Can We Talk About the Weather?
El Niño, global warming, and wacky conditions-something funny's going on
Is January the new April? Should Seattle build an ark? Has lifeless dirt replaced fluffy white powder? These questions and many more seem to have haunted much of the country during this strange winter season.
So, now for the big one: Is it time to panic? The short answer is, maybe. This year's bizarre weather patterns-torrential rain in the Northwest, springlike temperatures along the eastern seaboard, and repeated blizzards in the Rockies-aren't entirely understood. Meteorologists say an El Niño-a periodic warm patch in the Pacific-is largely to blame, but the mysterious weather phenomenon isn't acting alone. The National Oceanic and Atmospheric Administration announced last week that 2006 was the warmest year ever for the United States and pointed to global warming-at least some of it man-made-as a contributing factor. Even more worrisome: The past nine years are among the hottest 25 on record, a streak "unprecedented in the historical record," according to the agency.
As for El Niño, how it works and how it interacts with global warming are still being researched. The phenomenon occurs on average every five years, albeit with significant fluctuations, and dramatically affects the weather. The term describes a warming of the equatorial waters of the central and eastern Pacific. That water, and the warm air above it, wreak havoc on dominant jet streams, affecting the winter weather of the United States in strange ways. The Pacific jet stream plunges south, bringing rain to the West and, when it slams against high mountain ranges, snow. That explains the almost 3 feet of white stuff that has blanketed Colorado. Another jet stream, this one from the south, is being pushed by El Niño toward the American mainland and is bringing rain to the arid Southwest, while churning up storms from Texas through Florida.
The current El Niño developed last summer and, by producing a more stable atmosphere in the Atlantic, had the positive effect of stopping many hurricane formations last fall. While its effects are palpable, this El Niño is described only as "moderate" by Dennis Feltgen, a meteorologist with NOAA, and it doesn't entirely clear up how this past December came to be the fourth warmest since records began in 1895. "We have natural cycles," says Brenda Ekwurzel, a climate scientist with the Union of Concerned Scientists, "[but] global warming is adding warmth on top of that cycle."
Balmy. That may explain why cherry blossoms, typically a harbinger of spring, have been found budding in Washington, D.C. And why in New York City another record was broken. The latest date Central Park has gone without snowfall during any one winter was January 4, a record set back in 1878. As of last week, New Yorkers were still waiting for the white stuff. Europe is similarly balmy, but there the North Atlantic oscillation, which replaces cold Arctic air with warmer blasts from the Atlantic, is playing a role. Still, scientists say global warming is a primary culprit and likely to blame for what climatologist Reinhard Boehm is calling "the warmest period in the Alpine region in 1,300 years."
That has led to a debilitating lack of winter tourism in the Alps. But it's been a boon for Colorado resorts, some of which have picked up their advertising in Europe. Overall, though, warmer winters probably mean little for the economy in the short run. Retailers of cold-weather clothes suffer, but people tend to buy more cars and spend more money on entertainment. Low heating bills mean fatter wallets.
The unusually warm weather coincides with two major signals from the Bush administration acknowledging global warming. The first, in December, was a proposal to place polar bears on the endangered species list because of melting Arctic ice. The second was last week's measured but nonetheless significant statement by NOAA identifying a "long-term warming trend, which has been linked to increases in greenhouse gases."
In the short term, expect this weird weather to stick around. Meteorologists say this El Niño will last until mid- to late spring. But separating El Niño from the effects of global warming is a less certain business. "We know global warming is occurring," Feltgen says. "However, we know much less about global warming's impact on El Niño conditions." Some scientists suspect global warming raises not only the intensity of El Niño events but also the frequency, meaning that winters like this one could become more common. While cold weather and snow will still exist-even in El Niño years, freezing weather can occur across much of the country-climatologists say that trends show there's no reason to think that 2007 will be any cooler than 2006. January might be the new April, after all.
This story appears in the January 22, 2007 print edition of U.S. News & World Report.