If you think the weather has been misbehaving of late, you might not have seen anything yet. Government scientists in the United States now say there is a four out of five chance of a new El Niño taking hold this autumn or in early winter with all the usual disruptions to the world’s climate rhythms.

“We are now even more bullish that an El Niño is impending,” Michelle L’Heureux, a meteorologist with the federal Climate Prediction Centre in Maryland confirmed, basing her prediction on the latest data and computer models tracking ocean temperatures in the Pacific.

Writing on the realclimate.org website, Ms L’Heureux says that prospects for an El Niño reach “a peak probability of 80 per cent during the late fall/early winter of this year”. That still leaves a two-in-ten possibility that it won’t happen, of course. And if it does emerge, the likely strength of it can’t yet be gauged.

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“At this point, the team remains non-committal on the possible strength of El Niño preferring to watch the system for at least another month or more before trying to infer the intensity,” Ms L’Heureux wrote. “But, could we get a super strong event? The range of possibilities implied by some models allude to such an outcome, but at this point the uncertainty is just too high.”

The last major El Niño, which comes with the gathering of unusually warm surface waters in the tropical Pacific that in turn alters the course of the upper atmosphere jet stream, was in 1997. On that occasion, the surface of central and eastern sections of the ocean jumped by 5 degrees Fahrenheit.

Usually an El Niño is associated with higher global temperatures, though for northern Europe, including Britain, they can spell unusually cold and dry winters. Other regions could expect more far-reaching effects, some potentially beneficial others much less so.

Futures markets are already bracing for possible global food shortages amidst fears that a strong El Niño could see crops drowned by heavy rains in the American Midwest and Brazil and shrivelled by excessive heat and lack of water in Australia, Southeast Asia, India and Africa.

But an El Niño generally heralds elevated rain- and snow-fall amounts for the western half the US. That would be welcome news since California and other western states are currently suffering a serious multi-year drought. Equally well received would be the prospect of diminished hurricane activity in the Atlantic. More hurricanes would be likely in the Pacific, however.