Warm water (white) of El Niño off the
coast of South America in 1997
(Photo: NASA, Source: Wikimedia Commons).

Every two to five years the Pacific experiences a phenomenon that is known as the El Niño/Southern Oscillation (ENSO). The name El Niño, Spanish for “the child,” refers to the infant Jesus Christ and is applied because an El Niño event usually begins during the Christmas season. El Niño occurs every three to seven years and its effects are world wide observed. In Australia and Southeast Asia it brings extreme drought, and in the west the deserts of Peru bloom due to abundant rain and east Africa is either hit by extreme drought of flooding. The El Niño event of 1982 and 1983 was the most severe of the 20th century. Other recent occurrences began in 1972, 1976, 1987, 1991, 1994, 1997 and 2006-07. A strong El Niño has not been observed since 1997.

What is causing El Niño?

In short: El Niño is the occasional development of a warm ocean current along the Peru Coast as temporary replacement of the cold Peru Current which normally flows in this region. Under normal circumstances the air pressure over the cold waters off the coast of Peru is quite high. In the west, however, over the warm tropical waters of the western pacific, air pressure is normally low. The difference in air pressure creates an airflow from east to west creating the trade winds which push sun-warmed surface waters westward and exposing cold water to the surface in the east. During El Niño, however, the easterly trade winds collapse or even reverse due to a change in air pressure. The low pressure over the west is trading places with the high pressure normally prevalent in the eastern pacific. As this happens, the wet weather conditions normally present over the western Pacific moves to the east, and the arid conditions of the Peruvian coast appear in the west.

Historians and El Niño

The El Niño phenomenon is known for hundreds years, but exists certainly much longer. It is one of the tasks of environmental historians to find evidence of El Niño-effects in old records. This can probably shed more light on the impact of El Niño on the world’s climate and world history. To guide historians and others interested in the phenomenon, a selected bibliography of El Niño is presented here

Links to El Niño Websites:

• El Niño page Bureau of Meteorology Australia
• Noaa El Niño site

Aceituno, P (1988) On the functioning of the Southern Oscillation in the South American Sector. Part I: Surface Climate. Monthly Weather Review, 116, p. 505-524. Part II Upper air Circulation. Journal of Climate, 2, p. 341-355.

Allan, R.j. (1989) ENSO and Climate fluctuations in Australasia. In: T.H. Donnely & R.J. Wasson (Eds.) Climanz III proceedings of the third Symposium of the late quaternary Climatic Histry of Australasia, University of Melbourne, 28-29 November 1987, pp. 49-61.

Allan, R.J. (1993) Historical fluctuations in ENSO and Teleconnection Structure since 1879: Near-Global Patterns. Quaternary Australasia Papers 11/1. Meeting held at Monash University, 2-4 December 1992, pp. 17-27.

Anon. (1991) Report of the workshop on ENSO and climatic change. United Nations Environmental Programme (UNEP), Environmental & societal impacts group of the National Centre for Atmospheric research. Bangkok, Thailand, 4-7 November 1991, 28 p.

Berlage, H.P. (1966) The Southern Oscillation and world weather. Mededelingen en verhandelingen 88, Koninklijk Nederlands Meteorologisch Instituut, 152 p.

Bliss, E.W. (1925) the Nile flood and world weather, Memoirs of the Royal meteorlological Society, Vol 1, No. 5, pp. 79-85.

Bradley, R.S., Diaz, H.F., Kiladas, G.N. en Eischeid, J.K. (1987), ENSO signal in continental precipitation records. Nature, Vol 327, pp. 497-501.

Changnon, Stanley, A., and Gerald D. Bell, eds. (2000) El Niño, 1997-1998: The Climate Event
of the Century, New York/Oxford: Oxford University Press.

Caviedes, César N. (2002) El Niño in History: Storming through the Ages, Gainesville Fla.: Florida University Press.

Davies, M. (2001) Late Victorian Holocausts; El Niño Famines and the Making of the Third World, New York: Verso Books.

Diaz, H.F. and Markgraf, V. (eds.) (1992) El Niño, historical and paleoclimatic Aspects of the Southern Oscillation. Cambridge University Press.

Diaz, H.F. and Pulwarty, R.S. (1994) An analysis of the time scales of variability in centuries long ENSO-sensitive in the last 1000 years. Climatic change, 26, pp.317-342.

Eltahir, E.A.B. (1996) El Niño and the natural variability in the flow of the Nile River. Water Resources Research, Vol. 32, no.1, pp. 131-137.

Enfield, D.B. (1989) El Niño, past and Present. Review of Geophysics, 27, pp. 159-187.

Fagan, Brian M. (2000) Floods Famines and Emperors: El Niño and the Fate of Civilization, London: Pimlico.

Fraedrich, k and Muller, K. (1992) Climate anomalies in Europe associated with ENSO Extremes.International Journal of Climatology, Vol. 12, pp.25-31.

