long record of past droughts severe drought famine 英語版 Sahel drought (en) long record of past droughts global warming contributed to an African crisis of the 1970s long record of past droughts Sahel drought http://en.wikipedia.org/wiki/Sahel_drought extremely dry years (en) 英語版 Sahel drought Sahel drought http://en.wikipedia.org/wiki/Sahel_drought 英語版 Sahel drought Sahel drought 英語版 global warming contributed to an African crisis of the 1970s La zona lleva sufriendo sequías Sahel drought seca durante duas décadas Sahel drought English Sahel drought famine Sahel drought Sahel drought English English 英語版