[quote=@Sigma]
[@Isotope] Yup, the Cataclysm had a major effect on the environment, with the icecaps melting and whole landmasses sunken. And With that, yup, it's gotten more warmer. 
[/quote]

My idea for the areas around China was that a rise in humidity and precipitation had made the Tarim Basin and Tibet more fertile, allowing for the City-States in the Tarim, as well as Tibet to develop into an Imperial Power. Unless there are any objections to that