Complex sentence: Lake Bosumtwi can be used to argue that the drought over sub-Saharan Africa and the Sahel during the late 1970s orgininated from that of natural variability forced by a multidecadal oscillation in the thermohaline circulation, which in turn modulates sea surface temperature in the north Atlantic.
Split into simpler sentences: Lake Bosumtwi can be used to argue that the drought over sub-Saharan Africa and the Sahel during the late 1970s. It has been shown that the drought orgininated from that of natural variability forced by a multidecadal oscillation in the thermohaline circulation, which in turn modulates sea surface temperature in the north Atlantic.