Develop a screenplay for a 30 minute short film

I have a seed of an idea which I wish to pursue for a short film.
I need someone with imagination to produce a screenplay based upon the theme.
It is based on a post apocalyptic film global warming theme , where society has become tribal , with the tribes fight it out for limited resources such as food and water, depleted due to increasing temperatures , in a hot environment.
I will require someone to develop a story based upon this theme , where females have become dominant and males subservient. It will be centred on the struggles of two leaders of two competing tribes to hold their followers together with both inter- and intra- tribal conflict.
More information can be provided if anyone wishes to take up this challenge to develop a compelling story and contributing their own ideas and input, although I have the story outline already developed.
It will be helpful if anyone who is interested would list the scenes that they would write and a single sentence objective for each scene.
I WILL ONLY CONSIDER APPLICATIONS FROM WRITERS IN THE UK or USA .