A U.S. expert on China said U.S. President Barack Obama would discuss three major issues with the Chinese leaders during his coming visit to China, adding that the recent trade tensions would not impact the Sino-U.S. relations significantly.

Clayton Bube, associate director of the U.S.-China Institute at the University of Southern California, told Xinhua in an interview that three issues loom large during Obama's meeting with Chinese President Hu Jintao: the uncertain economic situation, worries over nuclear weapons proliferation, and the need to act to stem global warming.

On the economic front, Dube said, the two leaders would congratulate each other on the success of their economic stimulus plans. Because of their efforts, the longest recession in the past 70 years is now over, although not officially announced, but the growth of GDP serves as a proof, he said.

Dube mentioned the trade tensions between the two countries. The U.S. imposed tariffs ranging from 24 percent to 37 percent on China's largest exporters of steel pipe. Chinese officials called the tariffs a protectionist move. The imposition of steel pipe tariffs follows the decision in September to levy 35 percent tariffs on Chinese-made tires. China later launched an investigation into the export practices of U.S. automakers.

However, the U.S. expert said the impact of the trade disputes was relatively small. Even before the disputes, the U.S.-China trade registered 226 billion dollars in the first eight months of 2009, a drop of 15 percent from the previous corresponding period, due to the recession.

He said the impact of the trade disputes on actual amount of dollars was limited while the symbolic impact was greater. He said the drop of trade between the two countries was mainly caused by the economic recession starting from late 2008.

On weapons proliferation, Dube said the two sides could make progress. The Democratic People's Republic of Korea (DPRK) has sent out positive signals recently after Chinese Premier Wen Jiabao's visit to Pyongyang that the country will return to the six-party talks.

He quoted Jeff Bader, Obama's National Security Council Advisor for Asia, as saying that "we're less interested in process than we are in outcome."

Dube said if the DPRK demonstrated a commitment to the six-party talks, then the U.S. was open to a meeting directly with the DPRK in Pyongyang or elsewhere.

He said DPRK leader Kim Jong Il voiced the country's willingness to reenter the six-party talks during a visit to Pyongyang by the Chinese Premier Wen Jiabao.

With regard to climate change, Dube said, the two countries have made negligible progress toward an agreement to reduce greenhouse gas emission.

He said the U.S. had not agreed to a cap on its carbon emission without a similar commitment from China. Todd Stern, the chief U.S. negotiator on the issue asserts that developing nations will contribute the most to increases in emission.

Dube said the Chinese responded that, given their pressing need to raise living standards, they shouldn't be expected to match the U.S. in capping or reducing emission.

Dube said during Obama's visit to Beijing, the task for the Chinese and American leaders is to determine whether the other is likely to move far enough to permit both to sign on a United Nations agreement in Copenhagen in December. But he said it was unlikely any side would concede anything.

He said relations between U.S. and China were all important in terms of economics, national security and climate change. These are three major issues that unilateral capabilities are limited to solve. That's why Obama's visit to China is so important, he said.