Western Australia chemical plants threaten 40,000-year-old rock art

On a far flung peninsula halfway up the coast of Western Australia are strange piles of cubic boulders that look like rusty refrigerators and boxes. Decorating their flat faces are more than one million rock carvings, some believed to be as much as .

Environmentalists, scientists and archaeologists are campaigning to protect Australia’s oldest rock art
from emissions [Credit: Ken Mulvaney]

The petroglyphs at the Burrup Peninsula, also known as Murujuga by the traditional custodians, are Australia’s largest and oldest collection of rock art.

They provide an extraordinary and unique continuous record of the stories and life of the Yaburarra people who lived there until the 1860s when they were wiped out in a massacre.

But a kilometre away are some of Australia’s largest and dirtiest chemical plants. The air that hangs over this remote peninsula is often fouled with a yellow haze from the chimneys of the Yara ammonium nitrate and fertiliser plants, Woodside’s LNG gas processing plant and the emissions from ships burning sulphur-rich bunker fuel as they visit the port to pick up Rio Tinto’s iron ore.

The result is an increase in atmospheric acidity that archaeologists, scientists and environmentalists say is dissolving the rocks and threatening the future of the rock art.

This week a Senate committee is expected to release a report that will again put the spotlight on the delicate balancing act between preservation of this national treasure and industry.

But whether politicians will have the stomach for some of the costly and difficult measures they say are needed to protect the art remains to be seen. There is also a raging debate over the scientific studies that have been used to say that industry and the rock art can safely co-exist.

“The earliest rock art was done during the ice age,” says Judith Hugo, convener of Friends of Australian Rock Art. “It is a record of mankind’s survival over 40,000 years, through climate change and rising of sea levels,” she says. “There’s nowhere else like it in the world.”

Local archaeologist Ken Mulvaney explains that 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. The petroglyphs also record the life of the Yaburarra people.

There are also many images of human faces and figures, though the Indigenous custodians – whose tribes also regard the peninsula as a sacred place – request that these not be reproduced.

Woodside’s Pluto LNG plant at Burrup Peninsula , Western Australia, with rock
carving of an echidna in foreground [Credit: Ken Mulvaney]

The Burrup peninsula was opened up for industrial development in the 1960s and 1970s by the Western Australian government before people were aware of the significance of the huge trove of petroglyphs. Some rock art was almost certainly destroyed during development, but in 2007 the remaining carvings were placed on the national heritage register by the federal government and part of the peninsula was declared a national park.

Despite this, further expansion of industrial activity has been given environmental approval by both the federal and state governments based on what campaigners say was flawed science by the CSIRO on the ability of the rock art to withstand up to 1,000 times higher levels of acidity in the atmosphere. The most recent is the Yara ammonium nitrate explosives plant, approved in 2015.

There are still more vacant industrial sites on the peninsula.

John Black, a retired CSIRO scientist, whose specialty was animal physiology, has led the charge to point out the  in the science agency’s work. He fell in love with Indigenous rock art while working as a rural firefighter in the Blue Mountains and has used his background in science to take on his former employer.

He says CSIRO’s original conclusions on the type of rock at the site, based on satellite mapping, were incorrect and have failed to recognise the fragility of delicate desert patina that covers the rocks and gives them their distinctive red colour.

“These are igneous rocks. They cooled under enormous pressure and so are very hard and have very fine crystals,” Black says.

“The rock doesn’t exfoliate so there is almost no soil on the hills. But the rock develops a weathering rind of up to 5mm. Then it develops a desert varnish, which is believed to be formed by small microrganisms that can survive in temperatures ranging from 20 C to 80C and which use manganese and iron ore dust as a shield,” he says.

That patina develops very slowly and has helped protect the rock art over the centuries. It is now at risk from the higher acidity, he says.

“We know the acidity in the atmosphere has increased 1,000-fold due to industry,” he says. “We know the rock art is being destroyed, we just don’t know how fast.”

Johan Kuylenstierna, a Swedish scientist whose work on acidity and European monuments was relied upon by CSIRO to justify its approach to weathering of stone from industrial processes, gave evidence to the Senate inquiry that the use of his study was inappropriate.

Black has also analysed CSIRO’s monitoring of colour changes in the Burrup rock art. His conclusion is the data shows significant change to the colour of the rocks.

Rock engravings at Burrup Peninsula in Western Australia, Australia. The collection of petroglyphs is the oldest
and largest in Australia [Credit: Ken Mulvaney]

Those finding have been published in peer-reviewed journals, but the CSIRO was still pushing back on the criticisms when it appeared at the inquiry late last year.

“Black is basically right,” said WA Greens senator Rachel Siewart, who has spent years fighting for better protections for Burrup. “In my opinion the CSIRO really made a hash of it.”

But whether Siewert can convince her colleagues at the inquiry to embrace the tough recommendations she believes will be needed to protect the rock art is an open question.

The WA government has made supportive noises about seeking a world heritage listing which would increase the responsiblity on the federal government to protect the site. It would arguably act as a deterrent to companies who might be eyeing the vacant industrial land nearby for development.

Another, less easy change would be to require ships visiting the area to run on low-sulphur fuel as used by cruise ships while visiting cities.

But requiring world’s best practice on emissions stacks as well as banning future expansion of industry on the Burrup peninsula will come with serious costs.

The CSIRO studies are at the heart of those approvals, so if the Senate committee accepts Black’s findings, it is likely the plants will be forced to change the way they operate.

Siewert says she would like to see a recommendation from the committee that the Yara plant be moved elsewhere in the state.

Rio Tinto, Woodside and Yara have all made significant financial contributions to the documentation and preservation of the Burrup peninsula petroglyphs as part of their development conditions. Rio funds Mulvaney’s position as an archaeologist. Funds have also been earmarked by Woodside and Yara for a knowledge centre and the companies support the traditional owners in a ranger program.

But the companies are likely to baulk at options that require major changes.

Yara said in its submission: “To date, there is no credible scientific evidence to indicate that existing industrial emissions have had any measurable impact on the rock art on the Burrup Peninsula. The established monitoring regime for rock art is rigorous [and] has been modified to take account of potential issues raised by concerned parties.”

A spokesman for Yara said the company was concerned that the recommendations would be informed more by politics than science.

Author: Anne Davies | Source: The Guardian [February 06, 2018]