Heatwaves: ‘This is just the beginning’

South Africa will experience heatwaves of unprecedented duration and frequency within the next decade, warned professor of climatology Francois Engelbrecht.

“We should expect more heatwaves this summer and then, of course, because of climate change, we can also say with certainty that, in the next 10 years, South Africa and Southern Africa will experience heatwaves of unprecedented duration and frequency,” said Engelbrecht, the director of the University of the Witwatersrand’s Global Change Institute.

“We need to learn as much as we can about our vulnerabilities to these heatwaves during this El Niño because this is just the beginning of the intense and frequent heatwaves impacting on us in a changing climate.”

Engelbrecht was referring to the recent heatwave in November that seared parts of South Africa for 10 days, shattering temperature records. 

‘Hot to very hot’

On the morning of 19 November, the north-eastern parts of the country experienced extremely hot conditions because of a surface high-pressure system that was assisted by “convergence aloft”, according to the South African Weather Service (SAWS).

Heatwave conditions resulting in “persistently high temperatures”, exceeding average maximum temperatures, were expected in most parts of the country. The SAWS extended its heatwave advisory to 28 November.

“Following the heatwave conditions that prevailed from 19 November for several days in most parts of the country, November records were broken in both the maximum and minimum temperature measurements,” it said. 

“Hot to very hot conditions were experienced in most parts of the country, with isolated areas having extremely hot conditions for several days in a row.”

Sweltering Augrabies Falls

Hot conditions reached their peak on 27 November in large parts of the Northern Cape, extending to adjacent areas of North West and Free State. 

SAWS said that preliminary data indicates new temperature records for November over the three provinces. 

More than 10 stations recorded the highest temperature records on 27 November, with Augrabies Falls recording the highest maximum temperature of 46.7°C, breaking its previous record of 46.2°C, recorded on 28 November 2019.

Still, the highest maximum temperature record for Augrabies Falls remains at 48.6°C, which was measured on 15 January and 46.7°C is the new record for November.

The SAWS issued a further heatwave warning on the weekend, forecasting “persistently high temperatures above the maximum temperatures” expected over Gauteng, the central and eastern areas of the Free State and the south-western parts of Limpopo until Tuesday.

More to come

“This is a typical El Niño summer,” Engelbrecht said. “Usually, when we have an El Niño event, we tend to experience summers with above normal temperatures, below normal rainfall and also a high frequency of heatwaves. This is typical of an El Niño summer — before we even talk about global warming. 

“It is just because of the fact that, during El Niño summers, we get many strong high-pressure systems building up over Southern Africa and those are the weather systems that cause heatwaves and, at the same time, they are suppressing rainfall.”

The El Niño is taking place during the warmest year ever recorded, and became “strong” last month, but 2023 was already shaping up to be exceptionally warm. June to October all broke monthly temperature records.

From January to October, the planet was 1.43°C warmer on average than pre-industrial levels, he said. “Humanity is on the verge of exceeding for the first time the 1.5°C threshold of dangerous global warming.”

In 2021, the Intergovernmental Panel on Climate Change said the 1.5°C threshold would be permanently exceeded by the early 2030s, though other estimates say this will unfold towards the end of the 2020s.

Warmest summer for SA

“This year is definitely going to be the warmest year on record. We’ll finish this year somewhere 1.4°C above pre-industrial [levels],” he said. “This summer we have an El Niño occurring and contributing to the warmest year on record … It’s very likely that this will be one of the warmest summers in South Africa’s history and it’s possible that it’s going to be the warmest summer ever recorded.”

According to the panel’s latest sixth assessment report, at 1.5°C, 2°C and 3°C of global warming above pre-industrial levels, mean annual temperatures in Southern Africa are projected to be on average, 1.2°C, 2.3°C and 3.3°C warmer than the 1994 to 2005 average, respectively. 

It found that the annual number of heatwaves is projected to increase in Southern Africa by between two to four at 1.5°C, four to eight at 2°C and eight to 12 at 3°C. Hot to very hot days are “virtually certain to increase under 1.5°C and 2°C of global warming”.

“Children born in 2020, under a 1.5°C-compatible scenario will be exposed to three to four times more heatwaves in their lifetimes compared to people born in 1960, although in Angola this is seven to eight times.”

Impacts of heatwaves

In January, seven farm workers died during a blistering heatwave in Kakamas in the Northern Cape. It lasted for about 10 days, with nine days of maximum temperatures above 40°C. 

“That was during a La Niña summer,” Engelbrecht said. “We’re still far away from January which is the warmest part of the summer in most of South Africa and I don’t think we’ve changed anything in terms of how we look after the farmworkers of the Northern Cape during heatwaves. It doesn’t make sense to let people work during a heatwave in this part of the country.” 

South Africa needs an urgent heat health plan for farm workers toiling in these conditions, according to Engelbrecht, who is concerned about the effect of the heat on farmworkers in the Northern Cape this summer. 

“We need a formal plan, a set of laws and regulations that govern how farmworkers work during heatwaves. The interesting thing is in the mining sector, for the workers in the open-cast mines, who are extremely vulnerable to heat, they are fully protected. 

“Working during heat is strictly regulated and monitored by laws that are applicable to the mining industry. So, there we do have a plan, and it’s working, but we don’t have it for the farmworkers.” 

Load-shedding risks

Older people living in informal housing without access to water during a heatwave are in a similar life-threatening situation. 

“Now, we have this additional problem of load-shedding and from time to time the water purification plants fail and then there are even bigger problems with water available during a heatwave.”

Entities such as Rand Water and Johannesburg Water “must get their house in order”, said Engelbrecht, referring to the water cuts across large swathes of Johannesburg. 

“They need to get water into the most vulnerable areas during heatwaves because that will save lives. If they don’t do that, they can kill people … They must have a strategy that will allow them to pump more water before and during heatwaves. They cannot have a policy of keeping the water supply constant — they must proactively provide more water during heatwaves.”

He said a drier, warmer summer, coupled with heatwaves, would affect the maize crop. He referred to the drought that ended with the 2015/2016 El Niño. 

“Towards the end of that dry spell that ended with the El Niño, South Africa had to import substantial tons of maize for two consecutive years. Last year, we were able to export maize, so the maize crop is strongly influenced by the El Niño/La Niña weather pattern.”

The current El Niño returns after three years of good summer rainfall seasons from the La Niña. “We are moving into the summer in a much better state in terms of our dam levels … but we will take a step back through the El Niño in terms of water security,” he said, adding that there’s no immediate risk of a climate-induced water crisis.