On a peninsula halfway up the coast of Western Australia are heaps of cubic boulders decorated with more than one million rock carvings, some thought to be 40,000 years old. The petroglyphs are Australia's largest and oldest collection of rock art, providing a continuous record of the Yaburarra people who lived there until the 1860s, when they were wiped out in a massacre. Local archaeologist Ken Mulvaney says the older rock art shows land animals such as kangaroos, but as the sea rose, the images shifted to marine life such as turtles and fish.
     But a kilometre away are some of Australia's largest and dirtiest chemical plants. The air is often fouled with a yellow haze from ammonium nitrate and fertiliser plants, a liquid natural gas processing plant, and the emissions from ships burning sulphur-rich fuel, resulting in increased atmospheric acidity. A Senate committee report will spotlight the problem, but it remains to be seen whether politicians will support measures to protect the art.
     The peninsula was opened for industrial development in the 1960s and 1970s by the state government before people were aware of the significance of the petroglyphs. Some rock art was almost certainly destroyed during development, but in 2007 the federal government placed the remaining carvings on the national heritage register, and part of the peninsula was declared a national park. Despite this, further expansion of industrial activity has been approved by both federal and state governments.
     Retired scientist John Black says the original studies failed to recognise the fragility of the desert patina that gives the rocks their distinctive red colour: "We know the acidity in the atmosphere has increased 1,000-fold due to industry. We know the rock art is being destroyed, we just don't know how fast." Black has analysed colour changes, concluding there has been significant damage.
     Johan Kuylenstierna, a Swedish scientist whose work on acidity and European monuments was used by the government, gave evidence to the Senate inquiry that the use of his study was inappropriate.
     While corporations have made significant financial contributions to the documentation and preservation petroglyphs, they deny any environmental impact. Meanwhile, the state government has made noises about seeking world heritage status for the area.

Edited from The Guardian (6 February 2018)