Agence France-Presse: Reeling from consecutive lengthy droughts for 3,000 years, sub-Saharan Africa faces an inevitable repetition of mega-droughts, according to a study published Friday. A team of US geoscientists and climate scientists found that severe doughts lasting several decades and sometimes even centuries have been the norm in west Africa for the past three centuries. The most recent such drought lasted from 1400 to 1750, according to the researchers, whose study was published in the …