U.S. Vice President Joe Biden said Wednesday that the joint efforts made by the United States and China can generate many possibilities and the leadership of the two countries is vital to achieving a successful global climate agreement in Paris later this year.

At the closing ceremony of the China-U.S. Climate Leaders Summit in Los Angeles, Biden said: "There is no obvious reason why the U.S. and China can be competitors or enemies... Now we have an opportunity to use that relationship that can have the potential to have profound impact on our planet future."

"We must reach an agreement that is ambitious, effective, and drives down the global emissions in the decades to come," he said, adding that "it's in our power to do this."

The United States and China, the largest developed and developing countries in the world, together account for 40 percent of the global greenhouse gas emission.

The two-day summit, with the full name as the First Session of the U.S.-China Climate-Smart/Low Carbon Cities Summit, gathered officials from central, federal and local governments in both countries to discuss strategies and measures to combat climate change.

The summit fulfills a key element of the China-U.S. Joint Announcement on Climate Change by Chinese President Xi Jinping and his U.S. counterpart Barack Obama last November, and "helps to ensure that the ambitious actions to address climate change that both leaders committed to will be implemented at the state and local level, where they matter most," the White House said on its website.

The U.S.-China Climate Leaders Declaration, signed during the summit by leaders of local governments in both countries, is the first of its kind in the history, Biden said.

"The declaration lays out parallel steps to address climate change and slow the global warming on the planet," he said.

Through this kind of efforts, "we are bringing city leaders around the world for a simple goal -- share your ideas to work, learn from each other, and help to solve the climate change, city by city," the vice president said.

"This is not a zero-sum game. This is a win-win proposition," he concluded.