This is like the kinda movie that starts with a planetary establishing shot and then you assume it takes place in a different planet, but the plot twist is just global warming and it was earth all along
This is more like polarity shift Antarctica where sea level stays similar to current levels. Way back in college I used melted antarctica with sea level rise for an evolutionary biology seminar. And it is much less interesting.
I actually did use a rotated map of under-ice Antarctica as the world map for a campaign I made. It worked really well. Realistic looking terrain I didn't need to try to plan myself and unfamiliar wnough to most people that they wouldn't recognize it at a glance.