TThe Columbian Exchange refers to the exchange of diseases, ideas, food he Columbian Exchange refers to the exchange of diseases, ideas, food
crops, and populations between the New World and the Old World crops, and populations between the New World and the Old World
following the voyage to the Americas by Christo pher Columbus in 1492.following the voyage to the Americas by Christo pher Columbus in 1492.
The Old World—by which we mean not just Europe, but the entire Eastern The Old World—by which we mean not just Europe, but the entire Eastern
Hemisphere—gained from the Columbian Exchange in a number of ways. Discov-Hemisphere—gained from the Columbian Exchange in a number of ways. Discov-
eries of new supplies of metals are perhaps the best known. But the Old World also eries of new supplies of metals are perhaps the best known. But the Old World also
gained new staple crops, such as potatoes, sweet potatoes, maize, and cassava. Less gained new staple crops, such as potatoes, sweet potatoes, maize, and cassava. Less
calorie-intensive foods, such as tomatoes, chili peppers, cacao, peanuts, and pineap-calorie-intensive foods, such as tomatoes, chili peppers, cacao, peanuts, and pineap-
ples were also introduced, and are now culinary centerpieces in many Old World ples were also introduced, and are now culinary centerpieces in many Old World
countries, namely Italy, Greece, and other Mediterranean countries (tomatoes), countries, namely Italy, Greece, and other Mediterranean countries (tomatoes),
India and Korea (chili peppers), Hungary (paprika, made from chili peppers), and India and Korea (chili peppers), Hungary (paprika, made from chili peppers), and
Malaysia and Thailand (chili peppers, peanuts, and pineapples). Tobacco, another Malaysia and Thailand (chili peppers, peanuts, and pineapples). Tobacco, another
New World crop, was so universally adopted that it came to be used as a substitute New World crop, was so universally adopted that it came to be used as a substitute
for currency in many parts of the world. The exchange also drastically increased for currency in many parts of the world. The exchange also drastically increased
the availability of many Old World crops, such as sugar and coffee, which were the availability of many Old World crops, such as sugar and coffee, which were
particularly well-suited for the soils of the New World.particularly well-suited for the soils of the New World.
The exchange not only brought gains, but also losses. European contact The exchange not only brought gains, but also losses. European contact
enabled the transmission of diseases to previously isolated communities, which enabled the transmission of diseases to previously isolated communities, which
The Columbian Exchange:
A History of Disease, Food, and Ideas
Nathan Nunn is an Assistant Professor of Economics, Harvard University, Cambridge, Nathan Nunn is an Assistant Professor of Economics, Harvard University, Cambridge, Massachusetts. During the 2009–2010 academic year, he was the Trione Visiting Professor of Massachusetts. During the 2009–2010 academic year, he was the Trione Visiting Professor of Economics at Stanford University, Stanford, California. Nancy Qian is an Assistant Professor Economics at Stanford University, Stanford, California. Nancy Qian is an Assistant Professor
of Economics, Yale University, New Haven, Connecticut. Both authors are also Faculty of Economics, Yale University, New Haven, Connecticut. Both authors are also Faculty
Research Fellows, National Bureau of Economic Research (NBER), Cambridge, Massachu-Research Fellows, National Bureau of Economic Research (NBER), Cambridge, Massachu- setts, and Affi liates, Bureau for Research and Economic Analysis of Development (BREAD). setts, and Affi liates, Bureau for Research and Economic Analysis of Development (BREAD).
Their e-mail addresses are Their e-mail addresses are 〈〈nnunn@fas.harvard.edunnunn@fas.harvard.edu〉〉 and and 〈〈nancy.qian@yale.edunancy.qian@yale.edu〉〉..
doi=10.1257/jep.24.2.163
Nathan Nunn and Nancy Qian
164 Journal of Economic Perspectives
causedcaused devastation far exceeding that of even the Black Death in fourteenth-century devastation far exceeding that of even the Black Death in fourteenth-century
Europe. Europeans brought deadly viruses and bacteria, such as smallpox, measles, Europe. Europeans brought deadly viruses and bacteria, such as smallpox, measles,
typhus, and cholera, for which Native Americans had no immunity (Denevan, 1976). typhus, and cholera, for which Native Americans had no immunity (Denevan, 1976).
On their return home, European sailors brought syphilis to Europe. Although less On their return home, European sailors brought syphilis to Europe. Although less
deadly, the disease was known to have caused great social disruption throughout deadly, the disease was known to have caused great social disruption throughout
the Old World (Sherman, 2007).the Old World (Sherman, 2007).
