During the Eco-Crisis many wealthy corporation and citizens sought places free from governmental regulations where they could set up shop and live, free from rioters and marauding nations, within hugely expensive Bio-Dome and Bio-Network environments.
The final resort before departing the planet was Antarctica. In areas where the polar ice cap had melted enough to gain permanent footing on the continent micro-environments and Bio-Cities were hastily constructed.
As the wealthy nations regained control of their populations and food systems many of these were abandoned only to be later inhabited by refugees.
With the climate returning to normal life in Antarctica has become nearly untenable but these third generation Antarticans refuse to leave despite the fact they are entirely dependant on humanitarian aid.
UNSC forces regularly stop by to re-establish the peace while the scientific community is once again returning to the continent to restart many, long abandoned studies.