Premier Li Keqiang made the announcement while during a visit to Paris, where the global climate conference will take place at the end of the year.

"China's carbon dioxide emissions will peak by around 2030 and China will work hard to achieve the target at an even earlier date," Mr Li said in a statement after meeting with French President Francois Hollande.

China aims to reduce its carbon dioxide emissions per unit of gross domestic product by 60-65 per cent from 2005 levels, he said.

The world's second-largest economy also aims to increase the share of non-fossil fuels in its primary energy consumption to about 20 per cent by 2030, the statement added.

The 20 per cent target, as well as the headline goal of having carbon emissions peak by 2030, were consistent with its pledge made in a joint climate announcement with the United States in November last year.

But China has now formally made those commitments as part of its Intended Nationally Determined Contributions (INDC) climate plan ahead of the year-end UN conference in Paris, while crucially also outlining its carbon emissions intensity reduction targets.

Most analysts consider China's target to peak emissions by 2030 as conservative given the dramatic shifts in its energy mix which have already taken place.

Coal consumption in China peaked last year and has continued to fall – and at a faster rate – in the early months of this year, driven by slowing economic growth and an urgent government push toward cleaner energy to alleviate air pollution and other environmental damage that has sparked popular outrage in China.

"Today's pledge must be seen as only the starting point for much more ambitious actions," said Li Shuo, climate analyst for Greenpeace China. "It does not fully reflect the significant energy transition that is already taking place in China. Given the dramatic fall in coal consumption, robust renewable energy uptake, and the urgent need to address air pollution, we believe the country can go well beyond what it has proposed today."

Jiang Kejun, a key government adviser and director of the National Development and Reform Commission's Energy Research Institute, said the speed at which renewable energy sources like wind, solar, hydro and nuclear have formed a substantial role in China's energy mix had exceeded expectations.

Having predicted three years ago China's carbon emissions would peak by 2025, his team's model, updated last August, now suggests that will occur considerably earlier.

"Our newest modelling shows that it is very likely carbon emissions will peak just after 2020," Dr Jiang told Fairfax Media.

China's frenetic economic boom fuelled almost all the growth in global coal demand since the turn of the century. The country is the world's largest emitter of greenhouse gases, and consumes nearly as much coal as the rest of the world combined.

Some environmentalists had hoped Beijing would commit to more aggressive targets in its INDC, but Greenpeace's Li Shuo said in submitting its long-term climate plan to the United Nations, China was following the lead of the US and European Union and allowing room to bargain come Paris.

"People should not overlook the political layer of this plan," Mr Li told Fairfax Media. "We all understand nobody will play all of their cards at this early stage."

Having made significant strides to curb its carbon footprint, it is now in China's interests to get the rest of the world to follow suit, including countries like Australia who are seen as lagging behind.

"The targets from Australia are not very promising so, yes, there's a demand from not only China but also from the international community for Australia to take more efforts to reducing carbon emissions," said Wang Tao, who runs a program at the Carnegie-Tsinghua Centre for Global Policy which examines China's climate and energy policies.