In a changing climate, mould is here to stay

Industrial-grade dehumidifiers, damp walls, leaky ceilings: riding off the back of record rainfalls in Sydney, mould has once again invited itself into the homes of the North Shore. 

Intense weather, mouldy times ahead

Heavier, more intense rainfall events – and higher overall humidity – are two things we can expect to see as the climate warms. These two effects also happen to be driving factors in the growth of household mould. 

These weather patterns are a product of climate change. According to the Climate Council, “increasing global heat, driven primarily by the burning of fossil fuels is exacerbating extreme weather events around the globe.”

Does more mould create a greater health hazard?

Given Sydney's humid subtropic climate, mould isn’t anything new to most residents – but our construction guidelines have only relatively recently adapted to deal with the health hazard.

A study conducted by the Lawrence Berkeley National Laboratory in California found the growth of mould does increase with a warming climate, and also predicted “substantial health effects from even moderate increases” in building dampness and mould. These effects would include increases to both common respiratory infections as well as asthma. 

Are we prepared for more mould?

In 2019, additions were made to the National Construction Code — the legislated set of minimum requirements for buildings in Australia — to address the risk of condensation and mould in Australian houses. 

Despite this, architectural scientist Dr Tim Law estimated that in 2023 more than half of Australian properties still have a mould problem. 

In an earlier study on condensation in residential buildings, Law — along with other experts in the field — found that while in other developed nations, preventing mould and condensation was considered the responsibility of designers and builders, in Australia, “condensation and mould are the fault of the building occupant and not the building”.

NSW gets wetter and mouldier

If the precedent set by this month's record rainfall is anything to go by, New South Wales is set to get wetter and mouldier. While leaky roofs and moldy walls seem minute compared to floods that have ravaged the Mid North Coast and Northern Rivers regions, the broader impact of a mouldier country will be brutal.

Because the cost won’t just be measured in terms of health, but finance. 

In 2023 Rebecca Bentley, a Professor of Population and Global Health, told the ABC the financial impact of mould in Australia could reach $1.35 billion in healthcare expenditure and $7.5 billion in productivity losses.

Image Credit: Sandy Millar via Unsplash