Coal has no future in the world's energy mix, UN warns, ahead of New York summit

The UN has warned that coal has no future in the world's energy mix, as world leaders gather ahead of a major climate summit in New York.

The Federal Government says coal will serve as an affordable, dependable energy source for decades to come, but the UN's climate chief has questioned whether that is in Australia's best interests long term.

"It is certainly within Australia's purview to decide how Australia is going to pursue its energy generation and energy growth," Christiana Figueres said.

"It is just a question of really thinking through very carefully what is in the best long-term interest of Australia and of the Australian population, making careful decisions that are informed both by today’s reality of climate change impacts as well as tomorrow's but very soon reality of a low-carbon society."

More than 120 world leaders, including US president Barack Obama and UK prime minister David Cameron will attend the UN secretary-general's climate summit starting today.

It is due to be the largest leaders' climate meeting since the 2009 Copenhagen summit, which failed to reach an agreement to avoid catastrophic climate change.

But major emitters China and India will not be sending their leaders, raising questions about how effective the summit will be.

Ms Figueres said she was not worried.

"It is well known that China for one is taking this very seriously," she said.

"We know China is investing heavily into renewable energy ... they are going from 70 gigawatts of wind to over 200 gigawatts of wind, which is two times as much as the entire European Union has."

Prime Minister Tony Abbott will not attend the summit either, despite being in New York the next day.

Last week, the European Union's climate chief said that was a "pity".

"At least 125 heads of state have sent a strong signal to the rest of the world that ... climate change is important, and they know they have a role to play and a responsibility to take in order for the world to address climate change," EU Commissioner for Climate Action Connie Hedegaard said last Tuesday.

Fossil fuel reduction key to avoiding dangerous emissions

The UN has told the coal industry that most of the world's coal reserves should be left in the ground to avoid catastrophic global warming.

A report to be presented at the climate summit in New York predicts China could hit peak thermal coal demand by 2016.

The report, produced by the non-profit think tank Carbon Tracker, said this meant there should be a rethink of all green fields coal developments, including Australia's Galilee Basin.

China is the largest consumer of coal in the world, and a World Bank study found that air pollution kills 750,000 people every year in China.

To improve air quality, the country has recently announced plans to ban sales of dirty coal from January 1 and cut imports generally by 50 million tonnes.

The executive director of the UN's Environment Programme said the need to reduce fossil fuel emissions was one of the great "dilemmas" of the 21st century.

"There are countries that have oil, there are countries that have coal and there countries that have asbestos," Achim Steiner said.

"At a certain point human wellbeing and our collective wellbeing and security becomes an overriding criterion."

Mr Steiner likened it to phasing out leaded petrol.

"There will be a moment when the world will decide to phase out leaded petrol as it has done, even though many people made a lot of money just selling polluted petrol affecting literally millions of people in their health," he said.

"We have the same challenge that we will face if the world will go through the kind of global warming scenario that we are anticipating.

"The question is does does one do this now by design when the option of guiding this process? Or will it suddenly happen overnight?

"This is a question for which there is no simple answer ... but to simply ignore the problem and hope that someone can continue with business as usual because one happens to sit on a mountain of coal or on a great deal of oil I think is ultimately not going to be the answer."

Copenhagen repeat 'can be avoided'

Economist Nick Stern, a former UK adviser to the British government on climate change, said he did not believe the New York summit would be a repeat of the failed Copenhagen talks in 2009.

"The learning that's been done in the meantime about technology, about ways of doing this, has been very strong and the wish to collaborate has grown stronger," Lord Stern said.

"But having said that, I do worry whether the overall scale of commitment is going to be enough – that's my biggest worry."

Lord Stern last week helped release a report showing that investments to help fight climate change could also spur economic growth rather than slow it.

The former World Bank chief economist urged governments to abandon what he called an "artificial horse race" between economic growth and action to combat climate change.

"The challenge is to combine the two," he said. "That is the only sensible route."