Class 5
The role of nature in environmental change II: nature’s agency
Christos Zografos, PhD
Institute of Environmental Science & Technology (ICTA)
Universitat Autònoma de Barcelona, Spain
christos.zografos@uab.cat
Environmental Change and Governance
MA Environmental Humanities 2011-12
Masaryk University, Brno, Czech Republic

Introduction
•Main point: viruses, mosquitoes, monkeys, parasites, swamps, as well as humankind, make political
history
–Ecological changes themselves shape human fortunes
–
•Why you should know about it?
–Approach: complement to structure and discourse as sources of power (avoiding venturing towards
‘determinist’ lands…)
–
•Outline
–Discuss class question (assignment)
–Some implications of McNeill’s argument
–Class Activity: Section I of the course (PE)
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THE QUESTION
•McNeill argues that although it is probably a rude blow to our species “lowly mosquitoes and
mindless viruses” have the power to shape human international affairs.
•How did mosquitoes (A. aegypti) helped the Spanish Empire retain key fortifications in the
Caribbean against the attacks of other European powers (e.g. British, French, Dutch, etc.)?
•
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Yellow fever (YF)
•Yellow fever: lethal disease
–Until early 20th century: role of mosquitoes as disease vectors was found
•Virus vector (disease transmitter): females of Aedes Aegypti mosquito
–Other disease hosts: primates (humans, monkeys)
•Tropical and Sub-Tropical Africa & South America
•Incubation period: 3-6 days
•Most cases only a mild infection with fever, headache, chills, back pain, loss of appetite, nausea
and vomiting (lasts 3-4 days)
•But 15% enter 2nd toxic phase:
–recurring fever
–yellow skin colour (liver damage)
–abdominal pain
–‘Black Vomit’ (contains blood): caused by bleeding in mouth, eyes and stomach/intestines
•Toxic phase: fatal in approximately 20% of cases
•Surviving = life-long immunity
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Aedes Aegypti Mosquito (source: www.memphishistory.org)

Yellow fever (YF)
•Introduced to America via mosquitoes brought from Africa with slave trade (16th-17th century)
–Humid & crowded conditions of ‘crossing’: help mosquito survive
•Role of changing local ecologies: plantation ecology of colonies + pre-existing swamps
–Water for incubation (e.g. barrels for potable water storage)
4
A tobacco plantation (source: Public Broadcasting Service)

Differential immunity
•Mosquitoes and diseases wreck havoc but not indiscriminately: differential immunity (YF)
–If brought up as child in places where yellow fever common (endemic) then have some resistance and
less likely to fall ill or die when adult
–
•But if virus finds many organisms without anti-bodies becomes epidemic!
–Attacks those without immunity (to find hosts)
–‘Clean’ bodies provide loads of space to expand as a virus
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Military implications
•So, if all of a sudden you bring (e.g. in America) many non-immune bodies (e.g. people who have
grown up in places where there is no YF), virus (latent) finds space (human body) to expand ->
epidemic
•
–Such non-immune bodies: European soldiers
–Instead: African slaves + locally-born colonists/recruits + ‘seasoned’ troops: no space for
epidemic
•
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Military implications
•Colonial officials and aspiring attackers knew from observation (empirical knowledge) that this
happened
–Although did not know exactly ‘why’: the ‘Climate’
•Also knew that rains increased deaths
–More water for mosquitoes to reproduce
•…and that number of deaths would increase exponentially after 6-8 weeks
–Happily coincided with fortification durability!
•So, prepared themselves for a 6-8 week defence before letting YF “take its toll”
–Fortification and provisions + Soldiers
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Example: Cartagena, 1741
•Role in Imperial trading system: first port of call for gold & silver convoys (until 1739)
•Commercial hub (hinterland): emeralds, sugar, cacao, cotton, botanical drugs, silver, gold,
pearls, timber, etc.
•Seat: naval & military establishment of Viceroyalty New Granada
–Colombia, Ecuador, Venezuela, Panama, Guyana, Costa Rica, Nicaragua, parts: Brazil and Peru
•
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Battle for Cartagena (siege)
•Vernon’s fleet: largest amphibious expedition ever (after WWII Normandy)!
–186 ships + 29,000 soldiers (UK + N ‘US’)
•Cartagena defense:
–4,700: permanent battalion (‘fijo’) + local militia + Amerindian bowmen + sailors – Only 700 new
to environment
–6 ships
–Admirable fortifications
–Scarce: rifles, powder, food (Lezo)
•Series of delays resulted Brit (McNeill calculates)
–22,000 deaths/ 29,000 soldiers
–1,000 died in combat
•Compare this to:
–Brit army deaths in European war theatres = 8% deaths: wounds + disease
–ESP army: 200-600 deaths (no YF mention)
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Blas de Lezo (source: Museo Naval de Madrid)
Edward Vernon, by Thomas Gainsborough (source: National Portrait Gallery)

