“By the 2050s, median outdoor temperatures in Sydney’s hotter inland areas could rise by up to 5°C under high-emissions climate scenarios, with hot days becoming longer and more frequent,” said Dr Jingjing Liu from the School of Architecture, Design and Planning.
Under these conditions:
During extreme heat events, under the high-emission scenario, indoor temperatures could remain above 30°C for several consecutive days.
The findings have significant implications for public health, especially during prolonged heatwaves and potential power outages.
“In a future heatwave combined with a blackout, many apartments simply won’t be able to keep residents safe,” said Dr Haddad.
Heat stress is an increasingly important issue for the health and well-being of populations exposed to high temperatures and humidity.
“People often assume air conditioning (AC) will solve the problem, but not everyone can afford to install or run air conditioning due to cooling poverty, and during power outages, it may not be available.
“Also, while AC can provide relief against heat stress, widespread use of AC can add pressure on electricity systems and even more heat to our cities,” said Dr Haddad.
Older people, low-income households, renters and people with chronic health conditions are expected to be among those most vulnerable.
The research argues that Australia’s building regulations should move beyond measuring energy efficiency based on historical weather data and instead assess a building’s “passive survivability” - its ability to maintain safe indoor temperatures during extreme heat without relying on air conditioning.
Passive building strategies, including cool roofs, natural ventilation, and shading have proven to be effective in improving cooling comfort, while typically being affordable solutions.