Duncan Green is head of research at Oxfam GB and has written an article exploring the question of whether the drought in the Horn of Africa is caused by climate change. The article is here and an edited version appears at the Guardian. I'm sure that comment will be freer at Mr Green's place.
Green presents evidence to support the idea that the drought in the Horn of Africa is global warming in action: anecdotal evidence from the locals and increases in surface temperatures. He also notes rather more importantly that the rainfall records are ambiguous.