A hand-drawn warty pig has adorned a cave wall in southern Sulawesi, Indonesia, for more than 45,500 years. But now, the porcine image is deteriorating thanks to climate change, according to a new study published in Nature.
The study by Jill Huntley and other researchers from the Place, Evolution and Rock Art Heritage Unit at Australia’s Griffith University focused on a limestone karst area called Maros-Pangkep. Uranium-series dating established the warty pig as the world’s earliest known representational artwork. In addition to the warty pig, Maros-Pangkep’s more than 300 cave sites include the oldest known hand stencil in the world, drawings of human/animal composites and a hunting scene that some researchers claim is the earliest known narrative scene in prehistoric art.
Cave art worldwide is falling victim to extreme weather events and frequent cycling between monsoon rainfall and dry conditions. Additionally, salts build up on the cave surfaces, exfoliating the paintings. Also known as haloclasty, salt crystallization cracks the surface of rocks and makes artwork flake off.
Sulawesi is especially susceptible to climate change, as it’s in one of the planet’s most atmospherically dynamic spots. It’s the largest island in the biogeographically distinct zone called Wallacea, which consists of oceanic islands between Australia and Asia. Humans have inhabited these islands for an awfully long time, and their cave art proves it. They used mulberry for purplish-red and ochre mineral pigments for yellowish-brown. These early artists were prolific — contemporary researchers discover more cave art sites in Sulawesi every year.
Unfortunately, prospects for the cave art aren’t good. “The extent of salt efflorescence in the 11 Maros-Pangkep sites we investigated, coupled with conservative forecasts for a 1.5 to 2 °C raise in global temperatures and accompanying extreme weather events, have grave implications for the conservation of this globally significant cultural heritage,” the study explained. “Aside from continuing limestone quarrying for the burgeoning domestic cement and marmer (marble) industries, global warming should be regarded as the greatest threat to the preservation of the ancient rock art that survives in Sulawesi and other parts of tropical Indonesia.”
Lead photo © A. A. Oktaviana, ARKENAS/Griffith University