I think that one of the reason for the huge Mongol Empire creation as well as fast partitioning was the short climate period when majority of those territories

I think that one of the reason for the huge Mongol Empire creation as well as fast partitioning was the short climate period when majority of those territories provided best conditions for horse travel - i.e. not total desert, not swamp/forest, and instead it were plains with climate being just right for the good grass and reasonable rivers.