The Why Files The Why Files --

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


One wacko winter
Are we Why folks the only ones getting weirded out by the "winter" weather? Things ain't what they used to be: While the golf biz booms, there's a chorus of caterwauling in the ski industry.

Woman wears white t-shirt outdoors, in front of trees missing all leavesThis January, the temperature reached 70° F -- in New York City.

The blast-furnace called winter comes on top of a scorching 2006 -- the sixth-warmest year on record globally; the hottest ever in the United States and Britain.

If you live in the U.S. Midwest or East Coast and love golf, jogging or tiptoeing through the tulips, this "winter" is for you. "Gisele" enjoys the unseasonable weather.

December brought Minnesota, New York and three New England states the warmest such month on record. Cold-capital Minneapolis was 17° F above average for three weeks in December.

Not one U.S. state was colder than average in December.

Frightfully warm temps also rule Europe: The International Herald Tribune says Warsaw, Budapest, Berlin, Vienna and Stockholm have yet to report snowflakes.

Word of weird weather even reached Masha the bear, in a zoo north of Moscow. After one week, he decided hibernating was no longer appropriate.

Desperately seeking suspects
So what's going on? Is this a sudden spike of global warming, something we might call global crisping? Or are other, more natural weather patterns to blame, such as the cyclic warming in the tropical Pacific Ocean called El Niño?

US map has swathes of red covering northern states, white and gray seen in the south

In a Nov. 16, 2006 forecast, the National Oceanic and Atmospheric Administration said: "This winter is likely to be warmer than the 30-year norm (1971-2000) over much of the nation, yet cooler than last year's very warm winter season." Nice work, at least on the first half. Map: NOAA

The correct answer is "both of the above." A combination of ingredients is at work, say experts. "Global warming is raising the background, and then we have the natural variation riding on top of that," says Kevin Trenberth, head of the climate analysis section at the National Center for Atmospheric Research.

Even though global warming continues, more of the current heat-up is probably due to El Niño, a vast pool of hot water in the eastern tropical Pacific Ocean that affects weather around the globe. El Niño occurs every three to seven years and typically lasts about nine months.

Red patch cuts across southern hemisphere of globe and lines meander across northern hemisphere
The giant warm-water pool called El Niño pushes the jet stream north, altering weather patterns in the Northern Hemisphere. The unusual westerly winds push the warm water against the South American Coast. Image: NASA

Here's one simple explanation for how conditions in the tropical Pacific could affect North America and Europe: El Niño seems to shove the polar jet stream northward, insulating the Midwest and East Coast from the frigid Arctic air that normally sends residents lunging for the thermostat.

So it's that simple?


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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