“Each year, over one hundred million tons of Saharan dust gets blown across the Atlantic, some of it reaching as far as the Amazon River Basin. The minerals in the dust replenish nutrients in rainforest soils, which are continually depleted by drenching, tropical rains.” Quoted from NOAA.
Anyway, I doubt there will ever come a day when 100% of North Africa is green. I was just highlighting the impact Sahara has on the environment.