Being a Capetonian, it’s crossed my mind more than once that our home might not survive the implications of global warming over the next 25 years, and that we might need a plan B to move to higher ground!

The Times published an article a couple of days ago that brings to mind the adage – safeguard the future by being prepared. If the worst case scenario of two-storey waves battering the city shoreline within the next 25 years, comes to pass, then we’ll have to be (prepared, or inland).

It is rather difficult, when faced with the list published by the Times – “this is what the sea would devour”, which includes, well, just about the entire coastline and much of Cape Town – not to laugh out loud with disbelief.

And it isn’t sensationalist journalism. The story... is based on a study commissioned by the city of Cape Town that claims we have a one-in-five chance that this could happen in the next 25 years.

I bet you’re already skimming ahead for a link to which areas in Cape Town will be affected, and it’s coming. But I just want to get in here, that it doesn’t matter if your house remains standing or not as much as if parts of the city are affected, all of us are.

There is an 80% chance that that 4.5m waves will hit the city. And a 95% chance of 2.5m waves during this period (more or less the height at which they hit Ballito).

The good news is that the city of Cape Town intends adapting to these possibilities.

Cape Town’s options include moratoriums on:

• Land reclamation — the Foreshore, Paarden Island and Sea Point promenade are all examples of such developments
• The further degradation of coastal wetlands and estuaries, which are natural buffers against sea-level rise
• The degradation of dune cordons behind beaches in Blauberg, Milnerton, Hout Bay, Fish Hoek and the Strand, among other places, which provide a natural defence against sea-level rise but are “flattened” by residents seeking better sea views, and by construction sites and sand mining

Additional actions include engineering works. Of these, sea walls are the city’s most common form of protection against the sea, with varying degrees of success.

The Sea Point promenade, for example, has been in place for 70 years, but has to be periodically repaired following high tides and storm surges. This year the city issued a R12.5-million contract for its maintenance.
Other walls, like the one at Strand, are less successful.

“Biological options” are mooted as being the cheaper, more natural and more effective ways to counter sea-level rise. These include dune cordons, and estuary and wetland rehabilitation.
Seaweed, the study says, is also beneficial: “It is the practice on Cape beaches to remove kelp. .. in order to maintain ‘clean’ beaches for tourists and beach-goers. .. Unfortunately, the removal of kelp in conjunction with mechanical cleaning of beaches contributes to their destabilisation and vulnerability to erosion.”
Institutional responses to sea-level rises have also been suggested.

These include the development of early warning systems, the application of a “blue-line”, or coastal buffer zone, below which new developments should be prevented, and appropriate corrections to the insurance market.

Much of the insurance extended to coastal properties in the city does not factor in the risk of sea-level changes into assessments. [Times]

The areas in CT potentially affected by waves.