World’s largest collection of ancient rock art threatened by Australia’s petrochemical plants

Dec 25, 2023

The Murujuga rock art, the world's largest and oldest collection of petroglyphs, has survived 40,000 years or so out in the open on a finger of land extending from Australia's northwestern coast. "Murujuga is the most important rock art site in the world," says Michel Lorblanchet, an archaeologist at CNRS, the French national research agency, who is noted for his work on European cave art.

It may also be the most threatened. Scientists and the First Nations custodians of the site are warning that acidic emissions from a nearby petrochemical complex are etching away images densely spread across the 30-by-6-kilometer Burrup Peninsula and on nearby islands. And the pollution is about to get worse. Last month work began on a new fertilizer plant, and a new natural gas processing facility is in planning.

If realized, the expanded complex "would be the most polluting project ever to be developed in Australia," asserts the Conservation Council of Western Australia. The additional emissions could make it difficult for Australia to meet its commitment to reducing greenhouse gas emissions, says Bill Hare, a climate scientist with Climate Analytics, a policy institute. As for the rock art, "We will start to see degradation very clearly within people's lifetimes," predicts Benjamin Smith, a rock art specialist at the University of Western Australia.

The Murujuga rocks look like random jumbles of blocks with a reddish brown patina slowly built up by mineralization. Some 40,000 years ago, Aboriginal artists began pecking and scratching through the patina to expose the grayish rock beneath, ultimately creating more than 1 million images. "When these rock art images were made, they would have been very visible," Smith says.

The rock art provides an archaeological record of traditional use of the area over thousands of years. The petroglyphs include some of the world's earliest known depictions of human faces, complex geometric designs, and images of marine and terrestrial fauna, including extinct animals such as the fat-tailed kangaroo and the thylacine, that illustrate how the ecosystem changed through rising and falling sea levels. The artistry ended in 1868, when European settlers decimated the local Yaburara People in what is known as the Flying Foam Massacre.

Today, the rock sites hold a spiritual significance for First Nations peoples that many liken to what European cathedrals once meant for Christians. But the rock art is even more vital and important because Australia's First Peoples never developed a written language. Murujuga "is our parliament, it is a gathering place where we have our politics, our governance, our laws, and our protocols," says Josie Alec, a member of the Kuruma and Mardudhunera peoples and a Murujuga traditional custodian. Looking after Ngurra, or Earth, "is a way of making sure humanity's future generations have a safe place to live," adds Raelene Cooper, a member of the Mardudhunera People who also serves as a custodian.

In the 1960s, when officials were looking to build a cargo port on the northwestern coast to ship iron ore from inland mines, they knew little about the Murujuga rock art and did not consult with local First Nations peoples. Antiquities experts recommended the Burrup Peninsula to avoid damaging other known Aboriginal sites. Later, as the significance of the Murujuga rock art was recognized, people realized the port siting was a "terrible mistake," Smith says. Once built, the port attracted other industry. A large sea salt–evaporation operation soon came online. The discovery of offshore gas fields spurred the development of gas processing facilities and a mammoth fertilizer plant. The peninsula now hosts Australia's largest petrochemical complex.

Construction projects destroyed an estimated 10,000 petroglyphs before the rock art began to receive protection. In 2013, more than 40% of the peninsula was incorporated into Murujuga National Park, which is jointly managed by the Murujuga Aboriginal Corporation and the Western Australia state government.

That move hasn't protected the art from air pollution, researchers say. Satellite observations show the natural gas plants create clouds of nitrogen oxides. Smith and colleagues have shown that dust and rain drop oxides onto rock surfaces, and lab experiments indicate the oxides form acids that erode the patina. Reducing industrial emissions is "essential if damage to the rock art is to be limited and this iconic cultural place is to remain largely intact for future generations," the researchers wrote last year in Conservation and Management of Archaeological Sites.

In 2021, Alec and Cooper formed the group Save Our Songlines, which is demanding a halt to the new fertilizer and natural gas projects. Allowing construction to proceed will "harm our world and humanity with emissions," Cooper says.

So far, however, government officials have only committed to review the potential impact of emissions under a provision of a federal Aboriginal and Torres Strait Islander Heritage Protection Act. The review could stop the projects, but opponents say that is unlikely.

Woodside Energy, the company behind the existing and proposed natural gas plants, claims that the emissions do not pose a threat. "Peer-reviewed research has not demonstrated any impacts on Burrup rock art from emissions associated with Woodside's operations," reads a statement on its website. But in a recent study that compared past and current photographs of 26 petroglyphs, Smith's group found that half were damaged, two substantially. Those closest to the petrochemical complex suffered the greatest degradation.

Smith hopes worldwide concern for the rock art will put pressure on industry to "get its act together by putting [emissions] scrubbers in those stacks," and on the government to "get its act together by putting new industry somewhere else." Action is urgent, he says. "You can't remake this rock. Once it's gone, it's gone forever."