Time is gold
•Series of delays resulted in siege lasting for 54 days (8 weeks approx.): YF takes toll!
•Intentional delays
–British: Wentworth wants to use orthodox siegeing methods to capture Bocachica forts (reduce them
one by one by erecting artillery batteries and open breaches for troops to go in): time-consuming
method
–Spanish: sink merchant vessels in navigable channels of bay
•Unintentional delays
–British: failure of original plan for Cathcart’s army to arrive in Cartagena by late December
(start of dry season) instead of late March (start of rainy season) – due to military inactivity
and corruption
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Unintentional key factors
•“In an epidemiological irony … Cartagena’s defence was more secure because no large contingent of
reinforcements from Spain had joined the garrison
–“A few hundred reinforcements among an urban population of 10,000 who provided herd immunity gave
the yellow fever virus no foothold”
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IMPLICATIONS OF THE ARGUMENT
•Block 2
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Implications of McNeill’s argument
1.The argument
2.Implications of the argument
a)Human – environment relations: who has the power?
b)Analytical implications: studying and understanding human – environment relation
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THE ARGUMENT: PROF MCNEILL DISCUSSES BOOK "MOSQUITO EMPIRES”
•http://www.youtube.com/watch?v=JzZpeisdmJ4
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Political importance of differential immunity
•Pre-1800s, European colonial powers try take colonies from each other
•Spanish rely heavily on locally-recruited men (and fortifications of key strongholds)
•If they could hold out for 2 months, yellow fever and malaria destroy their foes
–when recruited from other places with no experience of malaria/ yellow fever mosquito, e.g.
northern Europe
–i.e. places that could not prepare human immune systems for disease environment of Caribbean
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•Yellow fever: crucial part of Spanish imperial defence
–Without it Spain would have lost much of her American empire in 18th century
–Same but vice versa for success of independence wars in 19th century Americas (e.g. southern parts
of US)
•Until 1770s, mosquitoes underpinned geopolitical order in Americas – after that they undermined
it!
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Political importance of differential immunity

Human–environment: who has power?
•Ecological conditions that prevailed governed probabilities of success and failure
–Mosquitoes
–Plantation ecologies and swamps: mosquito incubator & habitat sites
–
•Lowly mosquitoes and mindless viruses can shape human international affairs
–Blow to our species, but true!
•
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Human–environment: who has power?
•Quests for wealth and power changed ecologies in Greater Caribbean
•But also: ecological changes shaped fortunes of empire, war, and revolution
•Viruses, mosquitoes, monkeys, parasites, swamps, as well as humankind make political history
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2b) Analytical implications
•To fully understand colonisation and independence in Caribbean requires:
–not only understanding social and economic forces at play
–but also appreciate ecological contexts and environmental trends
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CLASS QUESTION
•
•
•Part of difference: degree they emphasise ‘determinant’ role of nature
–“I will, as authors often do, underplay other considerations”
–
–
•More clear difference: McNeill emphasis on interaction of physical – social factors rather than
determinant role of one of them
–“this is not an essay on mosquito or environmental determinism”
•So, McNeill tells us that ‘the environment’ (mosquitoes, swamps, etc.) is crucial for shaping
human fortunes
•
•This sounds similar to what JD said in his documentary: is it the same or is it different?
•
•How is McNeill’s argument about the importance of nature in making history is different from Jared
Diamond’s?
•
•
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Limits of argument: interaction
•Ecology shaped history but it could do so as a result of accidents of history and environmental
change brought about by humans (agency)
–Slave trade brought yellow fever and malaria
–Disease environment of Caribbean: cultural artefact (e.g. plantations)
–Haitian and American revolutionaries took stand, otherwise importance of differential immunity
would not materialise
–If doctors were more successful (earlier) -> erase effects of differential immunity
•“Humankind and nature make their own history together, but neither can make it as they please”
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Concluding remarks: disease and power
•With invention of yellow fever and malaria vaccines at end of 19th early 20th century
•Source of differential vulnerability changed
–“In this new world of effective vaccines and drugs”
–Rich and powerful societies capable of developing vaccines and inoculating their populations
–Became even richer and more powerful
•Source of power: from ‘nature’ (one’s own organism) to technology (external material affluence)
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Source: http://yellowfever.lib.virginia.edu/reed/commission.html

CLASS ACTIVITY
•What Stuck?
•An “Aha” moment
•A pleasant surprise
•Something that you had to struggle with to understand
•Something you don’t agree with
•Something that you agree with strongly
•Something you thought was particularly interesting
•Something you didn’t expect
•An insight or solution
•Something you want to know more about
•A question that you have
•We have looked at three ways in which power operates (and sources of power): structure, discourse,
and nature. I’d like to know what points ‘struck’ you the most!
•
•Get into groups, discuss and provide answers to following points (15 min)
•
•Then, present your answers in the class (5 min each group)
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