A Gauteng Day Zero — in which water supplies are depleted — is SA’s biggest single climate change risk in the near future, say local scientists who contributed to the Intergovernmental Panel on Climate Change (IPCC) report issued in July.
In 2018, Cape Town came within 90 days of switching off the taps, an event known as Day Zero, with residents restricted to 50l of water a day.
The IPCC is a 195-country intergovernmental body linked to the UN. Its reports are written by scientists from the member countries. SA scientists who contributed to its work presented their work to a colloquium convened by the presidential climate commission on Thursday. The commission is a broad stakeholder group established to advise President Cyril Ramaphosa.
Francois Engelbrecht, distinguished professor at the Wits Global Change Institute, said the evidence is that Southern Africa is warming twice as fast as the average for the rest of the globe. The region is projected to become “drastically warmer and drastically drier”. As it is already a hot and dry region, the opportunities for adaptation are greatly limited, he said.
Regional tipping points could cause devastation from which it will be hard to recover. The first of these is a Gauteng Day Zero drought, which is “not an unlikely event” in the next 20 years.
“At the end of 2015/2016, the level of the Vaal Dam fell below 25%. Should it fall below 20%, the supply to Gauteng is heavily compromised because of water quality reasons and engineering reasons, in terms of pumping the water up to Johannesburg. So we came extremely close.
“Another summer of drought may have brought us to a major water crisis in Gauteng,” Engelbrecht said.
The second regional tipping point could be increasing frequency of droughts that last three to six years, which will occur with more frequent and intense heatwaves.
“Our farmers and water management are used to big droughts, but the frequency may well be increasing. The special report in 2018 projected that at 3°C of global warming, it will become likely that both the maize crop and cattle industry will collapse in Southern Africa. It is absolutely in our interests to restrict global warming to 2°C or less,” said Engelbrecht.
More intense heatwaves will affect human health and more people will die, with living conditions being unsuited to extreme heat. There is also the possibility of more intense tropical cyclones making landfall more frequently in the region.
“In a warmer world, there is the possibility of a category 3 or 4 hurricane making landfall at Maputo or Richards Bay or moving into the Limpopo river valley. I don’t think we are prepared at all for that kind of event,” he said.
Another of the authors of the IPCC report, Council for Scientific and Industrial Research chief oceanographer Pedro Monteiro, told the commission that SA should be aiming to restrict global warming to 1.5°C. This is both to mitigate risk and to make a “just transition” — in which industry and employees in heavy carbon sectors are not left behind — to a lower-carbon economy viable.
The Paris Agreement seeks to keep global warming within 2°C, based on the correlation between carbon dioxide emissions and rising temperatures.
“The 1.5°C future is still within our hands but that future window is closing rapidly. If we continue to emit like we are, then we will go through the 1.5°C within 10 years,” said Monteiro.
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