South Africa unprepared for intense heatwaves of the next 20 years

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Garrith Jamieson and his paramedic colleagues were on high alert days before a scorching heatwave struck Durban earlier this month. With the mercury expected to soar to 40°C and above, they knew the signs of heat stress to look out for in their patients: fatigue, fainting, headaches, heat cramps and heatstroke, among others.

“It was exceptionally hot with temperatures soaring into the 40°Cs,” recalls Jamieson, an advanced life paramedic with ALS Paramedics. “We did see an increased number of calls, especially over the three-day period when it was excessively hot … and our paramedics responded to multiple incidents.”

These, he said, mostly involved people collapsing and fainting. “We attended to a lot of elderly folk who had collapsed in their premises. There was one person who was actually just doing their normal exercise and collapsed due to the excessive heat.”

Older people who “were going about their normal day”, walking or in crowded shops without air conditioning and minimal ventilation, fared poorly. 

“We saw extreme fatigue, dizziness, nausea, drowsiness and sweating. There was one patient who was quite severely dehydrated and had actually stopped sweating. That’s how long he had been sweating for and then only did they realise and call us to assist them.”

What struck Jamieson was how unprepared the city’s inhabitants seemed. “People weren’t hydrating themselves accordingly, and they weren’t taking heed of the multiple warnings about the heatwave, which were all over the news and social media. 

“So, people went about their normal daily lives and forgot — or didn’t realise — the heat … The temperature and the humidity that was in and around Durban central was exceptionally dangerous,” he said.

As the climate changes, the number, intensity and duration of heatwaves — defined as unusually high temperatures that last for three or more consecutive days — in South Africa will climb steeply in the future, according to Francois Engelbrecht, a climatologist at the University of the Witwatersrand’s Global Change Institute and an Intergovernmental Panel on Climate Change author.

In the past century, the average global temperature has risen by 1.2°C, but in the interior of Southern Africa, the temperature is rising at about twice the global rate of temperature increase. It is already 2°C warmer than a century ago. 

According to Engelbrecht, temperature increases are projected to range between 4°C and 7°C over the interior of sub-Saharan Africa — a climate change hotspot — by the end of the century if efforts to reduce or prevent the emission of greenhouse gases remain low. 

It’s plausible, he said, that temperature increases may reach 3°C to 4°C by the 2040s and these temperatures will bring drastic increases in the number of fire-danger days, very hot days and heatwave days.

“In a changing climate, in the subtropical parts of the world, these big high pressure systems form more frequently and they’re also becoming stronger,” he said. “Therefore, heatwaves are starting to occur more frequently. It’s a trend that can be clearly detected, just as we can detect the increase in the average temperatures. 

“And the next 20 years are projected to bring heatwaves of an unprecedented magnitude and duration to Southern Africa. 

“It means they will last longer than ever seen before,” he said, “and then they will also be more intense. So the high pressure systems themselves will become stronger, but can also bring higher surface temperatures than in the past. 

“So, instead of a heatwave bringing temperatures of say, 31°C for three days, it can bring temperatures of 35°C.”

In June this year, a devastating heatwave struck the Pacific Northwest areas of the United States and Canada, with temperatures smashing records as they surged past 40°C. 

In the small Canadian village of Lytton, the mercury hit 49.6°C on 29 June, setting a record for the hottest temperature ever recorded in the country. 

A wildfire swept through Lytton the next day, consuming most of the village.

“The average maximum temperature there in June is 25°C,” Engelbrecht said. “Then the heatwave came and it brought a temperature of almost 50°C. It was a massive heatwave in terms of its intensity. 

“That part of the world has a very moderate summer climate so people don’t have air conditioning.

“Such a heatwave is not supposed to occur there but because of climate change it suddenly became possible and the consequence was that several hundreds of people died across the northwestern states of the US and British Columbia during that heatwave.”

For Engelbrecht, this unprecedented event brings the message of heatwaves home to Southern Africa. “Here in our part of the world, heatwaves occur more frequently. It’s not uncommon for us to have heatwaves reaching maximum temperatures of over 40°C in Zambia, Botswana, Zimbabwe, Namibia and over our northern province. But getting temperatures close to 50°C is, of course, absolutely exceptional, even for us.”

In a changing climate, heatwaves will bring more oppressive temperatures “than ever seen before”, he said. 

“The problem is that, although our region is actually getting these types of heatwave events far more often than British Columbia does, we have millions of people without air conditioning. What makes it worse is that our informal housing makes all these people even more vulnerable because temperatures cannot be regulated in this kind of housing … Also, many people in informal settlements don’t have easy access to cool water.

“That is our big vulnerability and the problem is that I don’t think we are prepared in any way for the heatwaves of the next 20 years that will be even more devastating than [those] we’ve been getting over the last 20 years.”

People affected by heat, especially vulnerable groups such as caregivers and infants, older people and those with pre-existing diseases, may burden health and emergency services seeking help during heatwaves, said Caradee Wright, a senior specialist scientist from the South African Medical Research Council’s environment and health research unit.

“These services need to be prepared for such eventualities. This is one of the dangers of heatwaves in South Africa. 

“Are we sufficiently prepared to deal with people suffering from the impacts of heatwaves? Do we have the capacity to activate emergency services to extensive areas where people lack sufficient drinking water, or water for crops that support their livelihoods? she asked”

Engelbrecht said that in developing countries, cooling centres, “which weren’t seen even five years ago”, are now being provided during heatwaves. 

“That’s effectively, in many cases, a massive sports stadium with good air conditioning. People in informal housing that don’t have good air conditioning are moved to these centres and provided with a cool environment and water so that they can ride out the heatwave in the cooling centre,” she said. 

This is the type of intervention South Africa will increasingly need. “For as long as we have millions of people living in informal housing, we will remain exceptionally vulnerable to heatwaves and the problem is because of climate change, that vulnerability increases.”

South Africans, Wright said, need to be informed of what heatwaves are, what effects they can have on their health and well-being and “what they can do as individuals and communities during heatwave events to save lives”.