El Nino

– Persuasive Letter Essay, Research Paper El Ni o, it was learned, is as much an atmospheric event as an oceanic one. The winds and the waters communicate with each other halfway around the world. (Johnson) In a normal year, the trade winds blow from South America to Asia, pushing warm water to the far reaches of the western equatorial Pacific. During an El Ni o, this pool of warm water sloshes across the Pacific to Peru as the normal winds weaken. The warmer-than-normal water adds heat and moisture to the air above it, creating thunderclouds and a typical storm track with far-reaching effects. (Johnson) El Ni o is a mass of warm water now in the southern Pacific. It is having a global impact on the weather. The warm water increases the water vapor over the Pacific and the Earth s normal weather pattern. The result: heavy rains in the usually dry Southwest and fires in the drought-stricken rain forests of Malaysia. (Jarvinen) El Ni o is a seasonal ocean current that flows southward along the coast of northern Peru, it is often associated with atmospheric changes. Scientists generally refer to El Ni o and its related phenomena as the El Ni o-Southern Oscillation (ENSO). The current itself is warm, nutrient-poor, and relatively low in salinity. Its name (Spanish, “the child”) is derived from its arrival during the Christmas season. This current is most well developed from January to March, and it usually penetrates only a few degrees south of the equator before converging with the northward-flowing Peru Current. El Ni o is an extension of the eastward-flowing equatorial countercurrent. It turns south along the coast of Ecuador. Every four to five years, in an only partially understood cycle that appears to incorporate a 2-year subcycle, a weakening of normally strong southeasterly trade winds allows the El Ni o current to extend farther south. Water temperatures rise several degrees above average, with catastrophic results. (Katcher) The higher temperature along the coast kills planktonic organisms and fish, thus harming the major fishing industry in the area; important guano-producing birds starve or abandon their nests. The higher temperature also causes increased evaporation, which in turn produces excessive rainfall on some land areas. A major ENSO disturbance affects other ocean-current patterns and causes widespread climatic changes over the Western Hemisphere and even Europe and Asia, as well as over the southern Pacific Ocean. Disastrous flooding and droughts may result in some areas. Researchers have developed models of tropical ocean-atmosphere interactions that enable them to successfully predict ENSO variations and better forecast climatic disturbances. (Arbarbanel) (Fullmer) El Ni o is a periodic, weather-disrupting condition in the tropical Pacific, in which westward-blowing trade winds weaken, allowing warm water to drive east to South America. (Livezey) El Ni o is a large pool of unusually warm water that appears roughly every three to four years in the central and eastern Pacific Ocean along the equator. (Fullmer) The abnormally warm water causes a big increase in rainfall in central and southern South America, east Africa, and the central and eastern tropical Pacific. El Ni o created drought in Indonesia, Australia and the western tropical Pacific, Central America and the Caribbean. (Fullmer) Actually, the size of El Ni o doesn t change much from episode to episode but its strength does and that s what matters. The strength matters because if it is very strong, it has the potential to bring massive rainstorms that could cause many floods. It also matters because it has the capability to produce massive hurricanes. If the El Ni o is weak, then the effects are less and do not cause as much damage. El Ni o s cycle is very irregular. For instance, there were a number of very strong El Ni os between 1900 and 1920, a few in the early 1940s, and several per decade from the late 1950s to the present, but only very weak ones in the periods between. The last decade and a half have been a particular active period for strong El Ni os. (Weisser) Way back in the 1500s, fishermen in Peru noticed that unusually warm coastal currents reduced their anchovy landings. At the same time, local farmers noticed the warming coincided with increased rainfall. Wondrous gardens sprung from barren arid lands in some regions, and the years were called “a os de abundancia” – years of abundance in Spanish. In other regions, torrential rains brought ruin. (Johnson) The warming often peaked around Christmas so the current was nicknamed ‘El Ni o’ – the Christ child in Spanish. The late 1880s fascinated a few scientists fascinated by the phenomenon. From the mariners logs and farmers’ almanacs, it was impossible to piece together the El Ni o story or even to define a normal year