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What Effects do El

Niño have on Global Climate?

By: Julian Addison and Jason Davis

Abstract

El Niño, which means the "Christ child" in Spanish is the warming of the Pacific Ocean waters. During an El Niño event, the trade winds can stop, or even reverse causing the surface temperatures to increase. Also the warmest water is in the center of the Pacific near Hawaii and form two convective loops, thus causing warm air to rise and to effect weather patterns in the upper atmosphere. Global warming is a key factor in the intensity of an El Niño because of the increase of global temperature. We can detect El Niño periods by infrared satellites and ocean surface buoys. The mixing of hot and cold air creates violent storms and unusual weather patterns. Two scientists, Sir Gilbert Walker and Jacob Bjerknes, are responsible for all the information available today on El Niño. In 1983, Southeast Asia and South America were also devastated and in 1997, Southern Asia reported record flooding and severe droughts due to the last two strong El Niño. El Niño has caused countless deaths and billions and billions of U.S. dollars in damage. Around the world, 1997 was the warmest year on record and El Niño was a major contributor.

Thesis Statement

El Niño has caused widespread devastation around the world leading to around three million deaths, about eleven billion U.S. dollars in damages and leaving almost one million homeless.

Introduction

El Niño, which in Spanish means "Christ child", is the warming of the Pacific waters. It is also known as El Niño-Southern Oscillation (ENSO). ENSO is the change in the ocean-atmosphere system in the eastern Pacific.¹ During normal non-El Niño conditions, the famous Pacific trade winds blow towards west across the Pacific, from the coast of California to the islands of Japan. This is why in Hawaii, there is the constant warm breeze. The trade winds cause the ocean levels to accumulate to one hundred fifty or more centimeters above sea level higher near Indonesia than at the equator.² The "base" of these higher waters is called the thermocline and sits about one hunderd meters below the surface (NOVA Online | Tracking El Niño | Thermocline). The thermocline forms a base to this warm "iceberg".³

During an El Niño year, these winds can stop, or even reverse their direction. What this means is that the trade winds can now blow towards the east and the United States mainland. The trade winds travel along the surface of the water, warming it in the process.⁴ For example, the surface temperature in the middle Pacific is about 65°F under normal conditions. In an El Niño year, the temperature can increase up to near 75° or 80°F. This warming of the Pacific waters can lead to an increase in tropical activity in the Pacific. Some examples of this increase in tropical activity are more and stronger hurricanes and typhoons. One of the typhoons was Typhoon Winnie who in august of 1997 left forty-three [43] dead in China and Taiwan (NOVA Online | Tracking El Niño | Typhoon Winnie).⁵

Since all weather relies on water, El Niño also affects weather in general. Clouds are formed due to the accumulation of water vapor from land and ocean. When the clouds are fully saturated, it begins to rain or snow. Under warm temperatures, water vapors are evaporated into the atmosphere and the cycle repeats again, this is known as the water cycle. Thus, as the water temperature rises, the evaporation of water occurs even more rapidly accumulating more water vapor or moisture than normal. When heavy precipitation is combined with strong trade winds, heavy thunderstorms result. This is why we have strong thunderstorms in the summertime. In the wintertime, this leads to heavy snow and high snowfall totals.

How do trade winds influence El Niño?

The trade winds can be a blessing but they can be a nuisance at the same time. Trade winds are directly responsible for the occurrence of El Niño. When the winds start to die down or in some cases reverse, this is the first sign of El Niño. The winds are warmed by the sun and blow across the surface of the ocean. The trade winds usually blow towards the west, out of the east, or away from the United States' mainland. However, in an El Niño year, the winds reverse and blow towards the east, out of the west, and towards the United States' mainland. This leads to an increase in rainfall on the western coastline of the United States, as well as the western coastline of South America.¹ The winds in their normal state form a convective loop (GIF image 431x645 pixels) from the warm water of the Pacific. This loop occurs around Indonesia and Australia and travels to the cooler land masses on the western North and South American coastlines in the same direction as the winds, west to east. The convective loop pushes warm air towards these cooler land masses. During El Niño, the warmest water is in the center of the Pacific, near Hawaii, and forms two convective loops. One of these loops now push the warm air in both directions, towards the North and South American coastlines in the east, as well as Indonesia and Australia, in the west.¹