The effects of the Columbian Exchange were not isolated to the parts of the The effects of the Columbian Exchange were not isolated to the parts of the
world most directly participating in the exchange: Europe and the Americas. It also world most directly participating in the exchange: Europe and the Americas. It also
had large, although less direct, impacts on Africa and Asia. European exploration had large, although less direct, impacts on Africa and Asia. European exploration
and colonization of the vast tropical regions of these continents was aided by the and colonization of the vast tropical regions of these continents was aided by the
New World discovery of quinine, the fi rst effective treatment for malaria. Moreover, New World discovery of quinine, the fi rst effective treatment for malaria. Moreover,
the cultivation of fi nancially lucrative crops in the Americas, along with the devas-the cultivation of fi nancially lucrative crops in the Americas, along with the devas-
tation of native populations from disease, resulted in a demand for labor that was tation of native populations from disease, resulted in a demand for labor that was
met with the abduction and forced movement of over 12 million Africans during met with the abduction and forced movement of over 12 million Africans during
the sixteenth to nineteenth centuries (Lovejoy, 2000; Manning, 1990).the sixteenth to nineteenth centuries (Lovejoy, 2000; Manning, 1990).
The Columbian Exchange has provided economists interested in the long-The Columbian Exchange has provided economists interested in the long-
term effects of history on economic development with a rich historical laboratory. term effects of history on economic development with a rich historical laboratory.
Economic studies have thus far mainly focused on how European institutions, Economic studies have thus far mainly focused on how European institutions,
through colonialism, were transplanted to non-European parts of the world. The through colonialism, were transplanted to non-European parts of the world. The
seminal papers by Engerman and Sokoloff (1997), La Porta, Lopez-de-Silanes, seminal papers by Engerman and Sokoloff (1997), La Porta, Lopez-de-Silanes,
Shleifer, and Vishny (1997, 1998), and Acemoglu, Johnson, and Robinson (2001) Shleifer, and Vishny (1997, 1998), and Acemoglu, Johnson, and Robinson (2001)
examine the effects that European contact, taking the form of formal and informal examine the effects that European contact, taking the form of formal and informal
colonial rule, had on other societies.colonial rule, had on other societies.11
In this paper, we attempt to broaden the scope of economic studies of the In this paper, we attempt to broaden the scope of economic studies of the
Columbian Exchange by studying aspects of the exchange that have received less Columbian Exchange by studying aspects of the exchange that have received less
attention. First, we pay particular attention to the effects that the exchange had on attention. First, we pay particular attention to the effects that the exchange had on
the Old World, rather than examining outcomes in the New World. Second, rather the Old World, rather than examining outcomes in the New World. Second, rather
than concentrating on the effects of the exchange that work through institutional than concentrating on the effects of the exchange that work through institutional
and political structures, we focus on the less-studied, but no less-important chan-and political structures, we focus on the less-studied, but no less-important chan-
nels; namely, the biological exchange of food crops and disease. Our hope is that nels; namely, the biological exchange of food crops and disease. Our hope is that
our broad descriptive overview of some of the neglected aspects of the Columbian our broad descriptive overview of some of the neglected aspects of the Columbian
Exchange will spur further more-rigorous studies of the long-term consequences of Exchange will spur further more-rigorous studies of the long-term consequences of
these aspects of the exchange.these aspects of the exchange.
We are aware of only a handful of empirical papers that either focus on the We are aware of only a handful of empirical papers that either focus on the
effect of the exchange on the Old World or focus on channels other than legal effect of the exchange on the Old World or focus on channels other than legal
institutions. Acemoglu, Johnson, and Robinson (2005) examine the effects of the institutions. Acemoglu, Johnson, and Robinson (2005) examine the effects of the
three-corner Atlantic trade on Europe. They argue that the profi ts from the trade three-corner Atlantic trade on Europe. They argue that the profi ts from the trade
strengthened the merchant class, which resulted in stronger probusiness institutions strengthened the merchant class, which resulted in stronger probusiness institutions
and increased economic growth. Two studies have recently explored the effects from and increased economic growth. Two studies have recently explored the effects from
1 Subsequent studies have since added to the understanding of the long-term effects of colonial rule
and European contact on New World Societies. See for example Mitchener and McLean (2003),
Berkowitz and Clay (2005, 2006), Acemoglu, Bautista, Querubin, and Robinson (2008), Dell (2008),
and Nunn (2008a), as well as the review by Nunn (2009).
