China's water deficit 'will create food shortage'
[BEIJING] A leading climate change expert has warned that water shortage is the greatest threat to China's agricultural sector this century, amid a drought across the country.
As demand for water continues to rise and less is available for agriculture, "China will see a food shortfall of 5–10 per cent — a disastrous outcome in a country of 1.3 billion people — unless effective and timely measures are taken," said Lin Erda, one of China's top climate change experts and leader of a joint China–UK project, 'Impacts of Climate Change on Chinese Agriculture'.
Climate change is affecting an increasingly large area of crop-growing land in China — up from 3,882 hectares hit by natural disasters in 2005 to 4,899 hectares in 2007, Lin said.
"The recent drought, the worst in half a century, is just a fresh reminder," said Lin. "As climate change sets in, we can expect more frequent and damaging droughts in the northern part of China."
When the current episode of drought reached its peak in early February it was affecting 10.7 million hectares of farmland in at least 12 provinces in northern China — considered the country’s breadbasket. Thanks to snow and rainfall last week the affected area has dropped to 3.33 million hectares across eight provinces.
China can expect an increase of 7–10 per cent in annual precipitation across the country in the coming decades, according to a 2007 government report evaluating the possible results of climate change.
"However, most parts in China, especially north areas, will get drier," said Lin.
This is because the higher temperatures will increase water consumption, evaporation and plant transpiration rates.
The recent lack of rainfall has merely exacerbated — and will continue to exacerbate — a long-term problem in a naturally dry region where consumption has soared thanks to intensive agriculture, industry and an increasingly urbanised population, Lin said.
The northern half of China has less than 20 per cent of the nation's water, yet is home to more than 40 per cent of the population, much industry and over 50 per cent of arable land, according to dry-land farming expert Shan Lun, an academician of the Chinese Academy of Engineering.
This has resulted in a water deficit in the North China Plain exceeding 40 billion tons per year, he says.
Based on experiments simulating future atmospheric carbon dioxide levels, Lin and his colleagues estimate that China's harvests will decrease 14–23 per cent by 2050 due to climate change.