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Bringer of bounty and famine,
El Niño keeps experts guessing
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What is an El Niño? The ripple effect The El Niño of 1982-83 This El Niño is different (CNN) -- The village of Pringluan nestles in the eroded hills along the southern coast of Central Java, one of a necklace of islands left without water as Indonesia's worst drought in 50 years takes hold. For villagers it brings back horrific memories of the last great drought in 1962, when they survived on boiled barks and rats. They say all they can do now is pray for rain. Across Indonesia, more than 250 people have died of famine or cholera blamed on lack of clean water.
Thousands of miles away, on the other side of the Pacific, it's a different but equally devastating story. Chile, normally one of the world's most arid areas, is being pummeled by its worst rainstorm in a decade. Floods and landslides have killed 18 people and uprooted some 60,000. Some five countries across Latin America have declared national emergencies or states of heightened alert.
What's the connection? That powerful weather-maker El Niño. The ocean-warming phenomenon has appeared every so often since the 16th century, usually around Christmastime, which is why Peruvian fisherman long ago named it El Niño, or "boy child," a reference to the infant Jesus. Its touch is anything but gentle, though. In fact, scientists have warned that this latest current may become the "climatic event of the century."
What is an El Niño?
Simply put, El Niño is a vast swath of warm water -- the current stretch is about one and half times the size of the continental United States, or roughly the size of Europe -- that appears off Peru every two to seven years.
Most of the time, this expanse of bathtub-temperature water -- about 75 to 85 degrees Fahrenheit -- remains in the western Pacific ocean near Australia, pushed and held there by westbound trade winds. But once in a while, the winds slacken, and sometimes they even move in the opposite direction.
Normally, the trade winds -- which blow from east to west -- push water from the South American coast so that the ocean's surface is a couple of feet lower off Peru than it is off Indonesia. But when an El Niño begins, the tepid water piled up at Indonesia sloshes back across the Pacific to the South American coast.
Raging with the heat trapped in its waters, El Niño then proceeds to turn the world's weather machine topsy-turvy.
The reorientation of that pool of water creates ripples across the world; it can send debilitating storms to the California coast, droughts to Australia and cool, wet winters as far away from the Pacific as portions of Texas and other Gulf coast states.
The ripple effect
In meteorology, few things matter more than warm ocean puddles. They provide the thermal energy that steers evaporation and hence cloud formation and storms. The extra heat within the water acts like wood tossed on a fire, creating more, and bigger, storms.
As the warm water moves into the central and eastern Pacific, the storms inevitably follow, shifting the tropical storm belt from one part of the Pacific to another. Also, because the warm water doesn't get pushed away from the Peruvian coast, the deeper, cold water -- a reservoir of nutrients -- doesn't rise to the surface. So, the food supply for coastal birds declines, sometimes causing thousands to die or fly away to other regions.
El Niño does have some fringe benefits. Thanks to the wild weather variations:
-- Fisherman off Chile could look forward to hauling in anchovies normally found near Peru and other parts much further north.
-- Residents on the eastern board of the U.S. could enjoy a quieter hurricane season -- contrary to pre-season predictions. A milder winter and earlier spring is anticipated in the northeast.
The El Niño of 1982-83
Until some years ago, most weather scientists paid little attention to the periodic episodes of warm water that for countless centuries have appeared off the coast of Peru. It was mainly seen as a local event which affected mainly fish -- in particular Peru's lucrative anchovy catch -- and birds.
Not until the 1970s, when that fishery's collapse was accompanied by famine and drought across the world, did the global reach and impact of El Niño become evident. However, it took the harrowing weather of 1982-83 to convince scientists and policymakers that the tropical Pacific merited closer watching.
In fact, because of its broad expanse of water, the Pacific Ocean is thought to have more effect on the weather than all the world's rain forests. And, except for the seasons, nothing is thought to drive global weather as much as an El Niño.
In 1982, El Niño was blamed for some 2,000 deaths and estimated losses totaling up to $13 billion. Peru had its worst rainfall in history; 11 feet of the downpour in places which usually got six inches. Droughts, dust storms and forest fires swept through Australia, Indonesia and Africa. There was a warm, wet spring in the east coast of the United States, shark attacks off the Oregon coast and a rise in bubonic plague cases in New Mexico.
That devastation prompted the creation of the Tropical Oceans and Global Atmosphere Program (TOGA) in 1985. As part of this international project, some 70 buoys were spread across the Pacific along the equator to provide data to forecasters who need to know the depth of unusually warm water and speeds and directions of underwater currents to track and predict El Niño.
This El Niño is different
Nevertheless, this El Niño is different from the other 24 this century for two reasons: First, scientists predict it will be the worst. Second, for the first time the National Weather Service successfully predicted the start and scope of El Niño, giving emergency planners almost six months' warning of the disruptive current heading their way.
In some places, scientists' improved ability to predict the coming of an El Niño is already helping mitigate the potential damage. Australian farmers, warned six months ago of a possible drought, sold off cattle and changed planting plans to minimize losses. The only hitch with this kind of plan is that their crop yields will be lower than normal, even if a drought does not occur.
From Washington to Johannesburg, emergency planners and scientists are huddling together to map out plans to blunt the effects of El Niño. In the United States, disaster preparations are under way from California to Colorado as forecasters predict flooding, heavy rains and record snowfalls.
Washington has put up $18 million for an international El Niño research center in New York, and the Federal Emergency Management Agency will convene its first summit on the phenomenon in the middle of October. Latin American governments have allocated nearly $100 million to prepare for El Niño.
Because of the high economic stakes and public awareness, the El Niño of 1997-98 will be the most closely scrutinized in history -- a thought that makes climate experts wary. Indeed, given the vagaries of weather, it's entirely possible that an the predicted dire consequences attributed to El Niño may never happen.
At an El Niño symposium held in Boulder, Colorado, University of Washington atmospheric physicist Edward Sarachik suggested that those affected by El Niño should look at forecasts the way gamblers eye dice. "You wouldn't want to bet $100 on the first throw," he said. "But if you bet $1 on a hundred throws, you'll come out ahead."
Indeed, it is testimony to the fickle nature of weather forecasting that while scientists can use sophisticated devices to map, monitor and measure an El Niño by satellite, what actually triggers the phenomenon remains a mystery.
CNN Interactive Writer Rajee Suri contributed to this report
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