A global housing affordability crisis is underway, so when the Center for Demographics and Policy at Chapman University in the U.S. released a report this year highlighting the “disastrous” state of housing affordability for 94 markets — where median home prices far exceed median wages by many times, making housing much more expensive for the current generation of first-time homebuyers than for their parents — it wasn’t surprising.About 1.6 billion people currently need adequate housing, and UN-Habitat, the United Nations’ Human Settlements Programme, says that in just a few years that number could rise to three billion. That means the world will need to build 96,000 affordable homes every day, starting now, to address this problem. Such an effort will require not just addressing the equity of housing, but the sustainable use of materials, tax incentives, zoning policy, manufacturing, and upskilling workforces to adapt to new practices.On this third episode of the Mongabay Explores podcast season on the circular economy — the effort to design goods to be less resource-intensive, from their manufacture to disposal and recycling — Louise Dorignon, a postdoctoral research fellow and housing circularity expert at RMIT University in Melbourne, details a housing reform plan to address sustainability in the most unaffordable housing market in the English-speaking world: Australia.“Our goal was to find out how implementing a circular economy approach can lead to a more sustainable housing system. And we didn’t want to juxtapose sustainability and circular economy as two different things. But instead, we wanted to see how they work together,” Dorignon says.Australia is well known for its high home prices, where the housing market is treated like a speculative investment. Auctioning homes is common, and combined with a shortage of new housing stock, hundreds of thousands of empty homes in cities like Melbourne and Sydney sit empty while tax incentives favor the wealthy, entrenching inequality.A multitude of solutions and case studies exist internationally in places like Singapore, Tokyo, Vienna and elsewhere, Dorignon points out. Taking their approaches seriously in nations like Australia is crucial to solving housing sustainability issues.“The main lesson would be to look at examples of policies that Australia could perhaps develop, and things like you see in Europe like tax incentives and subsidies and grants to really [push] and lift sustainability,” she says.One solution is to reappraise property and incorporate sustainability into its value.“I think that would overall push landlords [to] improve the quality of the homes they’re trying to let. And so overall, the stock would be in better condition,” she says.However, overhauling manufacturing practices and zoning to allow densification in well-located areas is also necessary.“The ‘missing middle’ typology [would] focus our efforts on densifying our suburbs and buil