in rainfall and water temperature. It was impossible to piece together the El Ni o stories because they did not write down enough information that was accurate, every time El Ni o occurred. (Johnson) Peruvian fisherman first noticed it during Christmas over 200 years ago. El Ni o is a periodic and huge, phenomenon. This year’s is one and half times the size of the United States, has enough water to fill the Great Lakes 30 times over and has 93 times the energy Americans extracted from fossil fuels in 1995. (Wilson) No one knows when the first El Ni o occurred, but ice-core records from the Andes in Peru suggest these climate fluctuations have been part of Earth’s weather cycle for thousands of years. Some scientists speculate the topsy-turvy weather patterns began when glaciers stopped receding and sea levels stabilized some 5,000 years ago. Others believe they have identified El Ni o signatures hundreds of thousands of years old in coral growth rates. (Johnson) Indirectly, the warm current also crashed the local guano industry, which sold the nutrient-packed seabird droppings for fertilizer. Seabirds had either starved or migrated with the anchovies to colder fish-filled waters, leaving the local rocks guano-free. (Johnson) Interest in El Ni o rekindled in 1972-73, when a monster-sized warming event rolled across Peru, collapsing its anchovy fishery, then the largest in the world. As the fiscal effects of a fishmeal shortage rippled around the globe, the price of protein alternatives such as soybeans skyrocketed. Poultry farmers in the United States passed their soaring feed costs on to consumers, raising retail chicken prices 40 percent. This was the kind of science that interested Wall Street. (Johnson) Despite the progress, Mother Nature played havoc with scientists’ understanding of the unruly phenomenon in 1982, when a monster-sized El Ni o rolled across the Pacific with wildly unexpected consequences. It was to date the largest, most intense El Ni o in modern times. Farmers in Peru were up to their eyeballs in rain. Fires scorched Borneo. Droughts hit Australia. An estimated 2,000 people died. All told, the damage estimates ranged from $8 billion to $13 billion. (Johnson) El Ni o is back and no one has put out the welcome mat. This year is expected to be stronger and more destructive than the 1982-83 event that cost the world over 8 billion dollars. Scientists continue to document and study past events to gain a better understanding of the phenomenon. It’s no simple task because no two El Ni os are alike and each occurs at irregular intervals ranging from two to ten years. El Ni o caused the anchovy population along the Peruvian coast to drop from 20 million to 2 million in 1972-73. This in turn reduced the number of marine birds who fed on the anchovy. In 1982-83 the strongest El Ni o of the century occurred. Weather-related disasters hit all five continents. In 1991-92, the amount of damage was totaling over eight billion dollars. There were severe droughts in tropical places and major flooding in the Upper Mississippi Valley. A large number of hurricanes occurred in the Atlantic Ocean, Caribbean Sea and Gulf of Mexico. (Livezey) In other words, 1997-1998 El Ni o may be the biggest in 150 years, some scientists predict. (Livezey) The first clues were found in the 1920s by the British scientist Sir Gilbert Walker who discovered that there was a connection between barometric readings at stations on the eastern and western sides of the Pacific. He noticed that when pressure rises in the east, it usually falls in the west, and vice versa. Sir Gilbert dramatized this process by referring to it as the “Southern Oscillation”. The Southern Oscillation plays an important role in the behavior of prevailing winds in the equatorial Pacific. When the pressure is high in the eastern Pacific and low in the western Pacific, surface winds are driven toward the west along the equator from the Galapagos Islands nearly all the way to Indonesia. This is said to be a “high-index” (strong gradient) condition. When the pressure oscillates back to a “low-index” (weak gradient) condition, the easterly surface winds weaken. Walker noticed that Asian monsoon seasons under low index conditions are often linked to drought in Australia, Indonesia, India, and parts of Africa and mild winters in western Canada. Years later, researchers learned that desert islands in the central equatorial pacific receive little or no rainfall, except for low-index years when they experience torrential rains for months. Hence, Walker’s Southern Oscillation is also linked to dramatic changes in tropical rainfall. It wasn’t until the late 1960s that the connection between Walker’s Southern Oscillation and El Ni o was made. Some fifty years after Walker’s observations, the Norwegian professor Jacob Bjerknes at the