In one of my Alternate Earths, I have made the following changes to Africa:

1) Re-angle the mainland (meaning Madagascar stays right where it is) to the point that the Mediterranean is connected to the Indian Ocean, not the Atlantic.

2) Revitalize the Saharan Megalakes and Botswana's Lake Makgadikgadi.

3) Raise the continent's sea levels by 75 meters.

Using these three changes, what kind of climate would we expect to find in Africa?

  • $\begingroup$ Re: #3, do you mean lower the landmass by 75 meters into the sea? It doesn't seem like any of this would have a profound effect on continental climate. The Straits of Gibraltar and the Red Sea aren't large enough to affect major ocean currents; that little change in elevation should be negligible; and the lakes would derive from climatic changes, not vice versa. $\endgroup$ Jun 15 '15 at 14:37
  • $\begingroup$ continents don't have sea levels. $\endgroup$
    – Oldcat
    Jun 15 '15 at 17:33

It won't have much effect. You just need to see where the rain belt is. Right now, it over the Sahel. It will be located more or less at the same place not matter how much you rotate the continent because it depends on the global air circulation. Most of the Sahara will be dry even if you rotate it by 45 degrees. Chad, Sudan Egypt and the southern Part of Libya will receive more rain but West Africa will become more arid. Lakes might form like lake Chad but they would be mostly seasonal lake with great variation in water level between the dry and wet seasons.

With this configuration, Cape Town would be near Sao Paulo. So yes, the lakes in Botswana will be restored to their formal glory.

Lastly, compared to other continents, Africa has a relatively high altitude with a few low plains. These places can be densely populated but increasing the water level by 75m would only submerge a small portion of Africa.

Elevation map : http://sedac.ciesin.columbia.edu/downloads/maps/nagdc/nagdc-population-landscape-climate-estimates-v3/place3-elevationzones-africa.jpg


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