You have to keep in mind where old Lester is coming from here. Famine is really a symptom of the real problem, overpopulation, as Lester sees it. In particular, Lester's very concerned with the overpopulation of all those brown and yellow people, if you catch my drift. And so the ultimate solution, as far as he's concerned, is population control - Lester thinks that China's one-child policy, and all that it entails, is just swell, for example.
I'm wary of Brown for two reasons - one, he's been wrong for thirty years running, as I've noted. But, two, I'm wary because his preferred solution is more or less to fly cropdusters carrying Ortho-Novum over Africa and Asia.... ;)
Beijing has always suffered from massive dust clouds blowing out of central Asia on the winter monsoon. Whether they are greater than "normal," I have no idea. But you can read about them in Marco Polo and the writings of every other person who's ever lived in Beijing.