Habitat loss? What's the current status of the problem, how bad is it and what would happen in the future if nothing is done to fix it ?...

It is hard to say exactly how bad the problem of habitat loss is.  The amount of habitat loss for polar bears, for example, is much less than the amount of habitat loss for grizzly bears.  And, looking at the United States, the amount of habitat loss for grizzly bears in the "lower 48" states is much more than in Alaska.  So the amount of loss varies by species and by place.

If nothing is done about it, it is conceivable that all animals that cannot coexist with human beings could become extinct.  There would still be many animals.  There would be domesticated animals and there would be wild animals like birds that can live in places where people live.  But if habitat loss continues, many more wild species could become extinct (at least in the wild).