By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
(German text translated/edited by P Gosselin)
Today’s topic: Sea level rise around Africa. There the sea level is rising there like anywhere else. Already during the last warm phase, the Medieval Warm Period (WMP), sea level rose.
That makes sense because during the warm phases ice melts at the poles and high mountains glaciers. But what was the case during the Little Ice Age as the glaciers expanded? There aren’t any tide guage measurements from this time, but geological reconstructions have been carried out. And lo and behold, the south coast of Africa saw sea level drop during the Little Ice Age. See Scott & Lee-Thorpe 2004:
There is good evidence for a number of environmental shifts during the last 2000 years, but the most noteworthy event may be the climatic fluctuation during the Little Ice Age (LIA) period. Evidence for a lower sea level on the southern coast during its earlier phase (1520 or 1570 AD) may be a reflection of widespread anomalous conditions during this phase (Marker 1997).”
Also on the west coast of South Africa we find a small surprise. Five thousand years ago sea levels were 3 meters higher than they are today. This is nicely documented by Carr et al. 2015 in their Figure 7:
Sea level of the west coast of South Africa during the past 9000 years (BP=years before present). The solid curve applies here (not the dashed line). Source: Carr et al. 2015.
Next let’s move northeast to Mozambique. There scientists Achimo and colleagues, find that Maputo Bay already reached today’s levels 5000-7000 years ago:
The complete picture of Maputo Bay patterns with its modern sedimentary environments including Inhaca Island may have evolved when the sea level has stood close to its present level around 7000 – 5000 years BP, after which the Maputo Bay became more or less stable.”
A sea level drop between 800-1300 A.D. at Mozambique was documented in Sitoe et al. 2017 (see their Fig. 5).
Sea level rose again gradually after the year 1300 A,D, but hasn’t reached by any measure the level seen in 800 A.D.
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