Johannesburg - Warmer waters and changing wind patterns could bring unexpected weather across the world, including South Africa.
According to the World Meteorological Organisation (WMO), the current El Niño Southern Oscillations weather pattern may become one of the strongest in more than half a century.
In a statement, the WMO said expert opinion suggested surface water temperatures in the east-central tropical Pacific Ocean are likely to exceed 2 degrees above average, “potentially placing this El Niño cycle among the four strongest since 1950”.
“It can increase flooding in the Horn of Africa while making southern Africa drier,” the statement said.
El Niño involves a shift in winds in the Pacific Ocean along the equator every few years, warming the water more than usual and triggering a change in global weather patterns.
“These patterns are considered essential in triggering El Niño’s global climate impacts, which are more likely to be felt over the next six to eight months,” the WMO statement added.
The last major El Niño cycle took place in 1997 and 1998.
The phenomenon means severe storms in some countries and a much warmer winter in others.
In South Africa, El Niño has been blamed for droughts and lack of rainfall. But according to the SA Weather Service (SAWS), this isn’t always the case.
“Although most El Niño years have been associated with below-normal rainfall, the impact of El Niño is often reduced by the sufficient groundwater and soil moisture content carried over from previous seasons,” the SAWS pointed out.
When asked about the effect El Niño has on rainfall patterns, the SAWS said El Niño explains only about 30 percent of the rainfall variability.
“This means that other factors should also be taken into account when predicting seasonal rainfall.”
The SAWS added that despite the 1997-98 El Niño being the strongest on record, not all of South Africa received below-normal rainfall.
“Some regions had an abundance of rain because of moist air imported from the Indian Ocean.”
The weather service warned: “One should be careful not to make a general rule for rainfall and temperature changes.”
The Star