Explained: How climate change is destroying the world’s oldest cave art in Indonesia

The artwork in the area includes what is believed to be the world’s oldest hand stencil (almost 40,000 years ago), created by pressing the hand on a cave wall, and spraying wet red-mulberry pigments over it.

A nearby cave features the world’s oldest depiction of an animal, a warty pig painted on the wall 45,500 years ago.

The cave art of Sulawesi is much older than the prehistoric cave art of Europe.

Findings of the study

The researchers studied flakes of rock that have begun to detach from cave surfaces to find that salts in three of the samples comprise calcium sulphate and sodium chloride, which are known to form crystals on rock surfaces, causing them to break.

The artwork made with pigments was decaying due to a process known as haloclasty, which is triggered by the growth of salt crystals due to repeated changes in temperature and humidity, caused by alternating wet and dry weather in the region.

Indonesia has also experienced several natural disasters in recent years, which have quickened the process of deterioration.

The recommendations

The area is known to be home to over 300 cave paintings, and more are being discovered with further explorations.

While many of these have been studied for several decades, it is only recently that accurate dating has been made possible with newer techniques, enriching our knowledge of their cultural and historical significance.

With increased rapid environmental degradation, the researchers have recommended regular physical and chemical monitoring of the sites, akin to the preservation efforts at the French and Spanish prehistoric cave art sites such as Lascaux and Altamira.