Written originally elsewhere, elaborated here.
A new study by a California team looks at the effect of the warming of the Indian Ocean, which seems to be anthropogenic in origin, and how that influences precipitation in Africa. It decreases it. People go hungry as a result:
We present analyses suggesting that warming in the central Indian Ocean disrupts onshore moisture transports, reducing continental rainfall. Thus, late 20th-century anthropogenic Indian Ocean warming has probably already produced societally dangerous climate change by creating drought and social disruption in some of the world’s most fragile food economies.
The paper is Funk et al, Warming of the Indian Ocean threatens eastern and southern African food security but could be mitigated by agricultural development, in PNAS this week. It’s on on the web yet, but I’ll post a link when it goes up.