Global Warming and its Direct Link to El Niño

Global warming is the direct result of the increase of greenhouse gases.⁶ Ninety [90] percent of greenhouse gases are water, water vapor and ice clouds and the remaining ten [10] percent are carbon dioxide, methane, nitrous oxide, chlorofluorocarbons and ozone.⁶ As we increase the amount of greenhouse gases in the atmosphere such as aerosol, a chlorofluorocarbon, from spray cans and carbon dioxide that we use, we are creating something called "the greenhouse effect."⁶ Just like in a greenhouse, where you would try to keep the heat inside the greenhouse so that the plants can remain warm and grow healthy, the gases are trapped under the ozone layer and heats up the earth.⁶ As the earth's global temperature rises, it causes a direct effect on our weather patterns. These new patterns lead to more violent storms like hurricanes, typhoons, and tornadoes. These cyclones and tornadoes have also grown in intensity and have caused a lot of damage to people and businesses, especially the farming industry.

As this greenhouse effect gets worse, these patterns become stronger. One of these weather patterns becoming stronger every year is El Niño.⁶

How do we detect an El Niño?

The first way that we can detect El Niño is by infrared satellite images. An example is the U.S.-French TOPEX/Poseidon satellite (GIF image 640x800 pixels).⁷ NASA (National Aeronautics and Space Administration) with help from the French space agency, CNES (Centre national d'Etudes Spatiales) launched this satellite in August of 1992. At its orbit of 1,336 kilometers (830 miles) above the earth, It travels across the same path every ten [10] days. This satellite's prime mission was so successful that when it was over in 1995, it became an observer for the next four years. In May of 2000, it will begin its first follow-up mission, Jason-1, that will continue these long-term observations into the next century.⁸

Another way that we can monitor El Niño is by surface buoys. These buoys measure the Sea Surface Temperature, or SST (NOVA Online | Tracking El Niño | Kelvin Wave).³ They are controlled by the National Oceanic and Atmospheric Administration (NOAA) and are aligned in the Tropical Atmosphere Ocean, or TAO Array (GIF image 796x362 pixels).² There are two types of buoys that are used in this array, the ATLAS and the PROTEUS buoys.² There are about seventy [70] ATLAS buoys (GIF image 504x756 pixels & GIF image 487x715 pixels) in this array and they were designed to improve detection, our understanding and to predict El Niño.⁹ These buoys have worldwide support from an international consortium with cooperation from the United States, France, Japan, and Taiwan.⁹ The ATLAS buoys record the temperature closest to the surface of the Pacific.¹⁰ The PROTEUS buoys record the temperature up to five hundred [500] meters below the surface of the water (GIF image 875x807 pixels).¹¹ These two kinds of buoys are placed along the equator in the Intertropical Convergence Zone, or ITCZ (See Figure 1 below).¹² The ITCZ is where most eastern Pacific tropical activity takes place.¹²

What does El Niño do to the Atlantic and Pacific Oceans?

El Niño does not only effect the Pacific, but it effects all weather systems that travel across the globe. Since weather systems need water for energy, much like humans need food, the mixing of winds leads to the organization of strong and sometimes violent storms due to the unequal amounts of hot and cold air. This can lead to unusually high air pressure in the western Pacific and low air pressures in the east.¹³ Air flowing back and forth in convection cells, highways of air, is pushed sideways by the Earth's rotation.⁴ These cells are dragged by friction with the land and the sea, and squeezed by gravity. These distortions cause turbulent mixing of the winds, and soon lead to the development of storm centers due to uneven amounts of warm and cold air.⁴ The "sideways push" inherited by the winds from spinning around the planet is called the Coriolis Effect.⁴ The Coriolis Effect causes the continual convective loops to arrange in bands and the flow direction deviates according to latitude.⁴ These bands are responsible for the influential winds at surface level and jet streams in the upper atmosphere.⁴ El Niño changes the position of the jet stream, causing unusual weather patterns around the world. However, don't be fooled, El Niño can effect weather as far away from the Pacific as Africa and Antarctica. This is why El Niño is such a world problem.⁴

In the Atlantic Ocean, the 1997 Atlantic hurricane season was the least active season since 1914. Due to the fact that El Niño creates abnormal high-level winds which prevent Caribbean hurricanes to develop. This is not true in the Pacific where hurricane formation increases. In the Eastern Pacific a hurricane named Linda was the strongest hurricane ever recorded with maximum sustained winds of 200mph with gusts to 220mph. This surpassed Category Five [5], on the Safir-Simpson Scale, by so much that a new Category Six [6] is proposed by meteorologists. In Western Pacific Typhoon Joan, with winds of 185mph with gusts of 225mph, is one of the three most powerful typhoons ever recorded in the western Pacific Ocean.⁵

In 1997 El Niño was the strongest ever recorded as ocean temperatures were nine to fifteen degrees Fahrenheit above normal in parts of the ocean. These temperatures were measured off the west coast of Peru and stretched up to eight thousand [8,000] miles into the Pacific. These record temperatures reached record status twice as fast as the pervious record holder in 1982-83. The trade winds stopped and reversed three different times, another record for El Niños.⁵

What does El Niño do to the world's climate?

