El Niño Hotspots

Michael Glantz
5 December 2002

A search on the Internet using the keyword "hotspots" turns up two categories of sites. One category focuses on positive things (interesting, fun, recreational): for example, skiing, scuba diving, resorts, dancing, singles hotspots, and so on. The other category of hotspots highlights negative things: coral bleaching, toxic pollution, disease, biodiversity loss, conflict hotspots, and so forth. "Hotspots" identification seems to have gained popularity, especially with respect to environmental change. Here, "hotspots" refers to locations and situations where the results of air-sea interactions in the tropical Pacific Ocean affect human activities and the environment in harmful ways. Some of those effects are only short-term, while others may have long-lasting implications.

Despite the fact that there are hotspots for just about every environmental problem one can name, there are few, if any, focused on interactive hotspots - for example, the interface between agriculture and forests, or the interface between cultivation and grazing. Interestingly, there is no explicit mention of El Niño hotspots. I would define these as regions that are likely to be affected by an El Niño event. In the mid-1980s, a couple of researchers compiled maps of El Niño's likely impacts on temperature and rainfall (see maps below). They have been reproduced in hundreds of publications, both scientific and popular. The media like to use these maps in their popular science articles to explain what an El Niño event is and what it can, or might, do.

These maps are now almost twenty years old, and there have been some changes in where El Niño's worldwide impacts might show up. For example, it seems that the relationship that may have existed before 1980 between an El Niño in the tropical Pacific Ocean and drought throughout India may not be reliable today. Other relationships (called "teleconnections" by scientists), however, do seem to have enough reliability for use by decision makers. While one should not expect for example a drought in the US Pacific Northwest every time there is an El Niño, the probability of a drought in the region does increase. Drought may be expected to occur, say, 80 percent of the time southern Africa when there is an El Niño of a certain intensity.

The intensity of an El Niño event can vary from weak to moderate to strong to extraordinary. A strong event is more likely to influence the climate conditions far from the Pacific Basin, whereas weak events are likely to have their strongest impacts in Pacific Rim countries. A list of likely El Niño hotspots might include, among others, the following:

  • Drought in Zimbabwe
  • Drought in Mozambique
  • Drought in South Africa
  • Drought-related food shortages in Ethiopia
  • Warm winter in the northern half of the United States and southern Canada
  • Heavy rains in southern Ecuador and northern Peru
  • Drought in northeast Brazil (a region known as the Nordeste)
  • Flooding in southern Brazil
  • Drought and fires in Indonesia
  • Drought in the Philippines
  • Droughts in various South Pacific island nations
  • Drought in eastern Australia
  • Heavy rains in southern California
  • Fewer-than-average hurricanes in the tropical Atlantic
  • Coral bleaching worldwide

El Niño is a spawner of climate anomalies and climate-related hazards around the globe. Many groups focus on the forecast of its beginning and on tracking its development for 12 to 18 months. It pays to listen to their forecasts, even though they are not always correct. Often the actions that a society needs to take to mitigate or avoid the worst impacts of an El Niño-related societal or environmental impact are those from which society would benefit anyway: cleaning up our dry river channels so torrential rainwater can pass to the sea; repairing leaky roofs; shoring up bridges, rail lines, and roads that are in poor condition. El Niño forecasts, in fact, provide decision makers with the earliest possible warning of climate-related problems they might have to face.

Clearly, the science and art of forecasting El Niño are in their early stages. The maps above were composed almost two decades ago and are in need of updating. Nevertheless, for some locations around the globe, and for some socioeconomic activities worldwide, such information can provide a "heads up" to decision makers in climate- and weather-sensitive regions and sectors. Forewarned is forearmed, because such information provides power to those who choose to use it.

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