Since coming to Australia in 1999 I've been involved in many conversations about the size of this country. Foreigners, halfwitted politicians and some econimists point to its vast area and its relatively small population and suggest that we can carry many more people.
My response has always been to say that you need to think of Australia as an archipelago of fairly small islands surrounded by oceans, some of them wet, some of them dry; exceptionally dry. Now, at last US geogapher Steven Young has obliged that scenario with an animation based on rising sea levels.
When I think of Australia as a habitable continent, it looks almost exactly like the 300 metres sea level rise except for one thing, by that stage all the fertile land would be gone as well.