Time for El Niño's half brother to take a bow?

What kind of effect can it have? Last July, a trio of tropical-cyclone scientists at Georgia Tech in Atlanta published a paper in the journal Science showing that during these half-brother El Niños, North Atlantic hurricane activity reached normal or above-normal levels, rather than the expected below-normal pace.

Better seasonal hurricane forecasts?

That sounds grim if you combine the frequency of these pseudo events with the return rate for La Niña, which also leads to active hurricane seasons. The good news: Apparently these pseudo events are easier to forecast ahead of time than El Niño itself, which holds the promise of improving seasonal hurricane forecasts, says Peter Webster, an atmospheric scientist at Georgia Tech and one of the members of the team reporting the results.

The team received a pat on the back from Chris Landsea, a scientist at NOAA's hurricane forecast hub in Miami. He writes in an email that this work "may provide an advance in the field of seasonal hurricane forecasting."

At the least, he adds, it helps explain why the 2004 hurricane season was far more intense than seasonal forecasts suggested.

Global warming's potential role

The the prospect that global warming will drive an increase in this pseudo El Niño comes from a modeling exercise, in which the team reporting the results first identified the models that did the best job of capturing El Niño activity. Then they ran projections assuming business-as-usual greenhouse gas emissions through the rest of the century. These pseudo El Niños became more common than the traditional El Niños -- as much as five times more common.

Researchers still need to learn more about this phenomenon, note Karumuri Ashok and Toshio Yamagata, two of the Japanese scientists who uncovered this phenomenon in the first place. Not the least of which is testing the notion that this pseudo El Niño is itself a cyclical feature that may appear and disappear on timescales longer than El Niño's -- decades to centuries, rather than every few years.

If all of this seems a little too much, here's comedian Chris Farely's take on El Niño:

Editor’s note: For more articles about the environment, see the Monitor’s main environment page, which offers information on many environment topics. Also, check out our Bright Green blog archive and our RSS feed.

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