El
Niño events
have been more studied in recent decades as their regularity and disruptive
character has devastated areas around the globe. Such events are new or
restricted to modern times but have been part of the Earth’s climate history
for many millennia – at least. The most recently reported-on El Niño years are
1997-98 and 2015-16 when temperatures soared, droughts were widespread and
calamitous weather was experienced. Readers will find many reports of the
damage wrought by these two storms online and in news accounts.
The history of many regions is being re-examined with respect to El
Niño and La Niña events, specifically, to see whether these
weather conditions played a negative or positive role in their exploration,
settlement or development.
As described
on the Live Science
website, “El Niño is a climate cycle in
the Pacific Ocean with a global impact on weather patterns. The cycle begins
when warm water in the western tropical Pacific Ocean shifts eastward along the
equator toward the coast of South America. Normally, this warm water pools near
Indonesia and the Philippines. During an El Niño, the Pacific's warmest surface
waters sit offshore of northwestern South America. . . There is also an
opposite of an El Niño, called La Niña. This refers to times when waters of the
tropical eastern Pacific are colder than normal and trade winds blow more
strongly than usual. Collectively, El Niño and La Niña are parts of an
oscillation in the ocean-atmosphere system called the El Niño-Southern
Oscillation, or ENSO cycle, which also has a neutral phase.”
More
detail about El Niño and La Niña, along
with pertinent references can be found at the end of this post.
Prior
to the 18th century, there was little documentation for El Niño
events, at least is defining them as such. Many regions certainly suffered
droughts or exceptional rainfall in similar patterns to what we recognize as El
Niños today, so there seems to be no doubt these extreme weather conditions did
operate and had severely impacts on communities.
One
major El Niño event that affected most parts of the civilized and developing
world, perhaps serving as a great example of how ancestral communities and
families were affected, occurred during the Northern Hemisphere winter of 1791-92.
This was in the late part of the Little Ice Age, a time when most settled areas
had already undergone deprivation with cold, drought, famine and disease for
many decades. Such events will have exacerbated the harsh living conditions
extant during this time period.
An
article by Richard H. Grove (2007) describes the effects of the extended
1789-93 El Niño in areas around the globe very succinctly for the regions of:
·
Australia
(drought, rivers dried up, crop failures)
·
Brazil
(drought, cattle industry disseminated)
·
Caribbean
Islands (drought)
·
Chile
(drought)
·
East
Indies and South Pacific (cold and drought)
·
Eastern
North America (high temperatures, heavy rainfall, leading to rise in mosquito
population and spread of diseases like yellow fever)
·
Egypt
(low floods in successive years, poor crops, famine, social unrest)
·
England
(unusually high winter temperatures)
·
France
and Western Europe (unusual and extreme weather possibly resulting in the social
unrest that was part of the French Revolution)
·
India
(see below)
·
Mexico
(drought, major lake levels dropped)
·
Peru
(exceptional and prolonged rainfall, flooding)
·
Russia
(drought)
·
South
Africa (drought, military conflict with migrating people)
·
Southwest
USA (excessive rain, flooding, cropland and infrastructure destruction)
India
was among the regions hardest hit. The widespread drought over several years
created famine almost unprecedented even for that country. In many regions,
communities lost half of their populations to starvation and associated epidemics.
The famine was so intense that bodies remained unburied creating a spectre of rotting
corpses along roadways and in fields. The abundance of bleaching bones resulted
in the famine being called Doji bara, or the skull famine. Cases of cannibalism
were reported. Millions are reported to have died between 1789 and 1792.
Map
of India (1795) shows the Northern Circars, Hyderabad (Nizam), Southern Maratha
Kingdom, Gujarat, and Marwar (Southern Rajputana), all affected by the Doji
bara famine (retrieved 3 April 2018 from Doji bara famine Wikipedia)
And
the list goes on! Many areas hit were newly-established colonies such as those
in Australia, India and South Africa or developing communities such as those in
North America.
Family
historians my find, on closer examination, that El Niños were perhaps
responsible for problem their ancestors may have had in food production or
other employment. Such events may possibly have been behind their reason to
migrate to areas where they thought a better life and more opportunity might be
found. Whether they found those improved living conditions might well have
depended on the weather or climatic conditions in their new homes.
