Home Archeology Climate change turning Chilean mummies into gross tar

Climate change turning Chilean mummies into gross tar

Mummification is meant to preserve bodies. While it’s not perfect, past civilizations like Chile’s Chinchorro people did it well enough for bodies mummified thousands of years before the Egyptians to last to the present day. The mummies face a modern problem, though – according to Harvard researchers, rising humidity in the region is causing the mummies to rapidly decompose.

In some cases, the decomposition is shocking. Some of the specimens broke down into what the researchers described as a “black ooze” (imagine the smell).

“We knew the mummies were degrading but nobody understood why,” said Ralph Mitchell, Gordon McKay Professor of Applied Biology, Emeritus at Harvard School of Engineering and Applied Sciences (SEAS). “This kind of degradation has never been studied before. We wanted to answer two questions: what was causing it and what could we do to prevent further degradation?”

To answer the first question, Mitchell and co. hypothesized that the decomposition was microbial. In order to test that, they needed skin, and lots of it – samples from both compromised mummies and unharmed ones.

Mitchell, along with research fellow Alice DeAraujo, was able to isolate the microbe he believed to be responsible for the degradation. Since there was only so much skin to work with, the researchers used pig skin analogs to grow cultures in the lab and expose the microbe to different humidity levels. The analog tests seemed encouraging, and the tests on mummy skin confirmed their suspicions: High humidity allows the microbe to flourish.

Some quick climate research confirmed that, yes, humidity levels were on the rise along the coast of Chile and Peru where the Chinchorro buried their dead.

DeAraujo’s research found that the ideal humidity levels for mummy preservation fall between 40 and 60%. Lower humidity risks destructive acidification, while higher levels can result in the gross black goop the researchers witnessed in Chile. Their findings are invaluable for museums, who can use the knowledge to ensure their displays are ideal for mummy preservation. But what about in the field, where thousands of Chinchorro mummies are believed to be buried just below the surface?

Mitchell isn’t sure himself – he’s not a climatologist, after all – but the solution will likely be something very high tech, and something we don’t presently have.