If it was the first ever flood for Brisbane, people could then look at contemporary issues like global warming. But Brisbane has flooded periodically for centuries. It occurred because of a combination of weather events, not because of anything human civilisation did. It actually would have been a lot worse if we hadn't of 'interfered' by building the giant Wivenhoe Dam 30 years ago. It's still holding back several 'Sydney Harbours' of water that was prevented from going through the city last week with the rest of the rain.