How El Niños and La Niñas work
Understanding how El Niños and La Niñas
work will give a family historian a better idea of whether their ancestors
might have been affected in their normal lives or following migration to new
regions. The following descriptions are taken from El
Niño: The weather phenomenon that changed the world by Ross Couper-Johnston
(2000):
“Typically during El Niños, rainfall is
greatly reduced over much of Indonesia; the Philippines; northern and eastern
Australia; the populated Pacific Islands; New Zealand’s North Island; India;
southern Africa; Ethiopian highlands; Ghana; Nigeria; Sahelian Africa, most of
central America extending into central Mexico, Colombia and northern South
America; the Caribbean; northeast Brazil; and the Altiplano of Peru and
Bolivia. Most of the major droughts in these regions have occurred during El
Niños. The Sahel receives a moderately strong El Nino
signal but is also markedly affected by longer-term fluctuations. On the other
hand, heavier rain and increased probability of flood conditions are found over
much of southern USA and the Great Basin, northern Mexico; the Peruvian and
Ecuadorian coastline; central Chile; southeastern and northern Argentina;
Paraguay; Uruguay and southern Brazil; the islands in the central and eastern
equatorial Pacific such as the Galapagos and Nauru; New Zealand’s South Island;
the very southern tip of India and Sri Lanka; central China to southern Japan;
Vietnam; the western
cape of South Africa; Kenya; Tanzania; Uganda; and much of western Europe. There are many other regions such as central California and northern Europe, that experience significant impacts, although the nature of the anomalies is somewhat inconsistent.” [page 44-45]
cape of South Africa; Kenya; Tanzania; Uganda; and much of western Europe. There are many other regions such as central California and northern Europe, that experience significant impacts, although the nature of the anomalies is somewhat inconsistent.” [page 44-45]
Trade winds during an El Niño year
from Thomson Higher
Education website
“Broadly
speaking, the pattern for La Niñas is
the reverse of that of El Niños. Excessively wet or flood conditions are experienced
predominantly over the continents bordering the Pacific and Indian Oceans – in
particular, Australasia, northern China, India, southern Africa and parts of
north-eastern South America. Dry or drought conditions tend to occur most commonly
in the Gulf states of the USA, south-eastern Argentina, central Chile, central
China, South Africa’s western Cape, eastern Africa and much of western Europe.
Unusually colder temperatures are commonly
experienced across northern South America, the Caribbean, Alaska and north-western
Canada, Japan, South-East Asia, India, southern Africa, Sahelian and north
western Africa, and western Europe. North eastern Australia and central
south-western Pacific tend to experience warmer conditions.
The poleward shift of the sub-tropical jet
streams in La Niñas increases the
probability of stronger and more frequent tornado activity in the USA in all
tornado prone areas – particularly in the Ohio and Tennessee River valleys – with
the exception of the Florida peninsula
One of the most dramatic Impacts of La Niña and El Niño events on people is the reshuffling of
likely tropical storm formation zones. . .
During La Niñas, high pressure
cells in the sub-tropical Atlantic tend to be weakened and displaced off North
and South America, creating warmer waters than usual. This has the effect of
extending the hurricane season. The frequency of hurricanes occurring during La Niñas is approximately double that of normal years.” [page 46-47]
Trade
winds and rainfall during a normal year, from Thomson Higher
Education website
References:
Couper-Johnston,
R. (2000). El
Niño: The weather phenomenon that changed the world. London: Hodder and Stoughton.
Davis,
M. (2001). Late Victorian Holocausts: El Niño
famines and the making of the third world. London-New York: Verso.
Fagan,
B. (1999). Floods, Famines, and Emperors:
El Niño and the fate of civilizations. New
York: Basic Books, Perseus Books Group.
Grove,
R. H. (2007). The Great El Niño of 1789-93 and its Global Consequences:
Reconstructing and Extreme Climate Event in World Environmental History. The Medieval History Journal, 10(1&2),
pp 75-98.
Grove,
R. & G. Adamson. (2017). El Niño in
World History. London: Palgrave
Macmillan. (also in Kindle version)
Sandweiss,
D. H. & J. Quilter. (2008). El Niño,
Catastrophism, and Culture Change in Ancient America. Washington, DC:
Dumbarton Oaks, Harvard University.