If  US history is any predictor of the US concern about problems in sub-Saharan, (read Non-Oil Producing ) Africa, nothing will be done.  

Rwanda, which resulted in mega-deaths by starvation on Bill Clinton's watch,  is the first location that comes to mind. 

South Sudan,  genocide location in 1991 when Bill Clinton was President, and  another pending right now, is another example of US disinterest in any African country without mineral resources for us to exploit.  

Even if there were incontrovertible proof that global warming was causing these droughts instead of just that  "Climate change, disproportionately caused by carbon emissions from the United States, SEEMS to be behind a severe drought that has led crops to wilt across seven countries in southern Africa", the US won't really get concerned about impact on Africa.

When the link between Global Warming and Manhattan or Miami flooding is accepted, there might be some slight interest in doing something.  

Africa? Not even!