Two scientists, Sir Gilbert Walker and Jacob Bjerknes, (NOVA Online | Tracking El Niño | Through Time - Sir Gilbert Walker & NOVA Online | Tracking El Niño | Through Time - Jacob Bjerknes) contributed the most of our knowledge about El Niño. Back in the early 1920s, Walker was in India studying the monsoonal rains. He was asked previously in 1904 to study and predict the cycles of India's monsoons. He looked through records and came up with patterns showing a link between the total rainfall in South America and temperature variations in the Pacific Ocean.¹⁴ He also discovered a connection between the barometer readings on either side of the Pacific. He noticed that when the air pressure rose in the east, the pressure usually fell in the west and when the air pressure rose in the west, the pressure usually fell in the east. This is similar to a see-saw in a playground. He was the first person to use the term Southern Oscillation (SO) to describe this event.¹⁴ He also found a link between rainy seasons in Asia, with droughts in Australia, Indonesia, India, parts of Africa and mild winters in western Canada.¹⁴

His work was not recognized until almost fifty [50] years later by a Norwegian meteorologist named Jacob Bjerknes. Like most scientists, Walker's work was not uncovered until Jacob started to do his research into El Niño. Jacob was the first person to put the puzzle together. He discovered the connection between the unusually warmer sea-surface temperatures, weaker easterly winds and heavier rainfall around and near the Pacific. His discovery led to the identification of the warmer waters of El Niño and the variation of Walker's Southern Oscillation. Now the two are referred to by the acronym El Niño-Southern Oscillation, or initials of ENSO.¹⁴

In the past twenty years, the world has seen two of the worst El Niños in history. Between these past two ENSO's which occurred in 1983 and two years ago in 1997. They have caused widespread droughts, floods, famines, wildfires, and deadly tropical cyclones. In 1983, Indonesia and Australia had the worst droughts in the history of climatology. Northeastern Brazil received half its normal rainfall while southern Brazil experienced devastating storms and rainfall that caused the destruction of homes and bridges. Peru received more of the same weather as Brazil as Peruvians received as much as three meters, or three hundred [300] centimeters, of rain in six months. The Peruvian fishing industry, which is one of the richest in the world, was nearly wiped out by the 1983 El Niño. There was another strong El Niño event in 1986-87, but everyone was prepared thanks to increased study into El Niño events.⁶ Meteorologist developed an ENSO model that, after some improvements, now can predict El Niño events several months in advance.¹²

The "normal" El Niño conditions are usually abnormally dry conditions over northern Australia, Indonesia and the Philippines. Drier conditions can also be seen over southeastern Africa and northern Brazil, during the northern winter season. Reversibly during northern summer season, the Indian monsoons tend to have lesser amounts of rain, especially in northwest India. Wetter than normal conditions can be seen along the western coast of tropical South America, at the subtropical latitudes of North America, along the Gulf Coast, and South America, from southern Brazil to central Argentina. As for storm systems, middle latitude low pressure systems (storm fronts) tend to be more forceful than normal in the area of the Gulf of Alaska. These systems pump unusually warm air into western Canada, Alaska and the outermost northern portion of the "lower 48" of the United States. Storms also tend to be more powerful in the Gulf Of Mexico and along the southeast coast of the United States resulting in wetter than normal conditions in this vicinity.¹⁵

This is what happened during the most recent El Niño. In South America, the Atacama Desert is full of flowers due to the abundance of rain. This is a place known for its arid, or dry climate. In Ecuador heavy rains and landslides destroyed crops.⁵ In June of 1997, heavy snow and rainfall totals in the central Andes caused severe flooding in and around the capital city of Santiago, Chile.¹⁶ Peru experienced major snowstorms that stranded thousands in the mountain passes of the Peruvian Andes. Also they received floods, landslides and avalanches in September of 1997.¹⁶ According to Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), drought and weather patterns have caused widespread hunger in the highlands of Papua New Guinea and water shortages in Java.¹⁵ The drought has caused severe medical problems as typhoid, malaria, and diarrhea reach epic proportions.¹⁶ Both Pakistan and northwest India reported drier than normal conditions and "spotty" monsoonal rains in some parts of India.¹⁵

