The Columbian Exchange
Read this text on the Columbian Exchange, which caused a seismic event from an environmental perspective. Diets were globally transformed as crops such as tomatoes and potatoes traveled to Europe and Asia. However, this sea change had a dark side – diseases spread into previously unexposed populations, which led to mass death in the Americas.
Indirect Consequences of the Columbian Exchange
Quinine: The New World's "Gift" to Europe's Old World Colonies
Quinine, an important medicinal "gift" from the New World, had significant consequences for the relationship between Europe and its tropical Old World colonies, particularly its African colonies. Quinine and related anti-malarial alkaloids (quinidine, cinchonine, cinchonidine) are derived from the bark of cinchona trees native to the Andes.
The trees grow in scattered clumps in the eastern mountainous forests of Colombia, Ecuador, Peru, and Bolivia between 10 degrees north and 20 degrees south at elevations between 800 to 3,400 meters. Quinine was the first effective treatment of malaria caused by Plasmodium falciparum, the protozoan parasite that is transmitted between mammals by the female Anopheles mosquito. Quinine works by inhibiting plasmodium reproduction.
The use of quinine as a prophylactic was first discovered in 1841 by Dr. Thomas R. H. Thomson; the findings were later published in The Lancet. The British government, amidst the expansion of its empire into many malaria-ridden regions and seeing the potential benefits of quinine, encouraged the Royal Society to research the properties of quinine and explore the possibilities of farming it outside of the Andes.
In 1858, the British Botanical Gardens (headed by Kew Gardens, London) began the "cinchona transfer project" that aimed to ensure a stable, adequate, and cost-effective quinine supply to the colonizers of the British Empire by buying, stealing, bribing, and smuggling cinchona plants and seeds out of the Andes to London and colonial gardens in Ceylon and India. The British were successful in transferring plants to Kew Gardens in London, Calcutta, and the Nilgiri Hills of India. Within decades, production was also expanded to Singapore and Dutch Java. Estimates suggest that by 1880, enough was produced to supply ten million people with a daily dose.
The exact importance of quinine's use as an anti-malarial alkaloid is still being established by historians. Still, the evidence suggests that it was an important "tool of empire" and significantly enhanced Europe's ability to colonize tropical regions of the globe. Although debated, traditional historiography recognizes quinine as having facilitated European survival in malaria-ridden regions during the age of exploration and colonial expansion. The standard view is that Europe's colonization of Africa would have been virtually impossible without quinine.
Curtin notes that "between 1819 to 1836, the average annual death rate per thousand mean strength of European troops on the West African coast was 483 for enlisted men, and 209 for officers. Between 1881 and 1897, the annual average death rate for officials was 76 in the Gold Coast and 53 in Lagos…. since there were no further medical reforms between the 1850s and the 1880s comparable to quinine prophylaxis or the abolition of dangerous treatments, it is fair to assume that the medical reforms of the 1840s reduced European mortality on shore by at least half and perhaps more." Curtin concludes that "the history of tropical Africa would certainly have been very different if European mortality had continued at the old rate."
Rubber in the Heart of Darkness
Natural rubber is made from latex, which is produced when certain plants are cut or punctured. Although rubber can be made from many different plants from around the world, the only commercially viable rubber plants are the Hevea rubber tree from Central and South America and a wild vine that grows in West-Central Africa.
Historically, Africans made little use of rubber except as an adhesive to fasten spearheads and arrowheads to their shafts. Native Americans, on the other hand, had developed methods to prevent the latex from decaying, which was accomplished by smoking the latex over fires to form spools of usable crude rubber. The rubber was used to create a wide range of items that were of central importance in their daily lives: hoods, boots, tents, balls, torches, jars, containers, syringes, toys, breastplates, rubber-headed drum sticks, and adhesives.
Europeans did not recognize the benefits of rubber until 1770 when French naturalist Charles Marie de La Condamine noticed its use by Amazon natives. The first commercial use of rubber was in the production of shoes, primarily from New England, in the early 19th century. However, the real boom for the rubber industry did not occur until the process of "vulcanization" was discovered. This process includes heating the rubber and combining it with other chemicals to produce a more stable product with a wider range of uses.
Between 1851 and 1881, the world's production of rubber increased from 2,500 to 20,000 tons annually. This boom, although significant, was modest compared to what was to come. The following three decades witnessed an explosion in the demand for rubber. Hobhouse describes the rubber boom, which lasted from 1880 to 1910, writing that "rubber became the most important, most market-sensitive, most sought-after new commodity in the world." The rising demand for rubber was first driven by the rise of electricity since rubber was used as an insulator. The demand was also fed by the need for rubber to produce rubber tires for bicycles and later for motorcycles and cars.