Glantz, M.H. (1984) Floods, Fires and Famine: is El Niño to blame? Oceanus, 27(2) pp. 14-19.

Glantz, M.H. (1996) Currents of change. El Niño’s impact on climate and society, Cambridge: Cambridge University press.

Grove, R. (1997) The East Indian Company, the Australians and the El Niño; colonial scientists and the emergence of an awareness of global teleconnections. Discussion paper 231, department of Economic History, australian National university, Canberra.

Grove, Richard H. and John Chappell, eds. (2000) El Niño: History and Crisis, Cambridge: White Horse Press.

Grove, Richard, “Revolutionary Weather: The Climatic and Economic Crisis of 1788-1795 and the Discovery of El Niño”, in: Griffiths, Tom, Tom and Libby Robin, Libby, (eds.), A Change in the Weather: Climate and Culture in Australia (Canberra: National Museum of Australia Press, 2005).

Kane, R.P. (1990) ENSO relationship of Rainfall in different regions of India. Revista Braseliera de Meteorologia, Vol. 5(2) pp. 417-430.

Kiladis, G.N. and Diaz, H.F. (1986) An analysis of the 1877-1878 ENSO episode and comparison with 1982-83. Monthly Weather Review, Vol. 114, pp. 1035-1047.

Lindesay, J.A. and Vogel, C.H. (1990) historical evidence for Southern Oscillation – Southern African Rainfall relationships. International Journal of Climatology, Vol. 10, pp. 679-689.

Liu, Y and Ding, Y. (1992) Influence of El Niño on weather and climate in China. Acta Meteorologica Sinica, Vol.6, No. 1, pp. 117-131.

Meggers, B. (1994) Archaeological Evidence for the impact of mega-Niño events in Amazonia during the past two millennia. Climatic change, 28, pp. 321-338.

Nicholls, N. (1988) More on early ENSOs: Evidence from Australian documentary sources. Bulletin of the American Meteorological Society, Vol. 69. No. 1, pp. 4-6.

Nicholls, N. (1989) How old is ENSO. An editorial Essays.Climatic change, 14, pp. 111-11.

Ortlieb, l. and Machare, J. (1993) Former El Niño events: records from western South America. Global change and Planetary change, 7, pp. 181-202.

Philander, S. George, Our Affair with El Niño: How We Transformed an Enchanting Peruvian Current into a Global Climate Hazard (Princeton, N.J.: Princeton University Press, 2004).

Quinn, W.H. and Neal, V.T. (1983) El Niño occurrences over the past four and a half centuries. Journal of Geophysical research, Vol. 92, No. C13. Pp14,449-14,461.

Ramusson, E.M. (1985) El Niño and variations in climate. American Scientist, Vol. 73, pp. 168-177.

Rebert, J.P. and Donguy, J.R. (1988) The Southern Oscillation Index since 1882. Intergovernmental Oceanographic Commission technical series. Time series of ocean measurements, Vol. 4, Unesco, pp. 49-53.

Richardson, James B. (1998) Early Maritime Economy and El Nino Events at Quebrada Tachhuay. Science281: 1833-1835.

Richardson, James B. (2001) Variation in Holocene El Nino Frequencies: Climate Records and Cultural Consequences in Ancient Peru. Geology 29(7):603-606.

Schove, D.J. and Berlage, H.P. (1965) Pressure Anomalies in the Indian Ocean area, 1796-1960. Pure applied Geophysics, 61, pp. 219-231.

Stahle, D.W. and Cleaveland, M.K. (1992) Reconstruction and analysis of spring rainfall over Southeastern U.S. for the past 1000 years. Bulletin of the American Meteorological Society, Vol 73, No. 12, pp. 1947-1961.

Stahle, D.W. and Cleaveland, M.K. (1993) southern Oscillation extremes reconstructed from tree rings of the Sierra Madre Occidental and Southern Great Plains. Journal of Climate, Vol.6, No.1, pp. 129-140.

Trenberth, K.E. (1984) On the evolution of the Southern Oscillation. Monthly weather Review, Vol. 115, No. 12, pp. 3078-3096.

Walker, G.T. and Bliss (1934) World weather V. Memoirs of the Royal Meteorological Society, 4, No. 36, pp. 53-84.

Wang, S. (1992) Reconstruction of El Niño event chronology for the last 600 year period. Acta Meteorologica Sinica, Vol. 6, No. 1, pp.47-57.

Whetton, P. and Rutherford, I. (1994) Historical ENSO Teleconnections in the Eastern Hemisphere.Climate change, 28, pp. 221-253.

Zhang, X., Song, J. and Zhao, Z. (1989) The Southern Oscillation reconstruction and Drought/Flood in China. Acta Meteorologica Sinica, Vol. 3, No. 3, pp. 290-301.

