As the winter chill relinquishes its grip on South Africa, the nation is bracing for an enigmatic weather phenomenon that has the potential to disrupt the delicate balance of its ecosystems and communities: El Niño.
The phenomenon is no stranger to South Africa, and its cyclical arrival has been documented for decades. While this naturally occurring climate cycle, characterised by the warming of ocean waters in the equatorial Pacific, has long been anticipated and forecast, its impacts remain a complex riddle for meteorologists and climatologists alike.
Accordingly, the projected and likely outcomes of this year’s El Niño are both a source of concern and curiosity.
In separate interviews with Daily Maverick, Dr Neville Sweijd, director at the Alliance for Collaboration on Climate & Earth Systems Science (Access) and a senior researcher at the Council for Scientific and Industrial Research, as well as Dr Ramontsheng Rapolaki, an expert in agrometeorology and climate modelling with the Agricultural Research Centre, shared more details.
Difficult to predict
Sweijd explained that the links between specific impacts and El Niño are not simple to predict.
“We can only really see El Niño’s impacts when our summer rainfall comes… in general, there’s a relationship between the state of the ENSO (El Niño-Southern Oscillation) and the South African climate. In general, there’s an established relationship, but it’s kind of statistical because it’s not always a linear relationship. It’s more like, when we have El Niño, ‘this is the historical pattern and general likelihood of an impact’.”
Rapolaki noted that “the nature of extreme weather impacts varies due to the complex interaction between the El Niño event and other regional atmospheric circulation systems. These systems can either intensify or weaken the effects of El Niño over our region.
The climate risk for a full-impact El Niño is a failure of the summer rainfall.
“At this stage, we can only anticipate the occurrence of El Niño events, but we cannot precisely predict their exact impacts. As a result, expecting El Niño does not guarantee the occurrence of severe drought conditions, given the complex nature of ocean-atmospheric circulation at play.”
But what indications do we have of any impact El Niño is having right now?
Neighbours in the northern hemisphere hold clues
Sweijd suggested we look to our neighbours in the northern hemisphere for clues.
“We’ve seen these record temperatures in the northern hemisphere, which were kind of predicted. That doesn’t automatically mean we will see the same thing in the southern hemisphere summer… these record temperatures in the northern hemisphere are a combination of things.
“There is a general warming trend that’s taking place and then you’re adding an extreme on top of that. On average, if you’re starting with a temperature increase, and you add two more degrees to that, then you’re gonna hit a record.”
Asked what some of the risks associated with El Niño in South Africa are, Sweijd identified the risk to summer rains.
“The climate risk for a full-impact El Niño is a failure of the summer rainfall… so it’s drought. In 2015, we had extreme drought in the north of the country and in KwaZulu-Natal. However, what’s different about this year is that we have just come off the back of three La Niña years. La Niña does the opposite. It results in above-average rainfall in the summer rainfall period.
“So, the difference is that if the summer rainfalls fail, this year, there is a reserve. It’s hard to know, but that’s just the water. And so, assuming that water is available and is properly distributed, and managed, and so on and so forth, then it could offset the impact of an extreme drought should that happen.”
Severe droughts are not a given
Rapolaki concurred: “In general, El Niño events tend to bring drier-than-usual conditions in South Africa, particularly over the summer rainfall region. However, it is important to note that this relationship is not always straightforward. While several El Niño events coincide with dry conditions, not every occurrence leads to severe droughts.”
But rainfall and the lack thereof isn’t the only concern to be cognisant of, Sweijd explained. Extreme heat is another serious concern.
“If we follow the same patterns as we have seen in the northern hemisphere, and we get these extended heatwaves, the impacts of those can be enormous on all sorts of things on crops, on fire risk, on animals, livestock, on people’s health, on disease,” he said.
“Temperature and rainfall are both things to worry about. Both together and independently.”
What to do
Rapolaki echoed these sentiments, cautioning that extreme heat and the potential impact of El Niño on public health are serious concerns. “Extreme weather events associated with El Niño, such as extreme heat events, can significantly affect people’s health, leading to heat-related illnesses, for instance.”
Asked what is most important for South Africans to be aware of, Sweijd emphasised the need to be prepared.
“Be prepared for the worst and let’s rather be graciously incorrect about our prediction. We’d rather have people think about what they should be doing to prepare for a dry, hot summer than have them not prepared in case it does happen. So this is all the sectors that matter, agriculture, health, transport, housing – all of it.”
“I guess the question is what we need to do to adapt. To adapt both to this potential threat of El Niño and also to the longer term changes.”
This article was written by By Ethan van Diemen and originally published in Daily Maverick.
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