Conditions are now ripe in the Pacific Ocean for the onset of a record-breaking El Niño this winter which could dangerously disrupt weather patterns around the globe – but with the possible benefit of delivering rain to drought-gripped California.
Already nicknamed “Bruce Lee” after the late martial arts star, because of the punch that it might pack, forecasters are warning that this new El Niño seems set to be more powerful than any in the past 65 years at least and more potent even than the one of 1997-98, when the phenomenon first entered the popular lexicon. Its effects included fierce forest fires in south-east Asia and widespread flooding and mudslides in parts of Latin America.
“We’re predicting this El Niño could be among the strongest El Niños in the historical record,” noted Mike Halpert, deputy director of the Climate Prediction Centre for the National Oceanic and Atmospheric Administration (NOAA), pointing to a telltale warming of the surface waters in the eastern reaches of the Pacific that is already well under way and apparently accelerating.
While a strong El Niño could be a blessing for California, where four years of drought have seen water rationing and intense brush and forest fires this summer, some of which are still burning this weekend, scientists say all kinds of variables could yet intervene to hinder rainfall levels. A second area of warm waters in the northern Pacific, for example, could cause a dip in the jet stream that might propel expected stormy weather south into Central and South America, skipping California.
“There are still probably more unknowns regarding temperature and precipitation in the winter than there are unknowns,” Mr Halpert said. Asked how hopeful California should be, he added: “A big El Niño guarantees nothing. At this point, there’s no cause for rejoicing that El Niño is here to save the day.”
Even if predicting where its power will be most felt is difficult, that it will have great power does not seem to be in dispute. For a new El Niño to be born, the Oceanic Niño Index (ONI), which measures sea surface temperatures in the tropical Pacific, must rise to plus 0.5. (Zero is the average.) In 1997-98, the index topped out at 2.3, producing an event that took an estimated 23,000 lives around the globe and caused some $45bn (then £27bn) in damage.
According to the latest measurements, those same Pacific waters are now at an index of 1.0. But that number is climbing and seems certain to go past 2.0 and perhaps well beyond. And this could El Niño could be a long one. “There is a greater than 90 per cent chance that El Niño will continue through the northern hemisphere winter 2015-16, and around an 85 per cent chance it will last into early spring 2016,” the NOAA said.
It is an outlook that will have governments on the alert everywhere. Effects of a big El Niño can include drought conditions in Australia and south-east Asia and warmer global temperatures in general, a change that will only compound the already steady rise in global warming. The eastern US, however, could experience a milder-than-usual winter and Atlantic hurricane activity may be suppressed.
Rain shortfalls in Australasia and downpours in South America could also hurt agricultural production, creating a knock-on effect on commodity prices globally. Western Europe, far from the event itself, would normally expect minimal direct impact on its weather conditions.
Earlier significant El Niños occurred over the northern hemisphere winters of 1982-83 and 1972-73.Reuse content