El Niño as a Hazard-Spawner

November 30, 1998
By Michael Glantz

P.S. El Niño as a Natural Hazard

Fragilecologies By Michael GlantzEl Niño is a natural process that has been associated with various kinds of hazards. It has only recently been discovered to have such impacts around the globe. The hazards it spawns include, but are not limited to, droughts, floods, frosts, fires, and landslides. Perhaps if we link what spawns natural hazards (i.e., El Niño) more closely to its potentially spawned hazards, we can shift our short-term responses toward proaction (i.e., prevention and mitigation) and away from reaction (i.e., adaptation and cleanup). Doing so would tend to push the early warning of specific El Niño-related hazards further "upstream," thereby providing more lead time for societal coping mechanisms to come into play.

El Niño's characteristics fit well within the analytical definition of a natural hazard. However, it seems that hazards researchers prefer to argue why El Niño should not be viewed as a natural hazard. Perhaps it is time for them to broaden their perspectives of the phenomenon and its impacts on environment and society, so that El Niño can be viewed as a legitimate hazard (in this broader sense).

Those in the hazards research have opposed considering El Niño to be a hazard, because, they argue, like winter, it just is. For example, things may happen in wintertime, such as blizzards or ice storms, and, while these are viewed as hazards, the winter that spawns them, they argue, is not. The same reasoning that they apply to winter, they also apply to El Niño.

When one thinks about it, societies have coped with seasonal changes for as long as societies have existed. So, many things that will likely occur (e.g., cold temperatures, snow, ice, sleet), we have already learned to expect and to prepare for, even though any particular winter can be either long or short, warm or cold, early or late, mild or severe. Thus, winter potentially spawns lots of hazards (some real and recurrent, others potential and occassional, some even rare or unexpected). Therefore, in a general (and potential) sense, a good argument can be made for considering winter as a hazard.

Societies and individuals tend to put into action their coping mechanism strategies and tactics instinctively when winter approaches. They adjust on a seasonal basis their perceptions of how they expect their normal activities to be altered. The more lead time they have to respond to winter (i.e., to prepare in some way), the better prepared they might be for the weather extremes that wintertime climate may bring. While we don't explicitly consider the seasons as hazards in and of themselves, it would help to do so, because knowing a season is coming serves as an early warning to society and individuals to prepare for a different set of seasonal, climate-related problems with which they might have to cope.

By analogy, using the notion of winter-as-hazard-spawner as an example, one could make similar arguments for El Niño. Knowing that an El Niño is coming provides an early warning about possible changes in regional climate conditions and, therefore, in human activities and ecological processes that are likely to result from their adverse impacts. And, if a goal of managing the impacts of natural hazards is to reduce adverse aspects of those impacts, then by viewing El Niño as a hazard (in the sense that it spawns hazards), we can get an earlier start in determining how we might best cope with those hazards when they occur.

Furthermore, El Niño is a phenomenon that extends across several seasons and can generate different changes within the different seasons. Thus, one can and perhaps will in future years speak of an "El Niño winter" — a winter which enhances "normal" wintertime hazards in certain ways in some parts of the globe, while reducing the likelihood of such occurrences in other parts.

P.S. El Niño as a Natural Hazard

(Taken from Currents of Change, Michael Glantz, 1996, pp. 19-22)

There is a long-standing community of researchers with a focus on natural hazards, for the most part rapid-onset events, such as river flooding, blizzards, avalanches, tsunamis, earthquakes, and hurricanes. Although it meets many of the criteria used to describe them, El Niño has not as yet made this list of such hazards. Ian Burton and colleagues (1993, pp. 35-6) have listed characteristics that define a hazardous event: magnitude, frequency, duration, areal extent, speed of onset, spatial dispersion, and temporal spacing, each of which they define as follows:

  • Magnitude: only those occurrences that exceed some common level of magnitude are extreme.
  • Frequency: how often an event of a given magnitude may be expected to occur in the long-run average.
  • Duration: the length of time over which a hazardous event persists, the onset to peak period.
  • Areal extent: the space covered by the hazardous event.
  • Speed of onset: the length of time between the first appearance of an event and its peak.
  • Spatial dispersion: the pattern of distribution over the space in which its [impacts] can occur.
  • Temporal spacing: the sequencing of events, ranging along a continuum from random to periodic.

These characteristics apply well to El Niño. the magnitude of an El Niño is defined by degree of departure from a long-term average of anomalously warm sea surface temperatures in the central and eastern Pacific. Frequency relates to its return period, which scientists have suggested is of the order of 2 to 10 years (more specifically, one could argue that a major El Niño occurs every 8 to 11 years, and a minor one every 2 or 3 years). The duration of El Niño events is 12 to 18 months, with a few notable exceptions. The areal extent could be interpreted to mean the spatial extent around the globe of the impacts of El Niño and its teleconnections. This would vary directly with the severity of the event, with major El Niño events being linked to major worldwide impacts and minor ones linked to localized or regional impacts. The Speed of onset of El Niño is of the order of months. Occasionally, however, events have begun, only to collapse after a few months. Spatial dispersion refers to the area in the central and eastern Pacific that is encompassed by the anomalously warm sea surface temperatures. Temporal spacing, with respect to El Niño, refers to the return period which, on average, is 4.5 years.

Because the characteristics of an El Niño clearly meet the criteria used to define a natural hazard, El Niño merits inclusion in the list of natural hazards. An explicit designation could help to improve the level of research on its societal aspects, as has been the case with other designated natural hazards.

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