Weather experts have sent out an alert about the possible impacts of an El Niño manifesting in the central Pacific Ocean, but they are uncertain what effect it will have across southern Africa.

El Niño is a weather phenomenon that typically brings with it higher temperatures and lower rainfall as a result of warm sea surface temperatures along the South American coast and towards the central Pacific Ocean, caused by weaker trade winds (easterly winds near the equator).

Speaking at an El Niño summit hosted by the University of Pretoria on Monday, weather phenomenon observers said there had been record high sea surface temperatures, but it was still unclear what effect El Niño would have in southern Africa. 

Dr Neville Sweijd, a senior researcher at the Council for Scientific and Industrial Research (CSIR), was one of the experts at the summit.

He said that this year, the months of May and June, “have got sea surface temperatures higher than have ever been recorded. This may be an expression of El Niño itself. What the consequences are, we will find out shortly.”

The experts – including Professor Willem Landman from the University of Pretoria, Dr Christien Engelbrecht and Dr Katlego Ncongwane from the South African Weather Service, Dechlan Pillay from the National Disaster Management Centre, Dr Peter Johnston from the University of Cape Town, and Johan Malherbe and Mokhele Moeletsi from the Agricultural Research Council – emphasised that the summit was held to create awareness, not alarm, and preparation, not panic.

Read more in Daily Maverick: It’s here — El Niño has finally arrived, according to US National Weather Service

The previous and most severe El Niño event occurred in 2015/16, when southern Africa experienced severe droughts, which had negative impacts on agriculture, human health and food security, and led to an increase in the price of maize.

The parts of the country most affected by the 2015/16 El Nino event. Much of the central parts of the country, including the western maize production regions, experienced extreme drought conditions from October to December, while the northeastern parts were less negatively affected. (Image: Johann Malherbe / ARC)

This image shows the temperature anomaly (difference from the long-term monthly average over South Africa from October 2015 to March 2016) and demonstrates what effect an El Niño event could have. (Image: Christien Engelbrecht / SAWS)

Over the past three years, southern Africa has been experiencing a La Niña state (wetter and cooler conditions), which is why the northern parts of the country received higher than average rainfall, Sweijd told Daily Maverick.

“Now an El Niño is developing… What’s different about El Niño is that the sea surface temperatures globally are reaching new records already. What causes that? Well, there’s two things: one is the temperature of the water that comes to the surface is warmer than normal because of global warming; the other is the normal process of relaxed trade winds… So this is likely to be a very strong El Niño,” Sweijd said.

Experts at the summit said it was too early to predict the exact impacts of the weather phenomenon as more data were needed.

Read more in Daily Maverick: As El Niño looms, South Africa — including the southwest — looks set for a wet winter

Sweijd said: “In general, we have an impact… and the strength of that impact? It’s too early to tell. What we want to do is to prepare people. People have to understand there’s a higher likelihood of an impact, a drier than normal and warmer than normal summer… but we can’t say it’s going to be a drought.”

Experts will gather again in September for another summit to discuss possible El Niño impacts in the summer months. DM

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