University of California was the first to see a connection between unusually warm sea-surface temperatures, the weak easterlies, and heavy rainfall that accompany low-index conditions in the equatorial Pacific. It is now well accepted that a low-index Southern Oscillation condition is associated with El Ni o, oftentimes referred to as “ENSO” to emphasize the connection. (Livezey) The transport of water, and therefore heat, by the winds in the equatorial Pacific is central to understanding the mechanics of an El Ni o. The easterly winds that blow along the equator and the southeasterly winds that blow along the Peru and Ecuador coasts entrain surface water along with them. The Earth’s rotation deflects the surface currents northward in the Northern Hemisphere and southward in the Southern Hemisphere due to what is known as the Coriolis Effect. The surface waters are therefore deflected away from the equator in both directions and away from the coastline. Where the surface water moves away, colder, nutrient-rich water comes up from below to replace it, a phenomenon known as upwelling. Both the equatorial upwelling and the coastal upwelling are concentrated in narrow regions less than 160 km wide. When the winds are blowing strongly, this band of cold water takes the form of a distinctive “cold tongue” extending westward along the equator from the South American coast all the way to the international dateline. This feature can be observed using infrared satellite imagery, which measures the water temperature, and satellite altimetry, which measures the relative depression in sea level in regions of upwelling. (Allen) During an El Ni o year, the easterlies blow strongly for a number of months, the thermocline nearly reaches the surface in the eastern equatorial Pacific, and enormous volumes of warm surface water build-up in the west … then the winds weaken … all of that energy has to go somewhere. First, the easterly winds begin to retreat eastward. As the wind retreats, equatorial upwelling decreases, reducing the supply of nutrients to surface inhabitants. Sea level drops in the west and rises in the east as warm surface water surges eastward along the equator in the form of a pulse. When this pulse of relatively warm water reaches the eastern end of the basin, typically a few months later, it is forced to turn northward and southward along the coast, causing sardines and other species of fish to move, and raising sea level as it goes. These effects have been felt as far north as Canada and as far south as central Chile. As the moist air above the ocean warms, deep clouds are formed which produce heavy rain along the equator, shifting ever eastward. Atmospheric pressure adjusts accordingly. Barometers fall over the central and eastern Pacific and rise over Indonesia and Australia, resulting in further weakening and eastward retreat of the easterlies, just as Sir Gilbert Walker observed almost 75 years ago. Scientists now know that the devastating effects of El Ni o are not just confined to the equatorial Pacific, but throughout the Americas, and perhaps beyond. We are only beginning to appreciate how massive these disasters are. (Allen) The problem of detecting global warming has been considerably complicated. This is because some analyses have suggested that some of the features of the global warming oceanic signature resemble El Ni o. Picking these two apart in the records is tricky although some success has been achieved so far. Global warming s impact on El Ni o itself is not clear either because recent work has suggested that there are feedback effects in the tropics that offset some of the warming at the equator. (Arbarbanel) The Atlantic hurricane season was a lot less windy than usual, and El Ni o is the reason. Three hurricanes blew in from the Atlantic during a storm season that ended Sunday. The average is six, while the National Hurricane Center chased a hefty 17 hurricanes in the Pacific, it only watched seven named storms in the Atlantic. (Neely) Precipitation was above normal in November, but not unusually wet. Seasonal percentages were generally the highest in the Central Valley and in coastal areas, with some intense storms reported in the South Coast region early December. (Wilson) As of Dec. 22, rainfall was 116 percent of normal in Eureka, 163 percent in Sacramento, 185 percent in San Francisco, 127 percent in Fresno, 189 percent in Bakersfield, 231 percent in Santa Barbara, 147 percent in Los Angeles and 76 percent in San Diego. (Neely) The snow pack near Donner Summit, west of Lake Tahoe, was under 40 inches compared with more than 110 inches in late December 1982, when a previous El Ni o event gave California a record wet season. (Fullmer) As of mid-December, multipurpose reservoirs in the Central Valley had more than 7 million acre-feet of flood