El Niño, El Weeño, or El Hypo?

Editor’s Note: With this issue, we introduce a monthly follow-up to our popular “Earth Track” department, focusing on aspect of our climate when we don’t have any new global temperatures.

By now, there’s no one on the planet who hasn’t heard of El Niño—the natural oscillation in Pacific Ocean temperatures and winds that generates a climate of fear—but it seems there are few who have heard the truth.

There is nothing to fear but fear itself. El Niño doesn’t do very much to United States weather, and it’s not at all clear that what it does do is bad. That’s why we were so amused with the recent headline story in USA Today, which talked about how the last big one in 1983 caused a billion dollars in damage to, as they say, the USA. This damage occurred mainly in Southern California during a four-month siege of winter storms.

El Niño exerts subtle influences on the atmosphere, including a strengthening of westerly (“jet stream”) winds farther south than usual into the tropical Atlantic Ocean. Jet streams and hurricanes just don’t get along, because the westerly winds tear apart the delicately balanced circulations required to mow down subdivisions.

Readers might recall that in 1992 a major (category 4 out of 5) hurricane named Andrew hit just south of Miami Beach and wreaked somewhere between $14 billion and $20 billion worth of havoc. This damage occurred in four hours.

The thing is, 13 category 4 (and two category 5) hurricanes have hit the United States in the 20th century. That’s about one every seven years. If El Niño were to suppress, say, half of these, it clearly is a net moneymaker—and lifesaver—for U.S. citizens on the storm front.

For some reason, U.S. Under Secretary of State Timothy Wirth told his European friends that El Niños like the current one are a symptom of global warming.

But the true experts say otherwise. Jim O’Brien of Florida State University, who has written extensively on this subject, puts it bluntly:

El Niños have been going on forever. We can trace them in corals back a thousand years, so they have nothing to do with global warming, or anything like that. I just wanted to get that straight because there was a meeting in the Congress today. Some idiots, namely Kevin Trindberg [sic] at NCAR, kept saying that because this is the biggest one, this year, that it’s due to global warming. I hate this stuff...There have been bigger ones...we certainly can find bigger ones in the last century.

We think that Trenberth’s not an idiot; but the folks in Washington can rest assured. We examined the history of the El Niño yardstick, called the Southern Oscillation Index, for any significant correlations with monthly weather in our Nation’s capital. There was no relation to rainfall. There was a weak positive correlation—explaining only 7 percent of the variation over the last century—with December temperature. So OK, there’s a teensy chance that El Niño might make the winter less severe. And in D.C., above-normal temperatures almost always mean below-normal snowfall. (We’re sure that’s shocking, too!) El Niño also showed an equally weak positive correlation with May temperature. Yes, it’s true. Spring gets springier with El Niño. Maybe, in the eastern United States, it should be called El Weeño.

That’s not the case elsewhere. There’s little doubt that El Niño is associated with below-normal rainfall in the tropical western Pacific.

To clear land for crops, the natives practice “slashing and burning.” In the usually moist rain forest, it’s hard to keep these fires going. After farming them for a few years—until the soil’s nutrients are gone—they move on, and burn again. This year they started their fires during a drought.