Murujuga in Western Australia contains the world's largest, densest and most diverse collection of rock art engravings, known as petroglyphs, and some are estimated to be more than 50,000 years old.
The peninsula in northwest WA near Karratha is home to two gas plants, a fertiliser plant and iron ore and salt export facilities.
The industrial emissions they produce cause lower pH and higher acid levels in the local rainwater and on the rock surfaces, a study has found.
An accelerated weathering experiment simulating six years of exposure to rainwater with various acidity levels found industrial emissions were already likely to be degrading the outer layer of the rocks where the petroglyphs are etched.
"The rock varnish on petroglyph-bearing rocks from Murujuga is highly likely impacted by local industrial pollution, with weathering rates most likely already accelerated due to the lower pH of the rainwater," the Bonn University study said.
"Furthermore, it is highly probable that weathering rates will increase further if the pH continues to decrease, as the dissolution rates of the primary phases of the varnish tended to rise at lower pH values.
"The most important finding was that these dissolution rates increased significantly at pH < 5."
Previous reports show acid rain with a pH below 5.6 frequently occurs on Murujuga, with an average pH of 4.6, and that the environment has become more acidic over time, the study said.
Environment Minister Murray Watt announced on Wednesday he would travel to the United Nations Educational, Scientific and Cultural Organisation headquarters in France in a bid to have Murujuga listed as a World Heritage site.
The site was put forward to UNESCO in 2023 but Australia's application was referred back in May.
It recommended state and federal governments address concerns nearby acid emissions, including those from Woodside's Burrup gas hub, were degrading the art.
Mr Watt recently gave provisional approval for a Woodside project on the peninsula to continue operating until 2070.
Mardathoonera woman and Murujuga traditional custodian Raelene Cooper, who is in Paris at the UNESCO meeting, said the study showed how much danger the rock art was in.
"The German researchers found that pH values below five meant an increased rate of weathering and erosion of the rocks, including increased porosity and degradation of the surface layer of the rocks," she said on Thursday.
Murujuga and the surrounding islands are believed to contain more than a million petroglyphs.
They depict animals, plants and human figures, and are visible due to the colour and contrast between the removed varnish layer and the underlying brighter weathered rind of the host rocks.Â
9°C