摘要
The recent global food security crisis is garnering increasing attention and calls for innovative solutions to mitigate its negative impacts on people, especially the most economically vulnerable. In urban regions, this issue is aggravated by the fact that, on one hand, rapid urbanization and greater levels and diversity of food consumption associated with the growing affluence of urban inhabitants has led to rising urban food demand, while on the other hand, the rapid loss of farmland due to urban expansion or irrational sprawl and increasing extreme weather events for agricultural producers due to the impact of global climate change is sharply reducing the urban food production and local supply capacity. Therefore how to realize the urban food supply potential and optimize the utilization of the urban farmlands to enhance the local food supply rate and improve urban food security more generally is becoming a key issue. In this paper, we use the case of Beijing to examine the opportunities to enhance the supply of local, affordably priced food under existing land resource constraints, by restructuring farmland utilization. In this paper, we firstly calculate the changes in the food footprint needed by Beijing and its food self-sufficiency rate over the thirty year period from 1981 to 2011. We show that although Beijing’s food footprint has grown from 11 800 to 29 400 km2 over this 30-year period, its food self- sufficiency rate has dropped from 59.3%, 35.8%, 37.3% and 13.1% to about 39.0%, 27.0%, 6.7% and 2.2% for vegetable, fruit, grain and edible oil, respectively. Following this analysis, we calculate Beijing’ s potential food production under different agricultural production allocation scenarios. We conclude that with a proper shift of farmland use, full utilization of temporary idle land, and the development of rooftop farming, Beijing could increase its vegetable self-sufficiency rate to 60% without significantly reducing the production of other types of local food. Given the sensitivity of fresh vege
全球气候变化所带来的极端天气的频繁发生,水资源短缺情况下的农业用水的不断减少和伴随着人口增长与社会经济发展所引起的耕地面积下降,正在严重影响着世界范围内的食物安全。近年来由于食品价格的迅猛增长而导致的食品危机正在引起人们对增加地方食物供应的普遍关注。城市作为对食品安全更为敏感的地区,更是首当其冲受到食品危机的影响,城市一方面由于城市化快速发展,带来城市人口膨胀和消费多样性要求,从而形成需求的大幅增加,另一方面有由于城市周边耕地面积的不断减少,农业生产空间受到压缩,农业生产能力减弱,降低了城市的自我食品供给,引起自给率明显下降。如何保持供需之间的平衡,保障城市食品安全,成为亟需研究的问题。本文提出以食物足迹的概念,来衡量城市所间接消耗的土地资源,并以此为工具,以自给率为条件,来求得满足一定自给率条件下食物供给的空间对应格局。通过分析30年来北京食物足迹以及食物自给率的年际变化,得出结论:北京食物足迹从1981年的1.18万km2增加到2010年的2.94万km2,而自给率整体下降较多,蔬菜、水果、谷物及油脂类的自给率从1981年的59.3%、35.8%、37.3% 和 13.1% 下降到2010年的39.0%、27.0%、6.7% 和2.2%,可以看出蔬菜仍能保持相当的自给率,因此提高蔬菜自给率是增强城市自给能力的最佳选择。最后,以60%的蔬菜自给率为目标,提出了两种情景,包括完全以耕地为来源的空间应对格局,以及屋顶农业参与下的空间应对格局。
基金
funded by the National Natural Science Foundation of China (40971100)
