El Nino Essay, Research Paper
What Are We Going To Do?
What is El Nino? The man-made environmental disaster made out to be, or an escape from what researchers cannot explain? Understanding the events structure and global impact is the first step to interpreting these questions. The global population cannot take sides on an issue that they do not comprehend, yet recent data encourages the belief that humans are to blame for this ecological disaster and continuously make it worse. Accurately measuring recent El Ninos and predicting those that follow, will determine if we should be concerned about what is happening climatically.
This paper suggests that there is a lot to be learnt about this outrageous environmental fiasco. Without proper information there can be no judgement and there can be no correction. The only hardened fact that remains is that this topic, El Nino, should not be ignored, for if it does worsen, the whole world will be different.
What is El Nino?
For hundreds of years, Peruvian fishermen noticed an unusually warm water current that appeared every year around Christmas. These fishers dubbed this occurrence ?El Nino’, which is Spanish for The Little One. What was once an annual weather occurrence grew into a global phenomenon, linking many unconnected and unusual weather events around the world. El Nino refers to the warm phase of a larger warm/cold oscillation, or movement, occurring in the water and atmosphere of the Pacific region along the coasts of Peru and Ecuador. A typical warm El Nino phase could last between 8 and 18 months. The unheard of counterpart to El Nino is La Nina (or El Viejo), which is the cold phase that could be just as strong, but with opposing effects. Scientists know this complete phenomenon as El Nino/Southern Oscillation (ENSO), and the entire ENSO cycle usually last 3 to 7 years (Kessler-Internet). However, the cycle is unlike the changing seasons, and can vary in strength and timing. Currently, scientists do not completely understand what causes changes in the ENSO cycle.
How does El Nino work?
Under normal circumstances, cold water deep below the surface of the ocean tends to rise, and mixing with the water at the surface creates a transition zone called thermocline (Environment Canada-Internet). As cold water reaches the surface, small life forms begin feeding on its rich nutrients. Cold water will continue to rise because trade winds blow the warm surface water from east to west. Few thunderstorms and little rainfall result from these stable atmospheric conditions of a non-El Nino season. But during El Nino, the trade winds weaken leaving a deeper layer of warm surface water and making it difficult for cold water to rise to the
ocean surface. Since warm water lacks nutrients, the fish that relied upon the small life forms accompanying the cold water die off. An increase of thunderstorms and heavy rainfall may also occur.
El Nino is much more than a temperature change in the ocean levels. During a usual season, the trade winds blow from east to west across the southern Pacific, moving warm water to the west. The atmosphere above the South/Eastern Pacific is dominated by a high-pressure, while the Western Pacific is dominated by a low pressure system. These differing pressures, in turn, drive the trade winds. However, during El Nino the pressures seesaw, a high pressure dominating the west and a low in the east, thus changing the winds and flow of ocean currents (Thrive Online-Internet).
A mature El Nino will affect the weather around the world. Nevertheless, the most visible impacts generally take place in the tropical areas. It typically produces drought over southeast Asia, Australia and sometimes New Zealand. As well it frequently causes abnormally high rain falls over South America – in places which are often very dry (Environment Canada-Internet). As the El Nino phenomenon increases, its effects can be felt beyond the tropics. The warm water creates more uncommonly intense hurricanes in the Pacific. With a fierce El Nino, storms travel from the tropics producing heavy rainfall, flooding and damage across the globe. The 1982-83 El Nino, called the El Nino of the century, caused more than $2 billion in damage in the United States alone and included Australia’s worst drought in over 200 years (Environment Canada-Internet). The largest known ecological effect of El Nino took place in 1970 when the nutrient
supply for fish collapsed off the coast of Peru and Equador. Back to back El Ninos in 1972 and 1974 forced the Fisheries Minister of Peru to prevent anyone from fishing the near barren area. Several years later, despite a dramatic attempt to recover, the damage appeared to have been permanent and is not expected to recover.
In Canada, the most evident effects of El Nino take place in the winter. Air temperatures across the country rise an average of 3 degrees Celcius during El Nino. This creates uncommonly mild and dry winters, most noticeable over the Prairies and British Columbia. The Arctic regions and Atlantic provinces maintain unaffected by an El Nino event (Environment Canada-Internet).Measuring El Nino
An El Nino episode can be measured, and is done so quite easily. The most widely used scale is known as the Southern Oscillation Index (SOI), which is based on the surfaces atmospheric pressure difference between Tahiti and Darwin, Australia, which are on opposite sides of the Pacific (NOVA Online-Internet). Tahiti and Darwin are anti correlated, for example, when Tahiti pressure is high, Darwin pressure is low. Normally, Tahiti pressure is high, indicating that winds are blowing toward the west, but eastbound trade winds are a direct link to El Nino. The greatest advantage of SOI is that data has been available since the 1880’s. Therefore, it is far more accountable than any other measurement.
