So the other day I was chatting with a friend about a story she wants to write, and she brought up having a civilization of fire benders spring up in a desert.
And that got me thinking, do fire benders really fit into a desert? I mean I get it, fire, heat, desert, but why would people in the hottest place available want to make MORE heat? Seems to me they'd want to be able to burrow or pull water from the ground, not spontaneously combust, boiling away whatever precious water's close to you, and drying yourself out in the process.
Fire's a nice self defense mechanism and all, but you'd probably be shooting yourself in the foot if you developed it for life in the desert. Unless we're talking about an arctic desert (tundra) in which case heat and food are the big issues, not so much water (ice and snow everywhere).
Also, something completely counterintuitive, assuming firebending obeys the rules of chemistry, combustion makes water vapor, so anywhere with a lot of active fire-benders is going to get very humid, very quickly. So if you've got a bunch of fire benders in any place for a long time, shooting off fire every which way, eventually the environment will be affected by all the water vapor, which could explain why the Fire Nation in Avatar: The Last Airbender and The Legend of Korra is so full of lush jungles and stuff.
And even if you burn away all the vegetation in a place, you're just giving it nice ash and fertilizer to grow in. A periodic burn is actually GOOD for plant life. (crazy, I know, but true) and grass has a tendency of creeping in whenever other plants do, and they would probably at least try agriculture on some river bank somewhere (think Egypt).
So crazy and counter intuitive as it sounds, I can't see fire benders being able to exist for a long time (speaking in historical measures of time) in a desert. They'd either dehydrate themselves to the point of extinction, get out, or instigate climate change (intentionally or not) and make a prairie and then eventually forests and jungles.
This has been BIZARRE REALITY CHECK with 263px