Chinese Vice Premier Wang Yang (1st R), Chinese State Councilor Yang Jiechi (2nd R) and US Secretary of State John Kerry (1st L) attend a special meeting on climate change under the framework of the seventh round of the China-US Strategic and Economic Dialogue (S&ED), in Washington D.C., the United States, on June 23, 2015.[Photo/Xinhua]

China's post-2020 climate action plan will be "quite ambitious" and may involve estimated investment of more than 41 trillion yuan ($6.6 trillion) by 2030, according to a lead climate negotiator.

The action plan is to be announced by the end of this month.

The country's intended nationally determined contribution will differ from those of other countries because it will announce a series of objectives in addressing climate change up to 2030, Xie Zhenhua said.

Xie, the special representative for climate change affairs, was taking part in the Strategic and Economic Dialogue forum in Washington DC.

"Not only will we have objectives in our intended nationally determined contribution, we will also cover a lot of policy issues and projects to reach these objectives.

"I believe that after China's announcement of its INDC, you will see that our objectives are quite ambitious," Xie said at a media briefing on Tuesday. He also said it is likely to cost the country more than 41 trillion yuan to meet the greenhouse gas reduction goals.

An official at the National Development and Reform Commission, who did not want to be named, said, "The 41 trillion yuan is a rough estimate from experts.

"The figure largely refers to investment in promoting energy conservation and efficiency in industry, transportation and construction as well as investment in nuclear and renewable energy by 2030," the official said.

In a joint announcement by President Xi Jinping and his United States counterpart Barack Obama in November, China set targets for carbon dioxide emissions to peak around 2030 and to increase the share of non-fossil fuels in primary energy consumption to about 20 percent by that year.

US Secretary of State John Kerry said on Tuesday that the two countries have been working "extremely effectively together" since their joint announcement on combating climate change - presenting both with great economic opportunities.

US Treasury Secretary Jack Lew, Chinese State Councilor Yang Jiechi and Vice-Premier Wang Yang took part in the discussion.

Yang said the announcement "not only promoted our cooperation in tackling climate change, but also our cooperation on green and low-carbon economic growth".

China will continue to save energy and raise efficiency, increase forest carbon stocks, cut carbon intensity, and focus on efforts to promote a green economy, he said.

Wang said China's core action in tackling climate change from an economic perspective is to "shift its growth model", adding, "We must change our philosophy of 'pollution first and solution later'."

The environmental industry's output in China has grown by 50 percent year-on-year, generating more than $700 billion. More than 750,000 new-energy vehicles were sold last year, three times the number in 2013, providing growth opportunities for many companies.