"The two sides will...actively participate in the process on building an effective framework from 2013 and beyond," they said in the document.

The UN Kyoto Protocol, the present framework for capping greenhouse gas emissions, is in effect up to 2012.

China, which could become the world's biggest carbon emitter within the year surpassing the United States, is not subject to binding emissions targets under the Kyoto agreement.

Participation by major emitters such as China, India and the United States is essential if any post-Kyoto agreement is to be effective, experts have said.

Beijing has not set caps on its rapidly increasing emissions, saying that rising global temperatures are mainly due to fossil fuel use by industrialised nations and that China is entitled to pursue the same level of prosperity that they enjoy.

China's top climate change official said in March that a national plan on global warming set to be released this month would include policies for cutting back greenhouse gases, but did not say whether it would give an overall national target.

The two countries also agreed to cooperate on other measures regarding the environment including:

- technical assistance by Japan on desulphurisation of Chinese coal-fired thermal power plants.

- setting up an experimental model of recycling society in Qingdao.