From the article itself it seems that ascribing the problem sweepingly to global warming etc, as per the first quote, is rather problematic:
As weather patterns change due to global warming, ocean swell direction also altered. These slight changes in predominant wave direction could also cause erosion of beaches.
Nieuwoudt noted the importance of natural barriers such as dunes and wetlands, many of which have been compromised by development or the canalisation of estuaries. These needed to be restored as much as possible, and the City was seeing some success in the ongoing restoration of the natural sand dunes in Hout Bay, an ongoing project where R6 million had been spent so far.
The Coastal Managment Programme, published in 2015, noted that coastal erosion is occurring at “a number of points along the City’s coastline as a direct result” of urban development. The report gives an example: at the southern end of Table Bay the coast has been eroded by 35 metres over the last 45 years. Climate change is predicted to increase both the intensity and frequency of coastal storms, worsening the erosion problem and creating a long term risk to the city.