In Coober Pedy, subterranean buildings must be at least four metres (13ft) deep, to prevent their roofs collapsing – and under this amount of rock, it is always a balmy 23C (73F). While above-ground residents must endure oven-hot summers and frigid winter nights, where it regularly dips to 2-3C (36-37F), subterranean homes remain at perfect room temperature, 24 hours a day, year-round.
Apart from comfort, one major advantage of underground living is money. Coober Pedy generates all its own electricity – 70% of which is powered by wind and solar – but running air conditioning is often impossibly expensive. “To live above ground, you pay an absolute fortune for heating and cooling, when it’s often above 50C (122F) in the summer”, says Jason Wright, a resident who runs Riba’s.
On the other hand, many underground homes in Coober Pedy are relatively affordable. During a recent auction, the average three-bedroom house sold for around AU$40,000 (£21,000 or US$26,000). Though many of these properties were extremely basic or in need of renovation, there’s a large gap between these valuations and those in the nearest major city, Adelaide, where the average house price is AU$700,000 (£361,000 or US$457,000). Other benefits include zero insects – “when you get to the door flies jump off your back, they don’t want to come into the dark and the cold,” says Wright – and a lack of sound and light pollution.
Oddly, the subterranean lifestyle might also provide some protection against earthquakes, which Wright describes as producing a vibrating noise that builds to a crescendo, then rolls through to the other side of the dugout. “We’ve had two since I’ve lived here and I’ve never even flinched,” he says. (However, how safe underground structures are during seismic activity is entirely dependent on how large, complex and deep they are.)
An ideal setup
The question is, could underground homes help people to cope with the effects of climate change elsewhere? And why aren’t they more common?
There are several reasons why making dugouts in Coober Pedy is uniquely practical. The first is the rock – “It’s very soft, you can scratch it with a pocket knife or your fingernail,” says Barry Lewis, who works at the tourist information centre.
Back in the 1960s and 70s, the residents of Coober Pedy expanded their homes the same way they created the opal mines – using explosives, pickaxes and shovels. Some didn’t require much digging at all, with many locals using abandoned mine shafts as a starting point. Today they are often excavated with industrial tunnelling equipment. “A good tunnelling machine can do about six cubic metres (211 cubic ft) of rock per hour, so you could have a dugout made in less than a month,” says Wright.
However, it’s still possible to excavate by hand – so when residents need more space, they sometimes simply start hacking. And as an opal mining area, it’s not unheard of for a renovation project to actually make money. One man discovered a large gem sticking out of the wall when he was installing a shower, and a local hotel discovered opals worth AU$1.5m (£774,000/$985,000) while building an extension.