In my flintlock fantasy story setting, each of the nine Core Races (Humans, Elves, Dwarves, Orcs, Gnomes, Halflings, Faeries, Draconians, and Kobolds) has a Homeworld, a Planet in its own Solar System located in its own Galaxy. Travel between these Planets is accomplished by following routes through the eight Transitory Planes. You bypass the many, many lightyears of space (and the need for space-faring vessels) by taking a shortcut through another universe. I don’t have a name for the Dwarven Homeworld, but I do know that the reason my Dwarves migrated underground on their Planet and also expanded into the Plane of Earth was because, during the Divine War, the fighting of the gods caused their Homeworld to undergo extensive desertification. Well over half of the Dwarven Homeworld has become a desert. This forced the Dwarves to start building underground, both to escape the heat and desert winds and to get closer to what few sources of fresh water remained. However, I’ve never actually worked out what caused the Planet to undergo so much desertification. It occurred to me that the answer might not be in the Planet itself but the Star that it orbits. What if the reason so much of the Planet turned into a desert was because the Dwarven Sun started giving off more heat, grew larger, or some combination of the two, which meant that the orbit of the Dwarven Homeworld changed from the optimal part of the habitable zone of the Dwarven Solar System to a much hotter (but still survivable) section of the habitable zone? To put it another way, this would be akin to Earth relocating closer the orbit of Venus. The temperatures on the Dwarven Homeworld increase but not to the point where water cannot condense into liquid in some regions. I’m sure there are some factors I’m overlooking, which is why I could really use some feedback. Is this idea a sound one and what would be some of the ramifications of the Dwarven Sun getting hotter and/or larger?