I read William Langewiesche's travelogue where he crossed the Sahara overland after being a pilot who flew over for a few years. He said that the locals are rather fatalistic about living in such a massive and unforgiving place (people frequently die there); they say that when god decides it's your time, then it's your time. Langewiesche added that if you don't believe in god, then you can replace that with "The Sahara" and it still works quite well.
I cannot imagine that there is much humans can do to hold back the desert. I'm quite sure that the only thing that would matter, a rapid drawdown of carbon emissions, is not possible at this point. I know it sucks, sorry.