Coast KZN

06 Aug 2020

Climate change may mean hurricanes hitting Durban – and Transnet wants to be prepared

Phillip de Wet (Business Insider, SA) Picture: An aerial view of a neighbourhood devastated by Cyclone Idai on 24 March, 2019 in Beira, Mozambique. Transnet wants to know if such destructive storms could be heading south as far as Durban. (Photo by Andrew Renneisen/Getty Images)

Transnet says it wants to pin down some implications of climate change on South Africa – including whether category 4 and 5 hurricanes will hit Durban in future. The parastatal’s ports authority is currently looking for help with an in-depth climate change modelling project to forecast the detailed impact of climate change on “decadal to multi-decadal time-scales”.

That work, it says, will help close some serious gaps in research done to date, and allow it to formulate “suitable climate change adaptation strategies for each of the largest ports of South Africa”: Saldanha Bay, Cape Town, Mossel Bay, Port Elizabeth, Ngqura, East London, Durban, and Richards Bay.

When it comes to storms, it is the two KwaZulu-Natal ports Transnet is most worried about.

“It is critical for South Africa and Mozambique to determine the likelihood of a category four or five hurricane (or even smaller intensity cyclones or lows) making a direct hit on Maputo, Richards Bay or Durban,” says the Transnet Port Authority.

Existing studies suggest such high-intensity storms, which cause devastation in Mozambique every so often, could grow less frequent but more fierce, and could track further south. Just how far south is not clear. “The implications for South Africa’s coastal areas including ports have not yet been investigated comprehensively,” says Transnet.

The possible changes that concern it include the more obvious consequences of general warming: more heat waves and high fire-danger days, more intense thunderstorms, and more intense flooding. But Transnet also has some more unusual concerns: how sea level rises could eat into the overhead clearance of its cranes, the extent to which rising salinity and humidity could cause its steel infrastructure to rust faster, softening asphalt and buckling railway lines – and the extent to which heat-driven fatigue and exhaustion could cause a lack of concentration among workers, and so more accidents at ports.

It also wants to figure out whether changes in currents and wind could make for waves coming at its harbours from weird new directions, requiring major changes in berthing and approaches.

It hopes to have answers – and, incidentally, a quite granular forecast of what will happen to the entire coast of South Africa – in a little over three years.