Richard Grove

El Niño in the Twentieth Century

This chapter addresses El Nino’s impact in the twentieth century, a century for which descriptions are uniquely detailed. The El Ninos in the twentieth century that are perhaps best known are 1982–1983 and 1997–1998, respectively the first event to attract global news coverage and the first to be correctly forecast. The El Nino of 1924–1925 is significant as the first to attract international scientific interest. Other El Ninos were notable for associated mortality: the El Nino of 1941–1942 was responsible for the last major famine in the Indian subcontinent and the El Nino of 1972–1973 brought drought and famine to the Sahel. In general, though, the twentieth century was notable for a significant reduction in mortality due to meteorological extremes associated with El Nino.

The Influence of El Niño on World Crises in the Nineteenth Century

The impact of El Nino events from the time of the French Revolution to the present day raises wider issues about the connections between climatic events, social disruption and revolution when one examines the colonial context. The new structures of colonialism and western economic penetration that occurred during the nineteenth century significantly affected vulnerability to El Nino events within colonised populations in drought-prone regions. Although people had always died in droughts in India or Africa, for example, the new governing structures often significantly challenged traditional responses to drought. As a result, in several regions mortality figures during El Nino-caused droughts during the nineteenth century increased above earlier levels. The nineteenth century, though, may have marked the culmination of global El Nino-related mortality.

El Niño Events and the History of Epidemic Disease Incidence

The history of El Nino incidence can help shed light on some aspects of the history of disease and epidemics. A comparison of the chronologies of severe El Nino events and the chronologies of major disease pandemics indicates close connections between the two patterns, particularly in the case of plague, malaria, cholera and influenza, probably the four biggest epidemic killers historically. Most of these epidemic diseases flourish in El Nino periods because their (mainly mosquito) vectors flourish in the changed hydrological conditions that are characteristic of El Nino occurrences. This information on historical El Nino now allows us, for the first time, to present a synthesis of the evidence linking El Nino with disease epidemics and an evaluation of the arguments for climatic agency.

The Discovery of ENSO

The Southern Oscillation was named in 1924 and its discovery can be traced back to colonial attempts to forecast the Indian monsoon in the late-nineteenth century. The first use of the name ‘El Nino’ to describe a climatic phenomenon appeared in South America in 1893. The term did not, however, originally mean what it does today, being used to describe a seasonal warm water current that is manifest off the coast of northwestern Peru. The history of these two distinct phenomena and their eventual amalgamation into ENSO is closely linked to the activities of the international Guano industry and to efforts to strengthen US soft power in Latin America during the Cold War. Significant advances in El Nino forecasting have occurred since the 1982 event.

El Niño Chronology and the Little Ice Age

Thanks to the work of Hubert Lamb the effect of climate on society in the Little Ice Age (LIA) is well known in temperate latitudes. The subtropical and tropical history of the LIA and its El Nino events is far less analysed or documented. It does seem clear that the most severe drought periods in Asia and elsewhere (especially Africa) that were manifest during the LIA were associated almost exclusively with what we consider to have been El Nino events. In this way we are then able to ask the question: what happened in the tropics, and especially in Asia, during the El Nino events of the LIA, and what does this mean in terms of understanding the history of economic patterns and human crises?

Postscript: El Niño and Human Future

One thing that has been missing from this book is the effect of climate change on El Nino. The primary reason for this is the large uncertainty that currently exists in the science of future El Nino. Changes to El Nino itself are uncertain, although changes to teleconnections are more likely. This is because the atmosphere responds much more quickly to rising greenhouse gas concentrations than do the oceans, which are slower at heating up. This postscript concludes with a discussion of the 2015-16 El Nino, which had unexpected characteristics and demonstrated the need for continued research on El Nino in the past and present.

Cataloguing the El Niño

For the modern period, El Nino is measured through systematic observation by meteorological or oceanic instruments. Before the nineteenth century, however, systematic weather observation was almost entirely absent and alternative sources must be used, such as natural archives or references to El Nino-related phenomena in the written record. Beyond the past 500 years more generalised evidence has been gathered from fossilised microorganisms. This chapter is an important exposition in the context of this book as it helps to demonstrate how and why it is possible to state that El Nino and La Nina events occurred at various points of history, and where these data come from. This chapter thus serves as a foundation for other parts of this volume, as well as a stand-alone narrative.

El Niño in the Public Imagination

El Nino is often described in the media as a universal scourge that brings nothing but destruction. The last 40 years may, however, be the only period in human history where this description is not correct. This is because the El Nino presented in the media is not the physical phenomenon; it is instead an idea of El Nino, what might be termed ‘El Nino in the public imagination’. This idea is enabled by uncertainties within the science of El Nino and reinforced by the names ‘El Nino’ and ‘La Nina’, which provide a gender and personality. This chapter argues that, since the end of the twentieth century, the idea of El Nino has had as important an effect on society as the phenomenon itself.

The ‘Great El Niño’, 1790–1794

By the 1780s it starts to become possible to reconstruct the global impact of major El Nino events with some genuine statistical accuracy. This is largely because of the wealth of data gathered by the British East India Company. By far the greatest amount of information we have available relating to the droughts of the eighteenth century is of the ‘Great’ El Nino of 1790–1794. This was of particular significance on account of its strong global effects, the particular sequence of events which it manifested and the very prolonged nature of the droughts it produced, especially in South Asia but also Australia, America and Africa. The evidence of intense and prolonged global impacts suggests it may have been among the most severe in the written record.

El Niño in Prehistory

A western Pacific sediment core provides us with an indication of the early activity of the Holocene El Nino. Stronger activity is evident around 4200, 3700 and 3300 BP. These first periods of severe El Ninos correspond with a number of significant droughts that affected major northern hemisphere civilisations, especially in Mesopotamia and Egypt. The earliest literate societies, particularly those of Ancient Egypt, have left us with a clear impression of the colossal impact of these droughts: in 2200–1850, 1500–1650 and 1150–1250 BCE. A further series of droughts between 500 and 900 CE also had catastrophic impacts on human populations in India and the Americas, during a period that has been termed the ‘Dark Ages’. In all cases El Nino is highly implicated.