BEIJING, Apr 23 (AP) -- Climate change could seriously hinder China's development, hitting agricultural regions with increased droughts and coastal areas with worsening floods, a government report on global warming said.

But the National Climate Change Assessment Report, issued over the weekend, also reiterated that China -- expected to soon become the world's largest greenhouse gas emitter -- should focus on development before cutting those emissions.

Higher than average temperatures meant spreading deserts, worsening droughts, shrinking glaciers and increased spread of diseases, said the report, compiled by more than a dozen government bodies, including the Ministry of Science and Technology, Ministry of Foreign Affairs, National Development and Reform Commission and State Environmental Protection Administration.

"Climatic warming may have serious consequences ... as agriculture and coastal regions, suffer grave negative effects," the report said.

"By 2020, the average temperature in China will increase 1.1 to 2.1 degrees Celsius, causing worsening droughts in northern China and extreme weather," it said, while in eastern areas of the country there will be increased flooding.

China, the world's biggest producer and user of coal, is expected to overtake the United States as the world's largest carbon dioxide emitter within the next several years.

Burning coal releases carbon dioxide, which experts say worsens global warming.

But the report said emission limits were unfair and could cause economic problems, repeating previous government statements that the country lacks the technology to significantly reduce emissions. Leaders are also concerned that shutting older factories or power plants could wipe out jobs in poor areas, where the government worries about unrest among the unemployed.

"If we prematurely assume responsibilities for mandatory cuts in greenhouse gas emissions, the direct consequence will be to constrain China's current energy and manufacturing industries," the report said.

China has said richer countries are responsible for the accumulated greenhouse emissions and should take the lead in cleaning up the problem.

The report said China should improve its agricultural infrastructure, enhance water cleaning and protection measures, plant trees and set up forecast and surveillance systems.

It said China's wheat and rice output could fall by up to 37 percent in the second half of the century. "If we do not act, climate change will seriously damage China's long-term grain security."

China's rise as a polluter has worried other countries. This month Australian Foreign Minister Alexander Downer said his nation will help China develop cleaner coal technology, and Norway along with the U.N. Development Program signed an agreement to develop programs to combat the effects of climate change in China's rural areas, including the melting of glaciers in Tibet.

On a trip to Japan this month, Chinese Premier Wen Jiabao and Japanese Prime Minister Shinzo Abe signed an environmental agreement that called for the countries to work on a successor to the Kyoto Protocol on climate change by 2013. China's emissions are not capped under the Kyoto pact, but they are a rising concern as the economy rapidly expands.