El Niño: Who Is He, What's His Story, and When the *&$% Is He Getting Here?

Sometime during the hottest July on record in Austin, people desperate for some kind of salvation from this summer’s unrelenting, record-breaking heat began to speak hopefully about reports of warmer-than-usual water thousands of miles away, in the Pacific Ocean, the precursor to the phenomenon known as “El Niño”, that promises to bring rainfall and cooler temperatures to us as soon as September.

That’s right. We probably have to get through another month of this.

But while the cyclical event may be a savior for Texas, 25% of which is in “extreme drought”, with another 18.7% in “exceptional drought”, its impact on Earth’s weather and life is tremendous not only in scope, but in variation. Named after the Christ child by Peruvian fishermen who observed the warm ocean currents periodically arriving shortly after Christmas, the same mechanism that was a blessing for them caused droughts on one side of a continent, but floods on the other; milder winters and mellower hurricane seasons balanced against massive brush fires and mudslides. Whenever he’s a savior in one place, El Niño is certain to play the trickster in another, maintaining a humbling balance of life and death, prosperity and ruin.

Weak Wind and Sloshing Water = El Niño

Simply put, El Niño, which meteorologists and those seeking to impress refer to as “El Niño Southern Oscillations”, or “ENSO events”, are a continual but irregular cycle of shifts in oceanic and atmospheric conditions, beginning in the Pacific Ocean. Water temperatures in the central and eastern Pacific periodically swing between being warmer and colder than normal, providing the commonly-known engine for the phenomenon. Water temperature affects the patterns of the jet streams, which affect weather patterns across almost half of the planet, impacting rainfall from Indonesia to the western coast of South America. A warmer swing is known as “El Niño”, and the flipside – a cooler swing – was dubbed “La Niña” as recently as 1985.

Follow the chain of causality back far enough studying El Niño, and there’s a bit of a chicken-and-egg effect. Formally, though, it all starts with wind.

Winds usually blow over the Pacific from east to west, pushing water along with them, and actually causing water to be about 20 inches higher in the western Pacific. In response, in the eastern Pacific, deeper water, unwarmed by the sun, wells up to the surface, resulting in water 14 degrees cooler on the eastern side of the ocean.

In an El Niño, the winds pushing the water are weaker, allowing warmer water to slough back towards the east, causing less cooler water to rise, resulting in warmer water in the central and eastern Pacific. Positive feedback then nourishes the system – the warmer water weakens winds further, causing the ocean to get warmer, and so on.

This summer, oceanographers and meteorologists have seen warmer than usual waters in the Pacific, the first sign of El Niño’s imminent arrival. Warmer water warms the air above it. Warmer air rises faster and farther, creating convective systems that divert higher-altitude air currents and alter air pressure patterns. Then, the ripple effect begins.

Jet streams will shift, bringing tropical air from the Pacific across the southern United States as soon as September, bringing storm systems and their moisture to us here in Texas, hopefully alleviating our two-year drought. The National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center forecasts Texas with above-average rainfall by October, lasting throughout the winter. However, the same shift will typically mean drier-than-usual conditions in the U.S. Pacific Northwest, and a warmer winter with less snowfall for the north and northeastern United States that was pummeled relentlessly with snowstorms in 2008.

The hurricane season should see a lower number of Atlantic tropical storms and hurricanes, though meteorologists are quick to point out that El Niño doesn’t necessarily limit the strength or location of those storms. El Niño did lower the number of storms in 1992, but that was little comfort to Floridians hit hard by Hurricane Andrew that year.

Our two years of drought, as well as two years of greater-than-average rainfall elsewhere in the world, are thanks to a strong two-year long La Niña cycle. In that swing of the pendulum, cooler Pacific waters shifted the jet stream too far to the north, causing the storm systems that we rely on for precipitation to slide right over Central Texas, dropping neither rain nor temperatures.

The Grass Is Always Greener/Wetter/Drier on the Other Side of the Ocean

Texans and cattle need rain, but in England, Britons and puffins hoped as early as April that signs of warmer Pacific waters would bring heat and deliverance from two years of dreary, wet summers. The early summer months of 2007 were the wettest since records began in 1766. 2008 was the wettest summer since 1914, and its August was the most sunless since 1929. Populations of puffins, other seabirds, and bats were decimated by the ripple effect of heavy May rains lowering the number of insects, causing nests to fail, and birds to breed late with fewer young.

In April, the Met Office, the United Kingdom’s National Weather Service, forecast “a 65% probability of a warmer-than-average and near- or drier- than average summer.” Brits have indeed already experienced the hottest temperatures since the record-breaking month of July 2006, with a virtually rain-free Wimbledon. However, July brought higher-than-average rainfall, and August is projected to hold more of the same.

One Person’s Poison…

While debates rage about human impact on the climate, El Niño has been deemed worthy of study because its impact on human life and economics is undeniable. Peruvian fishermen recognized and named the pattern not just as a curiosity, but because it had an impact on their lives through their catch.

Just as El Niño’s effect on weather is an abject lesson in give-and-take, so are the consequences of the weather he dictates. With an estimated near-quarter of the United States’ Gross Domestic Product impacted directly or indirectly by weather and climate, more or less temperature, rain, snow, and storms is a good or bad thing, depending on where in the country you stand, and what business you’re in.

According to the National Oceanic and Atmospheric Administration (NOAA), the 1997-1998 El Niño had an estimated $25 billion economic impact. However, that’s an absolute total, totaling what the phenomenon gave as well as took away. NOAA points out that unusually warm weather in the Midwest boosted department store sales by five to 15 percent, but snow mobile and snowplow dealers took a 35% hit. Ski industries prospered in the West, but crawled in the Midwest. Households and businesses saved $2-7 billion in heating costs, which meant that energy production and distribution businesses suffered.

Overall, that season’s El Niño might have been a plus for the US economy overall. But it also caused “real” economic losses, which cannot be balanced out by gains elsewhere in the economy. El Niños tend to result in $2 billion in agricultural losses, and in 1997-1998, El Niño accounted for an estimated $2.6 billion in property losses.

Much of the British disappointment so far this summer is no doubt from its tourism industry, who hoped to see an upswing with a brighter, drier summer adding appeal as the global recession already has an estimated 20 percent of Britons who vacationed abroad in 2008 taking their holidays in-country.

Meanwhile, drier conditions in the U.S. Pacific Northwest could mean less snow for the 2010 Winter Olympics in Vancouver, surely causing more Olympic officials, Vancouverites, and hopeful Olympians to be conversant on El Niño and the polar jet stream.

El Niño May or May Not Care About Your Prius

Hot days cause some people to reach as quickly for the explanation of global warming/climate change as a cold beer. But meteorologists and climatologists caution people not to discredit real climate change (or meteorologists or climatologists) by jumping to draw connections between the effects of a single El Niño or La Niña event and the longer-term effects of global warming.

However, long-term climate change will certainly change the baselines from which El Niños and La Niñas arise, by altering the temperatures and patterns of water and air currents overall. But the precise impact is, once again, difficult to estimate.