基于混合生命周期评价模型的我国食物系统水资源消耗及二氧化碳排放核算

Accounting of Water Consumption and CO2 Emissions in China’s Food System Based on an Hybrid LCA Model

中文关键词:  食物系统  水资源消耗  二氧化碳排放  混合生命周期评价模型

英文关键词:food system  water  CO₂  hybrid LCA model

中文摘要:

      食物生产不仅依赖水资源，同时产生大量二氧化碳排放，这种资源环境影响存在于食物系统整个产业链。为促进食物系统节水降碳，本文构建了包含5大类共23种具体食物部门的混合生命周期评价模型，对各类食物系统的完全水资源消耗和二氧化碳排放进行了核算与比较。结果表明：①不同食物的水资源消耗和二氧化碳排放差异明显，动物性食物的平均水资源消耗和二氧化碳排放强度分别为植物性食物的1.9 ～ 15.0倍和1.9 ～ 2.7倍；②食物系统直接和间接水资源消耗占比较为接近，但二氧化碳排放主要源自上游产业链的间接排放，占比高达80.9%；③食物系统间接水资源消耗主要来自农业部门，而间接碳排放主要来自电力生产和供应业、基础化工原料制造业、非金属矿产品行业和交通运输业；④从营养元素供给看，动物性食物提供蛋白质和脂肪的资源环境影响高于植物性食物，蔬菜和主食分别在提供维生素C和碳水化合物上具有最小的环境成本。基于本文结果，食物系统节水应主要提高生产环节用水效率，而降碳则主要依靠上游产业减排，特别是发电和化肥生产等行业的协同节水减碳潜力。同时，本文结果也可为未来基于环境影响制定膳食指南提供数据支撑。

英文摘要:

      Food production not only depends on water resources, but also generates a large amount of CO₂ emission. These environmental impacts exist in the entire industrial chain of the food system. In order to save water and reduce CO₂ emissions in the food system, this research develops a hybrid LCA model that includes 5 categories and 23 specific food sectors. Then this research accounts and compares the total water consumption and CO₂ emissions of food systems. The results show that: (1) The water consumption and CO₂ emissions of different foods are significantly different. The water consumption intensity of animal food is 1.9- 15 times that of plant food, and the CO₂ emission intensity is 1.9-2.7 times that of plant food. (2) The direct and indirect consumption of water is close, but the CO₂ emissions mainly come from of indirect CO₂ emissions from the upstream industrial chain, which accounts for 80.9%. (3) Indirect water consumption in food system mainly comes from agricultural sector, while indirect CO₂ emissions mainly come from the power production and supply sector, basic chemical raw material manufacturing sector, non-metallic mineral products sector and transportation sector. (4) From the perspective of nutrient supply, when considering protein and fat supply, the environmental impact of animal foods is higher than that of plant foods. Vegetables and staple food have the minimum environmental cost in providing vitamin-C and carbohydrate respectively. Based on the results of this paper, water conservation in the food system should mainly rely on the improvement of water use efficiency in the direct production process, and CO₂ reduction should focus on the upstream sectors. Especially, it should be highlighted that there embodied synergistic potential for water conversion and CO₂ emissions reduction in the power production sector and fertilizer production sector. At the same time, the results of this paper also provide supportive data for designing a more sustainable dietary guidelines that will consider environmental impacts.