The recent visit to China by Nancy Pelosi, speaker of the U.S.House of Representatives, has set an important new agenda for the U.S.-China relations.

Called by the Wall Street Journal as “one of the most vocal critics of China,” Pelosi has literally seized every possible opportunity to attack China.  During her visit to Beijing in 1991, shortly after the suppression of the pro-democracy student movement, the junior Congresswoman unfolded a banner at the Tiananmen Square to show her support for the students.

Since then, Pelosi has irritated China on numerous occasions – by meeting Chinese dissidents and “public enemies” such as the Dalai Lama, opposing the granting of normal trade relations status to China and China’s accession to the World Trade Organization, and most recently, calling on U.S. President George W. Bush to boycott the opening ceremonies of the Beijing Olympics.

With her ascendency in American political power hierarchy, what Pelosi says carries a significant weight.  Because of this, before and during her China trip, the Chinese leadership was very nervous about hosting Pelosi, fearing she might be provocative, especially on human rights, just as the twentieth anniversary of the Tiananmen Square pro-democracy movement is approaching.

During her five-day stay, Pelosi did mention human rights, but only in her speech at Qinghua University in the context of “looking out for the needs of the poor in terms of climate change and healthy environment.”

Apparently, seeking Chinese cooperation on climate change has become increasingly and strategically important; in fact, a key issue in U.S. relations with China.

As the world’s biggest emitter of greenhouse gases, which are blamed for causing global warming, the U.S. has failed to take a leadership role in this area as it has yet to adopt the Kyoto Protocol.  It is imperative, therefore, for the U.S. to change that and to be proactive in the coming Copenhagen conference where the new carbon reduction quotas will be negotiated.

Moreover, U.S. President Barack Obama has linked containing global warming to economic recovery and job creation.  And the U.S. Congress under the leadership of Pelosi intends to pass climate-related legislation this year, on top of a bill requiring U.S. companies to reduce emissions of greenhouse gases by roughly 80 percent by mid-century.

The United States also finds that it is necessary to bring China, the second biggest carbon emitter, on board.  Speaker Pelosi indicated at Qinghua University that both governments must work together to tackle the “very urgent” and “new” challenge of global warming.  In fact, on her visit to Beijing earlier in the year, Secretary of State Hillary Clinton delivered a speech on the same topic at the same podium at Qinghua.

It is perhaps more than coincidence that Obama appointed Steve Chu, a Chinese American, as energy secretary.  In addition to tapping into Chu’s expertise, the president may want to leverage his connections with China, especially its leadership.

But China has been reluctant to take concrete steps to reduce carbon emissions.  It counterattacks rich countries, saying that they should not use global warming as an excuse to restrict its economic growth, which has incurred and surely will continue to incur emissions of greenhouse gases.  For the Chinese leadership, losing the momentum of economic growth would likely jeopardize its legitimacy.

China also argues that developed countries have the responsibility to provide funds and transfer technologies to developing countries to help cut greenhouse gas emissions.

One high-profile visit such as that of Pelosi’s is not sufficient to narrow the gulf of differences between the two countries on the issue.  But with her engaging China once again, this time not on human rights but on climate change, China will feel new pressure to make this a paramount issue in dealing with the United States.