Funny that only you noticed :)
China’s growth “may” be sustainable if it lasts as long as sustainability requires. The way things are going, HK will merge with a Cantonese speaking south, Tibet will disappear along with Qinghai and parts of Sichuan and Xinjiang will declare independence as East Turkestan in the not so distant future. After that, China’s growth (of environmental pollution, an aging population and general hopelessness) will definitely be sustainable...whatever it will be called then...
China can easily secure Sanjing and Tibet by instituting homesteading which allows settlers to register and own the lands they settle and make productive. There are enough poor Chinese willing to leave the cities or small farms to risk making it big in the frontiers of Tibet and Sanjing. Problem is Bejing cannot get over the psychological hurdle call “private property”. Thus China continues to suffer from overcrowding and insecure control of Tibet and Sanjing due to PC. Before we laugh at them, we Americans rather suffer high energy prices due to short supply of oil than get over the PC barrier of drilling offshore and in US territory.