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Hot water battle
Original painting from: "A Sea Battle" by Johannes Lingelbach, 17th century

POSTED 11 JANUARY 2007


El Niño in history
Back in the 1500s, fishermen along the Pacific coast of northern Peru started noticing periodic changes in the abundance and mix of fish species. Millions of sea birds washed up on the beach as their prey -- anchovies -- disappeared. Gatherers of guano (bird dung used for fertilizer) fell on hard times as the dead birds no longer made their nutrient-rich deposits. At the same time, sailors saw changes in coastal currents, and torrential rains inundated the typically arid coastline. And then things would return to normal for a few years.

Water covers street, warning sign denotes obvious flooding
March, 1998: Rains linked to El Niño caused floods along California's Russian River. Photo: NASA

Since the warming often peaked in December, in the 1890s it was dubbed "El Niño," in honor of a previous December visitor, the infant Jesus.

By then a few scientists had become intrigued by the phenomenon. But the vast Pacific is by nature secretive, and it was hard to know the true extent of the warming -- or even what was "normal." Interest intensified in the late 1960s and early 1970s, as it became apparent that El Niño was affecting a whole lot more than anchovies and bird droppings.

During the 1982-83 El Niño, the sea surface west of Peru was as much as 4° C warmer than average during the southern hemisphere summer. During this, the most intense El Niño on record, all hell broke loose with climate. There were torrential rains in normally arid regions of Peru, and floods in southern California. Fires scorched 3 million hectares of tropical forest in Borneo (now Kalimantan). An estimated 2,000 people died. The damage estimates ranged from $8-billion to $13-billion, including $2.5 billion for droughted crops in Australia, and $2.2 billion for flooding in the United States.

Intriguingly, scientists didn't know El Niño was taking place until late in the game, since they were reliant on delayed reports from ships rather than just-in-time data from satellites and buoys. (Things have changed: Catch an El Niño nowcast.)

El Niño's impacts
On a graph, blue-grey area indicates low global sea surface temps of past, red shows the current rising temps
Rising temperatures at the sea surface provide more fuel for the atmospheric heat engine. As baseline conditions change, phenomena like El Niño will also change. Thus global warming affects El Niño, even as El Niño affects current weather. Courtesy Kevin Trenberth, National Center for Atmospheric Research

The human element
In 1997, another monstro El Niño was associated with drought and massive fires in Indonesia, smog in Southeast Asia, and hurricanes in the Pacific. As scientists continued to study El Niños, they linked the shift in the warm water to increased rainfall in the Southeast United States and droughts in Indonesia, Australia and Ethiopia. Michael Glantz, who specializes in the human impact of climate at the National Center for Atmospheric Research, noted that Zimbabwe was droughted 22 times in 26 consecutive El Niños. In northeastern Brazil, during an El Niño-related drought in 1987, grain production was 85 percent below average.

El Niño also delays the seasonal tropical rainfall in Indonesia, says Daniel Vimont of the University of Wisconsin-Madison. "The onset of the monsoon is delayed, so the rice does not get planted until about a month late. The resulting one-month delay in the harvest extends "the 'season of hunger,' and has a huge effect on their economy."

Although El Niño is a climatic phenomenon, Glantz has argued that its effects are filtered through human activity. Five centuries ago, he says, Peruvian fishermen could still make a living even during El Niño, today, industrial-scale fishing has so damaged fish stocks that the swing in climate may deal the death knell to a collapsing fishery. "You can't get at the net effect of El Niño" without considering culture and economy, he says.

 On a graph, blue area indicates low global sea surface temps of past, red shows the current rising temps
Rising temperatures at the sea surface provide more fuel for the atmospheric heat engine. As baseline conditions change, phenomena like El Niño will also change. Thus global warming affects El Niño, even as El Niño affects current weather. Courtesy Kevin Trenberth, National Center for Atmospheric Research

This year, the warm "winter" in the Northern Hemisphere has already caused a slide in the price of crude oil. By cutting the price of fossil fuel, that's likely to put more carbon dioxide into the atmosphere -- and accelerate the greenhouse effect.

But El Niño has another, more profound, relationship to human activity: global warming caused by burning fossil fuels has already affected ocean temperatures around the world, and warming oceans will release more heat to the atmosphere.

The result of that change is almost certain: more warm winters in the decades to come. Dive into the hot water with our El Niño bibliography.

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Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive

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