Biological exchanges and invasions are important themes in history. Over the course of the Earth’s history there have been many biological invasions. Think for example of the species that took advantage of land bridges during ice ages, when sea levels were lower, to expand into new areas where they did not live before. These processes were relatively slow and only the most mobile species were able to migrate over long distances, most species stayed home. Geographic barriers, such as oceans and mountain chains, inhibited migrations of most species and divided the earth into distinct biogeographical provinces. But with the advent of long distance navigation in the 15th century people started to transport species from one continent to another on a scale and with a speed that the world had never experienced before.

This process of the exchange of biota is now familiar to many historians, as the Columbian Exchange, thanks to the work of Alfred Crosby. Crosby used the term to describe the exchange of agricultural goods between the Eastern and Western Hemispheres that has occurred since 1492.
To America, Europeans introduced crops like wheat, rice, bananas, sugar, and grapes. Europeans also brought a number of domesticated animals to the New World, including horses, cattle, pigs and sheep. The Eurasian species thrived in the America’s because their animals and plans encountered less competitions or it was even absent, altering eco-systems forever but also aiding the success of Europeans in the New World, a phenomenon dubbed “ecological imperialism” by Crosby.

However, the exchange process was not a one-way street. Africa and Eurasia acquired some very useful crops from the Americas, most notably potatoes and maize. The new food crops fuelled population growth in Europe, Africa and China.

At present the biological exchange between different parts of the world continues due to fast air transport and large-scale shipping. For this reason it is important to understand the dynamics and processes of past biological exchanges. Below is a short bibliography of biological exchanges and invasions in history, which is far from complete and intended as a starting point for people interested in the subject.

Beinart, William, Costs and Benefits of Plant Transfers and Bio-invasions in Historical Perspective with particular reference to Africa, unpublished paper presented at ISEE 2008 in Nairobi.www.ecoeco.org/conference08/pdf/Beinarrt_Plant_Transfers_Nairobi_Published.pdf

Burney, D., “Historical Perspectives on Human-Assisted Biological Invasions”, Evolutionary Anthropology, 4 (1996), 216-221.

Crosby, Alfred W., Ecological Imperialism: The Biological Expansion of Europe, 900-1900 (Cambridge; New York: Cambridge University Press, 1986)

Crosby, Alfred W., “Columbian exchange: plants, animals, and disease between the Old and New World”,National Humanities Center,nationalhumanitiescenter.org/tserve/nattrans/ntecoindian/essays/columbian.htm

Crosby, Alfred W., The Columbian Exchange: Biological and Cultural Consequences of 1492 (Westport, Connecticut: Greenwood Publishing Co., 1972)

Di Castri, Francesco, “History of Biological Invasions with Special Emphasis on the Old World”, in: J.A. Drake et al., Biological Invasions: a Global Perspective (Oxford: John Wiley & Sons, 1989), 1-30.www.icsu-scope.org/downloadpubs/scope37/scope37-ch01.pdf

Elton, C.S., The Ecology of Invasions by Animals and Plants (Chicago: University of Chicago Press, 2000 [Reprint of 1958 book]).

Groves, R. H., & Burdon, J. J., Ecology of biological invasions (Cambridge, UK: Cambridge University Press, 1986)

Hall, Marcus, “Editorial: The Native, Naturalized and Exotic–plants and animals in human history”,Landscape Research, 28, no. 1 (2003), 5-9.

Hughes, J. Donald, “Europe as Consumer of Exotic Biodiversity: Greek and Roman times”, Landscape Research, 28, no. 1 (2003), 21-31.

Leonie Joubert, Invaded: The Biological Invasion of South Africa (Witwatersrand: Witwatersrand University Press, 2009).

Lodge, D. M., “Biological invasions: lessons for ecology”, Trends in Ecology and Evolution, 8 (1993), 133-136. www.ese.u-psud.fr/epc/conservation/PDFs/Lodge.pdf

McNeill, John R., “Europe’s Place in the Global History of Biological Exchange”, Landscape Research, 28, no. 1 (2003), 33-39.

Middleton, Karen,
 “The Ironies of Plant Transfer The Case of Prickly Pear in Madagascar”, in: William Beinart and Joann Mcgregor (eds.), Social History & African Environment (Athens OH: Ohio University Press, 2003)

Pimentel, David, ed., Biological Invasions: Economic and Environmental Costs of Alien Plant, Animal, and Microbe Species (Boca Raton: CRC Press, 2002).

Sittert, Lance Van, “Making the Cape Floral Kingdom: the discovery and defence of indigenous flora at the Cape ca. 1890-1939”, Landscape Research, 28, no. 1 (2003), 113-129.

Sittert, Lance van, “Our irrepressible fellow-colonist’: the biological invasion of prickly pear (Opuntia ficus-indica) in the Eastern Cape c.1890–c.1910”, Journal of Historical Geography, Volume 28, Issue 3, July 2002, Pages 397-419

Smout, T. C., “The Alien Species in 20th-century Britain: constructing a new vermin”, Landscape Research, 28, no. 1 (2003), 11-20.