http://www.digitaljournal.com/news/environment/china-s-artificial-nuclear-winter-wrecking-havoc-on-agriculture/article/373208

China's artificial 'nuclear winter' wrecking havoc on agriculture

Posted Feb 26, 2014 by Karen Graham
In Beijing, the air is so thick with toxic smog that officials are warning citizens to wear masks when outdoors, or stay inside. With air-quality levels rising far above what is considered safe, one scientist compared the foul air to a "nuclear winter."
Green vegetable fields in January around Qilinpu Village  Qilin Town  Jiangning District  Nanjing.
Green vegetable fields in January around Qilinpu Village, Qilin Town, Jiangning District, Nanjing.
Vmenkov
As the thick, toxic air got worse this past weekend, one climate official in Beijing noted that “China’s pollution is at an unbearable stage.” The pollution is not limited to the capital city, but includes large areas of six northern provinces, around one-fourth of the mainland.
For the past seven days or more, the areas have been engulfed in a pea-soup morass of thick smog that's not expected to let up until at least Thursday. One climate-change official compared the blanket of smoke-laden air to "living through a nuclear winter." With little or no sunlight breaking through the dense air, photosynthesis in plants is slowed. This can result in stunted crops, affecting the country's food supply.
In Beijing, the concentration of PM 2.5 particles, those particulates small enough to penetrate a person's lungs, invading the bloodstream, was registered at 505 micrograms per cubic meter Tuesday night. The World Health Organization (WHO) recommends a level below 25 micrograms PCM.
The worsening problem with air pollution has taken its toll on China's economy. Flights have been grounded, highways have been closed, and tourism is down as people opt to stay at home. In Beijing's Forbidden City, tourism has fallen sharply, with only 11,200 people visiting on Monday, a quarter of the usual daily attendance.
Associate Professor He Dongxian, of the China Agricultural University's College of Water Resources and Civil Engineering, says research is showing that if the smog continues, Chinese agriculture will suffer effects "somewhat similar to a nuclear winter."
The professor has been able to demonstrate that air pollutants adhere to greenhouse surfaces, cutting the effects of sunlight inside by 50 percent, impeding photosynthesis, the process by which plants change sunlight to chemical energy necessary for life.
In He's tests, chili and tomato seeds, which take about 20 days to sprout into seedlings under artificial lighting in a laboratory, took more than two months to sprout in a greenhouse farm in Beijing's Changping district. "Membranes and pollutants sticking to the greenhouse's surface cut the amount of light available to the plants by half," he said.
He went on to explain that most of the seedlings were weak and sick looking. The professor said the findings have created a "smog panic" among farmers, saying, "A large number of representatives of agricultural companies have suddenly showed up at academic meetings on photosynthesis in recent months and sought desperately for solutions."
China's greenhouse farms, which cover more than four million hectares, supply most of the mainland's vegetables and would be the first to be hit. Professor He warns that if the smog persists in intensity, the country's food supply would face devastating consequences.
China's agriculture production contributes 10 percent to the GDP, and applying the experiment on a larger scale, farm output will likely be affected by the air pollution in the winter and spring. This will result in the price of agricultural products rising.