A sign of things to come

Back in 2010 the Western Cape Government commissioned a study to determine the impact of sea level rise on the coastal areas under its jurisdiction. One of the areas that was looked at was Knysna.

This map from the report:

The red line indicates a 2.5m above mean sea level, the orange 4.5m and the blue 6.5m. From the models they concluded the following:

“The town of Knysna is protected from storm surges by the narrow width and rocky nature of The Heads, although the risk of flooding and back flooding of the estuary is high and a large portion of the town is vulnerable to inundation. Thesen’s Island, Leisure Island, Brenton, Hunter’s Home golf course, the portion of Knysna town centre south of the N2, the sewerage treatment works, the edge of Belvidere and the Knysna River floodplain up to the head of the estuary all fall below the 2.5 mamsl floodline (see Figure 3-3), which has been breached in the past.”

This past week the town experienced a Highest Astronomical Tide (HAT) combined with a storm and some server winds causing a 2m+ tidal rise. This was the result (Pics Credit: Nichelle Swanepoel)

Considering the data available in 2010 regarding arctic glacier melting, the report concluded that:

“By 2100, extreme sea level events of this nature may occur every 2 weeks on spring highs with the combination of a small to moderate storm”

This will prove devastating to the road, water and sewage infrastructure not to mention the hundreds of millions of rands of stranded assets that would in direct line of impact. Based on data from 2019 we now know that the arctic melt Is happening faster than was predicted and therefore the time line associated with events like this will shrink meaning we could see this scenario play out by 2030.

This is just one tiny example of what will happen to most cities and towns that are built along the ocean. Take a look at this piece from the New York Times entitled Rising Seas Will Erase More Cities by 2050, New Research Shows