However, Dr Tan says Chinese demand for coal from Newcastle "may not completely cease" in the long term, despite the world's move away from fossil fuels.

While China has shut almost 300 coal-fired power plants, it continues to produce a massive amount of electricity from about 3000 coal-fired "power generation units".

Dr Tan, an international business and energy researcher, said long-term and short-term factors were "in play" regarding coal.

The trade dispute between Australia and China has hit the coal sector, with 70 ships of Australian coal stranded at Chinese ports.

Dr Tan said experience suggested the trade tensions would eventually ease, while the long term posed a more "fundamental threat to Australian coal exports to China".

He believes governments in China will continue to "replace energy- and pollution-intensive industries with advanced manufacturing and services".

"In coming years, southeast China will increasingly shift to renewable-based electricity and electric power transmitted from western provinces," he said.

"I think closures of coal power stations, especially in southeast coastal regions, would have already had impacts on Hunter coal. It's reasonable to argue that Australian coal would have had a bigger market without the closures."

He said the trade tensions had "a direct shock on Australian coal exports to China", while the coal power station closures in China "may take slow but lasting effects".

China unveiled a plan last September to reach net-zero emissions by 2060.

In a speech to the United Nations, Chinese President Xi Jinping called on "all countries to pursue innovative, co-ordinated, green and open development for all".

The Newcastle Herald asked Dr Tan whether China could achieve net-zero emissions by 2060 and if all its coal-fired power plants must close.

"The goal is ambitious and we need to assess the commitment as more evidence becomes available," Dr Tan said.

He intends to examine the next Five Year Plan of China [2021-2025] and "the trend of carbon emissions over the next few years".

"China has close to 3000 coal-fired power generation units - one power plant usually has more than one generation unit.

"Yes, almost all coal-fired power plants in China need to be closed, except perhaps a small number of stations using carbon capture and storage technologies, if China is to achieve its net-zero emission goal."

As well as China, the Port of Newcastle exports huge amounts of thermal coal to Japan, South Korea and Taiwan.

Japan and South Korea have announced a target of net-zero carbon emissions by 2050.

Dr Tan believes demand from these East Asian countries for coal from the Port of Newcastle "will fall in the long run".

"All these countries are undertaking transitions towards low-carbon energy," he said.

"However, it won't be a linear trend. We might see ups and downs in coal exports along the way."

Climate Council researcher Simon Bradshaw said China's commitment to reach net-zero emissions was "a hugely significant development", along with Japan and South Korea's commitments.

"When you put it all together, those countries account for more than 70 per cent of Australia's fossil fuel exports. So we can see that things are starting to change very quickly," Mr Bradshaw said.

"The most important thing from an Australian perspective is that we recognise this fast-changing reality and have a plan to support the communities that will be transitioning out of fossil fuel production."

Australia is under pressure to take tougher action on climate change following the election of Joe Biden in the United States. Mr Biden campaigned on the US setting a target of net-zero emissions by 2050, while the UK has committed to the 2050 target.

Prime Minister Scott Morrison has accepted the need to work towards a net-zero emission future, but has not agreed to the 2050 target.

The National Oceanic and Atmospheric Administration recently confirmed that 2020 was the "second-hottest year on record for the planet, knocking 2019 down to third hottest".

"The world's seven-warmest years have all occurred since 2014, with 10 of the warmest years occurring since 2005," the NOAA said a fortnight ago.

Dr Tan said China closed 291 coal-fired power plants - totalling 37 gigawatts of capacity - from 2015 to 2019.

In comparison, Australia decommissioned 5.5 gigawatts of coal-fired power plants from 2010 to 2017, he said.

He added that Australia currently has about 21 gigawatts of coal-fired power.

Furthermore, he said China's coal power capacity increased by about 18 per cent from 2015 to 2019.

"It currently has more than 1000 gigawatts of coal generation capacity - the largest in the world."

The Newcastle Herald reported last year that about 15 per cent of Newcastle's thermal coal goes to China.

In December, amid the trade dispute, coal exports from Australia rose to Japan [27 per cent], India [38 per cent] and South Korea [48 per cent].

Federal data shows Australia exported $64 billion worth of coal [thermal and metallurgical] in 2019.

Japan was Australia's largest customer, taking 27 per cent of total coal exports worth $17 billion. China ranked second, with a 21 per cent share worth $13.7 billion.

The Newcastle Herald reported on Wednesday that the Nationals' backbench policy committee believe the federal government should "support" a new coal-fired power plant in the Hunter, as part of a plan to revive Australian manufacturing.

Four of NSW's five coal-fired power plants are scheduled to close by 2035, but the Nationals' plan says the government should support a new plant in the Hunter using the "world's best and cleanest thermal coal".

However, city-based Liberal MPs Dave Sharma, Trent Zimmerman, Jason Falinski, Tim Wilson, Katie Allen and Andrew Bragg - oppose a new coal-fired power station subsidised by the federal government.

They support renewable energy sources backed up by gas, hydro and batteries.

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