学者观点 | 缓解气候变化对于中国粮食保障的威胁
作者简介
张俊杰 博士
昆山杜克大学iMEP项目主任、环境研究中心主任
杜克大学尼古拉斯环境学院环境经济学专业副教授
环境经济学方向，专长于有关空气污染，气候变化，和自然资源的政策设计
本文英文原文原载于CHINA DAILY。
English article attached below.
中国正在经受着气候变化带来的影响，第三次国际气候变化国家评估报告显示，中国的土地均温从1909年到2011年，已经由0.9℃上升到了1.5℃，这已经超过了全球的平均值。预测显示，到本世纪末这一温度还会继续上升1.3℃~5℃。
除了温度上升，气候变化还导致了中国海平面上升、冰川融化、降水分布改变、干旱和热浪频发以及台风威胁增多等，这对中国的自然环境和经济增长带来了非常大的影响。
中国有着复杂的气候环境和脆弱的生态系统，故对气候变化十分敏感，而农业发展尤其容易受到影响。
虽然气候变化能够改善局部地区农业生产的热力条件，但是它的负面影响更为显著，其中包括农作物的质量和产量的下降，可耕地质量的下降，灌溉和肥料价格的上涨，农作物病虫害的加重，极端气候事件更加频繁和严重等。现在的普遍观点认为气候变化对于农业的净影响是负面的。
所以，气候变化对于农业生产的稳定性和可持续性发起了巨大的挑战。在中国，农业雇佣了40%的劳动力，生产了世界上30%的水稻，17%的小麦和20%的玉米。气候变化对于农业的影响，不仅会威胁到大量人口的食品保障，还会引起全球食品市场的连锁反应。
要应对所有的这些挑战，则需要一个气候变化对于中国农业生产的经济影响的全面评估以及应对方案。
香港理工大学、昆山杜克大学和中国农业科学院的研究学者们最近在 Journal of Environmental Economics and Management 上发表了一篇论文评估了气候变化对于中国农业费用的影响。论文作者们声明气候变化很有可能使得中国的水稻、小麦和玉米减产，管理机构须采取紧急的行动来应对这一挑战。
在中国的不同区域，气候变化对于三大主要农作物的影响是不同的。对于水稻的生产，气候变化对中国南部产生负面影响时，却对北部有益。水稻生产的主要省份比如湖南、湖北、江苏和江西，将会面临严重的减产。
中国东北部的小麦生产将会得益于气候变化。与此同时，中国中部地区包括河南、山东和河北则会遭受中等程度的减产，而中国南部地区的减产将会非常严重。
除了新疆维吾尔族自治区的部分县市，中国所有区域的玉米生产都面临着气候变化的负面影响，尤其是玉米的主要生产区，比如吉林、黑龙江、河南和河北 。
因此，气候变化对水稻、小麦和玉米的生产都带来巨大的经济影响。另外有证据表明，气候变化还会威胁中国的粮食保障。如果技术提升和耕作方式改良不足以填补气候变化带来的粮食减产的鸿沟，那么国内粮食的总产量就很有可能会下降。如果中国需要依靠、甚至只是部分依靠国际市场来保证粮食供应，那么我们就很难实现粮食生产的自己自足，而这也是中国政府的首要考虑。
考虑到气候变化及其潜在威胁，中国需要立即采取行动来应对各种可能性。适应性技术可以帮助中国缓解气候变化带来的负面影响并且从正面影响中获益。一项由世界银行资助的研究：中国国家气候变化适应性技术需求评估，其结果表明中国首要的适应性技术措施包括抗逆性良种繁育、精细农业技术和农业节水灌溉技术。通过推广这些气候友好型农业技术，中国能够减缓气候变化带来的粮食保障威胁。
图片来源：
http://edu.qq.com/a/20151217/046673.htm
http://finance.chinanews.com/ny/2014/10-16/6685459.shtml
http://scnews.newssc.org/system/2008/05/06/010816771.shtml
http://www.agrogene.cn/info-3240.shtml
China is already experiencing the effects of climate change. According to the Third National Assessment Report on Climate Change, the average temperature of China's land area rose by 0.9 Celsius to 1.5 C from 1909 to 2011, which is higher than the global average. It is projected to rise another 1.3 C to 5 C by the end of this century.
Besides temperature rise, climate change has had other observable effects on China, such as rising sea levels, melting glaciers, changing precipitation patterns, more droughts and heat waves, and increasing risks of hurricanes. Climate change therefore has a significant effect on China's natural environment and economic growth.
Due to its complex climate conditions and fragile ecosystems, China is sensitive to climate change, with its agriculture being particularly vulnerable.
Although climate change will improve thermal conditions for agricultural production in some areas, the negative impacts are more pronounced. They include declining crop quality and yield, decreasing arable land quality, increasing price of water and fertilizers, aggravated crop pests and diseases, and more frequent and intense extreme climate events. It is widely believed the net effect of climate change on agriculture is negative.
Climate change therefore poses a huge challenge to the stability and sustainability of food production in China. Agriculture employs about 40 percent of China's population; it also produces 30 percent of rice, 17 percent of wheat, and 20 percent of corn in the world. The climatic shocks to agriculture will not only threaten the food security of the world's largest population, but also have a ripple effect on the global food market.
All these call for thorough assessment of the economic impacts of climate change on China's agriculture and a strategy to address the challenge.
The cost of climate change on China's agriculture has been assessed in a recent paper published in the Journal of Environmental Economics and Management by researchers from Hong Kong Polytechnic University, Duke Kunshan University and the Chinese Academy of Agricultural Sciences. The report's authors say climate change is likely to decrease the yields of rice, wheat and corn in China, and the authorities need to take urgent actions to deal with the challenge.
The impacts of climate change on the three staple crops are heterogeneous across Chinese regions. While climate change is harmful for rice production in southern China, it is beneficial in northern China. Additionally, the major rice-producing provinces, such as Hunan, Hubei, Jiangsu, and Jiangxi, will suffer significant losses.
For wheat, northeastern China could benefit from climate change. And while Central China, including several counties in Henan, Shandong and Hebei provinces, will suffer moderate losses, the impact of climate change on southern China will be severe.
When it comes to corn, all regions show the negative impacts of climate change, except for some counties in the Xinjiang Uygur autonomous region. In particular, the major corn-producing provinces, such as Jilin, Heilongjiang, Henan and Hebei, will be severely affected.
The impacts of climate change on rice, wheat, and corn productions are of great economic significance. And evidence suggests climate change can endanger China's food security. Domestic food production is likely to decline if advanced technology and improved farming methods cannot fill the supply gap caused by climate change. And if China has to rely, even if partly, on the world market for food security, it cannot achieve self-sufficiency in food production, which is a top priority for the Chinese government.
Given the impacts of climate change and potential risks, China needs to take immediate measures to deal with eventualities. Adaptation can help China mitigate the negative impacts of climate change and benefit from the positive impacts. According to the findings of a study, China's National Technology Needs Assessment for Climate Change Adaptation, funded by the World Bank, the priority adaptive measures include stress-tolerant varietal breeding, precision agricultural technology, and agricultural water-saving technology. By promoting these climate-friendly agricultural technologies, China can reduce the climate risks on food security.
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