If you have not noticed, China is in the habit of controlling information, and this is the kind of information China does not like to let out.
That said, the world is well aware of what's going on, thanks to satellite imagery. The problem is not the current heat wave, it's that for decades, China's economy was furled by the sand that was dredged from the bottom and shores of Poyang Lake, for use in the cement, glass and other industries. This altered the natural balance, and as a consequence, the lake is no longer capable of performing its primary function: as a reservoir for the rivers that drain in it.
