You are here: Home » Climate Extremes » Drought » Sea Level Rise » Bangladesh floods » Hurricane » El Niño? » La Niña?                                                                                                                                                                          Last updated    June 30, 2010                        El Niño and Its Economic Consequences El Niño and La Niña are important temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. The Southern Oscillation (SO) reflects the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin, Australia. What is the relationship between El Niño/La Niña and global warming? In simple terms of comparison, El Niño is caused by the warming of sea-surface temperatures in the Pacific Ocean off of South America, while La Niña occurs when sea-surface temperatures in the same area of the Pacific Ocean are colder than normal. The jury is still out on this. Are we likely to see more El Niño's because of global warming? Will they be more intense? These are questions facing the science community today. Research will help us separate the natural climate variability from any trends due to man's activities. If we cannot sort out what the natural variability does, then we cannot identify the "fingerprint" of global warming. We also need to look at the link between decadal changes in natural variability and global warming. At this time we cannot preclude the possibility of links but it is too early to say there is a definite link.  Origin: Climate Prediction Center - NOAA     However, a study by the Environment Illinois group may suggest indirect link: Global warming can result in more extreme rain and snowfall as warmer temperatures allow clouds to hold more precipitation, bringing extremes of events. There is a lot of confusion in the public about the interrelations connecting climate phenomena such as El Niño, La Niña and greenhouse effect. Global warming may affect El Niño, since both involve heat changes. However, more specific correlations are hampered due to inadequate data such as cloud and ocean effects.       Although ENSO originates in the tropical Pacific ocean-atmosphere system, it has effects on patterns of weather variability all over the world. It also affects Pacific marine ecosystems and commercially valuable fisheries such as tuna, sardines, salmon, and Peruvian anchovetta. The Peruvian water is one of five major fishing grounds in the world. The abundance of fish is supported by the upwelling of nutrient rich waters from deeper levels (below the thermocline).           During an El Niño event, the southeast trade winds weaken thus reducing the upwelling in the eastern Pacific, apparently deepening the thermocline. The deeper thermocline means that any upwelling that does occur is unable to tap into the rich nutrients found in deeper waters. Consequently, the warmer water with less nutrient predominates the region causing a decrease in the fish population.     ENSO is associated with floods, droughts, and other disturbances in a range of locations around the world. For people who live in Indonesia, Australia, or southeastern Africa, El Niño can mean severe droughts, deadly forest fires haze and decreasing air quality. Ecuadorians, Peruvians, or Californians, on the other hand, associate it with lashing rainstorms that can trigger devastating floods and mudslides.

1998 El Nino means severe drought in Australia (Bush fire in Australia,  photo origin of Fred Hoogervorst)		1998 El Nino means flood in Lakeport, California (Photo origin :Federal Emergency Management Agency)

The El Nino which started in Peru in late 1997 and ended Feb 1998 was the strongest on record. The event temporarily warmed air temperature by 1.5°C, compared to the usual increase of 0.25°C associated with El Niño events. It had claimed about 2 100 lives, left countless homeless, ruined highway and extensive road surfaces, caused outbreak of cholera and malaria  and property damage of US$ 33 billion. The El Nino, which has provoked unusually heavy rainfall, brought massive floods and mudslides throughout Peru. The rainfall is estimated to be about 26 times the normal, transforming the once arid desert into a lake encompassing some 6,000 to 8,000 square miles.

In February 2003 El Niño effect took place in Peru where abnormally high rainfall caused extensive flooding in the southeast of the country, destroying 6,000 homes and displacing 59,000 people. The most recent occurrence of El Niño started in September 2006 and lasted until early 2007. The unusually severe El Nino weather caused Peru 4.5% of its GDP.

On the other side of The Pacific Ocean on the same year of 1997, under the El Niño effect, unprecedented forest fires broke out in Indonesia. 24.1 million acres of forest were destroyed, releasing more than
2.6 Gt of carbon dioxide into the atmosphere. This is equivalent to 13–40% of the mean annual global carbon emissions from fossil fuels, and contributed greatly to the largest annual increase in atmospheric carbon dioxide concentration detected since records began in 1957.

The drought of El Nino in 1992 in Kalimantan of Indonesia created one of the worst forest fires in the world, destroying 27 000 square km of forests, countless plants and animals species within them. In El Nino year 1997, 'slash and burn' fires developed into uncontrollable inferno, emitting enormous amount of particulates forming dense haze. The peat fires burnt for months beneath the forest ground underlined with peat as deep as 20 m; making it impossible to put out, even with concerted international efforts.

The haze spread for thousands of kilometers from Indonesia to Singapore, Malaysia, Brunei and S. Thailand, causing significant economical, social and health impacts. Who finally managed to save this raging inferno? The rain! The rain!  The carbon dioxide emitted from the Indonesia peat forest fire is equal to one year combined greenhouse gas emissions from the EU. There were many other forest fires in Java and Sulawesi on the same year. 

Flood in Poland The El Niño event of 1997 also effected Europe indirectly and caused heavy rains which swamped towns and cities across nearly 10 percent of Poland. Many residents were stranded as floodwaters inundated the first floors of homes, swept away more than 200 bridges and left thousands homeless.		Xinhuanet news Jul 2002 Report: Severe droughts hit Vietnam's central provinces, destroying 65,000 hectares of rice fields, causing salinity problems and serious shortage of drinking water. More than 80% of local reservoirs ran dry and crop harvest heavily damaged. Meanwhile, flash flood hit the country's northern provinces inundating roads, houses and schools, and destroying crops.

 

Relating the years of poor crop yields of 1788-89 and the year of an unusually strong El Nino effect between 1789-93, and the French Revolution, one  might probably be able to strike certain degree of linkage story of the three events, but to what degree ?

 

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Climate Prediction Center - NOAA
Economic Consequences of El Nino: Ww2010.atmos.uiuc.edu

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