A few experiments have been done in other countries to simulate the atmospheric concentration of carbon dioxide, but those were alone in sealed space such as greenhouses. By contrast, FACE is done in an open field where carbon dioxide can flow freely, which is closer to the natural environment. Another advantage of FACE is that it can better take into account a number of variants such as pests, weeds, competition between different species, soil, water and air quality. FACE is generally considered an ideal research method to test crop reaction to changes in the atmospheric concentration of carbon dioxide.

"Sensors are needed to accurately measure the concentration of carbon dioxide in the test field, and a computer decides on the amount of gas to release," Lin added.

Usually a field experiment is repeated more than three times, "to reduce systematic and random errors, and produce a more reliable conclusion," said Lin. FACE is a powerful experiment platform and could provide support for policy-making by relevant government departments, he added.

Food security

On October 15, the day before World Food Day, Greenpeace, an international non-governmental environment protection organization, published a scientific report entitled "Climate Change and Food Safety in China." The report said that if immediate action is not taken, because of the effect of climate change, China would become unable to produce enough grain to feed its own people. Lin and other experts under the commission of Greenpeace wrote the report. According to these experts, future food security is contingent not only on the crop planting area, technological advancement, population and international trade, but also on the impact of climate change.

Lin has been a member of the Chinese People's Political Consultative Conference (CPPCC) for three sessions. His proposals usually focus on climate change and other environmental issues. During the CPPCC assembly last year, he called for attention to climate security as well as food and energy security.

"For such an agricultural country as China, the negative impact of climate change on agriculture is real and more and more obvious," Lin warned in a bilateral dialogue on agriculture and climate change between China and the United States held on September 18.

Lin said climate change could shorten the growth period of crops and reduce yields. Warm winters will cause crops to germinate earlier in spring, and become vulnerable to cold, and pests used to living in warmer weather in south China will also be found in north China and attack the crops there, he warned. Extreme events such as droughts and floods will become more frequent with the potential to devastate China's vulnerable agricultural sector, Lin said.

Although the Ministry of Agriculture of China announced that China has had bumper harvests for five consecutive years, Lin cautioned that a 2-to-3-degree Celsius increase in the average temperature would cause yields of rice, wheat and corn, the three major grain crops in China, to slide continuously.

"Each year, about 50 million hectares of crops in China are affected by climate disasters," Lin said. Climate change will cause more loss to China's agriculture in the future. According to projections by the National Population and Family Planning Commission of China, China's population will peak at 1.5 billion in around 2030, who will consume 600 million tons of grain each year. The current annual grain yield in China is 500 million tons. To meet the increase in demand of 200 million more people in the coming decades, the agricultural sector is trying to produce 100 million more tons of grain by 2030. "Climate change has made it more difficult to reach this goal," Lin said. If no action is taken to arrest climate change, China will have a shortfall of 5 to 10 percent in food. "If this happens, not only will food prices soar, but the society will also become unstable," he warned.

Some regions in China are adjusting their agricultural structure, and planning to grow new plants. Lin said that planners should take into account future climate change, and choose plants that can adapt to it. Proactive adaptation will reduce loss and protect food production, Lin said.

International recognition

On October 12 last year, the Nobel Peace Prize for 2007 was granted to IPCC and Al Gore, former U.S. Vice President, for their efforts in disseminating knowledge about climate change, and in seeking ways to mitigate it.