Nathan Nunn and Nancy Qian 165
the botanical exchange. In Nunn and Qian (2009), using a generalized difference-the botanical exchange. In Nunn and Qian (2009), using a generalized difference-
in-differences empirical strategy, we fi nd that the introduction of potatoes to the Old in-differences empirical strategy, we fi nd that the introduction of potatoes to the Old
World resulted in a signifi cant increase in population and urbanization. Our fi nding World resulted in a signifi cant increase in population and urbanization. Our fi nding
complements earlier research by Mokyr (1981) that estimates the effects of the potato complements earlier research by Mokyr (1981) that estimates the effects of the potato
on population growth within Ireland. Hersh and Voth (2009) examine the benefi ts on population growth within Ireland. Hersh and Voth (2009) examine the benefi ts
that arose from the increase in land for cultivating the Old World crops coffee and that arose from the increase in land for cultivating the Old World crops coffee and
sugar after 1492. According to their calculations (see their table 9), the increased sugar after 1492. According to their calculations (see their table 9), the increased
availability of sugar increased English welfare by 8 percent by 1850, while the greater availability of sugar increased English welfare by 8 percent by 1850, while the greater
availability of coffee increased welfare by 1.5 percent.availability of coffee increased welfare by 1.5 percent.
In the following section, we examine the most devastating and unfortunate In the following section, we examine the most devastating and unfortunate
consequences of the Columbian Exchange, which arose from the exchange of consequences of the Columbian Exchange, which arose from the exchange of
disease between the Old and New Worlds. Next, we turn to the effects of the disease between the Old and New Worlds. Next, we turn to the effects of the
exchange that arose from the transfer of foods between the New and Old Worlds. exchange that arose from the transfer of foods between the New and Old Worlds.
We then examine the indirect consequences of the exchange on Africa and Asia. We then examine the indirect consequences of the exchange on Africa and Asia.
The fi nal section of the paper offers concluding thoughts.The fi nal section of the paper offers concluding thoughts.
DiseaseDisease
The Spread of Disease from the Old World to the NewThe Spread of Disease from the Old World to the New
The list of infectious diseases that spread from the Old World to the New is The list of infectious diseases that spread from the Old World to the New is
long; the major killers include smallpox, measles, whooping cough, chicken pox, long; the major killers include smallpox, measles, whooping cough, chicken pox,
bubonic plague, typhus, and malaria (Denevan, 1976, p. 5). Because native popula-bubonic plague, typhus, and malaria (Denevan, 1976, p. 5). Because native popula-
tions had no previous contact with Old World diseases, they were immunologically tions had no previous contact with Old World diseases, they were immunologically
defenseless. Dobyns (1983, p. 34) writes that “before the invasion of peoples of the defenseless. Dobyns (1983, p. 34) writes that “before the invasion of peoples of the
New World by pathogens that evolved among inhabitants of the Old World, Native New World by pathogens that evolved among inhabitants of the Old World, Native
Americans lived in a relatively disease-free environment. . . . Before Europeans Americans lived in a relatively disease-free environment. . . . Before Europeans
initiated the Columbian Exchange of germs and viruses, the peoples of the Amer-initiated the Columbian Exchange of germs and viruses, the peoples of the Amer-
icas suffered no smallpox, no measles, no chickenpox, no infl uenza, no typhus, no icas suffered no smallpox, no measles, no chickenpox, no infl uenza, no typhus, no
typhoid or parathyroid fever, no diphtheria, no cholera, no bubonic plague, no typhoid or parathyroid fever, no diphtheria, no cholera, no bubonic plague, no
scarlet fever, no whooping cough, and no malaria.”scarlet fever, no whooping cough, and no malaria.”
Although we may never know the exact magnitudes of the depopulation, it is
estimated that upwards of 80–95 percent of the Native American population was
decimated within the fi rst 100–150 years following 1492 (Newson, 2001).Within 50 years following contact with Columbus and his crew, the native Taino popu-50 years following contact with Columbus and his crew, the native Taino popu-lation of the island of Hispanola, which had an estimated population between lation of the island of Hispanola, which had an estimated population between 60,000 and 8 million, was virtually extinct (Cook, 1993). Central Mexico’s popula-tion fell from just under 15 million in 1519 to approximately 1.5 million a century tion fell from just under 15 million in 1519 to approximately 1.5 million a century later.
Historian and demographer Nobel David Cook estimates that, in the end, later. Historian and demographer Nobel David Cook estimates that, in the end,
the regions least affected lost 80 percent of their populations; those most affected the regions least affected lost 80 percent of their populations; those most affected
lost their full populations; and a typical society lost 90 percent of its population lost their full populations; and a typical society lost 90 percent of its population
(Cook, 1998, p. 5).(Cook, 1998, p. 5).