The warming of the Pacific waters has killed fishes like tuna. The decrease in the marine food supply off the coast of California has lead to the stranding of seals and sea lions along the West Coast.¹⁶ The seals and sea lions are now forced to find another food source. In Antarctica, it has been observed that the number of births of Weddell seals has declined every four to six years with El Niño events.¹⁶ July of 1997 was the coldest July ever recorded at the South Pole with temperatures averaging minus 86.8 degrees Fahrenheit. This broke the old record by 3.1 degrees.⁵ The warmer waters have also prose a threat to the coral reef ecosystems.¹⁵

What are some statistics of the people affected by El Niño?

In Alaska, melting permafrost damaged roads, airports, and building foundations.⁵ In California, the Monterey Bay Aquarium had to add nutrients to the sea water it draws in from the ocean and that circulate through its tanks, in order to keep kelp healthy. They also had to chill the water, because some species such as octopus can not stand the heat.¹⁵ The Yangtze River in China becomes impassible to shipping in one hundred thrity-seven [137] different places due to drought during the months of August and September 1997.⁵ The Gulf States experience downpours that caused deaths and property damage.⁵

Twenty-three [23] people die in Kenya in torrential rains occur at Coast Province along with seven other deaths in other towns in October of 1997. Mombassa receives seven hundred sixty-one [761] millimeters of rain in the first twenty [20] days of October which is almost eight times more than the normal rainfall for the entire month of October. Hundreds are left stranded by the washing away of the bridge at Marere in Kwale.⁵ Mexico is hit by hurricane Pauline, packing winds of 125mph and dropping as much as twenty [20] inches of rain in twenty-four [24] hours. This storm devastates the Pacific coast here, killing over four hundred [400] people, many of which in Acapulco.⁵ Myanmar, formerly named Burma, experiences the worst flooding in three decades. Estimated reports of the number of people affected by the floods are between one and two million, with some five hundred thousand [500,000] left homeless.⁵

Southeast Asia had a abnormal complex of subtropical thunderstorms that moved ashore in China's Guangdong province in early September of 1997, that produced torrential rains, hail, and deadly tornadoes. The resulting landslides wiped out entire villages, and more than three hundred sixty thousand [360,000] residents are left homeless by rising floodwaters. At least one hundred seven [107] people died in Guangdong and close-by provinces.⁵

Conclusion

In 1997 alone there were worldwide effects of El Niño which ranged from droughts, to floods, to record temperatures, and powerful storms. Australia is an example of a place that experienced drought conditions along with bush fires. In India, drought was so bad that it led to a shortage of fresh water and a cholera outbreak. Indonesia, especially the Phillipines, suffered its worst drought in fifty years to that country. Hundreds of forest fires burned out of control for much of the first half of the year. This created a cloud of smoke that covered that entire area. The famous Panama Canal was effected by drought because there was not enough water to allow the ships to pass through the canal and its locks. Papua New Guinea also saw its major money maker become affected by drought as it was nearly impossible to transport gold and copper ore from mines down the dried up rivers. Many become sick and when the rain came, it was little too late. Southern Africa also had droughts and disease from malnutrition.

In many other areas the weather was reverse, as massive flooding took place in Brazil, Colorado, Ecuador, Kenya, and Myanmar. Brazil sees its worst flooding in 30 years as 15 people die in late August. The Uruguay River crested at 40 feet, 13 meters, above normal. Colorado receives flooding along with mud slides in the mountains. Ecuador's crops are wiped out by heavy rain and landslides. In Kenya 30 people die in torrential rains that occurred in October. Myanmar is effected by its worst flooding in three decades. Estimated numbers are that between one and two million were effected by this flooding.

Antarctica sees a record low at the south pole as the average temperature dips to 86.8 degrees Fahrenheit below zero. The Pacific Ocean had temperatures nine to fifteen degrees Fahrenheit above normal in certain parts. This was a record and was reached in record time as the Pacific reached these temperatures in half the time of the previous record holder in 1982-83. The warmer water lead to violent hurricanes in the Pacific as Hurricane Linda was the strongest ever recorded in the Eastern Pacific. A contrast to the Atlantic and its hurricane season as there was the fewest amount of hurricanes since 1914.

