Sydney is no stranger to extreme heat. In January 2020, Penrith in Western Sydney reached 48.9°C, the highest temperature ever recorded in Greater Sydney.

Now imagine Penrith in 2050: the heat lasts longer, extreme heat events happen more often, and power goes out on the hottest days because the grid can’t cope.

Our recent research, published in the journal Energy and Buildings, shows Sydney apartments built to current building codes may become very uncomfortable by 2050 far more often. In fact, we found that inside an apartment built to today’s standards, temperatures would stay above 30°C for several days in a row.

Sydney is rapidly rezoning, leads the nation in apartment living, and is still racing to build more homes. Many of the developments approved today will still be standing in 2050.

But while we are building for the future, we are designing for the past.

Building for yesterday’s climate

Our study used the latest climate projections for Sydney to test apartments built to today’s standards in inner-city Redfern and Western Sydney’s Penrith.

By the 2050s, owing to climate change, Sydney’s median outdoor temperatures could be up to 5°C higher than today in its hotter inland areas under the highest-warming regional projection (a high greenhouse gas emissions scenario known to researchers and policymakers as SSP3–7.0), with hot days becoming longer and more frequent.

We found apartments built to today’s standards........

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