Aboriginal elders call the ancient paintings and engravings that dot the landscape their history books.

But while Australia has some of the world's most outstanding and abundant rock art, experts say half of it could disappear over the next 50 years unless it is better protected.

Urban development, mining and vandalism – as well as erosion and other natural processes – are among threats to the art found in rock shelters, often in remote areas. Some sites have already been bulldozed, or had paintings defaced or carved out. Many Aboriginal communities have lost their connection with the art, which their ancestors looked after and retouched over generations.

One obstacle facing conservationists is that knowledge is fragmented; no one is even sure how many sites there are, although estimates suggest up to 100,000. Academics are calling for a national database to be set up, which would enable them to document the images properly and identify those most at risk. But they need to raise A$6m (£3.9m), which has not yet been forthcoming –although the Art Gallery of New South Wales spent a similar sum last year on one painting by the Australian artist Sir Sidney Nolan.

Few Australians know or care much about Aboriginal rock art, according to Paul Tacon, a professor of anthropology and archaeology at Griffith University in Queensland. "South Africa has a European colonial history too, but everyone in South Africa values their rock art heritage," he says. "Although the contemporary French are not related to the people who made their paintings, it's a source of national pride."

The oldest surviving Aboriginal art dates back 15,000 years, compared with the estimated 34,000-year-old cave paintings at Chauvet, in southern France. However, archaeologists have found evidence – including pieces of ochre, used for pigment – that Aboriginal people began producing art soon after arriving in Australia more than 45,000 years ago.

While sites are still being discovered, some of the most significant include Djulirri, in the Arnhem Land region of the Northern Territory, which contains 3,000 paintings, stencils and beeswax images. Created and added to over 15,000 years, they depict native animals long extinct, the arrival of Europeans on their ships, and modern inventions such as a the bicycle and biplane.

The Pilbara, in Western Australia, has vast quantities of art, but the resource-rich area has also seen a rapid expansion of mining activity. On the Burrup Peninsula, home to the world's largest concentration of petroglyphs, many sites were destroyed in the 1960s and 1970s. More recently, carvings have been cut out and relocated – to the chagrin of archaeologists, who say that context is all-important.

Rock art specialists want to pinpoint Australia's top 100 sites, and then use advanced technology such as laser scanning to produce 3D digital replicas. "The art is disappearing at an alarming rate, so we need to get good records of it before it's lost," says Wayne Brennan, an archaeologist with part-indigenous heritage.

Until now, archives have been kept by state and territory governments, museums, universities, national parks bodies, Aboriginal communities and individual researchers. Professor Tacon says: "It's extremely important to bring these diverse records together, because at the moment rock art research, conservation and management happen on an ad hoc basis. Some sites have been lost because people haven't realised their importance."

He laments the lack of regard for the art, which he attributes to generations of disconnection from and disrespect for Aboriginal culture. When he and his colleagues approached a major television network to discuss their plans for a national register, a producer told them: "That's just Abo stuff. We don't do Abo stuff."

Professor Tacon says: "A lot of people are simply not aware that this is part of our national heritage and identity; it's not just something indigenous. We want to raise awareness that these are important, special places; they are part of the Australian identity."

Although not as old as the art at Chauvet and other European cave sites, Aboriginal rock art is considered significant because of the sheer volume of it, the powerful quality of some of the work and the fact it was created continuously over the millennia until about 20 years ago. Unlike most other countries colonised by Europeans, Australia also has plentiful art from the "contact period".

And while artefacts such as wooden boomerangs and woven baskets have not survived in archaeological deposits, the paintings show how Australians lived, celebrated and hunted thousands of years ago.

Alistair Paterson, an archaeology professor at the University of Western Australia, says: "The art is globally significant because Australia was colonised by modern humans [Aboriginal people] earlier than they got to Europe. It tells the incredible story of how over time all these people have dealt with the Australian country and landscape."

Unlike the European cave art, the rock shelter images are relatively exposed. Over the years, rocks have cracked and crumbled, water has seeped through walls and wind has caused erosion. Paintings have also been lost as a result of pigs rubbing themselves against them. Bushfires represent another threat.