A national flood management conference has been told town planning might be the country's best defence.
About 500 experts and policymakers from across Australia and the world are at the three-day event in Sydney.
The President of Floodplain Management Australia, Ian Dinham, opened the conference with advice for those looking to solve Australia's housing crisis.
"Having made mistakes in the past as to where we have put dwellings, let's not build any more houses for people to live in flood-prone areas," he said.
"That's a message that's very difficult, with development pressures happening for governments to deal with.
"We need to get smarter about how to do that."
Bigger floods will happen
Recent years have been catastrophic for flooding in Australia and around the world.
One thousand people died from flooding in Pakistan, the damage bill from Hurricane Ian in the United States was more than US$100 billion.
In Australia, 38 have people died in recent floods, and the damage bill for the floods in Northern NSW and south-east Queensland is more than $5 billion, making it the most expensive disaster in Australian history.
Mr Dinham warned Australians to expect more of the same.
"Unprecedented floods can and will happen in the future," he said.
"We need to come together, pool our thoughts and deal with what we know is coming down the road."
Outdated planning guidelines
Tom Remenyi is a climate researcher and director of the climate education agency Acclimatised.
He has studied climate in relation to agriculture and the environment.
"We have not been taking enough action to mitigate climate change internationally. We are 20 years behind," Dr Remenyi said.
"We are on track to see [temperatures increase] by more than 1.5 degrees [Celsius], so we have some big international social issues to address."
While Mr Dinham wants governments to look at where houses are built, Dr Remenyi says we need to look at how we build.
Current construction guidelines are old and outdated, Dr Remenyi says, including stipulations on gutters and downpipes and street drainage sizes.
"Historically, we have assumed a stationary climate, which means you do those figures once and it's good forever. But that's no longer true," Dr Remenyi said.
"We need a team that is constantly reviewing that, and it is very different in different parts of Australia.
"We are definitely going to have a warmer climate [and] when it does rain, it will rain stronger. These two things are certainties."
Dangerous places to farm
The conference also heard about the dangers of farming in the future.
"It needs to be done in the best place for that task and sometimes the best place is a dangerous place; a floodplain," Dr Remenyi said.
"We have destroyed riparian zones across Australia, which hold our river systems in place.
"We need to re-build these zones so the water gets filtered by the natural system and gets slowed down and pushed out into the sub-soils."
That could mean giving up some prime farming land, which Dr Remenyi says must be done in fair ways to farmers and without hindering the nation's food supply.
The ABC approached the NSW Department of Planning and Environment, which had presenters at the conference, but they were not available for interview.
