the country’s climate future is fast becoming hotter, drier and more dangerous. (Delwyn Verasamy, M&G)
The biggest economic risk that South Africa faces from future climate change is the possibility of a Gauteng “Day Zero” drought.
This was the stark warning issued by Francois Engelbrecht, the director of the Global Change Institute (GCI) at the University of the Witswatersrand and the holder of the Wits-Nedbank chair in climate modelling.
“We are speaking here about a climate-induced drought, not shorter-term water shortages caused by infrastructure issues. We are talking about water not being available via the Vaal Dam to reach Gauteng,” he told a webinar at the launch of innovative climate change fact sheets, co-developed by the GCI and the South African National Biodiversity Institute, for all nine provinces and each of the 44 district municipalities.
Such a drought has never occurred before. “Our research is telling us that it is becoming possible, even in the next 10 years, and the risk increases for as long as the world continues to warm.”
Engelbrecht pointed to the devastating 2023/24 summer drought, during which Zambia and Zimbabwe lost more than 70% of their maize crop, with effects also felt on the Vaal Dam.
“Long-lasting, climate-fuelled droughts with devastating heatwaves are a very big risk for us moving forward,” he said.
The biggest question, he said, is whether the Vaal Dam and the Integrated Vaal River System (IVRS) will always remain as reliable as they have been since their construction.
“Can we always count on water from the IVRS in a world where climate change is making droughts worse?”
Unprecedented heatwaves, fenced-in wildlife
The next risk is long-lasting heatwaves combined with extreme drought that could push South Africa past a tipping point where it loses its maize crop and cattle industry, Engelbrecht said.
The Intergovernmental Panel on Climate Change (IPCC) has found that at 3°C of global warming, such a collapse is likely because of heat stress on crops and livestock.
“We should expect more devastating heatwaves in the next 10 years. For people in informal housing, without access to cool water, they can be life-threatening. We seriously need to think about heat-health action plans to protect people during extreme heat.”
The heatwaves as soon as the next decade “will be unprecedented — like nothing we’ve ever seen before”.
A further risk is the possibility of an intense tropical cyclone reaching Richards Bay. “We are completely unprepared for such an event because it has never happened before at that intensity in the historical record,” he warned.
Climate science now shows it is possible for a Category 3 or stronger cyclone to make landfall as far south as Maputo or even Richards Bay, because of higher sea-surface temperatures in the southern Mozambique Channel.
“This could happen within the next 10 years. Scientifically, we’d say the chance is ‘as likely as not’. That’s a very big risk for something so impactful.” And while a cyclone hitting Durban directly is unlikely, it can’t be ruled out.
Engelbrecht also highlighted the threat to fenced-in wildlife. “Our wildlife is fenced in and cannot migrate away from long-lasting droughts. When the grazing is gone, there may be mass die-offs in future droughts and fires — there’s no escape.”
A hotter world arrives
Last year, the world exceeded the 1.5°C threshold of global warming — an “unfortunate milestone,” Engelbrecht noted.
“Why do I call this a threshold? Because it’s linked to physical changes in the climate system. The IPCC’s 2018 special report on global warming of 1.5°C assessed that the tipping point at which the Greenland ice sheet will start to melt irreversibly is likely between 1.5°C and 2°C of global warming.”
While 2024 was the first year to exceed this threshold, this does not mean it has been permanently surpassed. “We’ll probably have slightly cooler conditions this summer due to a La Niña event.”
However, new research shows that, at the current rate of greenhouse gas emissions, humans will emit enough carbon to send the world permanently above the threshold within the next five years.
A 1.5°C world, he warned, is a more dangerous world for Southern Africa. “Across the world we expect more frequent extreme weather events once this threshold has been exceeded. We’re already seeing this trend and we expect further increases as the planet warms.”
The Paris climate Agreement aimed to achieve a 45% emissions reduction by 2030 (relative to 2010 levels) and net-zero emissions by 2050.
“Unfortunately this has not happened. The opposite has. Emissions have further increased. Last year, we saw the highest levels of carbon dioxide emissions from human activities since measurements began.”
The world, he said, still finds itself walking a path aligned with fossil-fuel futures and fossil fuels remain a major part of the global energy system.
He noted that current US policy can “be summarised with the words ‘drill, baby, drill’ and that is not going to help us phase out fossil-fuel dependence”.
Effective climate mitigation requires strong collaboration between China and the US, the world’s two biggest emitters. “Without that, we may well see 2°C of global warming as early as the 2040s.”
The Paris Agreement’s vision of keeping global warming below 1.5°C “is now a fairy tale — maybe it always was”, he quipped. “There’s no reason to think that in the next three years we will see a massive reduction in emissions.”
If fossil fuels remain dominant, “we can expect global warming levels between 3°C and 5°C by the end of the century — with devastating impacts in southern Africa.”
Warming twice as fast
By the time the world reaches 1.5°C of global warming, southern Africa will have warmed by about twice that rate. The highest rates of warming in the southern hemisphere are found in northern Botswana and southern Zambia.
If global warming reaches 2°C, “our region could experience about 6°C of warming across the southern African interior”.
Although a warmer atmosphere holds more moisture, southern Africa is one of the few regions projected to become generally drier. “Our region is already water-stressed – now it’s projected to become much warmer and likely drier. That means our options for adaptation are limited.”
Engelbrecht said there is strong evidence of a systematic later onset of summer rainfall in South Africa, which has serious implications for agriculture.
Observed data already show this trend, along with increasing variability linked to the El Niño and La Niña cycles. “There will always be some seasons with good rainfall, but La Niña also brings flood risks,” he said.
“If you look at projections of soil moisture and most models projecting reductions in rainfall, we need to think about what that means in terms of long droughts and impacts on agriculture and water security. In the eastern parts of South Africa, there is strong evidence that we should expect more frequent heavy rainfall events and that goes along with flood risk.”
Recent research published by Engelbrecht and his colleagues on the catastrophic Durban floods of April 2022, which claimed 544 lives and displaced tens of thousands of people, were made significantly worse by climate change.
The research showed that rainfall during the storm of 11 to 12 April was between 40% and 107% heavier than it would have been in a cooler, pre-industrial climate. More than 500mm of rain fell in just two days in parts of KwaZulu-Natal as measured by weather stations.
“In a cooler world, rainfall would likely have been around 250mm instead of 500mm. There probably still would have been flooding, but the event would have been far less catastrophic.”
The Indian Ocean — including the Agulhas Current — has warmed substantially, providing more moisture for storm systems over KwaZulu-Natal.
“We’ve just seen a repeat of this tragedy with the Mthatha floods, which claimed more than 100 lives. It’s a well-known risk for South Africa, the flooding caused by these cut-off lows, but now climate change is making them worse. That’s a clear message about the risks we must prepare for.”
Narrow window of hope
Despite these warnings, Engelbrecht said there is still hope. “We never have to reach 2°C of global warming. We can still mitigate climate change if the big economic powers collaborate to phase out fossil fuels. But we must be realistic about current geopolitics.”
He emphasised that South Africa’s climate-science base is strong and increasingly integrated into policy. “Our government and private sector are endorsing climate-change science.”
For South Africa, the focus is on adapting to climate impacts. “It’s about protecting people, climate-smart early-warning systems, disaster-risk management that saves lives and building long-term resilience in our cities and rural areas.”
There is hope, he concluded. “The impacts of climate change in the future don’t have to be unexpected. We have the science to help us prepare for what’s coming — even if those impacts are going to be unprecedented.”