World Issues I.S.U: El Nino

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World Issues I.S.U: El Nino

Introduction

El Nino has been a reoccurring phenomenon for centuries. Man has only started to realize how much of the worlds weather is effected by it. In the late 1990’s catastrophic droughts, floods, fires, and famines became synonymous with the term El Nino. But El Nino was stretching its imprint on the world in a myriad ways, long before it made the headline news. From the sinking of the Titanic to the Irish Potato famine, from the outbreak of the war of independence in Mexico to the collapse of Hitler’s Russian campaign, El Nino has shaped the world and will continue to do so. El Nino has been a reoccurring phenomenon for centuries, and currently plays a major role in global warming. The phenomenon does not bring just the negative aspects that scientists and the weather personnel’s are so quick to point out. El Nino has some positive aspects to it; that takes a deeper look into the phenomenon to be realized. El Nino’s global effects are not just confined to changes in the temperature of the world but it also affects the biological ecosystem, the economy of countries world wide, and creates an imbalance in nature.

What is an El Nino? How does it occur? When and where does it occur?

        The term El Nino refers to an irregular warming of the seas surface. El Nino is a natural phenomenon that occurs frequently or more precisely whenever the trade winds blow towards the west across the tropical pacific. “During an El Nino anomalous interaction between the sea and the air starts up where the normal air pressure patterns reverse it self”, (Rita Thievon Mullin, 1999). The trade winds pile up warm surface water in the west pacific, so that the sea surface is about half a meter higher at Indonesia that at Ecuador. Dense tropical rain clouds alter the air flow 5 to 10 miles above sea level (ex. Rocks distort the flow of a stream). These clouds create waves in the airflow that in turn determine the positions of monsoons, the storms tracks and belts of strong winds above the earth that separate warm and cold regions of the earth’s surface.(referred to as jet streams). The impacts of El Nino upon climate in temperature show up most clearly during wintertime. Most El Nino winters are mild over western Canada and parts over the United States, and wet over the southern United States from Texas to Florida. El Nino affects temperature climates in all other seasons as well. But even during wintertime El Nino is only one of a number of factors that influence temperature climates. El Nino years are not always marked by "tropical" El Nino conditions the way they are in the tropics. (Refer to dig 1). The sea surface temperature is about 8 deg C warmer in the west; with cool temperature off South America, due to an upwelling of cold water from deeper levels. El Nino’s in the tropical have important consequences for weather around the globe. Some of the consequences are increased rainfall across the southern tier of the U.S and in Peru, which have caused destructive flooding, and drought in the west pacific, sometimes associated with devastating bush fires in Australia (the latest in Dec 2001- still burning in 2002). Water temperatures increase along the coast as far as the Galapagos Islands. Strong events such as the ones that occurred 1982-83 will disrupt climate conditions around the world as well as local conditions. It has been linked to floods and droughts all over the world. Hurricanes and tropical storms are also altered in their numbers by El Nino. El Nino’s are reported to occur frequently off the coast of Peru. It may last for weeks, months or as long as a year in some cases. However El Nino has no set place or time as to where it will occur and how long it will stay. During the last 40 years there have been 10 significant El Nino occurrences, immensely affecting the coast of South America. Therefore it would be very helpful for people if El Nino could be predicted and prepared for in some form.

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The Ripple Effects in Biological Terms

        During an El Nino cycle there are many biological changes. Due to a depressed thermocline there is less photosynthetic activity resulting in a decrease in the primary life forms that form the beginning of the food chain. The warmer waters that are brought by these changing cycles hold less dissolved oxygen forcing fish to go deeper or venture elsewhere. Due to a lack of data during El Nino occurrences it is not fully known if fish populations are depleted solely due to exposure to El Nino. But whenever an El Nino does occur ...

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