If Ocean Heat Pump Switches On, Expect to Feel It

Scientists are chipping away at a question that has dominated public climate change discussions in the U.S. the last few years: Where's the heat? Despite unchecked carbon pollution, warming felt on the Earth's surface has slowed since 1998.

Clues keep pointing to the Pacific Ocean, and a new paper in Proceedings of the National Academy of Sciences (PNAS) predicts that the temperatures will rise again toward the end of this year.

More specifically, the authors predict the return later this year of El Nino , the tendency of the Pacific Ocean to vent more heat than normal into the atmosphere, often with dramatic effects on weather in North America. The last powerful warming phase of what scientists call the El Nino-Southern Oscillation (ENSO) was 1998, the hottest year on record. Since then, natural climate variability has been disguising the manmade warming.

"This might lead to an end of the present 'hiatus,'" Armin Bunde of the Institute for Theoretical Physics in Giessen, Germany, said in an email. He qualified the prediction, saying that the tool can't predict the strength of an El Nino, only that it's coming. "We can only predict that in 2014 there will be an El Nino event with 76 percent likelihood," he said.

In the PNAS paper, called, "Very early warning of next El Nino," the German, Russian and Israeli scientists introduce a technique for predicting what kind of trouble the Pacific Ocean might have in store for global weather patterns a year before it happens.

To calibrate and test the new El Nino prediction technique, researchers used atmospheric temperature data going back more than 60 years. Once they felt the algorithm was properly tuned, they made predictions for 2012 and 2013, successfully predicting that neither would have an El Nino.

The new tool doubles the warning time before an El Nino hits, from the six months offered by current models, to a year. The new El Nino "alarm," as the researchers call it, is right 76 percent, better odds than current prediction methods.

The scientists describe their advance, in the dispassionate, clinical tone of peer-reviewed research, as "non-trivial." A year warning of an El Nino could give farmers time to buy drought- or flood-resistant seeds.

The scientists are making a confident but big bet here, one they acknowledge comes with "reputational risks," if they call an El Nino that doesn't show up. "Should our alarm turn out to be correct, however," they write, "this would be a major step toward better forecasting -- and evenutally understanding" of how El Nino works.

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