The environment minister, Murray Watt, has given the greenlight to Woodside Energy’s application to extend the life of one of the world’s biggest liquified natural gas projects from 2030 to 2070.

Watt said he had told Woodside he planned to approve the life extension of the North West Shelf gas processing plant, on the Burrup Peninsula in northern Western Australia, with “strict conditions” relating to local air pollution. Woodside has 10 days to respond.

The proposed approval has come despite some experts raising concerns about the impact of local pollution on a globally significant collection of rock art in the Murujuga cultural landscape, which includes the Burrup Peninsula. The area is home to more than 1m petroglyphs, some nearly 50,000 years old.

Scientists and activists have said the life extension could be linked to up to 6bn tonnes of greenhouse gases being emitted in the decades ahead, mostly after the gas is shipped and burned overseas.

More details to follow