China and the United States are aiming to help combat climate change with new joint projects.
U.S. Secretary of State John Kerry, who is in Beijing meeting with Chinese counterparts, announced the launch of eight environmental pilot programs on Wednesday.
They include capturing and storing carbon and setting up more efficient energy grids.
However, the world's top two carbon emitters still differ over a wider global plan to cut emissions.
Xie Zhenhua, China's climate chief, told reporters his country still could't be expected to match the environmental reforms of the U.S. and other wealthy nations. He added his country was in a different developmental stage and had different capacities.
Kerry said the U.S. and China had an obligation to clean up pollution that their "robust economies" have created. He emphasized no country could do it alone.
A report released in March by Washington-based Pew Charitable Trusts showed China is a clean energy leader, with $54 billion in investments in renewable energy last year, compared with $36.7 billion in the U.S.
Some information for this report was provided by AP and Reuters.