California Gov. Jerry Brown and China's top climate negotiator on Friday signed the first agreement between a U.S. state and China that seeks greater cooperation on clean energy technologies and research meant to reduce greenhouse gas emissions.

The memorandum of understanding signed with China's National Development and Reform Commission was another aggressive move by California to combat climate change. The state has already passed the nation's most ambitious greenhouse gas limits, including a so-called ``cap and trade'' system that put a price on carbon pollution in the state.

"I see the partnership between China and ... California as a catalyst, and as a lever to change policies in the United States and, ultimately, to change policies throughout the world,'' Brown said just before signing the agreement.

Under the two-year commitment, Chinese and California environment and energy officials will work together to find ways to share new low-carbon technologies, as well as research and policy innovations meant to combat climate change.

China and the U.S. are the world's top two greenhouse gas emitters.

The two sides also agreed to immediately create a task force comprising top officials including China's director general of the Department of Climate Change and California's head of the state Environmental Protection Agency.

``That's the significance of this memorandum of understanding. It involves agencies of state government, agencies of the People's Republic of China ... the University of California, businesses, research scientists in both the public and private sector. This is a very important opportunity,'' Brown said.

Brown and NDRC Vice Chairman Xie Zhenhua said the idea is to help each side share in ways to tighten industrial performance standards to control methane, carbon and other greenhouse gas emissions. The two governments would also exchange experts and organize workshops.

``California is being a very good role model and taking a leading role (for climate change regulation) in the U.S.,'' Xie said through an interpreter.

Xie added that, in China, climate change has become more of a priority as people have realized that it is taking a severe economic and human toll.

Experts on U.S. and Chinese environmental law and climate policy said the agreement is promising at a time when international climate negotiations have stalled in recent years.

``NDRC is the most powerful Chinese agency when it comes to Chinese development and energy projects,'' said Robert Percival, director of the environmental law program at University of Maryland's Francis King Carey School of Law.

``The pattern that is emerging is that as consensus becomes virtually impossible in global climate negotiations, the U.S. and China are realizing that they can make huge progress simply by working bilaterally.''

Some environmental groups also applauded the agreement as progress on climate change.

``This is a remarkable outcome, one that has lessons for China as it tries to limit the emissions of its growing economy, and for California, which can learn from China's innovative policies to support electric vehicles,'' said Diane Regas of the Environmental Defense Fund. (AP)