During this period, rubber production increased rapidly, doubling every three to five years. This was accomplished, in part, by an increase in supply from tropical regions outside of the Americas. In 1876, 70,000 Hevea rubber tree seeds were taken from Amazonia to Kew Botanical Gardens in Ceylon and Singapore by Sir Henry Wickham. This was the genesis of the rubber industry that now exists in all of Asia. (The current domination of the rubber industry by Asian countries is evident in Panel A of Table 3 – the top six producers of natural rubber are all Asian countries.)
A second supplier of rubber during the period, one which became the most notorious example of European exploitation in sub-Saharan Africa, was the Congo region of West Central Africa. Here grew the only other indigenous plants that were able to provide commercially viable sources of natural rubber. Between 1900 and 1908, during the height of the boom, between 4,500 and 6,000 tons of rubber were exported each year from the Congo Free State.
The atrocities and human costs that were suffered in the production of rubber are well known and well documented (for example, Hothschild, 1998). In attempts to force natives to gather rubber, villages were burnt, groups were massacred, and hostages were taken, who were then typically starved and physically disfigured. The population of the Congo is estimated to have been about 25 million prior to the rubber boom in the 1880s. In 1911, after the peak of the boom, the population was 8.5 million, and in 1923, after the completion of the boom, it was 7.7 million. If one compares the population losses relative to the production of rubber, an astonishing conclusion is reached: an individual was "lost" from the Congo for every ten kilograms of rubber exported.
Forced and Voluntary Migrations to the Americas
Between the 16th and 19th centuries, over twelve million Africans were shipped to the Americas during the transatlantic slave trade, the largest involuntary migration in human history. The trade was fueled by the high demand for labor in the Americas, which was driven, at least in part, by two aspects of the Columbian Exchange: The first was the spread of Old World diseases to Native Americans, which resulted in extremely low population densities in the New World. The second was the cultivation of highly prized Old World crops, such as sugar and coffee, which were particularly well-suited to New World soils and climates.
The forced movement of African slaves to the Americas reached its height in the 18th century. In the 19th century, the flow of slaves slowed, first as a result of the British Slave Trade Act of 1807 that banned imports of slaves into British colonies, and later because of the British Slavery Abolition Act of 1837, which abolished any use of slave labor within the British colonies.
In response to the abolition of the slave trade, many employers resorted to bonded labor contracts as a way to obtain a continued supply of cheap labor. Most of the migration occurred between Europe's Old and New World colonies. Caribbean plantations provided the main demand for laborers from French Indochina and the British colonies in Asia. For example, over half a million indentured laborers were moved from the Indian subcontinent to the British Caribbean during the 19th century and the beginning of the 20th century. China, after its forced opening to the West upon losing the Opium Wars (in 1842 and 1860), provided another important source of indentured labor. Employers of these "coolies" included guano pits, cotton and sugar industries in Peru, sugar cane fields in Cuba (following the abolition of slavery in 1886), and railways in the United States and British Columbia.
Although most indentured laborers entered servitude voluntarily, many parallels can be drawn between the harsh conditions of slavery and those faced by the indentured laborers. For example, many would die on the voyage to the Americas, where crowded conditions and malnutrition made the laborers vulnerable to disease. Like slaves who were denied the rights of ordinary citizens, indentured laborers were often denied the right to naturalize and obtain citizenship after their contracts were over.
The 19th and 20th centuries also witnessed a dramatic increase in voluntary migrations from the Old World. Between 1851 and 1924 alone, 45 million people migrated from the Old World to the Americas, with the majority, 34 million, choosing to migrate to the United States. Those who migrated to Latin America primarily went to Argentina and Brazil. Between 1850 and 1940, seven million went to Argentina and 4.5 million to Brazil.
A recent data construction effort by Putterman and Weil (2009) provides comprehensive estimates of the magnitudes of post-1492 population flows from the Old World to the New World. The authors construct a matrix showing the share of a country's current population (in 2000) whose ancestors were originally from other countries of the world. Using this matrix, we are able to calculate, for the 27 New World countries in their sample, the share of their current populations originally from the Old World. These figures are reported in the first column of Table 4.
The share ranges from 26 percent for Guatemala to 100 percent for the New World island economies of Haiti, Jamaica, and Trinidad and Tobago. In the second and third columns of the table, we further disaggregate the Old World category, reporting explicitly the population shares from Africa and Europe. (The remaining share, not reported, is for Asia and Oceania). For many countries, most of their current population is from either Africa (for example, 98 percent for Haiti) or Europe (for example, 91 percent for LTruguay or 84 percent for Argentina).