Climate change may not be what he is worried about.
What is he worried about? Civil war?
It's just a guess, but if there's one thing super rich people have been scared of throughout history, it's an uprising.
Yep. Super rich people have a strong tendency to abuse everyone else (often without even realizing that what they do is abusive), and if you abuse people enough then sooner or later they're going to try to kill you, because there isn't any other way to make the abuse stop.
Also seems like a bad place to hide in a war with China :)