Minecraft biome editors:

http://www.minecraftforum.net/topic/...-retro-biomes/

https://www.youtube.com/watch?v=sATuT9h_

I came across these after looking at my former desert biome north of my village. Half of it is covered in snow due to biome changing. I don’t know how difficult these tools are but hopefully they can be used to solve the problem.