CANBERRA, AAP – New coal mining proposed for the Hunter region must be stopped because there isn’t enough rail or port capacity or global demand to shift it, a report backed by Malcolm Turnbull warns.

“We want it to decline,” the ex-prime minister said on Wednesday.

“If it doesn’t decline, we’re going to keep burning coal and we’ll never reach our greenhouse gas emission reduction goals globally, let alone nationally.”

Proposals for new coal projects have a combined output of almost 100 million tonnes per year or 10 new Adani-sized mines in the Upper Hunter Valley alone, according to the left-leaning Australia Institute.

Now head of the NSW Net Zero Emissions and Clean Economy Board, Mr Turnbull said a comprehensive plan and moratorium needs to replace the focus on transient royalties.

Coal-rich NSW has a net zero emissions by 2050 policy that is matched, or bettered, by all of Australia’s states and territories.

Prime Minister Scott Morrison has said Australia should get to net zero emissions “as soon as possible”, perhaps by 2050, but is yet to make that a federal policy.

Richard Denniss, chief economist at the institute, said existing coal mines are already operating well below their approved capacity.

“Trying to build 10 new Adani mines’ worth of coal mines in the Upper Hunter at precisely the time world demand for coal is falling is absurd,” he said.

Dr Denniss said the coal industry is currently proposing 23 new coal mines and mine extensions across all of NSW with a combined additional annual production of more than 155 million tonnes.

These proposals follow the doubling of production from 130 million tonnes in 2000 to 260 million tonnes in 2014, the report found.

Governments and the coal industry expected this growth to continue, but NSW production peaked in 2014.

Plans to expand the export capacity of the Newcastle Port were scrapped in 2018, with the coal industry itself citing a lack of world demand for export coal.

Approving ‘zombie’ coal mines, since many of the planned projects won’t be built, also prevents communities and industries from growing as no one wants to invest next door to a mine site, the report warns.

Mr Turnbull – who owns land in the Hunter – said when mining companies are not able, for one reason or another, to meet their rehabilitation obligations, it is the community and state government that pick up the tab.

“You could have billions and billions of dollars in liabilities,” he said.

“We are not going to be coal mining in the Hunter in 30 years’ time. They’re seeking to get mines, get in before the party ends.”

Dr Dennis said new coal mine approvals destroy prime Australian farmland, which impacts current and future investment in agriculture, wine, and tourism industries, leaving significant liabilities for the NSW government and lasting scars on the Upper Hunter.

Mr Turnbull said there was already enough capacity in the Hunter for coal mines to meet existing export demand and not damage the local thoroughbred industry.

Unlike coal, it could still exist in 100 or 500 years, he said.