The effects of the 1997 event ranged from extremes in rainfall and in hurricane activity. These patterns also are true for past El Niño events and scientists say that the patterns will stay the same for future events. Since this is a world problem, the world is working together to see what they can do about El Niño. With surface buoys to detect ocean surface temperatures and many satellites in space, we will know in advance when the next "great" El Niño will arrive. When will it happen is still a mystery but the next El Niño cycle it set to begin around 2001 or 2002.

Our recommendation for the future is that more time, money, and effort be put in to study this phenomena to greater understand what causes this cycle of warming and cooling. More research into El Niño can tell us how and why it happens and what we can do to prepare or counteract its effects. We think that El Niño has a great deal to do with weather and that we spend more money and time trying to predict tomorrow's forecast than to understand something that continually repeats and seems to be getting worse every time.

1) Environmental News Network; Katherine Hughes; What is El Niño?; September 22, 1997.

2) NOAA/PMEL/TAO; (no author); What is an El Niño?; 1998.

3) NOVA Online | Tracking El Niño; Mark Hoover; Origins -- Ground Zero; 1998.

4) NOVA Online | Tracking El Niño; Mark Hoover; Global Weather Machine; 1998.

5) NOVA Online | Tracking El Niño | Across The Globe; Image from http://www.pbs.org/wgbh/nova/elnino/reach/#.

6) Worldpaper; Ronald G. Prinn & others; Climate Change; April 1993.

7) El Niño/La Niña Watch; (no author); Satellite image shows Pacific stabilizing; July 16, 1998.

8) TOPEX/Poseidon: At-A-Glance; (no author); TOPEX/Poseidon: At-A-Glance; 1998.

9) NOAA/PMEL TAO Home Page; (no author); The Tropical Atmosphere Ocean (TAO) Array; 1998.

10) GIF image 504x756 pixels from http://www.pmel.noaa.gov/images/atlas.gif.

11) GIF image 583x741 pixels from http://www.pmel.noaa.gov/images/proteus.gif.

12) Weatherwise; Stanley David Gedzelman; Our Global Perspective; June/July 1995.

13) Christian Science Monitor; Robert C. Cowen; The El Niño Climate Connection; January 29, 1992.

14) Environmental News Network; Hillary Mayell; History of El Niño: Tracking a global mystery; September 22, 1997.

15) Typical Impacts of Warm (El Niño/Southern Oscillation - ENSO) and Cold Episodes from http://nic.fb4.noaa.gov/ products/analysis_monitoring/impacts/enso.html.

16) Environmental News Network; John Roach; The impacts of El Niño; September 22, 1997.

Bibliography

Articles and Books

Worldpaper; Ronald G. Prinn & others; Climate Change; April 1993.

NOVA Online | Tracking El Niño; Mark Hoover; Global Weather Machine; 1998.

Environmental News Network; Hillary Mayell; History of El Niño: Tracking a global mystery; September 22, 1997.

NOVA Online | Tracking El Niño; Mark Hoover; Origins -- Ground Zero; 1998.

Weatherwise; Stanley David Gedzelman; Our Global Perspective; June/July 1995.

El Niño/La Niña Watch; (no author); Satellite image shows Pacific stabilizing; July 16, 1998.

Christian Science Monitor; Robert C. Cowen; The El Niño Climate Connection; January 29, 1992.

Environmental News Network; John Roach; The impacts of El Niño; September 22, 1997.

NOAA/PMEL TAO Home Page; (no author); The Tropical Atmosphere Ocean (TAO) Array; 1998.

TOPEX/Poseidon: At-A-Glance; (no author); TOPEX/Poseidon: At-A-Glance; 1998.

Environmental News Network; Katherine Hughes; What is El Niño?; September 22, 1997.

NOAA/PMEL/TAO; (no author); What is an El Niño?; 1998.

Internet Sites

GIF image 504x756 pixels from http://www.pmel.noaa.gov/images/atlas.gif.

GIF image 583x741 pixels from http://www.pmel.noaa.gov/images/proteus.gif.

NOVA Online | Tracking El Niño | Across The Globe; Image from http://www.pbs.org/wgbh/nova/elnino/reach/#.

Typical Impacts of Warm (El Niño/Southern Oscillation - ENSO) and Cold Episodes from http://nic.fb4.noaa.gov/products/analysis_monitoring/impacts/enso.html.

Other sites to go to from here:

The Weather Channel

El Niño.Com

NOVA Online | Tracking El Niño

El Niño: Research, Forecasts and Observations

El Niño Theme Page: distributed information on El Niño

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