Transportation and Disease: the Means to a Threat

Diego Garcia-Montufar

Since its inception, human transportation brought with it adverse environmental effects in both direct and indirect ways. One of the major impacts that the development of transportation technologies had on the environment was through the spread of diseases, which were carried by human populations and their accompanying animals to the new areas that they invaded and colonized. This not only affected the human populations involved in the colonization process (both the colonizers and the colonized), but in some instances it also might have affected the biosphere as a whole. In this essay, we will focus on how transportation affected the environment by facilitating the spread of disease, focusing on three main case studies. First, we will look at the human colonization of Australia, about 50 000 years ago, and the extinction of 85 per cent of the island’s species that occurred at the same time. We will explore whether the arrival of humans on the continent caused – either directly or indirectly - this mass extinction of species. We will then focus on the European invasion of the American continent and the role that transportation and disease played in it. Finally, we will look at a contemporary case study, that of uncontacted indigenous tribes in the Peruvian Amazon, to look at how both transportation and disease continue to affect the environment even today.

We do not normally associate the first arrival of humans in Australia with transportation technologies, which we tend to link with the advent of European transatlantic ships and galleons. However, the first humans arrived in Australia from Indonesia approximately 50 000 years ago by means of primitive rafts (Diamond, 300). It is now a widely held view that the arrival of humans had severe environmental consequences, among them the extinction of the Australian megafauna. According to geologist Gifford Miller, from the University of Colorado, the fact that almost 85 per cent of Australian animal species became extinct around the time of the arrival of humans on the island suggests that the extinction was induced by humans, not naturally induced (Megafauna Extinction, NPR Archives). Cycles of wet and dry climate patterns had operated in Australia for hundreds of thousand of years without any major consequences on the fauna; however, the climate change that occurred 50 000 years ago and the extinction of all major animal species were accompanied by one additional factor: the arrival of humans. Miller postulates that humans did not cause these extinctions directly by hunting, but did so indirectly by changing the climate patterns of the island (Megafauna Extinction, NPR Archives). Continuous burning of plants for purposes of cooking, heating and hunting reduced the vegetation landscape on which many animals were dependent, and it also changed climate patterns by reducing the amount of transpiration and thus monsoon rainfall. This, Miller suggests, caused a significant increase in aridity to which most animal and plant species could not adapt (Aboriginal Climate Change, NPR Archives).

Mammologist Ross McPhee’s hypothesis for the extinction of the Australian megafauna is even more in line with the topic of this essay. McPhee suggests that the mass extinctions could have been caused by the “highly virulent diseases” that humans or the animals that they brought with them carried (Megafauna Extinction, NPR Archives). Although this could account for the extinction of animal species, it is difficult that disease alone could account for the climate and environmental changes that accompanied the arrival of humans in Australia. However, his hypothesis is very useful to illustrate how transportation technologies and diseases combined to produce very severe effects on the environment.

The arrival of Europeans in America in the 15 th century and the subsequent conquest of the Inca and Aztec empires were events heavily influenced by disease and improvements in transportation technologies. When talking about the European overseas expansion, Carlo Cipolla mentions that “[t]he technological progress accomplished by Atlantic Europe during the fourteenth and fifteenth centuries provided the means.” (Cipolla, 136.) The fact that Europe had achieved mastery of the oceans, but was militarily weak inland, was one of the factors that drew Europeans to look for oceanic trade routes with the Indies and Asia. It was precisely looking for such a route that Columbus came upon the American continent in 1492. As such, the “discovery” of America by Europe was the result of their advanced maritime transportation technology, which gave them the possibility to explore maritime routes. Once the conquest of America was underway, Cipolla writes, not only did transportation play an important factor, but so did the diseases that the Europeans brought with them: “Moreover, [the natives] turned out to be highly susceptible to European infectious diseases and the spread of deadly epidemic further weakened their meager possibilities of resistance.” (Cipolla, 142.) It is also worth noting that Cipolla identifies the European conquest of America as economically motivated: “European expansion was essentially a commercial venture, and the fact that the colonial policies of the European powers had a very pronounced mercantile tone was the natural consequence of the basic motives behind the expansion.” (Cipolla, 135.) I include this because it is a motivation that continues to influence the effect of transportation and disease in the environment even today, as we will later examine.

Whereas Cipolla focuses more on the effect of transportation on the colonization of America, Jared Diamond takes a close look at the effect of disease, which almost literally wiped out the indigenous population of the continent: “The importance of lethal microbes in human history is well illustrated by Europeans’ conquest and depopulation of the New World. Far more Native Americans died in bed from Eurasian germs than on the battlefield from European guns and swords. (…) By 1618, Mexico’s initial population of about 20 million had plummeted to about 1.6 million.” (Diamond, 210.) The Europeans brought with them a wide array of infectious diseases to which the Native Americans, who had never been exposed to them, were highly vulnerable. Moreover, the conditions in America did not favour the evolution of highly virulent infectious diseases, which meant that the Natives were not used to coping with major killer diseases (Diamond, 212). All of this contributed to a catastrophic decline in the Native American population: “For the New World as a whole, the Indian population decline in the century or two following Columbus’s arrival is estimated to have been as large as 95 percent.” (Diamond, 211.) Thus, the death of millions of Americans was an immediate environmental effect of transportation and disease.

Nowadays, transportation and disease continue to have an effect on the environment. In the Amazon region of Peru, some uncontacted tribes, among them the Isonahua and the Cacataibos, are facing the threat of becoming extinct precisely because of the same reason that produced the deaths of many millions of Native Americans before them: disease (Collyns, BBC News). These uncontacted tribes, which live in isolated protected areas of the Peruvian Amazon, have had no or very little contact with society or other tribes, therefore remaining vulnerable to the European diseases. According to an article by Dan Collyns from BBC News, “[i]ndigenous leaders say the tribes have already suffered untold deaths from diseases contacted by outsiders.” (Collyns, BBC News.) The reason why these tribes, which have been traditionally isolated, are now having contact with outsiders is because of the economic motivation of the latter. The regions that these tribes occupy are very rich in mahogany, a highly priced wood in the US, which motivates illegal loggers to penetrate into them in order to chop down the forests. David Hill, a campaigner for Survivor, an NGO dedicated to helping indigenous communities, argues that diseases introduced by outsiders are a threat to these tribes: “ Illegal mahogany logging is the biggest threat. I was shocked by reports of loggers regularly killing Indians, and by how open the mahogany trade is. Oil exploration is the other big threat. It opens up remote parts of the rainforest to outsiders, including more loggers, who introduce fatal diseases to the isolated tribes. More than half of one tribe died following oil exploration in the1980s.” (Hill; the italics are mine.) Like in the example of the conquest of America, money provides the incentive, transportation the means and disease represents the threat to the environment.

As these three example show, transportation has had disastrous environmental consequences when paired up with disease. On its own, transportation technologies had indirect effects on the environment simply by transporting the agents of environmental destruction: humans. However, when paired up with disease, the destructive capacity of humans reached catastrophic levels: the extinction of 85 per cent of species and a major change in the climatic and environmental conditions in Australia 50 000 years ago, the extermination of 95 per cent of the Native American population less than 400 years ago and, finally, the possible extinction of the last remaining uncontacted human tribes in the Amazon Rainforest today. These examples reveal that disease is one of the major threats on the environment, humans are the agents that spread them, and transportation technologies are the means by which the agent and the threat propagate.

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last updated 02/06/07