Climate change, such as global warming and changes in rainfall, has become a challenge to food security across the world, scientists said at a workshop in Lanzhou, capital of northwest China's Gansu Province.

The workshop, scheduled from Tuesday to Sunday, was held at Lanzhou University, where agricultural scientists and organizations from the U.S., Australia, Canada and Japan met to discuss the productivity and sustainable development of agricultural ecosystems.

As rainfall is diminishing and basic resources are degrading, food security is seriously threatened, said Kadambot Siddique, director at the Agriculture School of the University of Western Australia.

Also, the increase in carbon dioxide emissions, as well as rainfall changes, has impacted the agro-ecosystem, especially crop yield and water resources, Siddique said.

Researchers from the World Watch Institute of America warned in a report that global warming caused by carbon emissions would lead to a reduction of agricultural yields, acceleration of land desertification and an increase in plant diseases, posing great threats to food security worldwide.

Chinese researchers agreed that in the past few decades, climate changes have influenced China's agricultural ecosystem and caused negative influences on dry-land agriculture in arid areas of north China.

Wang Chunyi, vice-president of the Chinese Academy of Meteorological Sciences, said rising temperatures have quickened crops' development rates and, accordingly, shortened their growing period, which results in a reduction of crop yields.

Wang expected China's staple yields would be reduced by 5 to 10 percent by 2030, and things would get worse if no adaptive measures were carried out.

"The agro-product system in the future needs to be flexible and adapt to changes of climate, markets, decreasing natural resources, policies and human demands," said Siddique.

"Every country is required to explore the best way to balance between food demands and environmental protection," said Li Fengmin, director of the Key Laboratory of Arid and Grassland Ecology, Lanzhou University.

Li said that it is significant to focus on improvements to the productivity and sustainable development of fragile arid and semi-arid agro-ecosystems in conditions of global climate change.