Wind turbine generators are used to generate electricity in Hami, Xinjiang, in this Oct 25, 2013 file photo. [Photo/Xinhua]

The statement aimed to show "the determination of both countries to act decisively to achieve the goals set last year."

"For the world's two largest economies, energy consumers and carbon emitters to come together like this, there is no reason for other countries, whether developed or developing, not do so as well," Obama told a joint press conference with Xi.

China also commits to promote low-carbon buildings and transportation, with the share of green buildings reaching 50 percent in newly built buildings in cities and towns by 2020 and the share of public transport in motorized travel reaching 30 percent in big- and medium-sized cities by 2020, according to the joint statement.

China also announced on Friday that it would channel 20 billion yuan ($3.14 billion) for setting up the China South-South Climate Cooperation Fund to help developing countries combat climate change, a significant financial pledge from an emerging economy.

The United States reaffirmed a pledge it made last year to allocate $3 billion into a UN-backed Green Climate Fund.

China also announced for the first time that it will join the United States, Britain, the World Bank and other countries and institutions to "strengthen green and low-carbon policies and regulations with a view to strictly controlling public investment flowing into projects with high pollution and carbon emissions both domestically and internationally."

China and the United States also agreed on the need for an "enhanced transparency system" in a United Nations climate agreement to ensure trust and confidence in the framework to be agreed at the Paris Climate Conference in December.

The two sides recognize that their mitigation efforts are "crucial steps in a longer-range effort to transition to low-carbon economies," the joint statement said.