credit: HaxHeaven/Flickr)
In Tibet elevation has heavily influenced the location of the surrounding region’s population of Han Chinese, who make up 92 percent of China’s population and originate from the country’s eastern plains. Tibet has an average elevation of roughly 14,370 feet (4,380 meters) above sea level.
The number of settlements with a large Han Chinese population peaks at around 8,900 feet (2,700 meters), while Tibetan settlements only begin to peter out beyond 17,000 feet (5,200 meters).
The sudden drop in the Han Chinese population can be attributed to altitude sickness, researchers say, citing existing research showing that Han Chinese are indeed susceptible to altitude sickness in areas where Tibetans thrive.
Published in the journal Applied Geography, the research adds a new dimension to the study of how terrain influences demographic patterns, says first author Christopher Paik, who undertook the study as a postdoctoral research scholar in the Empirical Studies of Conflict Project at Princeton University.
The biological effects of elevation make altitude a particularly objective and reliable measurement for helping determine and understand how populations around the world’s highest areas form.
“There is very little research about the effect of altitude on migration patterns,” says Paik, who is now an assistant professor of politics at New York University Abu Dhabi. “One of the nice things about using this geographical indicator as an independent variable is that there isn’t any human intervention in determining the altitude of the region because it’s established by nature.
“Rather than saying there is merely a correlation between settlement patterns and altitude, our research takes it one step further and suggests that altitude can directly determine the settlement patterns we see today. There’s a causal story here.”
The separation that results from these settlement patterns could result in greater ethnic friction, says Paik, who initiated the current study in the wake of the 2008 unrest in Tibet, a series of protests that lead to imprisonment, detainment and clashes with Chinese security forces.
He noticed that the most violent outbreaks occurred in areas of Tibet with the lowest relative concentrations of Han Chinese—regions that also have the highest elevations.
Paik and co-author Tsering Shawa used 2000 Chinese census data to determine the Han population in settlements within the traditional Tibetan homeland, which includes the Tibetan Autonomous Region as well as portions of the Chinese provinces Qinghai, Gansu, Sichuan and Yunnan. They also gauged past Han Chinese presence through maps and a database developed by Shawa that indicate whether the official name of the 1,960 settlements in this area is Han Chinese, Tibetan, or both.
They found a similar distribution pattern of towns where at least one-third of the population are Han Chinese and traditional Han settlements (most of which date as far back as the 13th century)—the bulk are located lower than 8,900 feet above sea level. No towns with a Chinese name exist above 15,000 feet (4,600 meters).
Meanwhile, the greatest number of settlements with a Tibetan name stands at an only slightly lower elevation of 14,760 feet (4,500 meters), an area that the census shows has a minimum of Han Chinese inhabitants.
“What the outcome suggests is that there is a direct effect of altitude now as well as in historical settlement patterns,” Paik says. “On the one hand there are settlements where Han Chinese came 1,000 years ago and established roots in that region, which makes it easier for migrants to come in. That provides a channel through which more Chinese live there today because their ancestors lived there as well.
“But if historical settlement is the only channel through which altitude influenced current settlement patterns, then there wouldn’t be the direct influence of elevation through altitude sickness that we still see,” Paik says. “Han Chinese still suffer from altitude sickness and the influence on settlement seems to persist today.”
Nature vs. public policy
Paik and Shawa reference at least 10 studies that delve into the genetic adaption of Tibetans’ blood cells and lung tissue to the low-oxygen conditions of a life on high—a tolerance research suggests they share with Andes dwellers in countries such as Bolivia.
Han Chinese do not enjoy this predisposition even in modern times. The researchers cite a 2009 paper in the journal Clinica Chimica Acta that explored the genetic susceptibility of Han Chinese laborers to the pulmonary edema—potentially fatal fluid buildup in the lungs—they experienced during construction of the Qinghai-Tibet railway completed in 2005.
“The main contribution of this research is to point out geography does matter in ethnic demographic patterns,” says Enze Han, an assistant professor of politics and international studies at the University of London. Han, who had no role in the research but is familiar with it, agrees with the researchers when they write that modern technology and transportation makes migration into high-altitude lands easier.
But, Paik says, the population distributions he and Shawa document show that geography—via altitude sickness—continues to play a strong role in regional diversity despite modern trappings such as the Qinghai-Tibet railway and government initiatives such as China’s Western Development Program.
“Ethnic integration policy seems to work in the long run, but it will be harder to implement in the higher altitude regions,” Paik says. “There seems to be a strong enough influence of altitude on settlement patterns such that even if you try to have integration happening there, nature works against those initiatives.”
The Air Force Office of Scientific Research supported the research.
Source: Princeton University
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