Global warming affecting farmland

Droughts and floods stoked by global warming threaten to destabilize China's grain production, the nation's top meteorologist has warned, urging bigger grain reserves and strict protection of farmland and water supplies.

Extreme weather damage can now cause annual grain output in the country to fluctuate by about 10 to 20 percent from longer-term averages. China is the world's biggest grain producer.

But with global warming intensifying droughts, floods and pests, the band of fluctuation in annual production could widen to between 30 and 50 percent, Zheng Guoguang, head of the China Meteorological Administration, wrote in a new essay. He did not say how long it might be before that could happen.