Archaeologist Jannina Campos walks on a sandy hillside in Arica, a port city on the edge of the Atacama Desert, the driest place on the planet. On the hillside there are dozens of orange flags placed last December. Each flag marks each set of remains discovered by unusually strong winds and increased rainfall. “Every time a mummy appears, we put a flag and bury the skeleton. The remains have been preserved there for 7,000 years,” Campos said.

Chinchorro mummy at the San Miguel de Azapa museum in northern Chile.

Archaeologists are faced with a dilemma: find a way to save everything they can or just bury the remains and focus on preserving and studying the unearthed mummies. According to Bernardo Arriaza, a leading expert on the Chinchorro civilization at the University of Tarapacá in Arica, museums are overcrowded.

The rising humidity in the Atacama is destroying the mummies in the collections. Some mummies were moldy, others were dry or gnawed by insects. The combination of multiple wrapping materials makes it difficult for researchers to establish suitable storage conditions. At a museum near the hill, Campos points to dozens of Chinchorro mummies, the sand around which is littered with white debris. “There’s no magic solution. It’s bones turning to dust,” Campos said.

Chinchorro mummy was included in UNESCO’s World Heritage list in July last year after 20 years of applying for certification. There is a project to build a new $19 million air-conditioned museum this year near Arica and growing interest could help prevent the mummies from disappearing.

The Chinchorro mummy is the oldest example of intentional mummification, dating back to 5,000 BC, two millennia older than the Egyptian mummy. The Camarones River valley in the middle of the desert may have attracted the first Chinchorro people to settle here. But the river also contains 1,000 micrograms of arsenic per liter, 100 times higher than the safe level for humans. Every time they drink water, the Chinchorro people inadvertently poison themselves, according to analysis of hair samples. As a result, they also have high rates of miscarriage and stillbirth. Many children were mummified and decorated with masks carved from black manganese.

The researchers hope the Chilean government can better protect the mummies. “Look how many remains appear. If we don’t keep an eye on it, Chinchorro mummy will disappear due to climate change,” said Cristian Zavala, the mayor of Arica.