300 billion dollars is a lot of money. But that's the possible damage this century in Australia - from sea level rise alone. That consists of around 250,000 homes, and a range of other infrastructure including Sydney's main airport.
The science now has the expected sea level rise at between 0.8 and 1.1 metres. The ABC report has links to map simulations of what that might look like.
PS. i still find it a bit sad that things have to be put in dollar values for us to grasp the full severity of the impact.