Keep it cool in remote areas

The heat is heating up in the remote town of Coober Pedy in South Australia. The hottest summer temperatures in this treeless, rocky desert reach 52°C (126°F). Despite this, many of the city’s roughly 2,000 residents found it possible, if not comfortable, to live in the harsh environment: about half of them lived underground.

The discovery of opals in the area led to the creation of the city and eventually to its unconventional architectural style. Located about 850 kilometers (530 mi) northwest of Adelaide, the opal fields were named Coober Pedy, an Aboriginal term meaning “white man in a hole,” in 1920. The city’s growth began to take off in the late 1960s. Driven by increased demand for opal, an increase in the number of workers seeking wealth, and improvements in mining tools.

OLI (Operational Land Imager) on Landsat 8 acquired this image of Coober Pedy on November 6, 2023. The outlines of human settlements and the remains of mining activities stand out against the surrounding dry red areas. The geological environment provided favorable conditions for the formation of colored gemstones. Opal is chemically similar to quartz but lacks its highly organized crystal structure. They formed abundantly around Coober Pedy millions of years ago when dissolved silica precipitated from groundwater and filled cracks in the sandstone.

Hidden from satellite view is a network of subterranean spaces excavated from the soft, porous bedrock. Living underground allows for effective, low-energy, low-tech climate control through passive cooling. In these homes, hotels and restaurants, the temperature remains almost constant at 23 °C (73 °F). Ventilation shafts extend to the roof to ensure oxygen supply and moisture release. The dry climate of the outback also helps prevent rooms from becoming damp and mouldy. In addition, passengers can customize the spaces to their liking.

While opal mining has declined in recent years, the city attracts tourists who want to experience life underground. Visitors can also tour ancient opal mines or venture to the surface to play 18 holes of golf on a grass-free course. To the north of this landscape, Kanku-Breakaways Conservation Park is known for its colorful hills, flat mesas and rocky desert landscape known as the “Jeber Plains” or “Moon Plains.”

A mostly renewable energy grid now supplies the city’s energy needs, augmenting the ancient sustainable technology of passive cooling. An energy project completed in 2017 that integrates solar, wind and battery storage technologies with an existing diesel generator. On several occasions, the grid has operated on 100 percent renewable energy for more than 90 hours at a time.

NASA Earth Observatory image by Wanmei Liang, using Landsat data from the US Geological Survey. Story by Lindsay Dorman.