Sahel- and West African monsoon
This is a region that have experienced rapid devastating droughts from the late 1960s through the 1980s. Climate change and a global mean warming of three to five degrees Celsius could cause a collapse of the West African monsoon. This could lead either to drying of the Sahel or to wetting due to increased inflow from the West. The latter could imply a greening of the region in what would be a rare example of a positive tipping point.