Premier Li Keqiang on Tuesday unveiled the hotly-awaited climate promises in Paris, which will host UN talks at the end of the year tasked with producing a global pact on curbing climate change.

"China's carbon dioxide emission will peak by around 2030 and China will work hard to achieve the target at an even earlier date," Li's office said in a statement as he lunched with President Francois Hollande on the first day of a three-day visit.

The pledge is exactly the same as one unveiled by President Xi Jinping in a meeting with US President Barack Obama last November.

After that announcement officials stressed that the wording was crucial, and that "around" could mean before or after the date.

China is widely expected to meet the goal, with some analysts predicting emissions will peak years earlier.

Wang Tao, a resident scholar on energy and climate at the Carnegie-Tsinghua Center for Global Policy in Beijing, said of Li's declaration: "It's not a significant leap forward from what China announced last year during Obama's visit.

"I wish China could do more, along with other countries, in tackling climate change."

Last year's announcement had set the tone for China's climate policy and no one expected a major change from that, Wang added.

China also aims for non-fossil fuels to grow to a 20 percent share of primary energy consumption -- a promise that was also made at the time of Obama's visit.

In addition Beijing is pledging to cut its "carbon intensity" -- carbon dioxide emissions per unit of GDP -- by 60-65 percent over 2005 levels by 2030.

Its climate change plan is part of, but subordinate to, the larger goal of transforming the economy, Wang said.

"While this means less reliance on heavy industry and more investment in clean energy like solar, the Chinese government doesn't want to upset the economy."

Other analysts hoped more could be done to stem the effects of warming the planet, saying China was already on track to fulfil many of its goals.

"Today's pledge must be seen as only the starting point for much more ambitious actions," Li Shuo, a climate analyst for Greenpeace China, said in a statement.

Investment in clean energy and improvements in efficiency over the past decade will contribute to much of the carbon intensity reductions.

The premier's pledges do "not fully reflect the significant energy transition that is already taking place in China", Li added.