control space, more than 2 million more than required. Statewide river runoff is about 80 percent of average for this time of the year. (Katcher) The National Weather Service said that this year s warming in the tropical Pacific could lead to Christmas snow in Texas, New Mexico, the Mississippi valley, even as far south as Mexico. (Neely) The Thai Interior Ministry, meanwhile, has ordered provincial authorities to prepare personnel, equipment and water trucks to help in areas worst affected by the drought. (Wilson) The Asian Disaster Preparedness Center, which is scheduled to hold a crises meeting in Bangkok next month, has warned that El Ni o will exacerbate the financial crisis that is already pounding Thailand and several other Southeast Asian countries. (Katcher) El Ni o finally hit northern California with drenching rains and coastal floods over he weekend and meteorologists said that on Tuesday the region was set to receive more wallops of rough weather this week. After months of listening to doom-and-gloom predictions about the likely effects of El Ni o, residents in the San Francisco Bay area were treated to a display of the weather phenomenon’s might when heavy rains snarled traffic and raised fears of mudslides in hilly areas. Forecasters said the rains along the California coast were influenced by El Ni o, a warm-water mass off the coast of South America that has powered climatological shifts across the globe. (Wilson) It appears that many people in the Midwest are overlooking El Ni o. They probably think that just as long that El Ni o isn t affecting us in any really bad ways, they shouldn t worry about it. I think what comes around, must go around. In the spring and in the summer we will experience extremely low temperatures. These could affect us by killing off many agricultural products and creating very low or no profits for the midwest farmers. The opposite effects of El Ni o could also occur. The unusually cold temperatures could occur in the late summer and early fall, which would result in a huge loss of crops. The same could also happen to another country that we depend on for buying a particular product. If that happens to another country s product, then we would have to pay a lot more for the same product. Therefore I think we should put more effort into predicting El Ni os. I think we could look back in to the past records of serious weather storms and try to find a pattern to the El Ni o. If we could do that, we could better predict El Ni o and save many lives and much money. If we save could save money and lives, I think we should be willing to pay any price to predict El Ni os better. I think that if we work hard enough, we could obtain the technology and we would be able to better predict the El Ni o. Then if the temperature was going to drop in the first part of spring, we could wait until it was over to plant our crops. Or if the temperature was going to drop later in the summer farmers could harvest the crops sooner. If my plan isn t accepted, El Ni o will continue to destroy personal and Federal property. El Ni o will also continue to kill thousands of people every time it occurs. If my plan is accepted damages to property and deaths may still occur, but it will significantly reduce the number. We will be able to predict the effects and better prepare for it. Allen, Jane. El Nino. http://www.quest.arc.nasa.gov/topex/QA/What_ Causes_El_Nino.txt. Arbarbanel, Henry. El Nino. 11 January 1998. http://www.abcnews com . Fullmer, Brent. El Ninos Energy. http://www.umassd.edu/Public?Kamaral /thesis/ElNino/Energy.htm. Jarvinen, Brian. El Nino. http://www.dir.ucar.edu/esig/currents.html. Johnson, Christina. A Brief History of El Nino. http://www.elnino.com. Katcher, Oliver. El Ninos Size. http://www.enn.com/special reports/el/nino/size/index.htm. Livezey, Robert. El Nino. http://www.wcco.com/news/enso. Neely, Vivan. Results of El Nino. http://www.vision.net.au/ daly/elnino/results.htm. Weisser, Pete. El Ninos of the Past. http://www.broadcast.webpoint.com/ tic/elnino/elninohistory.htm. Wilson, Robert. Water Picture Normal-So Far. http://www.ogp.noaa.gov/enso. Outline Theme Statement: El Ni os occur about every couple of years, and each year they are blamed for countless deaths and billions of dollars in damage. When the technology came out, we developed software to predict tornadoes, hurricanes, and most other natural disasters. Now we must put more effort into predicting strong and destructive El Ni os. I. History of El Ni o A. What is El Ni o B. Naming of El Ni o C. Past El Ni os II. Theoretical Causes of El Ni o A. Southern Oscillation B. Global Warming III. Effects of El Ni o A. Hurricanes B. Rainfall C. Other Disasters IV. Solutions A. Realize the El Ni o B. What we should do C. What will happen A. If we accept my plan B. If we don t accept my plan