中国土壤污染问题影响国际粮食安全

    2005年，中国政府完成了首次全国土壤污染调查。由于调查结果令人震惊，政府当即宣布这份数据为“国家机密”。

    现在中国领导人显然改变了主意。几天前，环境保护部（the Ministry of Environmental Protection）和国土资源部（the Ministry of Land Resources）联合发布了2005年调查的主要结果。

    中国政府难得展现的透明度值得赞赏，但公布中国近20％的耕地面积已经遭到重金属污染的结果不仅表明中国环境恶化的程度非常严重，而且对国际社会的经济和地缘政治也将产生深刻影响。

    披露这项数据之前，涉及中国土壤污染最悲观的估计认为，中国最多有10％的耕地面积已经被污染。而现在官方数据显示，实际被污染的土地面积是预估数据的两倍。大约6600万英亩（约合39600万亩）耕地含有危险化学品，无法进行农业生产。中国政府设定确保国家粮食安全所需的最低耕地面积为3亿英亩（约18亿亩）。截至2012年，中国拥有3.34亿英亩（约20亿亩）耕地。如果政府宣布这6600万英亩被污染的土地不适宜生产粮食，则耕地总面积将比中国设定的“红线”还少3200万英亩（约19200万亩）。

    由于人口众多，土地资源稀缺，中国的人均耕地面积只有全球平均水平的一半。自从35年前中国启动现代化进程以来，城市化、工业化和消费增长一方面进一步削减了耕地面积，一方面又增加了对粮食生产的需求。虽然在此期间，中国农作物产量增长了4.5倍，但需求增长得更快。中国的食品进口（尤其是粮食进口）因此快速增长。2011年，中国进口了990万吨粮食。去年，中国粮食进口量为2280万吨，占全球粮食进口总量的7％。根据经济合作与发展组织（OECD）的统计，2001年，中国有6.2％的粮食来自进口；到2012年，这个比例已经上升至12.9％。

    When the Chinese government completed its first national soil pollution survey in 2005, the findings were so alarming that Beijing promptly declared the data a "state secret."

    Chinese leaders apparently changed their minds and, a few days ago, the Ministry of Environmental Protection and the Ministry of Land Resources jointly announced the key results of the 2005 survey.

    While the rare display of transparency from the Chinese government merits applause, the admission that close to 20% of China's arable land has been contaminated by heavy metal not only demonstrates the severity of China's environmental degradation but also has profound economic and geopolitical consequences for the international community.

    Before Beijing's latest disclosure, the most pessimistic estimate of China's soil pollution suggested that perhaps up to 10% of China's arable land had been contaminated. Now, the official data show that the actual amount of polluted land is twice as large. Roughly 66 million acres of arable land are laced with dangerous chemicals and should be taken out of agricultural production. The Chinese government has set 300 million acres of arable land as the minimum amount of land needed to ensure the country's food security. As of 2012, China had 334 million acres of arable land. If the 66 million acres of polluted land were to be declared unfit for food production, the total amount of arable land would fall 32 million acres below Beijing's self-defined "red line."

    Due to its large population and land scarcity, the amount of arable land on a per capita basis in China is only half the global average. Since China launched its modernization drive 35 years ago, urbanization, industrialization, and rising consumption have further reduced available arable land and increased demand for food production. Although Chinese agricultural output has grown by a factor of 4.5 in this period, demand growth has outpaced production. As a result, Chinese imports of food, particularly grain, have risen rapidly. In 2011, China imported 9.9 million tons of grain. Last year, China imported 22.8 million tons, roughly 7% of total global grain imports. According to the OECD, China imported 6.2% of its food in 2001. That figure rose to 12.9% in 2012.