Plain and simple: Obviously, the really important missing elements are bodies, ...human and animal...in varying states of decay.
Give us bones, bodies on the wire, bodies half-buried, etc.
(Also you could add a few living elements.)

I tend to think that realism should take a backseat to fun.
Perhaps, during a journey form one point to another, a really skilled player can choose to pick off avian creatures in the air, and a sloppy player can comically hurl land-based creatures, bodies, or other elements into the air with a well-placed blast. But, why stop there. Maybe the player might like to discover that the two elements can be combined,...throw entities into the air with a well placed blast, and with the proper skill, swat them in mid-air.
(This is really important during 'live cutscenes' near NPCs which claim livestock, as it is slightly satisfying, initially, to apply the proper timing and watch livestock fly off into the air, then come down and bounce in the background, while a particular NPC is rambling on about this or that 'important' objective-related topic.)

Nevermind, just stick to the realistic, safe and boring formula.

I like the orange-like appearance of the sky, but the sky could definitely scream 'fiery hell', or 'bloody apocalypse' a little harder.