Our Affair with El Niño: How We Transformed an Enchanting Peruvian Current into a Global Climate Hazard

  • S. George Philander
Princeton University Press: 2004. 296 pp. $26.95, £17.95 0691113351 | ISBN: 0-691-11335-1
The El Niño effect: temperature changes in the Pacific can trigger severe droughts in Vietnam. Credit: NGUYEN DONG/UNEP/STILL PICTURES

The 1997–98 El Niño was a watershed event in the history of climate research. It was by some measures the strongest El Niño on record and by far the most publicized. El Niño is a periodic disruption of the ocean–atmosphere system in the tropical Pacific that affects weather and climate around the globe. Once a scientific curiosity studied by a handful of specialists, by 1998 El Niño had become a household word recognized by people from every corner of the planet.

What accounts for the extraordinary public interest in El Niño? The answer lies in the scientific advances of the preceding two decades. The 1982–83 El Niño, which was the strongest of the century until then, was neither predicted nor even detected until nearly at its peak. This failure stunned the scientific community, which at the time was planning a major ten-year international research programme to study El Niño. The Tropical Ocean Global Atmosphere (TOGA) programme, when it was finally launched in 1985, placed a premium not only on developing a deeper understanding of El Niño, but also on implementing new observational and seasonal prediction capabilities. TOGA was largely a success. The observing system it engendered captured the explosive growth and epic magnitude of the 1997–98 El Niño in real time and, once under way, computer models were able to forecast the subsequent development of the El Niño two to three seasons in advance.

George Philander, author of Our Affair With El Niño, was part of the community of oceanographers and meteorologists who helped to shape this exciting period of rapid scientific progress. He writes with the enthusiasm of an eye-witness and the authority of an expert. The book skilfully weaves together descriptions of El Niño physics, the historical backdrop that led to widespread interest in El Niño, and philosophical perspectives on the role of scientific research in addressing present-day environmental problems.

A central purpose of the book is to describe simply but accurately what El Niño is, how it works, and what its consequences are. El Niño's hallmark attributes are unusually weak trade winds and warm sea surface temperatures in the tropical Pacific. It is the warm phase of what is often referred to as the El Niño/Southern Oscillation (ENSO) cycle, which results from dynamical feedbacks between the upper ocean and the overlying atmosphere. La Niña, the opposite phase of the ENSO cycle, is associated with stronger than normal trade winds and unusually cold sea surface temperatures in the tropical Pacific.

Deciphering the underlying physics of the ENSO cycle is an ongoing challenge for the research community, and explaining it coherently to non-specialists is even more difficult. Philander uses easily understandable analogies, such as that of a swinging pendulum, to highlight key aspects of the oscillation. He also draws on metaphors from literature, music and painting to illustrate some of the physical concepts and research methods used in the study of El Niño.

As Philander observes, however, our fascination with El Niño derives not only from the intricate interplay of oceanic and atmospheric dynamics, but also from its effects on patterns of weather variability around the world. El Niño changes the spatial distribution of tropical Pacific rainfall, the effects of which are felt directly in the tropics and indirectly at higher latitudes through atmospheric ‘teleconnections’. It is through these impacts that El Niño science intersects with human affairs.

Disparate parts of the globe may experience droughts, floods, heatwaves and intense storms that can be causally related to El Niño during periods of unusual warmth in the tropical Pacific. Likewise, El Niño-related weather patterns can create environmental conditions favourable for wildfires, outbreaks of infectious diseases and the degradation of air and water quality. The many faces of El Niño that were highlighted in the press and on television in 1997–98 helped to inform the public about the phenomenon and its global consequences.

As the 1997–98 El Niño began to unfold, the ready availability of long-range forecasts prompted many individuals, businesses and governmental organizations to take preventive measures in anticipation of El Niño's impending onslaught. Unfortunately, there are many factors besides El Niño that govern the climate system. Also, El Niño forecasts are by their nature probabilistic, a concept that is difficult for forecast-providers to convey and for forecast-users to understand. Our climate crystal ball is, at best, still fuzzy, so there are inherent risks involved in using these forecasts to guide important decisions.

Philander offers a sceptic's view of the El Niño prediction enterprise, examining at length the failed 1997–98 drought forecast in Zimbabwe and its consequences, but not giving equal time to forecast successes elsewhere. The reader may therefore wish to refer to Stanley Changnon's book El Niño 1997–1998 (Oxford University Press, 2000), which attempts to quantify forecast benefits in a case study focused on the United States.

Also, Philander portrays El Niño as predominantly perilous, hence the book's subtitle, How We Transformed an Enchanting Peruvian Current into a Global Climate Hazard. This characterization is fair but incomplete, ignoring the many opportunities that El Niño creates. The author refers to the positive aspects mostly in the nostalgic past tense, citing the años de abundancia (years of abundance) resulting from rains in normally arid regions of Peru, as described by nineteenth-century writers. Yet for the United States, the 1997–98 El Niño resulted in far more economic gains than losses, and fewer fatalities, than during other years because of the reduced number and intensity of landfalling Atlantic hurricanes and the record winter warmth in the Midwest.

Perhaps the book's most important message is that: “The solutions to serious environmental problems will elude us unless we are all aware of, and respect, the profound differences between the world of science and human affairs.” This harks back to C. P. Snow's lectures on the ‘two cultures’ but with a twist: whereas Snow viewed science and technology as a panacea for solving the world's great social problems, Philander recognizes that science and technology are only part of the solution. Effective use of scientific information to benefit society must also reckon with prevailing cultural values and political imperatives.

Our Affair with El Niño is a very readable, entertaining and instructive book that will appeal to scientists and non-scientists alike. The author does not shy away from controversy in expressing his opinions about the sociological and political aspects of climate research. Whether or not you share his opinions, Philander unquestionably excels at describing the physics of the ocean, the atmosphere and El Niño in lucid terms.