Australia is unlikely to meet water quality targets designed to protect the Great Barrier Reef, researchers from the federal government’s marine science agency have warned.

Scientists, including two from the Australian Institute of Marine Science (AIMS), have published a study that says current efforts to reduce pollution run-off into the reef’s waters are not enough to meet set targets.

Their findings, published in the Global Change Biology journal on Sunday, came as the Queensland government gave the go-ahead for Australia’s largest coalmine to proceed.

“We reviewed the most recent science and also looked at the report cards on progress towards the targets, and we found that it’s unlikely that the Reef 2050 Plan water quality targets will be met,” AIMS researcher Dr Frederieke Kroon said.

Australia’s Reef 2050 plan was submitted to Unesco last year and was key to keeping the Great Barrier Reef off the world heritage committee’s “in danger” list.

The plan includes goals to reduce nitrogen run-off in key catchments by up to 80% by 2025, and to cut total suspended sediment run-off by up to 50% within the same timeframe.

Using land for grazing or for growing crops such as sugar cane and bananas causes nutrients, sediments and pesticides to run off into catchments and end up in the waters of the Great Barrier Reef.

Land-based pollution is just one of the threats faced by the natural wonder.

Kroon said current efforts to reduce pollution run-off were based on voluntary adoption of best management practices and weren’t enough.

Her paper cites successful international interventions in Denmark and China and recommends three options for meeting water quality targets in Australia – introducing legislation, changing agricultural land use, or retiring cropping land.

The researchers found that success in reducing nutrient or sediment loads to coastal waters overseas involved legislation combined with a long-term political commitment over decades.

“It’s not a quick fix. It’s just not feasible and certainly not at the scale of the Great Barrier Reef,” Kroon said.

On Sunday the Queensland government announced it had granted mining leases for Adani’s Carmichael coalmine in the Galilee basin, a move conservationists warn will compound threats to the Great Barrier Reef.