A warming of the central Pacific Ocean this year will change weather worldwide, US forecasters predict.
The warming, called an El Niño, can mean an even hotter year coming up and billions of dollars in losses for food crops.
Australia and South Africa should be dry while parts of South America become dry and parts become wet in an El Niño. Peru suffers the most, getting floods and poorer fishing.
But it could bring good news for some parts of the planet, leading to fewer Atlantic hurricanes and more rain next winter for drought-stricken California and southern US states. It could also bring and a milder winter for the frigid US north next year, meteorologists say
The National Oceanic Atmospheric and Administration issued an official El Niño watch on Thursday. An El Niño is a warming of the central Pacific once every few years, from a combination of wind and waves in the tropics. It shakes up climate around the world, changing rain and temperature patterns.
Mike Halpert, acting director of NOAA’s Climate Prediction Centre, says the El Niño warming should develop by this summer, but that there are no guarantees. Although early signs are appearing already a few hundred feet below the ocean surface, meteorologists say an El Niño started to brew in 2012 and then shut down suddenly and unexpectedly. The flip side of El Niño is called La Niña, which has a general cooling effect. It has been much more frequent than El Niños lately, with five La Niñas and two small-to-moderate El Niños in the past nine years.
The last big El Niño was 1997-1998. Neither has appeared since mid-2012. El Niños are usually strongest from December to April.
Kevin Trenberth, a senior scientist at the National Centre for Atmospheric Research, who was not part of NOAA’s forecast, agreed that an El Niño is brewing.
“This could be a substantial event and I think we’re due,” Trenberth said. “And I think it could have major consequences.”
Scientific studies have tied El Niños to farming and fishing problems and to rises in insect-borne disease, such as malaria. Commodity traders even track El Niño cycles.
A study by Texas A&M University economics professor Bruce McCarl found the last big El Niño of 1997-1998 cost about $3 billion in agricultural damage.
Trenberth said this El Niño may even push the globe out of a decade-long slowdown in temperature increase, “so suddenly global warming kicks into a whole new level”.