Cape Town is eroding, storm by storm
City resolves to tackle ‘significant’ damage from rising sea level
● Cape Town may be one of the world’s most beautiful cities, but how much of it will be left in 100 years?
“Significant” damage to coastal infrastructure over the past year has prompted city officials to accelerate efforts to deal with the effects of sea-level rise and storm surges linked to climate change.
Damage to coastal roads, tidal pools and retaining walls is among some of the visible effects, with the city now seriously considering redirecting Baden Powell Drive, a major coastal road between Muizenberg and Khayelitsha.
A sea-level rise of between 28cm and 98cm is on the cards by 2100, according to figures presented this week to the city’s sustainability & resilience committee. The “return period” of extreme storms is also set to shorten, with so-called one-in-50-year storms likely to occur on average every 20 years.
One of the city’s major 20th-century engineering triumphs — the construction of Cape Town harbour on reclaimed land — is adding to the problem by disrupting the dynamics of Table Bay and speeding up erosion along part of the shore.
In response, the city’s coastal managers this week resolved to finalise a list of interventions to be approved by the council.
“We are seeing significant impacts, especially in the Milnerton and Big Bay areas where beach erosion has exposed infrastructure and development to significant damage over the last 12 months,” said mayoral committee member for transport & urban development Brett Herron.
Similar damage has been observed in False Bay, prompting formal motions for the council to address the broader issue of climate impact, Herron said.
In False Bay “these challenges primarily relate to the exposure of infrastructure to coastal processes, and climate pressures”, Herron said.
Councillor Farouk Cassim, who tabled the motions, said Cape Town was one of the cities most likely to be affected by climate change due to its exposure to storm surges.
“Cape Town is very well known for its beaches and panoramic sea views, but at the same time we are witnessing the seas becoming much more aggressive and gouging out big portions of land that were previously change-induced used for roads and entertainment,” Cassim said.
The Strandfontein and Monwabisi resorts on False Bay were seriously degraded “because the sea is claiming them”.
Cassim told the Sunday Times: “One just needs to stand on the beach at Monwabisi to see how storms are rising and why we urgently need to take account of the fact that for the city to be resilient it has to accept that storm surges are really going to be very problematic. We are reaching very close to the tipping point. Once you reach that point then a whole lot of things are triggered and then it becomes a lost cause. The window of opportunity is very small.”
This week’s presentation coincided with the release of alarming scientific research suggesting a “perfect storm” of climate effects could tip Earth into a “hothouse” state, rendering emission-reduction efforts useless.
The findings suggest that “feedback loops” may already be operating, fuelling the summer heatwave in Europe.
“The heatwave we now have in Europe is not something that was expected with just 1°C of warming [Earth’s current level of warming],” said Stockholm Resilience Centre director Johan Rockström.
He said international efforts to keep this warming below 2°C may be too little, too late. “Fifty years ago, this would be dismissed as alarmist, but now scientists have become really worried.”
The combined effect of sea-level rise and increased storm surges could have a devastating effect on Cape Town’s transport infrastructure flanking Milnerton lagoon, according to a study finalised in May 2016.
“This city-owned land, together with its transport infrastructure and services, will be inundated in storm and flood conditions,” the study warned.