And these rises threaten to overturn patterns of rainfall and slash crop output, said the official, whom Xinhua did not name.

"Our country's precipitation distribution over time and space will become even more unbalanced," Xinhua said, citing the official, who said the changes would lead to less rain and the accelerated spread of arid land in northern China and around the Yangtze River, the country's largest river.

But in other areas, climate changes may lead to more severe and frequent rainstorms that "will present a massive threat to our country's disaster prevention system", the report said.

The official said disturbed weather patterns could cut China's crop production by 5 to 10 percent by 2030, with wheat, rice and corn suffering the steepest falls.

"Under the impact of cimate change, instability in our country's agricultural production will increase and turbulence in production volumes will grow," the report said.

Scientists believe industrial pollution and human consumption are raising global temperatures by producing greenhouses gases that trap heat in the atmosphere, especially carbon dioxide from burning coal and other fossil fuels.

Greenhouse gas pollution from China and India rose steeply over the last decade, but rich countries, especially the United States, remain the world's biggest polluters, according to the World Bank.

The United States accounts for nearly a quarter -- 24 percent -- of all emissions of carbon dioxide, the main greenhouse gas.

But China and India are catching up. China, the world's second-largest polluter after the United States, increased carbon dioxide emissions by 33 percent between 1992 and 2002, according to the Bank.

Chinese Vice Premier Hui Liangyu told the Beijing meeting on Thursday that China needed to upgrade its weather tracking and climate research to address impending change.