Even though my knowledge of color is not that great, I’ll try and speak what I know.
The problem that you have with this image is that the colors are too muddy. When I look at it, nothing really pops out, it’s all of the same dynamics and intensity. The first thing you need to work on is making a clear distinction between the warm and cool colors (lights and shadows). And see how you can use it to your advantage to draw in focus and lead the viewers eyes across the canvas and back again.
One thing to think about would be this. If they’ve been in an ice-age for thousands of years, there would be absolutely no moisture in the air, it would all be frozen on the ground. Clear blue skies. The only clouds that I could comprehend existing would be the very highest of altitude flat clouds that could maybe give some shape to your sunrise. So if this were the case, most of the sky except for the parts immediately around the sun and close to the horizon, would be a darker blue, i believe. One of the problems I had from the start of your coloring was I did not have a clear distinction of the horizon and the objects in the background, it was hard for me even to tell that there were mountains there. The skie would be less of the muddy orange and more blue I believe.
The shadows of the mountains and landscape would become closer in color to the blue of the skie the further it went out in the horizon. If the mountains were very far out, maybe the shadows would be indestinguishable, but the highlights around it’s ridges and crevasses would give a definite shape to the mountain. It would just all be this flat orange.
I would leave the oranges and yellows, ie. where the sun is directly hitting, saturated in the foreground, and of course becoming more muted as it travels to the horizon. Focus on contrast, sharpness in shape and color.
Also, look at any photo with the sun in it, or better yet, look at the sun in real life. Our eyes and cameras naturally adjust to the light, so when there is an extremely bright light in our view, our pupils dialate and less light is let into our eyes (in other words, everything gets darker except the brightest of brights) So, the sun is in your image, and I think it would help you realistically express your idea if the entire scene, minus the parts of direct sunlight, were darker
I’ve included some referances to kind of explain what I’m saying
On the issue of perspective, I do think it should be considered a little more. Maybe a view of someone actually on an island, so the viewer feels themselves on the island, see’s how large these islands are, see’s them in referance to other figures around the viewer on these islands, and sees the sheer power of the islands crashing down around him/her. If you’ve ever been on a plane, you’ll know what I mean when I say, from a height, everything looks simply like a model or toy, no matter how large it actually is. Huge buildings and semi-trucks look like little child play-toys. The same thing with this. With this raised altitude, even if it were an actual photograph of a city going to ruins, it wouldn’t look as large, scary, and convincing unless you were actually on the same plain as it was. In order for something to be grand, it needs to have a relationship with something that is not. Notre Dame, in all it’s glory and grandeur could be floating in space with nothing around it and not be intersting or grand at all. It takes that building to be jutting up in the middle of the city, next to small houses which are still larger than the cars which are still larger than the pedestrians walking by to give it that sense of enormity and grandeur. Give the ‘grand’ things in your painting a relationship to something that is not grand, and make the viewer feel like he/she is not grand by placing them in a position to feel as such. When you place the viewer above it, you give them a godly position, out of harms way. They can sit and watch the destruction with no fear (no sense of grandness). If you place them on an island that is about to fall with multiple islands around them already careening down to the base below, the viewers going to feel a little differently.
I don’t know if you watched any footage of the twin towers on september 11th. it was a horrific, scary thing. But did you get the sense of how bad it was with the footage capture by helicopter or by the person running away from huge clouds of smoke (that wouldn’t look so huge from helicopters) on the street with hundreds more people being consumed behind them? Just rethink it, make some more quick sketches to see what works!
Hope this helps a little, take care!