The Southern Oscillation Index is given in units of standard deviation. For example, SOI values for the 1982-83 El Nino were about 3.5 standard deviations, by this measure that event was roughly twice as the 1991-92 El Nino, which measured only about 1.75 in SOI units (NOVA Online-Internet). Although, scientists do not believe that the Southern Oscillation Index should be
the single source summarizing the intensity of an entire El Nino event.
Predicting and Detecting El Nino
In 1997, El Nino began reeking havoc across the globe. The difference between this occurrence and others in the past was that this one was predicted. Relying on satellites, temperature-measuring buoys, and simulations of the ocean and atmosphere, meteorologists were able to forecast El Nino’s latest appearance. The Pacific Marine Environmental Laboratory in Seattle operates the Tropical Atmosphere Ocean (TAO) buoy array across the Pacific. TAO measures sea surface temperatures, surface winds, air temperature, humidity and even subsurface temperatures. These buoys transmit daily information to orbiting satellites (NOVA Online-Internet). Using the satellite information, NASA is able to monitor the changing atmospheric and oceanic conditions in the tropical Pacific Ocean to predict the next few weeks and months. Distinct indications of future El Nino events include stronger than normal easterly winds and above average sea surface temperatures. With both satellite and buoy information meteorologists now visualize graphic displays of what is happening, rather than trying to make sense of numbers on computer paper.
Is El Nino Linked to Global Warming?
Starting in 1976, oceanic warmings known as El Ninos have popped up with a frequency unmatched in the last 113 years (Monastersky 54). A number climate researchers have suggested that recent El Ninos have not been consistent with the natural patterns of those two decades ago.
Using computer simulation and past information researchers believe that the recent El Ninos are highly unusual. Long-lasting deviations such as the last El Nino occur only once every 1,500 to
3,000 years and twenty-year-long periods of frequent warmings occur only once every 2,000 years (NOVA Online-Internet). These statistics encouraged climate researchers Kevin E. Trenberth and Timothy J. Hoar to conclude that, “The possibility that the [El Nino] changes may be partly caused by the observed increase of greenhouse gases,” produced by the burning of fossil fuels (Monastersky 54). It is possible that as greenhouse gases heat the globe, more frequent and long-lasting El Ninos could occur. On the other side, there are those researchers that suggest these climate variations are within normal limits and that all climate events are natural. Oceanographer Tim P. Barnett debates, “I have problems with generating 1 million years of variation using 100 years worth of data,” he continues to say, “It doesn’t convince that this is rare” (Monastersky 54). Neither interpretation should be taken for the truth, whereas the truly significant statistics will not be available for another 100 years.
El Nino is a naturally occurring phenomenon, that is understood. But it remains unexplained as to why it occurs or when it does, and even with what force it emanates. Impacting the globe as it does, it’s surprising to see how lightly the world can take it. Current measurements are only examples of current events, and even current technology. Therefore, ideas for the future remain current too. The attempts taken to understand the future of this climatic event are tiny in comparison to what it does and could mean for Earth. El Nino is not the only thing that influences weather, yet it cannot be overlooked. Undoubtably, as the present El Nino begins to fade, our intentions for its future should not go with it.
Diaz, Henry F. ed. El Nino: Historical Paleoclimatic Aspects of the Southern Oscillation. Cambridge University Press: New York, 1992
El Nino – Overview. [Online] Available http://www.mb.ec.gc.ca/Nino/Overview.html,
March 26, 1998.
Hjfree@ios.bc.ca. Brief Notes On Biological Effects. http://www.ios.bc.ca/ios/sos/elnino/biol.htm, March 26, 1998
Glossary of Terms. [Online] Available http://www.dir.ucar.edu/esig/elnino/glossary.html,
March 26, 1998.
Kessler, Brian. Not So Frequently Asked Questions about El Nino [Online] Available http://www.pbs.org/wgbh/nova/elnino/resources/elninofaq.html, March 26, 1998.
Monastersky, R. “The Loitering El Nino: Greenhouse Guest?” Science News. 27 January 1998: 54.
Simon, Tamar. El Nino Threatens on the Horizon. [Online] Availablehttp://www.exn.net/news/0.cfm?ThisStory=19970529-03.html
Svitil, Kathy A “They Saw It Coming.” Discover. January 1998: 82-83.
Warm Water, Cold Water and El Nino. [Online] Availablehttp://broadcast.webpoint.com/kwgn/elnino/elnino_upwellings.htm, March 26 1998.
What’s El Nino? [Online] Available http://www.thriveonline.com/outdoors/gordo.07-25-97.html, March 26, 1998.