Surf’s up for SA’s coastal cities
Experts warn of risks posed by rising seas as climate changes
● Headline-grabbing coastal apocalypses tend to involve tsunamis or hurricanes. But in SA a quieter storm is coming to get us: waves are changing, sea levels are rising and sand is burying infrastructure.
Cape Town and Durban are under threat, with policymakers already working on adaptation strategies to save the country’s two main coastal cities.
A new study just published in the scientific journal Nature Climate Change shows that a warming planet will alter waves along half the world’s coastlines, and SA is already suffering the effects.
Anton Cartwright, a climate economist at the African Centre for Cities at the University of Cape Town (UCT), said the frequency and intensity of the summer south-easter and “associated wave action” had “contributed to the collapse of the railway line to Simon’s Town”.
According to Cartwright, “very problematic erosion” is happening at Milnerton because of changes to swell action caused by the construction of Cape Town harbour.
Marian Nieuwoudt, the City of Cape Town mayoral committee member for spatial planning and environment, confirmed this week that experts were conducting a detailed analysis of erosion at Big Bay in Milnerton.
In Durban “the piers have affected the coastline” and various studies had shown waves could be affected by cyclones and high tides, said Cartwright.
The massive sewage pump station on Mahatma Gandhi Road — which sprang a major leak in May — is on the cards for relocation.
Andrew Mather, project executive of coastal policy for Durban, told the Sunday Times: “The sewage treatment plant was basically built right on the beach mid-century and now we are seriously looking at how we can relocate it. It is a major pollution risk.”
Judith Wolf of the National Oceanography Centre in the UK, an author on the new study, said it looked beyond sea-level rise to the impact of storms — and the resulting winds and waves —and how these were changing.
“In SA winter mean waves are projected to increase in height,” said Wolf.
Phoebe Barnard, a research associate at UCT’s African Climate and Development Initiative, said: “A grim scenario of broken, rusting infrastructure littering our coasts is getting more likely around the globe each year that countries prevaricate about climate change.” She said Cape Town and Durban were “getting their acts together”.
According to Mather, Durban’s 2007 storms resulted in the city “moving a lot of infrastructure away from the coast”.
“It is very difficult to persuade someone that a perfectly good piece of infrastructure should be demolished. But when we have had damage to infrastructure, there is an opportunity to build elsewhere,” he said.