I just imagined me looking down at this part of town when i was in the Shanghai world financial center and then thought about the city coated in green. I loved it when i visited China. Can't wait till i go to the burj khalifa. Then im going to imagine the city coated in green like your other ruins.
It might eventually, but it would probably take thousands of years. Keep in mind, it's not just the occupation of humans, but the climate conditions and geographical features that make a region a desert. For instance, deserts often form behind mountain ranges due to the rain shadow effect.