Facing up to climate change

China's worst drought since 1951, which is taking its toll on agricultural production in eight provinces, is raising awareness across the nation of the long-terms risks posed by climate change.

The Chinese government announced a severe drought emergency in Hebei, Shanxi, Anhui, Jiangsu, Henan, Shandong, Shaanxi and Gansu provinces on Feb 5.

As of Feb 9, 18.4 million hectares of farmland and 9.1 million hectares of cropland had been hit by the drought, which had left 3.46 million people and 1.66 million livestock short of drinking water.

Lin Erda, a member of China's national climate change expert panel and a senior researcher with the Chinese Academy of Agricultural Sciences, said that temperatures in some regions of southern, northern, and southwestern China had approached the upper limit which is suitable for crop growth.

Because global warming has accelerated the growth of crops and shortened their period of maturity, there is not enough time for grains to ripen, which could cause a decline in output, Lin warned.

Over the past two decades global warming has led to a rise in the amount of farmland affected by droughts and greater fluctuations in crop output, Lin added.

In recent years, around 22 million hectares of farmland have by been hit by droughts annually, leading to the loss of 10 million tons of grain annually. The most serious loss happened in 2000 and 2001, with China's crop yields falling by 50 million tons each year.

The National Assessment Report on Climate Change, which was published in 2007, points out that climate change will continue to have a significant impact on China's environment and economy, especially on agriculture, animal husbandry and water supply, with some of this proving to be irreversible.

It says that the country's average temperature increased 0.5 to 0.8 C over the past century, while the national average temperature is likely to rise 2 to 3 C in the coming 50 to 80 years as climate change will accelerate.

According to the report, in the coming five to eight decades, the country's average precipitation will increase 7 to 10 percent, however, it is impossible to change the trend of drought across the country, especially in northern China.

It says global warming will reduce the streamflow of rivers in northern China while river streamflow in southern China will increase. However, the annual evaporation capacity will also rise. As a result, the frequency of droughts and floods will rise while water supplies will come under intense pressure.

The annual water shortage in western China is expected to reach 20 billion cu m between 2010 and 2030.

If no measures are taken to tackle this situation, the output of China's basic crops, such as wheat, rice and corn, would fall by 37 percent at the most.

The report predicts that the country's agricultural production would be seriously affected by climate change, while its long-term food security would be threatened without any action.

Besides, global warming will increase farmers' demand for water, making agriculture a costlier business.

A project jointly undertaken by the Chinese and British governments, Impacts of Climate Change on Chinese Agriculture (ICCCA), warns that climate change will present a major challenge to China in feeding its growing population by the middle of the century.

The study points to an increase in the intensity and frequency of crop diseases and pests. With the warmer climate, some diseases and pests now find it easier to survive the season, and cause problems especially in the spring and autumn.

In addition, climate change is expected to result in more extreme and frequent droughts.

The study echoed the National Climate Change Review Report, and predicts that China is likely to see a reduction in yields of key crops - wheat, maize, and rice - from the 2020s.

The study also shows that increased levels of carbon dioxide in the air, which helps plants to grow and, improvements in farming techniques may help boost yields, but whether this can significantly reduce the effects of climate change is very uncertain.

Lin said that the best way to minimize the impact of climate change is "to adjust measures to local conditions, to modify the agricultural structure based on our forecast of changes in the climate".

"Depending on our scientific research and forecast, we should grow optimum crops at most suitable place at an opportune time, while also strengthening management and making improvements to agricultural infrastructure," he said.

(China Daily 02/16/2009 page4)