Scientists around the world say the findings of a new report claiming industrial pollution has no effect on ancient rock art are patently wrong and could have disastrous ramifications.
Rock conservationists Ian MacLeod and Warren Fish recently published a paper, commissioned by fertilizer manufacturer Yara Pilbara, that suggests there is no adverse impact on the engraved rock art of Murujuga from industrial pollution.
However, many other scientists believe their findings are flawed.
What is at stake is Western Australia's 50,000-year-old natural rock art gallery of more than 1 million petroglyphs at Murujuga, also known as Burrup Peninsula.
Murujuga contains the highest concentration of ancient rock engravings in the world, some of which are thought to depict the earliest known representations of the human face.
They are said to capture more than 50,000 years of Indigenous knowledge and spiritual beliefs.
But on Murujuga's doorstep is the ever-expanding operations of Woodside Petroleum, Rio Tinto and Yara Pilbara — with the area flagged to become one of the largest industrial hubs in the Southern Hemisphere.
Rock art could be 'gone in 100 years'
To refute the claims by Ian MacLeod and Warren Fish, seven world renowned scientists have compiled four years of research to prove the ancient rock art at Murujuga is under threat from industrial pollution.
University of Western Australia world rock art professor Benjamin Smith led the research, and said it was important to get the facts right.
Nitrogen oxides, released from industrial activity, land on the rocks as dust, which then mixes with rain and dew to form acids that degrade the patina, a varnish that coats the rocks into which the engravings are carved.
Professor Smith said that over time, the patina would be dissolved by the acid and the petroglyphs would be permanently lost.
What is in question, is the rate of acceleration of the decay caused by industrial pollution.
Professor Smith said he was unsure of an exact point of no return for the rocks, but believed it was imminent.
"The emission coming out of Woodside and Yara are enough, we know, to start eroding the manganese and iron out of the surfaces of the rock," he said.
"What we are trying to work out is how fast they are degrading.
Among the team of scientists who contributed to Professor Smith's paper were petroglyph authority Professor John Black from the University of Western Australia, Dr Stéphane Hœrlé from the University of Bordeaux in France, and Dr Thorsten Geisler from the University of Bonn, Germany.
'Juukan Gorge in slow motion'
The Conservation Council of WA believes Woodside's proposed Burrup Hub LNG expansion would further exacerbate the precarious future of the rock art.
The $16 billion Scarborough gas field development is projected to produce 3.31 million tonnes of CO2 equivalent per annum.
The council's policy and legal director, Piers Verstegen, said the long-term impact of the expansion project was most concerning.
"Woodside's plans to further expand gas production would add significant amounts of new emissions and pollution," Mr Verstegen said.
"It's almost a case of Juukan Gorge in slow motion.
"We've got reliance on Section 18 approvals that were provided many years ago, and we've got traditional owners who are constrained from speaking out."
The controversial findings
In 2016, Dr MacLeod, a conservation scientist whose career with WA's Maritime Museum spanned almost 40 years, told the ABC that he was "sure as night follows day" that increased emissions would fast-track the demise of the rock art at Murujuga.
But now, five years later, Dr MacLeod estimates that has more than 1,385 separate pH rock measurements under his belt, with evidence pointing to the contrary.
"A pattern is emerging that it is largely controlled by the natural environment and the impact of man-made emissions appears to be steady and is certainly not getting any worse," Dr MacLeod said.
However, Dr MacLeod said he could not deny there was evidence to support that industrial activity caused acidic emissions that could impact the rock art.
Industry and government response
Environment Minister Amber-Jade Sanderson said the WA government was committed to protecting the Murujuga rock art through a suite of measures.
"We are also considering other measures including limiting the land available for industrial development."
A Woodside spokesperson said the company's growth projects were informed by archaeological and ethnographic surveys, consultation with traditional custodians and the development of cultural heritage management plans.
"No impacts are predicted to the sites identified by these surveys," the Woodside spokesperson said.
Yara Pilbara said it had maintained an annual rock art monitoring programme using independent experts for the past five years.
"The analysis undertaken by the independent experts has concluded that there is presently no adverse impact on the rock engravings from Yara Pilbara's operations," a Yara spokesperson said.
