If greenhouse gases continue to rise as they have been, precipitation in the Huaihe, Liaohe and Haihe river regions could decline by 30 percent by 2040, says a Chinese meteorologist.

Global warming may also lead to less rain in areas that feed the Yellow, Liaohe and Haihe rivers, said Dong Wenjie, director general of the National Climate Center with the China Meteorological Administration.

If China can effectively control greenhouse gas emissions, precipitation is likely to increase in its major river valleys over the next 60 years.

In a global model that didn't include increasing greenhouse gases, annual precipitation in China's Yangtze, Huaihe and Liaohe rivers are predicted to increase by 2 percent from 2011 to 2040.

Rainfall in the Yellow and Haihe river regions will both rise by 3 percent yearly in the 30 years, Dong said at a forum sponsored by "Sino-Italian Green Week," which concluded on Friday.

Under the same model that did not take into account the accumulation of greenhouse gases between 2041 to 2070, the flood-prone Yangtze and Huaihe river regions increase by only 3 percent per year, he said.

Experts point out that effective control of greenhouse gases will help form a more balanced precipitation distribution in China.

China, with a relatively high emission volume of carbon dioxide per unit of gross domestic production, has written "effective control of greenhouse gases" into its 11th Five-Year Program (2006-2010).

In 2002, China's carbon dioxide emission totaled 4.08 billion tons, ranking second in the world after the United States.