Introduction
Parking lots and celebrity homes near Southern California's famous beaches, normally supposed to be on dry land, are slammed by unusually high tides and ocean waves. Fishermen off the coast of Oregon spot giant sea turtles and marlin hundreds of miles farther north than they would normally be seen. Reduced winter snowpack in the Cascade Mountains leads to water-rationing and brown summer lawns in famously-rainy Seattle. Villagers on Vancouver Island off Canada's southwest coast see brown pelicans, usually associated with Californian and Mexican shorelines. Dry Arizona and New Mexico are far wetter than normal. Humid Hawaii suffers from drought conditions, and soggy southeast Alaska gets even soggier than usual. And even normally-frigid ocean beaches up and down the West Coast see a flux in water temperature, causing human swimmers to venture into the water.
What's going on here? What powerful force could possibly affect these far-flung places so profoundly? The answer, of course, is El Niño. It is a big or small disruption in the way oceans and climate systems normally interact with each other all over the Pacific Ocean, (which is the biggest single expanse of water on this small, interconnected planet). The name, which means The Little One in Spanish, comes from Peruvian fishermen who typically first notice an upcoming El Niño around Christmas, (weeks or months before we feel its effects in western North America). El Niños are completely natural events that happen every few years. However, their frequency and intensity may now be increasing as part of a larger pattern of global climate change, which is, in turn, partly caused by human activities.
Although El Niño's causes and consequences are very complex, scientists from many disciplines working together, have put together a pretty good picture of what's going on. El Niño does not work alone; like Clark Kent and Superman, it appears only when its alter ego, La Niña, isn't around. Over much of the Pacific Ocean, when an El Niño occurs, the water is unusually warm. In alternate periods, when La Niña is in the Pacific, the water is unusually cool. This great alternation produces changes in weather, sea level, surface temperature, snowpack, and distribution and abundance of organisms at localities over a large swath of the Earth. It does so by means of the complex but increasingly well-understood ocean-atmosphere interconnections that produce our climates. Because El Niño is basically an incredibly big wave of warm water, starting in Peru every few years and eventually spanning most of the Pacific Ocean, its effects are greatest on those who live near the Pacific. Why? The Pacific Ocean is simply the Earth's biggest ocean and so is less influenced by adjacent land masses the way the smaller Atlantic and Indian Oceans are. Big waves, like this El Niño, demonstrate, perhaps, more than any other single phenomenon how interdependent the Earth's biosphere, hydrosphere, and atmosphere really are.
History
While they are currently the rage as explanations for nearly any strange weather or oceanographic event, El Niños have been around for a long time. Climatologists using hindcasting techniques to reconstruct past climates can detect El Niños back at least to 1567. They have almost certainly happened at 2-7 year intervals since then and long before. El Niño events have only been moderately well known by the scientific community for most of this century. However, the massive El Niño of 1982-3 changed all that. In the last 15 years, our understanding has increased dramatically with new field and modeling methods aiding in our ability to predict El Niños. This great leap forward in predictive ability is generating the current attention being paid to the 1997-8 El Niño event, which may surpass the 1982-3 El Niño, (until then, the biggest of this century).
Current Status
Our understanding of El Niño and associated phenomena has been greatly enhanced by the Operation of El Niño / Southern Oscillation (ENSO) Observing System , a coordinated effort by the National Oceanographic and Atmospheric Administration to integrate information sources available about El Niño. The research efforts include an ocean-wide network of moored and drifting buoys that measure sea surface temperature, sea level measurements around the Pacific, and computer models that are skilled in forecasting ocean temperatures (based on past variation) a year or two in advance.
Pro/Con Arguments
Because El Niño is a natural phenomenon it is difficult to say whether there are pros or cons - it simply is part of global variability that individuals and policy makers must acknowledge. However, on a local scale, there are clearly some arenas in which there are costs and benefits (e.g. agriculture, fisheries, tourism, water and energy use, etc.).
Pro Arguments
- 1. Profits of Warmer Water
- El Niño is good for the sportfishing industry in California, Oregon and Washington as it brings warmer-water species to places they would not normally be. This equates to a short-term economic boost to the local communities involved in the sportfishing industry.
