Grain of hope for Yangtze river climate impact

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[BEIJING] Food production in China’s Yangtze River Basin will be severely challenged by climate change — but these obstacles could be overcome with innovations such as new grain varieties, according to a new report.

The Yangtze River Basin Climate Change Vulnerability and Adaptation Report’ — released by the World Wide Fund for Nature (WWF) today (10 November) claims to be the first report to offer a large-scale analysis of the impact of climate change on a given river.

It used data from nearly 150 monitoring stations across the basin and explored the influence of climate change on its ecosystems, including grassland, forests, water resources, agriculture and wetlands.

The Yangtze is China’s longest river, extending 6,300 kilometres. The basin forms about one fifth of the country’s territory, is home to one third of its population and contains one quarter of its arable land — producing 70 per cent of the nation’s rice.

Over the past decades, the Yangtze River Basin has become hotter. It is expected that the temperature will increase by up to 2 degrees Celsius, by 2050, relative to 1950 temperatures.

Researchers warn that the temperature change alone would reduce rice production by up to 41 per cent by the end of this century, with corn and winter wheat production declining more rapidly — a corn reduction of up to 50 per cent is estimated by 2080.

"Corn is one of the most vulnerable crops to climate change in the region," says the report, which advocates replacing it with rice. However, the rise in carbon dioxide emissions will lead to a slight increase in single harvesting rice, although double harvesting rice — a different species employing different farming methods — will experience a reduction of just under three per cent.

The researchers suggest that a single-rice cropping system — producing just one harvest per year — be replaced by a double-rice system and double systems by triple-rice systems, in transition zones where cropping systems are able to take advantage of the extended growing season and warmer days.

In areas where new cropping systems can’t be supported, breeding new strains with longer growing periods should be encouraged.

"If enough adaptation measures are taken, the unfavourable impact of climate change on farming will be negated. Grain production can even be expected to grow by taking advantage of the positive impact of climate change," the report says.

"While prioritising the development of new species of grains, we should also give due attention to local farming knowledge, which has not been fully recognised so far," Xu Ming, lead author of the report and a researcher at the Chinese Academy of Sciences’ Institute of Geographical Sciences, told SciDev.Net.

Zhang Shihuang, a grain expert at the Chinese Academy of Agricultural Sciences, says that it is hard to expand the size of rice farmland because of water shortages across the nation.

He adds that in reality multi-farming practices consume more material resources and are more costly. He proposes prioritising the development of new maize strains resistant to drought and radiation.