城市餐饮业食物浪费碳足迹——以北京市为例

食物浪费及其造成的环境影响已成为全球广泛关注的热点。无论从生命周期还是碳足迹的视角来看,食物浪费意味着生产、运输、加工与储存这些被浪费掉的食物过程中所投入的各种资源的浪费以及不必要的温室气体排放。以北京市餐饮食物浪费问题为切入点,在通过问卷调查和称重方法对餐饮食物浪费状况进行调查的基础上,将整个食物生命周期各供应链环节相应的温室气体排放纳入考量,估算了北京市餐饮食物浪费的碳排放量。研究结果表明:北京市餐饮食物浪费总量为39.86×10~4t/a。其中,蔬菜类浪费量最高,约占浪费总量的43.16%,其次为肉类和主食类,分别占食物浪费总量的20.59%和16.66%。北京市餐饮食物浪费所产生的总碳足迹为192.51×10~4—208.52×10~4t CO_2eq。其中,农业生产阶段的碳排放量最大为99.34×10~4t CO2eq,占食物浪费总碳足迹的47.64%。其次是消费阶段的碳足迹77.96×10~4t CO_2eq,占食物浪费总碳足迹的37.39%,再次是餐厨垃圾处理阶段的碳足迹28.54×104tCO2eq,占食物浪费总碳足迹的13.68%。这些不同供应链环节的碳排放比例,为透视食物浪费所带来的环境影响提供了新的认知,也为遏制食物浪费提供了科学的理论依据。

The carbon footprint of catering industry food waste: a Beijing case study

Recent years have seen increasing global interest in the study of food loss and waste, and their related environmental impacts. Wasted food creates carbon emissions throughout the duration of the food supply chain, from agricultural production, food processing, and distribution, to consumption and waste disposal. While it is widely known that the generation of food waste must be reduced, the lack of quantitative information on the production of household and catering food waste has led to the underestimation of waste volumes and hampered the development of proper policy interventions designed to decrease food waste. This study investigated the volume of catering food waste generated in Beijing and calculated its carbon footprint. In this study we focused on avoidable food waste, i.e., all wasted food and raw materials that could have been consumed had they been prepared differently. Other bio-wastes, such as vegetable peelings, bean dregs, or bones, were not measured. During first-hand surveys of the catering sector of urban Beijing in 2013, 136 restaurants were studied. These establishments can be divided into large, medium, small, canteen, and fast food restaurant categories. A total of 2704 samples were collected, each consisting of two parts:a consumer questionnaire, and the weight of each sample consumer''s food waste generated by the establishment. The greenhouse gas emissions produced during each stage of the food supply chain were calculated, and then scaled up using the restaurant data to determine the total quantity of carbon emissions produced by the production of catering food waste in Beijing. The main conclusions of this study are as follows:(i) The total amount of food waste generated by the Beijing catering industry is 39.86×10⁴ t/a, or about half of the total weight of food consumed in Beijing. (ii) The food waste was comprised of many different food types, the most prominent (by weight) being vegetables (43.16%), followed by aquatic products (10.51%), pork (8.79%), wheat flour (7.35%), beans and bean products (7.19%), poultry (6.93%), rice (6.09%), other grains (3.20%), mutton (1.94%), eggs (1.84%), beef (1.70%), other meat (1.23%), and dairy products (less than 1%). (iii) The total carbon footprint of the catering food waste produced in Beijing was 192.51×10⁴-208.52×104 t CO₂ eq. By food category, the largest proportion of the calculated total carbon emissions was generated by meat (61.76%), vegetables (25.09%), and grains (11.30%). By process, the food production stages producing the largest proportions of the emissions are agricultural production (almost 50%), catering consumption (37.39%), and waste management (13.68%).These results reveal clear differences between the distribution of waste and the carbon footprint of different wasted products. Although food waste can be more accurately quantified in terms of mass or value, these metrics does not provide sufficient information about its potential environmental impacts. Therefore, analyzing food waste in terms of both wasted mass and the carbon footprint of the wastage is a better means of identifying priority targets for the development of efficient waste reduction measures.