Con Arguments
- 1. Effect of Climate Change
- With the reduction of precipitation (and therefore snowpack) during Pacific Northwest winters, El Niños can lead to summer drought conditions. For example, we in the Western United States can learn lessons from the crash of the Peruvian anchovy fishery off the Pacific coast of South America. The anchovy populations, once the largest single-species fishery in the world, plummeted in 1972. Fishing for anchovies, once comprising 18% of the entire global fish catch, has never recovered as an economically viable industry. Part of the problem, of course, was overfishing. However, the El Niño in 1972 reduced nutrient-rich cold-water upwelling off the coast of Peru and in turn generated less food supplies for baby fish, causing a population crash that was truly catastrophic. The critical fisheries concept of Maximum Sustainable Yield (MSY) was not heeded; the anchovy population was harvested in excess during a bad year for anchovies and their population never recovered. A lower annual catch (MSY) may have allowed the population to recover after an El Niño year. Failure to take El Niño into account in designing fisheries policy therefore helped destroy one of the largest food fisheries in world history.
Connection to Environmental Science
The intertidal, coastal, and oceanic habitats most affected are described in the foldout between pages 42 and 43. The possible connection between El Niño and broader phenomena of global warming is treated on page 414. The important concept of upwelling, which is disrupted by El Niño events in the northeast Pacific, is described on page 65. A discussion of marine fisheries and maximum sustainable yield, critical concepts when El Niño disrupts population cycles, occurs on pages 487-489. Pages 264-270 describe the water cycle movements between oceans and the atmospheres that are also altered dramatically by El Niño events.
Hyperlinks
- National Marine Fisheries
- This site supported by the National Marine Fisheries Service in La Jolla, California provides a frequently updated and graphically striking view of the SST (sea surface temperature) anomalies off the West Coast of the United States. It also shows deviation from normal patterns of upwelling off the Pacific Coast.
- Background on El Niño
- This site is a clearinghouse for general background and current developments on El Niño, supported by the National Oceanographic and Atmospheric Administration (NOAA).
- Sea Data Collection
- This site explains the nitty-gritty of how oceanographers collect data on sea temperatures over vast regions of the Pacific Ocean and over many years. It is supported by California Cooperative Oceanic Fisheries Investigations, and offers an animated movie of temperature change off California over a 12-year period (if you have the right software).
- Monterey Bay Aquarium Research
- This site is a place to meet a person behind the science, a research technician at the Monterey Bay Aquarium Research Institute in Moss Landing, California. It explains what it would be like to work or be a student at an oceanographic research laboratory of the sort which has contributed to much of our understanding of El Niño.
- 1997-1998 El Niño Developments
- This very interesting site is a summary of many recent developments on the West Coast associated with the 1997-98 El Niño. There are recent reports on strange things people have observed throughout the country and around the world.
- Congressional Hearings on El Niño
- This link shows the fascinating link between science and public policy. It contains testimony before the United States Congress by experts on how the country should prepare for and react to El Niño events, from regional, national, and international perspectives.
References
- Anonymous. "Science: Tempest in the Pacific." Time 150(7): 56, August
18, 1997
- Clark, Larry, Ralph W. Schreiber and Elizabeth A. Schreiber. "Pre- and Post-El Niño Southern Oscillation Comparison of Nest Sites for Red-tailed Tropicbirds Breeding in the Central Pacific Ocean." The Condor
92: 886, 1990.
- Hall, J. W. and H. A. Quamme. "Winter Freezes of Fruit Trees in the Okanagan Valley, British Columbia: Relationship with the Pacific North American Teleconnection and the El Niño/Southern Oscillation." Canadian Journal of Plant Science 74: 841, 1994.
- Johnson, Mark A. and James J. O'Brien. "The Northeast Pacific Ocean Response to the 1982-1983 El Niño." Journal of Geophysical Research 95:7155, 1990.
- Paine, R. T. "Benthic community - Water Column Coupling During the 1982-83 El Niño." Limnol. Oceanogr. 31: 351, 1986.
- Tibbetts, John. "Farming and Fishing in the Wake of El Niño." Bioscience 46: 566, 1996.
